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2010 - 2011: Earth's most extreme weather since 1816?

Posted on 27 June 2011 by Jeff Masters

Every year extraordinary weather events rock the Earth. Records that have stood centuries are broken. Great floods, droughts, and storms affect millions of people, and truly exceptional weather events unprecedented in human history may occur. But the wild roller-coaster ride of incredible weather events during 2010, in my mind, makes that year the planet's most extraordinary year for extreme weather since reliable global upper-air data began in the late 1940s. Never in my 30 years as a meteorologist have I witnessed a year like 2010--the astonishing number of weather disasters and unprecedented wild swings in Earth's atmospheric circulation were like nothing I've seen. The pace of incredible extreme weather events in the U.S. over the past few months have kept me so busy that I've been unable to write-up a retrospective look at the weather events of 2010. But I've finally managed to finish, so fasten your seat belts for a tour through the top twenty most remarkable weather events of 2010. At the end, I'll reflect on what the wild weather events of 2010 and 2011 imply for our future.

Earth's hottest year on record
Unprecedented heat scorched the Earth's surface in 2010, tying 2005 for the warmest year since accurate records began in the late 1800s. Temperatures in Earth's lower atmosphere also tied for warmest year on record, according to independent satellite measurements. Earth's 2010 record warmth was unusual because it occurred during the deepest solar energy minimum since satellite measurements of the sun began in the 1970s. Unofficially, nineteen nations (plus the the U.K.'s Ascension Island) set all-time extreme heat records in 2010. This includes Asia's hottest reliably measured temperature of all-time, the remarkable 128.3°F (53.5°C) in Pakistan in May 2010. This measurement is also the hottest reliably recorded temperature anywhere on the planet except for in Death Valley, California. The countries that experienced all-time extreme highs in 2010 constituted over 20% of Earth's land surface area.

Figure 1. Climate Central and Weather Underground put together this graphic showing the nineteen nations (plus one UK territory, Ascension Island) that set new extreme heat records in 2010.

Most extreme winter Arctic atmospheric circulation on record; "Snowmageddon" results
The atmospheric circulation in the Arctic took on its most extreme configuration in 145 years of record keeping during the winter of 2009 - 2010. The Arctic is normally dominated by low pressure in winter, and a "Polar Vortex" of counter-clockwise circulating winds develops surrounding the North Pole. However, during the winter of 2009 - 2010, high pressure replaced low pressure over the Arctic, and the Polar Vortex weakened and even reversed at times, with a clockwise flow of air replacing the usual counter-clockwise flow of air. This unusual flow pattern allowed cold air to spill southwards and be replaced by warm air moving poleward. Like leaving the refrigerator door ajar, the Arctic "refrigerator" warmed, and cold Arctic air spilled out into "living room" where people live. A natural climate pattern called the North Atlantic Oscillation (NAO), and its close cousin, the Arctic Oscillation (AO) were responsible. Both of these patterns experienced their strongest-on-record negative phase, when measured as the pressure difference between the Icelandic Low and Azores High.

The extreme Arctic circulation caused a bizarre upside-down winter over North America--Canada had its warmest and driest winter on record, forcing snow to be trucked in for the Winter Olympics in Vancouver, but the U.S. had its coldest winter in 25 years. A series of remarkable snow storms pounded the Eastern U.S., with the "Snowmageddon" blizzard dumping more than two feet of snow on Baltimore and Philadelphia. Western Europe also experienced unusually cold and snowy conditions, with the UK recording its 8th coldest January. A highly extreme negative phase of the NAO and AO returned again during November 2010, and lasted into January 2011. Exceptionally cold and snowy conditions hit much of Western Europe and the Eastern U.S. again in the winter of 2010 - 2011. During these two extreme winters, New York City recorded three of its top-ten snowstorms since 1869, and Philadelphia recorded four of its top-ten snowstorms since 1884. During December 2010, the extreme Arctic circulation over Greenland created the strongest ridge of high pressure ever recorded at middle levels of the atmosphere, anywhere on the globe (since accurate records began in 1948.) New research suggests that major losses of Arctic sea ice could cause the Arctic circulation to behave so strangely, but this work is still speculative.

Figure 2. Digging out in Maryland after "Snowmageddon". Image credit: wunderphotographer chills.

Arctic sea ice: lowest volume on record, 3rd lowest extent
Sea ice in the Arctic reached its third lowest areal extent on record in September 2010. Compared to sea ice levels 30 years ago, 1/3 of the polar ice cap was missing--an area the size of the Mediterranean Sea. The Arctic has seen a steady loss of meters-thick, multi-year-old ice in recent years that has left thin, 1 - 2 year-old ice as the predominant ice type. As a result, sea ice volume in 2010 was the lowest on record. More than half of the polar icecap by volume--60%--was missing in September 2010, compared to the average from 1979 - 2010. All this melting allowed the Northwest Passage through the normally ice-choked waters of Canada to open up in 2010. The Northeast Passage along the coast of northern Russia also opened up, and this was the third consecutive year--and third time in recorded history--that both passages melted open. Two sailing expeditions--one Russian and one Norwegian--successfully navigated both the Northeast Passage and the Northwest Passage in 2010, the first time this feat has been accomplished. Mariners have been attempting to sail the Northwest Passage since 1497, and have failed to accomplish this feat without an icebreaker until the 2000s. In December 2010, Arctic sea ice fell to its lowest winter extent on record, the beginning of a 3-month streak of record lows. Canada's Hudson Bay did not freeze over until mid-January of 2011, the latest freeze-over date in recorded history.

Figure 3. The Arctic's minimum sea ice extent for 2010 was reached on September 21, and was the third lowest on record. Image credit: National Snow and Ice Data Center.

Record melting in Greenland, and a massive calving event
Greenland's climate in 2010 was marked by record-setting high air temperatures, the greatest ice loss by melting since accurate records began in 1958, the greatest mass loss of ocean-terminating glaciers on record, and the calving of a 100 square-mile ice island--the largest calving event in the Arctic since 1962. Many of these events were due to record warm water temperatures along the west coast of Greenland, which averaged 2.9°C (5.2°F) above average during October 2010, a remarkable 1.4°C above the previous record high water temperatures in 2003.

Figure 4. The 100 square-mile ice island that broke off the Petermann Glacier heads out of the Petermann Fjord in this 7-frame satellite animation. The animation begins on August 5, 2010, and ends on September 21, with images spaced about 8 days apart. The images were taken by NASA's Aqua and Terra satellites.

Second most extreme shift from El Niño to La Niña
The year 2010 opened with a strong El Niño event and exceptionally warm ocean waters in the Eastern Pacific. However, El Niño rapidly waned in the spring, and a moderate to strong La Niña developed by the end of the year, strongly cooling these ocean waters. Since accurate records began in 1950, only 1973 has seen a more extreme swing from El Niño to La Niña. The strong El Niño and La Niña events contributed to many of the record flood events seen globally in 2010, and during the first half of 2011.

Figure 5. The departure of sea surface temperatures from average at the beginning of 2010 (top) and the end of 2010 (bottom) shows the remarkable transition from strong El Niño to strong La Niña conditions that occurred during the year. Image credit: NOAA/NESDIS.

Second worst coral bleaching year
Coral reefs took their 2nd-worst beating on record in 2010, thanks to record or near-record warm summer water temperatures over much of Earth's tropical oceans. The warm waters caused the most coral bleaching since 1998, when 16 percent of the world's reefs were killed off. "Clearly, we are on track for this to be the second worst (bleaching) on record," NOAA coral expert Mark Eakin in a 2010 interview. "All we're waiting on now is the body count." The summer 2010 coral bleaching episodes were worst in the Philippines and Southeast Asia, where El Niño warming of the tropical ocean waters during the first half of the year was significant. In Indonesia's Aceh province, 80% of the bleached corals died, and Malaysia closed several popular dive sites after nearly all the coral were damaged by bleaching. In some portions of the Caribbean, such as Venezuela and Panama, coral bleaching was the worst on record.

Figure 6. An example of coral bleaching that occurred during the record-strength 1997-1998 El Niño event. Image credit: Craig Quirolo, Reef Relief/Marine Photobank, in Climate, Carbon and Coral Reefs

Wettest year over land
The year 2010 also set a new record for wettest year in Earth's recorded history over land areas. The difference in precipitation from average in 2010 was about 13% higher than that of the previous record wettest year, 1956. However, this record is not that significant, since it was due in large part to random variability of the jet stream weather patterns during 2010. The record wetness over land was counterbalanced by relatively dry conditions over the oceans.

Figure 7. Global departure of precipitation over land areas from average for 1900 - 2010. The year 2010 set a new record for wettest year over land areas in Earth's recorded history. The difference in precipitation from average in 2010 was about 13% higher than that of the previous record wettest year, 1956. Image credit: NOAA's National Climatic Data Center.

Amazon rainforest experiences its 2nd 100-year drought in 5 years
South America's Amazon rainforest experienced its second 100-year drought in five years during 2010, with the largest northern tributary of the Amazon River--the Rio Negro--dropping to thirteen feet (four meters) below its usual dry season level. This was its lowest level since record keeping began in 1902. The low water mark is all the more remarkable since the Rio Negro caused devastating flooding in 2009, when it hit an all-time record high, 53 ft (16 m) higher than the 2010 record low. The 2010 drought was similar in intensity and scope to the region's previous 100-year drought in 2005. Drought makes a regular appearance in the Amazon, with significant droughts occurring an average of once every twelve years. In the 20th century, these droughts typically occurred during El Niño years, when the unusually warm waters present along the Pacific coast of South America altered rainfall patterns. But the 2005 and 2010 droughts did not occur during El Niño conditions, and it is theorized that they were instead caused by record warm sea surface temperatures in the Atlantic.

We often hear about how important Arctic sea ice is for keeping Earth's climate cool, but a healthy Amazon is just as vital. Photosynthesis in the world's largest rainforest takes about 2 billion tons of carbon dioxide out of the air each year. However, in 2005, the drought reversed this process. The Amazon emitted 3 billion tons of CO2 to the atmosphere, causing a net 5 billion ton increase in CO2 to the atmosphere--roughly equivalent to 16 - 22% of the total CO2 emissions to the atmosphere from burning fossil fuels that year. The Amazon stores CO2 in its soils and biomass equivalent to about fifteen years of human-caused emissions, so a massive die-back of the forest could greatly accelerate global warming.

Figure 8. Hundreds of fires (red squares) generate thick smoke over a 1000 mile-wide region of the southern Amazon rain forest in this image taken by NASA's Aqua satellite on August 16, 2010. The Bolivian government declared a state of emergency in mid-August due to the out-of-control fires burning over much of the country. Image credit: NASA.

Global tropical cyclone activity lowest on record
The year 2010 was one of the strangest on record for tropical cyclones. Each year, the globe has about 92 tropical cyclones--called hurricanes in the Atlantic and Eastern Pacific, typhoons in the Western Pacific, and tropical cyclones in the Southern Hemisphere. But in 2010, we had just 68 of these storms--the fewest since the dawn of the satellite era in 1970. The previous record slowest year was 1977, when 69 tropical cyclones occurred world-wide. Both the Western Pacific and Eastern Pacific had their quietest seasons on record in 2010, but the Atlantic was hyperactive, recording its 3rd busiest season since record keeping began in 1851. The Southern Hemisphere had a slightly below average season. The Atlantic ordinarily accounts for just 13% of global cyclone activity, but accounted for 28% in 2010--the greatest proportion since accurate tropical cyclone records began in the 1970s.

A common theme of many recent publications on the future of tropical cyclones globally in a warming climate is that the total number of these storms will decrease, but the strongest storms will get stronger. For example, a 2010 review paper published in Nature Geosciences concluded that the strongest storms would increase in intensity by 2 - 11% by 2100, but the total number of storms would fall by 6 - 34%. It is interesting that 2010 saw the lowest number of global tropical cyclones on record, but an average number of very strong Category 4 and 5 storms (the 25-year average is 13 Category 4 and 5 storms, and 2010 had 14.) Fully 21% of 2010's tropical cyclones reached Category 4 or 5 strength, versus just 14% during the period 1983 - 2007. Most notably, in 2010 we had Super Typhoon Megi. Megi's sustained winds cranked up to a ferocious 190 mph and its central pressure bottomed out at 885 mb on October 16, making it the 8th most intense tropical cyclone in world history. Other notable storms in 2010 included the second strongest tropical cyclone on record in the Arabian Sea (Category 4 Cyclone Phet in June), and the strongest tropical cyclone ever to hit Myanmar/Burma (October's Tropical Cyclone Giri, an upper end Category 4 storm with 155 mph winds.)

Figure 9. Visible satellite image of Tropical Cyclone Phet on Thursday, June 3, 2010. Record heat over southern Asia in May helped heat up the Arabian Sea to 2°C above normal, and the exceptionally warm SSTs helped fuel Tropical Cyclone Phet into the second strongest tropical cyclone ever recorded in the Arabian Sea. Phet peaked at Category 4 strength with 145 mph winds, and killed 44 people and did $700 million in damage to Oman. Only Category 5 Cyclone Gonu of 2007 was a stronger Arabian Sea cyclone.

A hyperactive Atlantic hurricane season: 3rd busiest on record
Sea surface temperatures that were the hottest on record over the main development region for Atlantic hurricanes helped fuel an exceptionally active 2010 Atlantic hurricane season. The nineteen named storms were the third most since 1851; the twelve hurricanes of 2010 ranked second most. Three major hurricanes occurred in rare or unprecedented locations. Julia was the easternmost major hurricane on record, Karl was the southernmost major hurricane on record in the Gulf of Mexico, and Earl was the 4th strongest hurricane so far north. The formation of Tomas so far south and east so late in the season (October 29) was unprecedented in the historical record; no named storm had ever been present east of the Lesser Antilles (61.5°W) and south of 12°N latitude so late in the year. Tomas made the 2010 the 4th consecutive year with a November hurricane in the Atlantic--an occurrence unprecedented since records began in 1851.

Figure 10. Hurricane Earl as seen from the International Space Station on Thursday, September 2, 2010. Image credit: NASA astronaut Douglas Wheelock.

A rare tropical storm in the South Atlantic
A rare tropical storm formed in the South Atlantic off the coast of Brazil on March 10 - 11, and was named Tropical Storm Anita. Brazil has had only one landfalling tropical cyclone in its history, Cyclone Catarina of March 2004, one of only seven known tropical or subtropical cyclones to form in the South Atlantic, and the only one to reach hurricane strength. Anita of 2010 is probably the fourth strongest tropical/subtropical storm in the South Atlantic, behind Hurricane Catarina, an unnamed February 2006 storm that may have attained wind speeds of 65 mph, and a subtropical storm that brought heavy flooding to the coast of Uruguay in January 2009. Tropical cyclones rarely form in the South Atlantic Ocean, due to strong upper-level wind shear, cool water temperatures, and the lack of an initial disturbance to get things spinning (no African waves or Intertropical Convergence Zone.)

Figure 11. Visible satellite image of the Brazilian Tropical Storm Anita.

Strongest storm in Southwestern U.S. history
The most powerful low pressure system in 140 years of record keeping swept through the Southwest U.S. on January 20 - 21, 2010, bringing deadly flooding, tornadoes, hail, hurricane force winds, and blizzard conditions. The storm set all-time low pressure records over roughly 10 - 15% of the U.S.--southern Oregon, California, Nevada, Arizona, and Utah. Old records were broken by a wide margin in many locations, most notably in Los Angeles, where the old record of 29.25" set January 17, 1988, was shattered by .18" (6 mb). The record-setting low spawned an extremely intense cold front that swept through the Southwest. Winds ahead of the cold front hit sustained speeds of hurricane force--74 mph--at Apache Junction, 40 miles east of Phoenix, and wind gusts as high as 94 mph were recorded in Ajo, Arizona. High winds plunged visibility to zero in blowing dust on I-10 connecting Phoenix and Tucson, closing the Interstate.

Figure 12. Ominous clouds hover over Arizona's Superstition Mountains during Arizona's most powerful storm on record, on January 21, 2010. Image credit: wunderphotographer ChandlerMike.

Strongest non-coastal storm in U.S. history
A massive low pressure system intensified to record strength over northern Minnesota on October 26, 2010, resulting in the lowest barometric pressure readings ever recorded in the continental United States, except for from hurricanes and nor'easters affecting the Atlantic seaboard. The 955 mb sea level pressure reported from Bigfork, Minnesota beat the previous low pressure record of 958 mb set during the Great Ohio Blizzard of January 26, 1978. Both Minnesota and Wisconsin set all time low pressure readings during the October 26 storm, and International Falls beat their previous low pressure record by nearly one-half inch of mercury--a truly amazing anomaly. The massive storm spawned 67 tornadoes over a four-day period, and brought sustained winds of 68 mph to Lake Superior.

Figure 13. Visible satellite image of the October 26, 2010 superstorm taken at 5:32pm EDT. At the time, Bigfork, Minnesota was reporting the lowest pressure ever recorded in a U.S. non-coastal storm, 955 mb. Image credit: NASA/GSFC.

Weakest and latest-ending East Asian monsoon on record
The summer monsoon over China's South China Sea was the weakest and latest ending monsoon on record since detailed records began in 1951, according to the Beijing Climate Center. The monsoon did not end until late October, nearly a month later than usual. The abnormal monsoon helped lead to precipitation 30% - 80% below normal in Northern China and Mongolia, and 30 - 100% above average across a wide swath of Central China. Western China saw summer precipitation more than 200% above average, and torrential monsoon rains triggered catastrophic landslides that killed 2137 people and did $759 million in damage. Monsoon floods in China killed an additional 1911 people, affected 134 million, and did $18 billion in damage in 2010, according to the WHO Collaborating Centre for Research on the Epidemiology of Disasters (CRED). This was the 2nd most expensive flooding disaster in Chinese history, behind the $30 billion price tag of the 1998 floods that killed 3656 people. China had floods in 1915, 1931, and 1959 that killed 3 million, 3.7 million, and 2 million people, respectively, but no damage estimates are available for these floods.

Figure 14. Paramilitary policemen help evacuate residents from Wanjia village of Fuzhou City, East China's Jiangxi province, June 22, 2010. Days of heavy rain burst the Changkai Dike of Fu River on June 21, threatening the lives of 145,000 local people. Image credit: Xinhua.

No monsoon depressions in India's Southwest Monsoon for 2nd time in 134 years
The Southwest Monsoon that affects India was fairly normal in 2010, bringing India rains within 2% of average. Much of the rain that falls in India from the monsoon typically comes from large regions of low pressure that form in the Bay of Bengal and move westwards over India. Typically, seven of these lows grow strong and well-organized enough to be labelled monsoon depressions, which are similar to but larger than tropical depressions. In 2010, no monsoon depressions formed--the only year besides 2002 (since 1877) that no monsoon depressions have been observed.

The Pakistani flood: most expensive natural disaster in Pakistan's history
A large monsoon low developed over the Bay of Bengal in late July and moved west towards Pakistan, creating a strong flow of moisture that helped trigger the deadly Pakistan floods of 2010. The floods were worsened by a persistent and unusually-far southwards dip in the jet stream, which brought cold air and rain-bearing low pressure systems over Pakistan. This unusual bend in the jet stream also helped bring Russia its record heat wave and drought. The Pakistani floods were the most expensive natural disaster in Pakistani history, killing 1985 people, affecting 20 million, and doing $9.5 billion in damage.

Figure 15. Local residents attempt to cross a washed-out road during the Pakistani flood catastrophe of 2010. Image credit: Pakistan Meteorology Department.

The Russian heat wave and drought: deadliest heat wave in human history
A scorching heat wave struck Moscow in late June 2010, and steadily increased in intensity through July as the jet stream remained "stuck" in an unusual loop that kept cool air and rain-bearing low pressure systems far north of the country. By July 14, the mercury hit 31°C (87°F) in Moscow, the first day of an incredible 33-day stretch with a maximum temperatures of 30°C (86°F) or higher. Moscow's old extreme heat record, 37°C (99°F) in 1920, was equaled or exceeded five times in a two-week period from July 26 - August 6 2010, including an incredible 38.2°C (101°F) on July 29. Over a thousand Russians seeking to escape the heat drowned in swimming accidents, and thousands more died from the heat and from inhaling smoke and toxic fumes from massive wild fires. The associated drought cut Russia's wheat crop by 40%, cost the nation $15 billion, and led to a ban on grain exports. The grain export ban, in combination with bad weather elsewhere in the globe during 2010 - 2011, caused a sharp spike in world food prices that helped trigger civil unrest across much of northern Africa and the Middle East in 2011. At least 55,000 people died due to the heat wave, making it the deadliest heat wave in human history. A 2011 NOAA study concluded that "while a contribution to the heat wave from climate change could not be entirely ruled out, if it was present, it played a much smaller role than naturally occurring meteorological processes in explaining this heat wave's intensity." However, they noted that the climate models used for the study showed a rapidly increasing risk of such heat waves in western Russia, from less than 1% per year in 2010, to 10% or more per year by 2100.

Figure 16. Smoke from wildfires burning to the southeast of Moscow on August 12, 2010. Northerly winds were keeping the smoke from blowing over the city. Image credit: NASA.

Record rains trigger Australia's most expensive natural disaster in history
Australia's most expensive natural disaster in history is now the Queensland flood of 2010 - 2011, with a price tag as high as $30 billion. At least 35 were killed. The Australian Bureau of Meteorology's annual summary reported, "Sea surface temperatures in the Australian region during 2010 were the warmest value on record for the Australian region. Individual high monthly sea surface temperature records were also set during 2010 in March, April, June, September, October, November and December. Along with favourable hemispheric circulation associated with the 2010 La Niña, very warm sea surface temperatures contributed to the record rainfall and very high humidity across eastern Australia during winter and spring." In 2010, Australia had its wettest spring (September - November) since records began 111 years ago, with some sections of coastal Queensland receiving over 4 feet (1200 mm) of rain. Rainfall in Queensland and all of eastern Australia in December was the greatest on record, and the year 2010 was the rainiest year on record for Queensland. Queensland has an area the size of Germany and France combined, and 3/4 of the region was declared a disaster zone.

Figure 17. The airport, the Bruce Highway, and large swaths of Rockhampton, Australia, went under water due to flooding from the Fitzroy River on January 9, 2011. The town of 75,000 was completely cut off by road and rail, and food, water and medicine had to be brought in by boat and helicopter. Image credit: NASA.

Heaviest rains on record trigger Colombia's worst flooding disaster in history
The 2010 rainy-season rains in Colombia were the heaviest in the 42 years since Colombia's weather service was created and began taking data. Floods and landslides killed 528, did $1 billion in damage, and left 2.2 million homeless, making it Colombia's most expensive, most widespread, and 2nd deadliest flooding disaster in history. Colombia's president Juan Manuel Santos said, "the tragedy the country is going through has no precedents in our history."

Figure 18. A daring rescue of two girls stranded in a taxi by flash flood waters Barranquilla, northern Colombia on August 14, 2010.

Tennessee's 1-in-1000 year flood kills 30, does $2.4 billion in damage
Tennessee's greatest disaster since the Civil War hit on May 1 - 2, 2010, when an epic deluge of rain brought by an "atmospheric river" of moisture dumped up to 17.73" of rain on the state. Nashville had its heaviest 1-day and 2-day rainfall amounts in its history, with a remarkable 7.25" on May 2, breaking the record for most rain in a single day. Only two days into the month, the May 1 - 2 rains made it the rainiest May in Nashville's history. The record rains sent the Cumberland River in downtown Nashville surging to 51.86', 12' over flood height, and the highest level the river has reached since a flood control project was completed in the early 1960s. At least four rivers in Tennessee reached their greatest flood heights on record. Most remarkable was the Duck River at Centreville, which crested at 47', a full 25 feet above flood stage, and ten feet higher than the previous record crest, achieved in 1948.

Figure 19. A portable classroom building from a nearby high school floats past submerged cars on I-24 near Nashville, TN on May 1, 2010. One person died in the flooding in this region of I-24. Roughly 200 - 250 vehicles got submerged on this section of I-24, according to wunderphotographer laughingjester, who was a tow truck operator called in to clear out the stranded vehicles.

When was the last time global weather was so extreme?
It is difficult to say whether the weather events of a particular year are more or less extreme globally than other years, since we have no objective global index that measures extremes. However, we do for the U.S.--NOAA's Climate Extremes Index (CEI), which looks at the percentage area of the contiguous U.S. experiencing top 10% or bottom 10% monthly maximum and minimum temperatures, monthly drought, and daily precipitation. The Climate Extremes Index rated 1998 as the most extreme year of the past century in the U.S. That year was also the warmest year since accurate records began in 1895, so it makes sense that the warmest year in Earth's recorded history--2010--was also probably one of the most extreme for both temperature and precipitation. Hot years tend to generate more wet and dry extremes than cold years. This occurs since there is more energy available to fuel the evaporation that drives heavy rains and snows, and to make droughts hotter and drier in places where storms are avoiding. Looking back through the 1800s, which was a very cool period, I can't find any years that had more exceptional global extremes in weather than 2010, until I reach 1816. That was the year of the devastating "Year Without a Summer"--caused by the massive climate-altering 1815 eruption of Indonesia's Mt. Tambora, the largest volcanic eruption since at least 536 A.D. It is quite possible that 2010 was the most extreme weather year globally since 1816.

Where will Earth's climate go from here?
The pace of extreme weather events has remained remarkably high during 2011, giving rise to the question--is the "Global Weirding" of 2010 and 2011 the new normal? Has human-caused climate change destabilized the climate, bringing these extreme, unprecedented weather events? Any one of the extreme weather events of 2010 or 2011 could have occurred naturally sometime during the past 1,000 years. But it is highly improbable that the remarkable extreme weather events of 2010 and 2011 could have all happened in such a short period of time without some powerful climate-altering force at work. The best science we have right now maintains that human-caused emissions of heat-trapping gases like CO2 are the most likely cause of such a climate-altering force.

Human-caused climate change has fundamentally altered the atmosphere by adding more heat and moisture. Observations confirm that global atmospheric water vapor has increased by about 4% since 1970, which is what theory says should have happened given the observed 0.5°C (0.9°F) warming of the planet's oceans during the same period. Shifts of this magnitude are capable of significantly affecting the path and strength of the jet stream, behavior of the planet's monsoons, and paths of rain and snow-bearing weather systems. For example, the average position of the jet stream retreated poleward 270 miles (435 km) during a 22-year period ending in 2001, in line with predictions from climate models. A naturally extreme year, when embedded in such a changed atmosphere, is capable of causing dramatic, unprecedented extremes like we observed during 2010 and 2011. That's the best theory I have to explain the extreme weather events of 2010 and 2011--natural extremes of El Niño, La Niña and other natural weather patterns combined with significant shifts in atmospheric circulation and the extra heat and atmospheric moisture due to human-caused climate change to create an extraordinary period of extreme weather. However, I don't believe that years like 2010 and 2011 will become the "new normal" in the coming decade. Many of the flood disasters in 2010 - 2011 were undoubtedly heavily influenced by the strong El Niño and La Niña events that occurred, and we're due for a few quiet years without a strong El Niño or La Niña. There's also the possibility that a major volcanic eruption in the tropics or a significant quiet period on the sun could help cool the climate for a few years, cutting down on heat and flooding extremes (though major eruptions tend to increase drought.) But the ever-increasing amounts of heat-trapping gases humans are emitting into the air puts tremendous pressure on the climate system to shift to a new, radically different, warmer state, and the extreme weather of 2010 - 2011 suggests that the transition is already well underway. A warmer planet has more energy to power stronger storms, hotter heat waves, more intense droughts, heavier flooding rains, and record glacier melt that will drive accelerating sea level rise. I expect that by 20 - 30 years from now, extreme weather years like we witnessed in 2010 will become the new normal.

Finally, I'll leave you with a quote from Dr. Ricky Rood's climate change blog, in his recent post,Changing the Conversation: Extreme Weather and Climate: "Given that greenhouse gases are well known to hold energy close to the Earth, those who deny a human-caused impact on weather need to pose a viable mechanism of how the Earth can hold in more energy and the weather not be changed. Think about it."

Reposted from Weather Underground by Dr Jeff Masters, Director of Meteorology.

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Comments 151 to 200 out of 419:

  1. Norman @145, your counter-argument against Father Theo is specious. The tornado peak in 1974 was a consequence of the very strong 1974 La Nina, while the 2011 peak (expected to be almost as large, and possibly larger) is also correlated with a very strong La Nina. Therefore attributing the large 1974 peak to "chaos" is not justified and your counter-argument fails. The annual run off for the Missouri does not show any correlation to ENSO discernible by eye. However, it does show a distinct rising trend, with 9 out of 12 MAF 34.3 events occurring in the last 40 years of a 110 year record, and the highest three occurring in the latter period in nice sequential order. This does not prove a causal relationship between global warming and high run off. However, there is a proven relationship between global warming and higher specific humidity, so the maths here isn't that hard.
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  2. Devils Lake is not far from the Missouri River Basin and experiencing very simliar long term precipitation trends. This study shows long term Devils Lake basin hydrology. Long Term Hydro study of Devils Lake
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  3. I can only recommend everyone read response number 6 in the following thread. The author of said response is a scientist at NOAA. Bill Patzert
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    [DB] "The author of said response is a scientist at NOAA."

    Umm, no.  If it is indeed the same Bill Patzert as this one, then he is a scientist at JPL.

  4. Norman @94 (By special request) Norman is arguing against my contention (@88) that:
    "You think there is an important distinction only because you have in your mind that an Earthquake is a big thing hitting a large region. Of course, the damaging region of most earthquakes is in fact small, but you typically think of the big newsworthy quakes. In contrast your idea of a weather related disaster is just a single thunderstorm or twister. In fact, for statistical purposes it is a weather front, or a tornado outbreak; so while a big earthquake is pretty much guaranteed to damage nearby cities, a large weather related disaster is very likely to hit multiple states, or even countries."
    (Emphasis added) Against this contention he supplies the following evidence:
    "The quake just before 4:37 a.m. was centered six miles from West Salem, Ill., and 45 miles from Evansville, Ind. It was felt in such distant cities as Milwaukee, Des Moines, Iowa, and Atlanta, nearly 400 miles to the southeast. "It shook our house where it woke me up," said David Behm of Philo, 10 miles south of Champaign. "Windows were rattling, and you could hear it. The house was shaking inches. For people in central Illinois, this is a big deal. It's not like California." In West Salem itself, a chimney on one house fell and there were reports of cracks in walls. "We're very thankful we had no one injured," said Harvey Fenton, the town's police and fire chief. He was at first unsure what to make of the sudden rumbling when it woke him up. "A major shaking is the best way I can describe it," said Fenton, 58. Fifteen miles to the southeast, in Mount Carmel, a woman was trapped in her home by a collapsed porch but was quickly freed and wasn't hurt, said police dispatcher Mickie Smith. A century-old apartment building there, a former schoolhouse, was evacuated because of loose and falling bricks."
    (emphasis added) As the point of contention is the damaging radius of small earthquakes, evidence that a small earthquake has a damaging radius of around 10 miles (six miles from West Salem to the epicentre in approximately the directionof Evansville, and hence Mount Carmel, which was 15 miles from West Salem). I assume Norman has focussed on the fact that the earthquake was felt up to 400 miles away. However, what is at issue is not detection, but whether the event would have been recorded as a natural disaster, and for that, the relevant issue is the radius of damage, not of detection. Norman also presents evidence that magnitude 7 quakes can have damaging radii of up to 100 miles. Again, I do not see how this does anything but support my claim that "a big earthquake is pretty much guaranteed to damage nearby cities", and nor is it relevant to my claim that "a large weather related disaster is very likely to hit multiple states, or even countries". To put this into context, there are seven earthquakes listed by wikipedia as occurring in the US in 2010. They were: The Eureka Earth Quake (6.5), 463 buildings damaged, $43 million in losses; The Illinois earthquake (3.8) no damage or injuries; The Pico Rivera earthquake Not worth more than a stub, so no futher information; The Baja California Earthquake (more details later); The Borrego Springs earthquake (5.4) apparently no injuries or damage; The Potomac-Shenandoah earthquake , again only worth a stub; and The Indiana Earthquake (3.8) no injuries or damage. The important thing to note is that of these earthquakes, only two would count as natural disasters according to the criteria of Neumayer and Barthel, 2011, and only one, the Baja California earthquake, would count as a major natural disaster by their criteria. As it happens, the Baja Earthquake is listed as number 17 on Munich Re's list of 50 major natural disasters in 2010. They list it as causing, 2 fatalities, overall losses of $US 1.15 billion, and describe as follows:
    "Mw 7.2. 6,000 homes damaged. Water and sewage systems damaged. Telecommunication, electricity cut off. Injured: >230, evacuated/displaced: 25,000"
    Five other natural disasters in the US make the 2010 list of major natural disasters: 15) Severe storms and floods in New York and New Jersey, causing 11 fatalities, $US 1.7 billion in damage, and "Thousands of homes, businesses, cars damaged/destroyed. Losses to airport facilities and infrastructur[e]"; 22) Severe storms, tornadoes, and floods in Tennessee causing 32 fatalities, $US 2.7 billion in damages, and ">70 tornadoes. Thousands of homes and cars damaged. Water supply affected. Crops destroyed, livestock killed. Losses to infrastructure."; 26) Severe storms, tornadoes, and flash floods in "USA esp CO" (Connecticut?) causing 1 fatality, $US 0.85 billion in damages, and "Buildings, cars damaged. Losses to infrastructure and agriculture."; 33) Severe storms and tornadoes in "USA esp MT, MN", causing 4 fatalities, $US 0.83 billion and "Buildings, cars damaged. Losses to infrastructure and agriculture."; and 42) Wildfires in " USA: esp. CO" causing no fatalities, $US 0.31 billion in damage, and "170 homes, mobile homes, numerous cars destroyed, thousands of buildings damaged." (Number 50 on the list is also from the US, but does not meet the Neumeyer and Barthel's criteria for a "major disaster".) Bear in mind that the annual rate of "major disasters" have doubled over the last thirty years. Norman's contention that weather related natural hazards are not increasing is only plausible if detection rates of major natural disasters have risen by close to 100% or more over that period. If they have only risen by 50%, then there is still a substantial increase in events over that period. Looking at the list of major weather related disasters above, clearly that claim is not reasonable.
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    [DB] Fixed tags.

  5. Tom Curtis @ 146 Thank you for the links to the Amazon and past droughts. You are a better cyberman than myself. Most my searches for any type of record on Amazon droughts pulled up page after page of the 2010 drought with no history.
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  6. Tom Curtis @ 150 I did not know I had any credibility with you in the first place but thanks for pointing out my error. I did mean North America and for some reason put Northern Hemisphere. I checked again and I did have it correct on my original link.
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  7. Camburn @153, if that is supposed to be a rebuke to this thread, it is ill placed. Jeff Masters does not mention tornadoes in his post. Nor has anyone here, to my knowledge, argued that there has been a statistically significant increase in the number of severe tornadoes. I and others have argued that there has been a significant increase in severe weather events in general, and that that is related to global warming, but to suggest that we should not discuss extreme weather in general is nonsense.
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  8. skywatcher @ 148 Sometimes I am not clear enough in the point I am making and I apologize for that. I was talking about the wet years cycle and it level. The wet cycles from 1950 to the present do not show any significant upward trend that I can see. You are correct during the cooler years the Global precipitation was mostly dry except a few wet years. I am thinking of connections buy may not present them well. I am not a professional presenter and I think my fingers move faster than my brain. If this was a formal paper I was writing in college, I would be more careful with my wording and thought process. I have been assured if I make a mistake in one of my posts then some interested member will point them out, I will then attempt to correct the error the best I can. Here is the connection I was getting at with the wet cycle trends on the Jeff Masters global precipitation chart. GISS global temp anomaly. You can see the temp was going down from the 1940's to the 1970's. Then it begins its rapid rise for the next 40 years. The precipitation graph does not show this increase. I am saying I can't see a similar upward trend in the precipitation graph that would prove the expected result of global warming prediction. Warmer air holds more water and this will lead to increased precipitation.
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    [DB] "Warmer air holds more water and this will lead to increased precipitation."

    What source do you have for that declaration?  As written, the logic does not parse.  As warmer air does indeed hold more water, the evidence shows that desertification and soil aridity increases overall, while precipitation events may become more severe, with greater potential for runoff and erosion.

    To have an expectation that temperature increases will then show similar upward trends is an unsupported fallacy.

    You are faring poorly in your argumentation.

  9. Tom Curtis # 149 You chop too much off my concept and then use it as an agrument against my point... I continued my line about the proxy link of Munich Re. "The best posted so far is the Munich Re disaster trend. And this is an indirect proxy with too many other varialble to create a conclusive argument of the overall thesis." On the paper you reference, what did you think I was trying to show? My point of adding that paper was the larger point. Weather extremes happen all the time. The article of this thread is concerned that 2010 is so unusual and is proof that Global warming is now drastically changing weather patterns. I do not happen to share this view and post long term historical records of various locations and ask for evidence that shows a drastic or unusual nature in our current weather or climate patterns. So far I have looked at droughts. I looked at droughts in Texas, North America, Australia, the Pacific Coast. In the data I pull up I cannot see any increasing droughts in intensity, duration or frequency. I have mentioned flooding. I have found China has floods at least every other year. A proxy with too many variable that can effect it is not the best type. Some proxies are very direct. The expansion of a liquid based upon its temperature. What we are directly measuring is expansion. The expansion translates well to a temperature of the liquid. There are few other variables, besides temperature, that expand the fluid so it works well. Munich Re even mentions the many possible variables when linking disaster events to extreme weather events. It is the last page of the Munich Re report you linked to. I am not against proxies but data using them may only give you an approximation. If many variables effect a proxy then it probably would not be used.
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  10. Norman @158, your conclusion that warmer air will hold more water, and hence there will be fewer droughts is to simplistic. As a first order effect, it is in fact true that warm air can hold more water; and all else being equal, this will lead to greater precipitation. Indeed, that is just what we see globally (over land). As can be seen below, the expected daily rainfall over the globe is increasing with increasing temperatures. Based on the GRCM3 model, the expected increase is about 0.06 mm per day over course of the 20th century, and as much as five times that increase over the course of the twenty first: A 0.06 mm/day increase translates to an annual increase of 22 mm over the period 1900 to 2010, or about 2 mm per decade. That does not sound like a lot, but it is an increase in the mean global anomaly, ie, the average of the increase at all recording stations. In other words, your typical city is expected to be receiving 242 mm more rain per annum now than they where in 1900. According to Australia's Bureau of Meteorology, the trend over that period has been 2.08 mm/decade, or a mean increase of 243 mm. As a hindcast, that retrodiction was not bad. But that is just the simple stuff. In fact, the change in precipitation is not expected to be, and has not been evenly distributed in space: Some areas are expected to receive less rainfall, and consequently other areas must receive more. The natural consequence of that is that some regions are now more prone to droughts, and some more prone to floods. And one crucial point you neglected is that, if air is dry, its increased capacity to carry water just means it sucks more moisture out of the environment than it used to. That means just looking at changes in precipitation understates changes in aridity in some areas.
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  11. Further to Tom's point - a proper evaluation of an hypothesis is compare observation to actual model prediction not just what you think the model predicts. The models for regional effects of weather as the globe warms are not that robust but do clearly delineate areas which will get wetter and which will get dryer. The worrying thing about the Min et al paper was that there was more extreme precipitation events than models than their models predicted.
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  12. DB in 158 Thanks for the correction. I did reread Jeff Masters point on that and it is not that warmer air woould cause more overall rainfall (as you pointed out) but more extermes. Heavier rain in some areas and stronger droughts in others. You are completely correct. This is a very intelligent website and the posters expect and demand a higher level of reasoned responses. Too many mistakes and misunderstandings is too sloppy. I am trying to demonstrate points of histrorical weather patterns but a failure to keep it error free will work to make my posts seem sophmoric and not worry of consideration.
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  13. Camburn @ 152 I did read through your Devil's lake article. It does show a similar concept of what I have been trying to point out in my numerous posts. Histroically the climate does not appear to be getting worse. There are large variations in rain amounts (drought and flood cycle) going back several centuries. When looking at the long history of any given area I have examined, I cannot conclude from the evidence that climate patterns are becoming more extreme or that flood/drought cycles are more intense, more frequent, or longer in duration.
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    [DB] The inescapable conclusion is that one cannot draw regional or global inferences based on single point references.  So the premise of your comment and your concept is based on a fallacious understanding of time series analysis.

  14. Tom, Have you compared your rainfall anomaly graph with the GISS temperature anomaly posted in #158? The rainfall follows temperature, but with an ~15 year lag.
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    [DB] What physics-based explanation do you propose for that?  Otherwise it's another case of "I see cycles".

  15. Tom Curtis @ 154 If you go back to your post on 55 with the two types of disaster graphs (disasters and major disasters). If you look at the number difference between geophysical and weather related at the start of each graph. The number of weather related disasters is so many times higher. I have not worked it out yet but I am wondering if the starting higher number would increase the probability of a disaster from weather over geophysical when the population rate goes up at about the same rate as the disaster chart. Wheras the increasing population is not changing the lower number as much, the geophysical disaster frequency is going up on both graphs, just more slowly. Also with large geophysical disasters, being a much smaller yearly number have less probablility of disaster. But with severe storms just in the US there are about 2000 to 3000 supercell thunderstorms a year. Link to number of annual supercell stroms in US. Of those 2000 storms, anyone which could become a disaster, only a few of these become listed as disasters. With Earthquakes you have a much smaller number that cause disasters (need to be close to the 6 magnitude to cause one in areas with better construction). Your short list does show this. You can also see by matching the numbers on your post at 55 with the earthquake numbers that most large earthquakes do cause a disaster somewhere. Earthquake number and magnitude. The logic (not sure it will satisfy you). Most large earthquakes are already counted as disasters (percentage wise) whereas the vast majority of supercell storms do not become disasters but each one has the potential to. So an increase in population and property value could still explain this situation. Munich Re also points this out in there report.
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  16. DB @ 163 The writers of the article do believe it is a valid proxy for determining wet and dry cycles for the larger region of the Northern Great Plains. "Devils Lake is of glacial origins, and the fact that it is a closed lake has allowed meaningful paleoclimatological studies using proxy information to estimate elevation changes several thousand years before the present time. These reconstructions (Bluemle, 1991; Murphy et al., 1997).reveal numerous cycles between high and low water levels that have been interpreted to indicate wet and dry cycles over the northern Great Plains (Fig. 1)" There is no global climate there are regional climates. To determine if these regions are changing you can only examine one region at a time to look for a signal of increasing extremes. I did post a local point on snowfall for Omaha Nebraska earlier and was rebuked for this. After this I am trying to find historical information on various regions and it seems Devil's lake is considered a regional proxy.
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    [DB] The author's of that study use statistical analysis tools to arrive at their conclusions (which apply to the Devil's Lake area only).  In your prosecution of your narrative you do not use any statistical analysis of your own, relying instead on the sturdy Eyecrometer and "common sense".  On a science-based forum such as this, you are not living up to the standards of believability.

  17. Tom Curtis @ 160 My post at 158 was a poor one and I should not have made it. I just want to comment on the trend line in your second graph. I might have a different view here. I see a dry period followed by a wet period which may be linked to global warming or it could be some longer term cycle that produces dryer and wetter periods. A trend line from the dry cycle to the wet cycle indeed shows an increase. What if the trend line is drawn just in the wet cycle and just for the dry cycle considering the possibility that these are some cycles of unknown mechanism but cycles never-the-less. I would doubt you could show an upward trend of the wet cycle in graph two of your post. That was my observation.
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  18. Eric the Red @164, I had noticed that, and even checked out a number of possible causes including: Insolation (which peaked in 1950) ENSO PDO NAO Sulfates (global dimming) Correlation between SST and Land Temp In each case there was either no obvious connection, or in some such as insolation there was good reasons to rule it out as a cause. The most important feature to note is that the NH and SH peaks do not correlate. In particular, there are many high precipitation years around 1920 in the SH as in the NH, but they are not the same years, and there is no equivalent to the 1950's peak in the NH in the SH (which rules out insolation as a cause). The best correlation with an oceanic oscillator is with the PDO (1950's peak), but the rise in precipitation in the 1980s starts far to early and far to strong for the PDO to be the cause. Consequently I would say the precipitation is tracking temperature, but imperfectly because of the noisy nature of the data.
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  19. Norman @167, the SH data does not have the same dry period wet period pattern you are commenting on, but it has an even stronger trend (3.31 mm/decade) than does the NH (1.53 mm/decade). Interestingly, the SH lacks both the mid century temperature peak and the (slightly out of phase) mid century precipitation peak which are both so prominent features of the NH and global data. Further, you are inventing an unexplained cycle from the whole cloth as the pattern does not correlate well with any of the great oceanic oscillators (including such dubious ones as the AMO, which I just checked. Further, even if it was a cycle, you would not be able to check phase only trends without at least two positive and two full negative phases to check. Finally, as noted above, the SH trend is much stronger than the NH trend. The NH trend dominates the global trend, never-the-less because this is a land only index, and there is so much more land in the NH. This suggests that if it was a land/ocean index (unfortunately not possible due to lack of data) it would show a much stronger trend dominated by the SH, and hence lacking the features you are trying to build a case on.
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  20. Tom, With the exception of the early 20th century, I think the precipitation does correlate rather well with PDO. The more negative the PDO, the higher the rainfall.
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  21. Norman @165, there where about 326 in North America including the Caribbean in 2010. Of those, about 60 occurred outside the US, and 4 where geophysical, leaving approximately 260 weather related disasters in the continental United States. But for the sake of argument, let's pin that as the US figure. According to your source, there are an estimated 2,000 to 3,000 supercells in the US annually. Taking the higher figure, that means that supercells have around an 8% chance of causing a disaster. From your source, there where around 2,100 category 5 plus Earthquakes would wide in 2010. Of the 960 natural disasters in 2010, 9% or 86 where geophysical. Assuming them all to be earthquakes, that means about 4% where damaging. The US figures are 80 5 plus earthquakes, and 2, possibly 3 reported as disasters; and hence a 2.5 to 3.75% chance of being reported. Therefore on these rough figures, a magnitude five plus quake is less likely to be identified as a natural disaster than is a supercell. Your logic was:
    "The logic (not sure it will satisfy you). Most large earthquakes are already counted as disasters (percentage wise) whereas the vast majority of supercell storms do not become disasters but each one has the potential to. So an increase in population and property value could still explain this situation. Munich Re also points this out in there report."
    But as we have just seen, the probability of reporting as a natural disaster are the reverse of what you claim. So if we accept your logic, which I do not, we would expect an increase in population to result in more reports of geophysical disasters relative to weather related disasters, rather than the reverse. With regard to your initial comment, geophysical disasters are almost flat (no increase) over the period that weather related disasters increase threefold. Major geophysical disasters increase by about 50%, but major weather related disasters increase by about 100%, leaving a 33% increase unexplained by reporting issues.
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  22. Eric the Red @170, you also ignore the negative PDO index from 1960 to 1970 but low rainfall, and the period from 1980 to 1990 with positive PDO index and high rainfall. Adding those two periods to the early twentieth century you have around 50 years in which there is no correlation, or the opposite correlation to that predicted. It doesn't correlate well in the 2000's either. Establishing a correlation over fifty years and then asking me to ignore the other sixty because it does not suite the hypothesis does not impress.
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  23. Tom, I think you are looking too much at each individual value. If you smooth the values over 5 years, then the scatter dissipates, and a good correlation is evident. I did not say it was perfect, but it does show possibilities. I agree that the period from 1960-1970 does not correlate as well. The PDO was negative for most of the decade, while the rainfall fluctuation, but was only low for three years; 1963,5, & 8. For most of the 80s, the PDO index was possitive, and the rainfall was low. Rainfall was only high for two years, which corresponded to a negative PDO around 1990. This was one of the better periods of agreement. Since 2000, the PDO has bounced from negative to positive, and back to negative. Rainfall started high, fell, and rose again, but you could argue that timing was not the best. Also, look at the periods of highest rainfall; mid 50s, mid 70s and ~2000. During these periods, the PDO was the most negative. During the periods of lowest rainfall; early 1930s, early 40s, mid 80s, and early 90s, the PDO was most positive.
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  24. Eric the Red, if you want to actually run a correlation between the precipitation data and the PDO index, and also with Crutem, or hadCRUT3v by all means. As it stands, I do not think the correlation will be significantly better, if at all. Given that, there is a clear causal connection between high temperatures and high precipitation. In contrast, it is not even clear that the PDO is a genuine oscilation distinct from ENSO effects, and you have no explanatory path from PDO to higher precipitation. More importantly, the correlations you are trying to find certainly do not apply in the SH, so you are then left trying to find to distinct and non-compatible explanations, one for the NH and one for the SH. If you think there is something in it, do the leg work. If not, then there is nothing to discuss.
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  25. Tom, Yes, I did some leg work, that is why I presented the last post. A casual connection does exist between precipitation and either temperature or PDO. Neither is a good correlation statistically, however, the correlation is better with PDO. The only explanatory path for the PDO would be similar as for temperature; increase in pacific ocean temperature wouls enhance NH rainfall.
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  26. Eric, the eyechrometre is not leg work. Unless you at least do a side by side graphic comparison, or better yet run the data through a spread-sheet there is really nothing to discuss. I will note however that your response effectively concedes the connection between temperature and precipitation. Specifically, it makes not claim for explanatory power in the SH, where the larger increase in precipitation must be explained by global warming. And it attempts to explain variation, but not the trend in NH precipitation by warmer NH oceans. Finally, it leaves the trend in NH precipitation to be explained by the trend in temperatures. Given that, even if you do the legwork (which may be interesting), it would probably be more appropriate to another topic.
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  27. Tom Curtis @ 171 I would humbly disagree with your calculation. You are using a 5 magnitude (and stronger) earthquake as a disaster causing one to get the calculation of 4% of 2100 earthquakes led to disasters (86 disaster geophysical events in 2010). Yet in your post you show a 5.4 will produce little damage and not lead to a disaster (Borrego Springs Quake). I am not sure at what level in the 5's an earthquake will become a disaster if it strikes a populated area nor do I have the number broken down but it could be a safe speculation that as the magnitude goes up there are a lot fewer so most of the 5's may be lower non damaging earthquakes. For the US you state maybe 2 or 3 were disasters. In the US only 9 had a magnitude of 6 or more. If you go with the higher figure of a 6 magnitude or above earthquake as being reported as a disaster (some will hit in non populated areas) you get 173 for 2010. If the 86 listed geophysical events are earthquakes (a few could be volcanoes) then your number of earthquakes being reported as disasters is now very close to 50% which is the point I was making. Most disaster causing earthquakes are counted already and an increasing population, with higher propery values (disaster reporting is based upon number of people killed and a certain level of property damage) will not have much effect on the number reported. Whereas if only 8% of supercell storms lead to disasters but the potential is for a higher number, a higher number of wealthy individuals will increase the odds of a supercell being counted as a disaster.
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  28. DB @ 166 I do respect your intelligence and appreciate your thoughtful comments in my posts. On this issue I have to respectfully disagree with your point. If one is looking for a small signal in noise your point would be most valid. But in this case I do believe the Eyecrometer and common sense are all that are needed to determine if climate (rainfall, drought, temperature extremes) is drastically changing for the worse. Case of point. When you look at any of the global temperature graphs you can clearly use the "eyecrometer" to determine that the globe has warmed since the 1970's. You can roughly get a slope of that change by looking at the number of years and seeing the increase and looking at the type of line that is on the graph. People do have good skills at pattern recognition and for obvious changes one would not need a detailed statistical analysis to see any trends. That is my primary point of the links I post. If the weather and climate are changing so drastically because of the recent increase in global temperatures then the "eyecrometer" would certainly be able to see such changes without having to fine tune the statistcal mechanics to find these extremes. I posted various graphs of droughts over a very long period of time. The "eyecrometer" is sensitive enough to see if there are changes in intensity, frequency or duration of a drought cycle. If such changes are not so apparent by visual examination then how can the claim be made by Jeff Masters: "The pace of extreme weather events has remained remarkably high during 2011, giving rise to the question--is the "Global Weirding" of 2010 and 2011 the new normal? Has human-caused climate change destabilized the climate, bringing these extreme, unprecedented weather events? Any one of the extreme weather events of 2010 or 2011 could have occurred naturally sometime during the past 1,000 years. But it is highly improbable that the remarkable extreme weather events of 2010 and 2011 could have all happened in such a short period of time without some powerful climate-altering force at work. The best science we have right now maintains that human-caused emissions of heat-trapping gases like CO2 are the most likely cause of such a climate-altering force." If 2010 extemes are so outside the normal they should stick out in the long term history of regional events as obvious exceptional events. I have done some regional droughts. The next attempt would be long term regional precipitation events (hundreds of years long if possible, then one can see if the nature of such events is Tom Curtis pointed out in a post, you need at least a couple cycles to determine if they are present) if such events are determined in the literature. Hopefully I am making a valid point on claiming the "eyecrometer" should suffice to determine extremes in a long term trends. I guess one more example would be Tom Curtis post about the modeled ENSO future predictions. The trend is upwards and I would not need Tom Curtis to generate Standard deviations from normal to see an upward trend. Maybe to get an exact slope you would but that is not the determination of this article. The claim made is that weather related events are more extreme and it would require a powerful climate-altering force.
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  29. Norman @ 178... Your comment here contains a common theme that I see in those who wish to dismiss climate change as man made and a serious issue. We hold a train schedule in our hands that says that a train runs on these tracks on a regular schedule. We can hear a whistle blowing. We can see a light starting to emerge from the tunnel behind us. We can even feel the vibration of the track we're standing on. We can come up with lots of explanations for the signs we see. Could the schedule be a misprint? Maybe that's a factory whistle. Maybe it's a train on a different track. But the best research available says we are going to be hit by a train unless we find a way to get off the track we're on. But we have not been hit by the train yet. The argument you seem to be putting forth is that we shouldn't move until the train is about to hit us. Prudence suggests that one should move well before being absolutely positive so as to make sure you CAN move off the track. History tells us that "common sense" often fails us. This is why science has served humanity so well. It has told us the truth in spite of our common sense. Data is data. Physics is physics. Even if it looks wrong or if your "eyecrometer" can't detect it, proper analysis will properly inform us. Cows and deer don't move off the track until it's too late because they do not have the capacity we have to analyze a situation. Let's not willfully be a cow.
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  30. Norman @177, your really do take the cake. You take a single example of a magnitude 5.4 earthquake, that located 15 kilometres from the nearest human inhabitation, which human habitation was a small village with a population of only 3,500; and because it didn't cause any deaths conclude that magnitude 5 earthquakes cannot cause natural disasters. Tell that to Newcastle. I'm sure the thirteen dead in "one of Australia's most serious natural disasters" will be consoled to no that only magnitude 6 plus earthquakes can cause natural disasters. Or tell that in Lorca, where the ten dead will no doubt be very consoled that the earthquake that killed them was 0.9 magnitudes to small to cause a natural disaster. Or perhaps you want to restrict the comparison to California, in which case you should reassure the people of Kern Valley, of">Concord, of Daly City, and of Santa Rosa that their fatalities where illusory because their earthquakes weren't big enough to cause natural disasters. Or are they to early, before architecture caught up with life an an earthquake zone? Tell that to Whittier Narrows, Santa Cruz County, and Sierra Madre. As recently as 2005 people were injured by an earthquake below magnitude 5 in Los Angeles. Where somebody is injured, with a little bad luck somebody could have died. Your problem is that you keep on trying to load the dice for your argument. The vast majority of tornadoes (74%) are relatively undamaging EF0 and EF1. They cause just 4% of tornado related deaths, but if you are unlucky they can still cause fatalities. Even EF2 and EF3 tornadoes are unlikely to cause natural disasters. They constitute 25% of tornadoes, and cause 29% of tornado deaths between them. But EF4 and EF 5 tornadoes, just 1% of all tornadoes, are devastating, causing 67% of deaths from just one percent of tornadoes. If I where to apply your reasoning, I would exclude all but EF3 plus tornadoes from the comparison. Or I would exclude all supercells that do not spawn at least five tornadoes. If you have any intellectual integrity, that fact that you are resorting to such egregious cherry picking should be a warning to you that your approach to the subject is biased and that (consciously or subconsciously) you are trying to reach a pre-determined conclusion regardless of the data.
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  31. Norman @178:
    "If one is looking for a small signal in noise your point would be most valid. But in this case I do believe the Eyecrometer and common sense are all that are needed to determine if climate (rainfall, drought, temperature extremes) is drastically changing for the worse."
    (my emphasis) "Drastically"? Who said anything about "drastically". My understanding of the science is that we expect climate change to drastically alter the frequency of extreme events when the Earth has warmed by 3 plus degrees by the end of this century, but that we are starting to see an increase already because the effect of global warming. Nobody claims that the effect is drastic as yet. Especially not Jeff Masters, whose question you quote, but whose answer you ignore:
    " However, I don't believe that years like 2010 and 2011 will become the "new normal" in the coming decade. Many of the flood disasters in 2010 - 2011 were undoubtedly heavily influenced by the strong El Niño and La Niña events that occurred, and we're due for a few quiet years without a strong El Niño or La Niña. There's also the possibility that a major volcanic eruption in the tropics or a significant quiet period on the sun could help cool the climate for a few years, cutting down on heat and flooding extremes (though major eruptions tend to increase drought.) But the ever-increasing amounts of heat-trapping gases humans are emitting into the air puts tremendous pressure on the climate system to shift to a new, radically different, warmer state, and the extreme weather of 2010 - 2011 suggests that the transition is already well underway. A warmer planet has more energy to power stronger storms, hotter heat waves, more intense droughts, heavier flooding rains, and record glacier melt that will drive accelerating sea level rise. I expect that by 20 - 30 years from now, extreme weather years like we witnessed in 2010 will become the new normal."
    (my emphasis) What is more, given that the rise in temperature that has driven the increase of extreme events has been small, and only occurred over the last thirty years, I do not expect an examination of individual phenomena to show a statistically significant trend. Some may, but many may not. But the conjunction of many slight statistically insignificant trends may well result in a statistically significant trend in the total number of extreme weather events. You keep on setting up this strawman of trends you can detect with an eyecrometre and of events completely outside the range of normal experience because on the real issue, the overall statistics of extreme events, you are taking a hiding.
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  32. Rob @179, "Your comment here contains a common theme that I see in those who wish to dismiss climate change as man made and a serious issue." It is interesting that you should post that. Earlier today I drafted a post but it was lost b/c SAFARI crashed on me. Anyhow, as you probably know Tamino has just posted a devastating refutation on one section of the NIPCC report. And that got me thinking about the fairly steady stream of papers being posted by "skeptics" (e.g., Norman)on this thread trying to convince people that there is nothing un-towards or unusual going on with the climate system. Let me just say that the framing and language has a certain tone to it that raised flags for me. So I went and cross-referenced some of the sources being referenced here by "skeptics" (see here, for example)and those that appear in the NIPCC report. Even just the most cursory of checks found that two of the papers being cited here (Herweijer et al. (2006), Hallett et al. (2003) to try and convince people that all is well are referenced in the NIPCC report and one of those (Herweijer et al. (2006)),appears in the section on extreme weather. A curious coincidence? Unlikely. And I for one am incredibly tired of people alleging to post here in "good faith" when all they appear to be doing is regurgitating stuff from a highly questionable political document prepared in the guise of science. And that said regurgitations do not even accurately represent the findings of the original paper or are not applied in context. I will also note that one of the papers that they (NIPCC; Idso and Singer) cite in reference to drought in N. America is being used for purposes not intended by the authors. I happen to know the authors of the paper in question and I know for a fact that they are not "skeptics" or in denial about AGW. So these it is worrisome to see Idso and Singer to misrepresent the science in papers that actually do not go against the theory of AGW. And worse yet, to see uncritical "skeptics" perpetuate the misinformation and distortion. If some people wish to deny the reality, the science, then they are welcome to do so, but please do not tie the rest of us to the train tracks.
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  33. Norman @178 The trouble with the eyecrometer is that it is entirely subjective and prone to cherry picking. My eyecrometer looks at the last year and sees a series of work trips to remote sites cancelled due to floods in Queensland and Western Australia, my home town of Brisbane flooded, and a return trip from a desert site where we had to push vehicles across five kilometre wide puddles while up to our arsecrometers in flood water. When the subject came up recently amongst my colleagues about the frequency of extreme weather events I showed them the graphs presented by Tom Curtis @55 on this thread. Eyebrows were raised and comments were made that there was proof of a trend over time towards more extreme events. The question was asked about what might be causing this. When told the answer was that it was a likely outcome of AGW and was consistant with scientific predictions, half the peopled gathered just walked off in a huff mumbling about lefty conspiracies and the other half stopped and gave the matter some thought. Our groups' observations of local problems due to weather were just cheerypickings until they could be incorporated into a broader picture. When that picture was revealed in the form of a graph, all were initially convinced that there was a pattern developing. Once AGW was identified as the cause the denialists broke away and claimed it must be some kind of political fabrication. Like I said, its all subjective. The eyecrometer is simply not enough to go by.
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  34. Tom Curtis @ 180 I would like to respond to your good post about the earthquake events and I would like to demonstrate intellectual integrity. This line of reasoning is based upon your post of the Munich Re graph demonstrating an increasing number of weather related disasters. I suggested the possibility due more to population increase rather than climate change of more extremes. Before I can comment I need a really good definition of disaster. I looked at your Munich Re report and they did not give a definition of what they were using to build their charts. I looked at this web page... Is this Munich Re standard for Disaster classification used on their graphs you posted?. "International Strategy for Disaster Reduction (ISDR), at least one of the following criteria must be met: • a report of 10 or more people killed • a report of 100 people affected • a declaration of a state of emergency by the relevant government • a request by the national government for international assistance" 3 of these are absolute and easy to quantify. The 2nd one is elusive as it does not further define affected. Is this an injury? How bad of an injury? In my hometown a few years ago we had a strong hail storm that damaged many roofs in our community (including mine). At least 100 people had their roofs repaired so would this be listed as a disaster? Or say 100 cars in a parking lot during a hail storm that triggers insurance claims? Or a snow storm that does not cause any death but leads to 100 hospital visits caused by shoveling snow? Without a strong definition of what is counted as a disaster it becomes difficult to carry on this line of reaoning. If you are able to give a more certain definition of disaster I will be able to more reasonably explain my point on the earthquake vs weather related difference in slope on the Munich Re graphs. Thanks!
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  35. Rob Honeycutt @179 I read your train analogy. It is simialar to the one posted by Sphaerica @ 88 about falling out the window of a tall building and assuming everything is alright until you hit the ground. I did post a reponse to Sphaerica @ 96. If you read my post it will demonstrate I am indeed wanting to move away from fossil fuel and find alternate replacements that can not only maintain a high standard of living for industrial nations but for all the people on Earth. Fossil fuels (even without CO2 byproduct) could not meet the need of raising the standard of living for all people. Your quote "Norman @ 178... Your comment here contains a common theme that I see in those who wish to dismiss climate change as man made and a serious issue." I do not believe any of my posts suggested that climate change was not man made or that is a position I advocate. Man is releasing a large amount of CO2 while destroying some carbon sinks, that is factual information. CO2 has been empirically demonstrated to redirect IR in its absorption bands (measures of down-welling longwave radiation and also a lower amount of IR in these bands being emitted to space as measured by orbiting satellites). It could even be a serious issue in the future. My posts are a basic challenge to the linking of extreme weather events to global warming without providing the actual mechanisms that would verify this conclusion. An extraction of Jeff Masters from Tom Curtis post @181 "But the ever-increasing amounts of heat-trapping gases humans are emitting into the air puts tremendous pressure on the climate system to shift to a new, radically different, warmer state, and the extreme weather of 2010 - 2011 suggests that the transition is already well underway." I am questioning if 2010 was really that extreme. The only way to do this is to look at historical weather information, to have something to compare it to. I am questioning if Global warming is causing a noticeable change in climate or weather patterns. Climate defined here.
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  36. Stevo @ 183 "Norman @178 The trouble with the eyecrometer is that it is entirely subjective and prone to cherry picking." Is that really the case? Here is a graph of all the major temp records of the globe. Major global temp graphs combined. Would your "eyecrometer", looking at this graph, not conclude the Globe is warming? For large and obvious trends statistical analysis is not necessary, the eyecrometer does fine. How could one subjectively claim that the graph does not indicate global warming? If you look at many of my posts, I am attempting to find peer-reviewed articles or at least ones with indepth explanations of large regions. Sometimes difficult to find. Why would this qualify as cherry=picking? Cherry Picking. “Choosing to make selective choices among competing evidence, so as to emphasize those results that support a given position, while ignoring or dismissing any findings that do not support it, is a practice known as “cherry picking” and is a hallmark of poor science or pseudo-science.” – Richard Somerville, Testimony before the U.S House of Representatives Committee on Energy and Commerce Subcommittee on Energy and Power, March 8, 2011 [1] "Good science looks at all the evidence (rather than cherry picking only favorable evidence), controls for variables so we can identify what is actually working, uses blinded observations so as to minimize the effects of bias, and uses internally consistent logic."" I have stated what my goals are with my many posts. Would it not be cherry-picking to accept a list of extreme weather events of 2010 without at least investigating other years and long term climate patterns of given regions? Jeff Masters did good research work to compile his list of extreme weather events for 2010. Now it is my research work to see if the extreme weather events for 2010 are really so extreme in a historical context. If you agree that you can see global warming from the temp graphs using your eyecrometer, than why is it subjective to look for obvious trends in other data? Lastly, I am still in the process of figuring out the Munich Re disaster list. I am in need of a clear definition of a disaster as used as a number in the graphs.
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  37. Norman @184, the information you are after can be found from Loew and Wirtz, "Structure and needs of global loss databases of natural disasters". Loew and Wirtz describe the classification system used by Munich Re. The categorise by disaster type, by the quality of the source information, with events documented from low quality sources not included in the data base for analysis, but retained in case of confirmation, and by the "disaster category". The disaster category is a scale from 1 to 6, with one being from 1 to 9 deaths, and/or minor damage; 4 being a Major Disaster, more or less as defined by Neumayer and Barthel, but with a stepped scaling for property damage; and 6 being a Great Natural Disaster, ie, a Great Natural Catastrophe as defined by the UN. More information can be found in this Munich Re document, which includes a category 0 for not fatalities/losses, ie, a natural hazard. I presume category 0 events are retained on the record but not included in the data base.
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  38. Norman "... a list of extreme weather events of 2010 without at least investigating other years and long term climate patterns of given regions?" What you seem to be overlooking is that 'extreme weather events' include 'long term climate patterns' of all the the places mentioned, by definition. Everyone would probably accept that my local, record-breaking 1 in 3000yr heatwave event of a few years ago counts as hot by almost anyone's notion of hot weather. But more recently, Sydney had a record heatwave, temperatures nothing like ours, but devastating nevertheless. (It's probably a fairly subjective judgment whether 40C+ with literally breath-taking <15% humidity feels worse than 32C at >70%. After a week, nobody really cares.) Heatwaves are defined as x degrees above local climate norms for the time of year. Excessive rainfall likewise. After all, monsoons are 'normal' in some places. Here normal monsoon rainfall would be unbelievable. In Adelaide at any time of the year, an overnight minimum of -1C would set a record - Canadians would laugh themselves sick at that idea. Queensland flooded in the Gulf country around the same time as the devastating floods in SE Queensland. Only the SE floods count as extreme. The floods in the north might have been a bit on the high side of normal (I don't even know) - but they don't count as extreme because flooding is normal for that area in that season. Extreme events are anomalous - by definition. If you want to check meteorologists' reports for those areas for 100+ years, you're setting yourself a large, and largely futile, task.
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  39. Albatross @ 182 "curious coincidence? Unlikely. And I for one am incredibly tired of people alleging to post here in "good faith" when all they appear to be doing is regurgitating stuff from a highly questionable political document prepared in the guise of science. And that said regurgitations do not even accurately represent the findings of the original paper or are not applied in context." Sorry to disappoint but I have not heard of NIPCC report until I went to your Tamino link. It is not that curious of a conincidence. I go on Google and put in key phrases looking for historical data. I am seeking peer-reviewed publications. It is an easy coincidence. The claim made is that droughts are increasing and intensifying. So I put in the History of droughts and other search titles looking for .pdf material (seems a better chance for peer-review or at least well explained data, usually good graphs and detailed explanations of how data was collected and compiled and maybe good statistical analytical tools). The compilers of NIPCC report would probably be doing the same thing...looking for .pdf files for their material on droughts, flooding, hurricanes, tornadoes, all the typical events counted as weather extremes. They would be able to find the same articles. I do not understand your point ("And that said regurgitations do not even accurately represent the findings of the original paper or are not applied in context") based upon my posts. I post a link to the article, read the material and then look at the graphs. I then ask you to tell me where is an obvious trend that indicates an increase in frequency, intensity or duration of historical droughts in North America. You know Tamino uses his "eyecrometer" with his graphs on arctic ice loss. Here is his posted arctic ice graph Tamino Arctic ice graph. What he says about this graph. "Identifying a change in Arctic sea ice extent that can be attributed to temperature is as easy as looking at this graph:" Note also in this post by Tamino, he goes on to show how statistics and trend lines can easily be distorted to show a false picture of reality. That is why I am seeking very long trends and just posting the graphs. Because of the nature of my posts I still would like to understand "And that got me thinking about the fairly steady stream of papers being posted by "skeptics" (e.g., Norman)on this thread trying to convince people that there is nothing un-towards or unusual going on with the climate system." I am not trying to convince you of this, I am posting the information and asking for you to explain to me an upward trend in the data provided. If it is there, I am fine with it. A simple request I would think. Last one. Can you clarify this statement as I think the last sentence is about my posts.... "I will also note that one of the papers that they (NIPCC; Idso and Singer) cite in reference to drought in N. America is being used for purposes not intended by the authors. I happen to know the authors of the paper in question and I know for a fact that they are not "skeptics" or in denial about AGW. So these it is worrisome to see Idso and Singer to misrepresent the science in papers that actually do not go against the theory of AGW. And worse yet, to see uncritical "skeptics" perpetuate the misinformation and distortion." What misinformation and distortion am I perpetuating? Here is the content of my post @140: "Here is one with droughts across North America. In the text they explain that the causes of drought in North America were also responsible for Global Climate patterns (more rain in some areas droughts in others). From this study it states there were much worse droughts in the past than today. They also have graphs at the end of the article which show 1000 years of droughts. I would challenge you to find an increase in frequency of droughts today as compared to the long 1000 year history." Here is a direct quote from their conclusion (Paper on 1000 year droughts posted @ 140): "Many of these reconstructions cover the last 1000 years, enabling us to examine, in detail, how the famous droughts of modern times compare to their predecessors during a time of quite similar boundary conditions (e.g. orbital configuration). Upon examination, what becomes apparent, is that the famous droughts of the instrumental era are dwarfed by the successive occurrence of multi-decade long ’mega-droughts’ in the period of elevated aridity between the eleventh and fourteenth century A.D. Whilst these mega-droughts stand out in terms of persistence, they share the severity and spatial distribution characteristics of their modern-day counterparts." My question asked for evidence of increased frequency, intensity or duration. The mega-droughts were of the same intensisty but had a much longer duration.
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    [DB] "You know Tamino uses his "eyecrometer" with his graphs on arctic ice loss."

    Note also that Tamino always performs background analysis to check for significance, which work, sadly, he does not always show).  But he always performs them anyway.

  40. #183 Stevo - very interesting insight into the human psyche there! It it possible to say that more of your audience gave the link between extreme weather and climate some thought because you presented the data before suggesting humans mightbe the cause? I suspect that if you had said something like "this human-caused global warming is driving severe weather, see this graph", more of your audience might have been incluned to avoid the evidence, their minds having shut up and gone home on mention of AGW. But by seeing the evidence first and acknowleding the trend, it might be rather harder for them to back out an pretend nothing is happening. It's a sad state of the politicisation of a scientific issue, but I have hope the people will observe the world changing around them, then wonder why? Harder to avoid the truth, then...
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  41. The dismissal of evidence and search for other explanations, reminds me of an analogy where acceptance of the facts is also too much to bear : Shortness of breath ? "I've been short of breath in the past. In fact, I've had worse episodes after running." Wheezing ? "Must be related to the shortness of breath, as it has been in the past." Nausea ? "It's nothing. I've had worse nausea in the past, especially after several beers." Vomiting ? "Obviously related to the nausea, which has easily explicable causes." Feeling light headed ? "Means nothing. Had it before. It's nothing." Pain in the left arm ? "I've had worse pain before and in the other arm too. Simple explanation is that it could be anything." Pain in the chest ? "I had worse pain last year and 10 years ago. So what ? Doesn't mean anything." "Hang on, put them all together and it could be a heart attack ! Why did I look at them all in isolation and dismiss the symptoms separately as nothing untoward or more serious than anything else I've experienced previously ? I must do something." Too late...
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  42. Tom Curtis and Albatros, On an earlier thread "Linking Extreme weather and Global Warming" at post 148 for Albatros (a link to US CEI index at NOAA) and then 149 for Tom Curtis. To look at the CEI graph for Extremes in 1-day precipitation in the US was suggested by Tom Curtis. US CEI 1-day preciptiation extremes. At post 151 on the same thread Albatross comments "Tom @149, Indeed. Up." The graph shows a clear upward trend. However that is one on the points I am making and trying to demonstrate. There could be longer patterns that need more time to determine. That is why I like to look back as far as data will take. The longer the data trend the better (provided it does not fuzz to greatly looking back, generally some type of proxy has to be selected for really long trends as there is not direct measurements available to study). Here is another version of the Extreme 1-day preciptitation for the US (they use a different index to measure but the graphs follow the same trend over the parallel time scale). Note: I could not get the graph itself to link in its format. I will link to the article and state that the graph of interest in on page 297 of the article. Page 297 has a 1-day US extreme preciptiation graph. Abstract for the article linked above. "Abstract. An analysis of extreme precipitation events indicates that there has been a sizable increase in their frequency since the 1920s/1930s in the U.S. There has been no discernible trend in the frequency of the most extreme events in Canada, but the frequency of less extreme events has increased in some parts of Canada, notably in the Arctic. In the U.S., frequencies in the late 1800s/early 1900s were about as high as in the 1980s/1990s. This suggests that natural variability of the climate system could be the cause of the recent increase, although anthropogenic forcing due to increasing greenhouse gas concentrations cannot be discounted as another cause. It is likely that anthropogenic forcing will eventually cause global increases in extreme precipitation, primarily because of probable increases in atmospheric water vapor content and destabilization of the atmosphere. However, the location, timing, and magnitude of local and regional changes remain unknown because of uncertainties about future changes in the frequency/intensity of meteorological systems that cause extreme precipitation."
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  43. adelady, I liked your post, as it added reason and perspective to extreme events. Can we really call a period of record rainfall an extreme event when it occurs in the monsoon season in an area which typically experiences heavy rainfall? If it occurs outside of the monsoon area, then yes. We get into a gray area when the heavy rains falls outside the area, but are associated with typical rains. For eaxmple, I had an argument a year ago concerning record rains in Texas as a result of a tropical storm moving inland. Texas is not immune to tropical activity, although the area in question had been spared such storms in the past. Consequently, I prefer to eliminate these area from extreme weather discussions. I do not know how many weather reporting stations exist in the world, but let us say 10,000 for this exercise, and for simplicity that they have data for 100 years. Statistically, about 99% of the stations will fall within the extremes for the 100 years, but 1% (half above, half below) will fall outside the range. All things being equal, 50 stations would report a record high, while 50 report a record low. However, we know all things are not equal, such that warm years will produce more highs and fewer lows, and cool years, the converse. Also, areas in which stations are clustered could report a greater abundance of records during such a period. When you get down to daily records, statistically every station should produce at least one daily record high and low every year. I may have rambled a little, but my point is that a certain amount of records (or extreme weather) can be expected every year, and oftentimes the records are clustered together (in the U.S. most states set their records highs in the 1930s, while records lows are evenly divided before and after 1940). When the extremes start occurring year after year, then we have a problem.
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    Moderator Response: (DB) Your comment contains specious logic (ie, "Gilles-isms") and calls out for correction; no doubt one of the regulars here will oblige you.
  44. Eric@193 "Can we really call a period of record rainfall an extreme event when it occurs in the monsoon season in an area which typically experiences heavy rainfall?" Yes. If the rainfall was an extreme event in the context of a monsoon season at that location, then it is an extreme event regardless of the season as the maximal rainfall ocurrs in the monsoon. If an event is a one in a hundred year event, and extreme rainfall only happens in monsoons and there is one monsoon a year, then an "once in 100 monsoon" event is very likely also a "once in 100 year" event and vice versa. If the extreme rainfall ocurred outside the monsoon season, it would be extremly extreme ;o) Eliminating areas that have extreme rainfall is a neat way of simplyfying statistical analysis of extreme rainfall! ;o) The penultimate paragraph is getting into multiple hypothesis test territory, for which there are standard methods. Of course there will be extreme rainfall happening somewhere every year. The question is has the propensity for extreme rainfall changed (i.e. have the return periods shortened). There is a branch of statistics called "extreme value theory". You can bet that climatologists and statisticians that have worked with climatologists will be familiar with this (there is a very good book by Stuart Coles sitting on my bookshelf), will have applied it, and understand the caveats well.
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  45. DB @ 189 Because Excel does have an easy to use trending tool I did apply it to Perth Heatwave data set. I am not sure how to transfer the data to this webpage but I can at least describe the results and if anyone doubt them they can add the data to an excel sheet and use the trend line tool available. I was searching for historical data on Heatwaves on Google and Yahoo. Mostly the only search results that came up were of specific droughts in various parts of the world or how global warming is increasing heatwaves or models that show heat waves will increase in the future. All good and well but I wanted specific historical data especially one with individual data points I could use on an Excel spread sheet to satisfy your demand for more statistical analysis of data as opposed to using an "eyecrometer" or using common sense interpretation of a data set. I finally found what I was looking for on a page that describes the heat waves in Perth Australia over a longer period of time (81 years of data). The webpage is good as it not only lists various heat wave data but it also gives a reasonable explanation of what causes heat waves in Perth (it is a blocking pattern). One could use that information to determine if a warming globe (ocean and land) would generate more of these blocking patterns. Here is the link to Perth Heatwaves. Perth Australia heat waves. I used the Perth Airport temperature readings for my temp graphs as the article gives an * for the city temperatures. On the duration of the 15 listed heat wave events, the trend line was flat. There was no trend in the duration of the heat waves and one severe anomaly of 64 days in 1978 (this did not change the trend line as it took place in the mid area of the heat waves). The trend line for the average temp of the heat waves was negative, down from 38C to 37C at the end of the series. The trend line for the maximum temp was also negative from just below 44C at the start of the series to just below 43C at the end. About a 1C difference. The frequency of the heat waves was strongly positive. The time between the first few droughts was 13 years and then 23 years. After 1978 the time between the droughts is close to one every three years. My own conclusion. Drought frequency has shown a marked increase. Duration of each drought is flat. Temperatures of each drought is decreasing. DB, is that what you were requesting?
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    [DB] Time series analysis is a tricksy thing that even those who have done it for years can often make mistakes on.  This goes more than double when performing single-point trend analysis'.  By focusing on one station's worth of data only, how do you know the results of your analysis mean anything?  As Albatross points out below, that's essentially cherry-picking.  You need something to compare it to, either as a control or to make it meaningful.  Without context, there is no meaning.

    As for a good resource for you, since you appear to prefer Excel's analytical tools, D Kelly O'Day has an excellent primer on climate analysis using Excel here.  He even supplies spreadsheet examples of his work.  Highly recommended, as it will save you endless hours of false starts and shinnying down rabbit holes.

  46. Dikran, WHile I agree with most of your post regarding records and extremes, I maintain that record rainfall during monsoons or tropical cyclones is tenuous. Two reason for this: 1) the amount of rainfall is highly variable such that only a slight variations in conditions (atmosperic and oceanic) are needed to create the extreme, and 2) rainfall is highly variable within the measurement area creating a larger spread in the data. These aspects are absent in other readings such as temperature.
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  47. Norman @189, I'm really busy this weekend, but for now I'll address this: "I am not trying to convince you of this, I am posting the information and asking for you to explain to me an upward trend in the data provided. If it is there, I am fine with it." I beg to differ, read JMurphy's post @191. You seem to be doing your best to dismiss the trends in extremes, or to "hide" the incline-- you'll probably deny that of course, but that is how your posts come across. Your Perth heat wave example is just the latest example of cherry picking data from one location that goes against the trend-- no problem seems to be your deduction. You will probably even be able to keep this up if you are still around in 2050, yet the climate system then will be very different from what it was 100 years before, or even from what it is now. You claim to have stumbled on the same papers that happen to appear in the NIPCC report and you claim that you only now became aware of it. Did you know that I have been into space? Claims and assertions are easy to make on the web...and after dealing with self-professed 'skeptics' for several years now please pardon my cynicism and skepticism of their claims and motives. Climate scientists and climatologists and paleo climate scientists are all too aware of variability in the historical data, and yet, surprise, surprise most of them understand that AGW is real, and that current events are unusual and they expect the climate system to respond in ways that may not be pleasant for many. In fact, research suggests that we are already very likely seeing such a transition. Any reasonable person would by now, after reading this thread understand that certain (not all) extreme/intense weather phenomena are on the increase. They would also understand that yes lo and behold there have always been extreme events, but that is not the point. And repeatedly seeking out those data which support your beliefs or go against the trend, even when said papers do not support your position, or even if they are not relevant, or if the papers' conclusions have been misinterpreted to support said position, is not 'skepticism', it is denial not skepticism.
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    [DB] An Albatross in space?  Now I've witnessed everything.

    It is a good thing to be wary of unsupported claims.  For example, I will list 4 unsupported claims about me, 1 of which is untrue:

    1. My great-grandfather owned a gold mine
    2. I used to work for the CIA
    3. I have appeared on national television (NBC's the Today Show)
    4. I am a direct lineal descendant of Bailey's Irish Cream founder R.A. Bailey
  48. Eric@196 If the variability is high, that just means that an extreme with a hundred year return time is of a larger magnitude than it will be in an area with less rainfall variability. But it is still a once in a hundred year event. If a slight variation in conditions were enough to cause an extreme, it would happen often enough that the return tiem would be less than 100 years. Extreme value theory has that sort of issue well covered. Likewise variability within an area (that would not apply to monsoon rain, but it would apply lo localised storms or convective precipitation. Again a combination of spatial statistics and EVT has this covered.
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  49. Skywatcher @190, Yes, that was exactly how I perceived their reactions. It was easy to demonstrate the phonomenum but as soon as AGW was mentioned as being the cause I lost half of them. My guess is that if I'd mentioned AGW before demonstrating the data I'd have lost far more than half, including a few who'd have walked off just so that they would not appear to be splitting from the herd.
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  50. Tom Curtis @ 187 Thanks much for the links to Munich Re. I was looking around for this type of material but was unable to unlock its location. The detail that Munich Re employs to generate their graphs is impressive. On both links you posted, the 1 and 2 levels on the charts are not considered disasters. Loew & Wirtz call the first two "small and moderate loss events" the next four levels are various degrees of disaters. Munich Re lists the higher levels as catastrophes and not disasters but the meaning would be the same. The point I need to be clear on is it the events go into the graphs of increasing disasters (catastrophes) or are left out. It is necessary to know this for the point I am trying to make about earthquake disasters and weather related disaters (and the variable of population and monetary wealth). There is a question I have for you. In the Munich Re report you linked to, there is a graph of the aggregated disaters from 1980 to 2005 for each country: Same Munich Re report you already linked to. Topic I am wondering about. The USA and Chile have the highest aggregate disaster count at over 651 followed by many other developed Nations (Europe, Canada, Australia, expanding economies of India and China). Then you look at Africa and only South Africa is in the higher bands. Most of African countries have less than 50 reported disasters in 15 years. The strange thing about all this is US 30 year trend in deaths from natural weather related natural disasters is 575. US 30-year average death rate from weather related disasters. But you read this IPCC material on Africa and it states that Africa has the highest percentage of death from natural disaters...60% of the total 123,000 people killed each year by natural disasters, which would be 73,800 Africans die from natural disasters. Report stating the percentage of Africans killed in natural disasters. So many more than the US but US shows a much higher number of aggregate disasters. Africa does have severe weather, even tornadoes, but they have droughts and floods like the other countries. It makes me believe that the Munich Re reporting is based more on financial concerns than on human life for their reporting, but it gives a misleading view of disasters. Which could also be the reason disaster rate is rising. Americans have become more wealthy in the last few decades (or deeper in debt) and smaller storm events of hail or smaller tornadoes could reach the $50 million mark and be classified as a disaster on their chart. I looked back at your post 116 on the thread "Linking Extreme Weather and Global Warming" where you posted the Munich Re Graph. I guess the graph shows about a 55%increase in 25 years in number of disasters (about 400 in 1980 to 900 in 2005, and annual rate of 2.2%) Here is a link on the yearly rise in home prices. National average was 2.3% but some areas were at 3% and more. A yearly rise of 2.3 in a home's value (not to mention the items in the house) will get you a 57.5% increase in value in 25 years. The value of property rose at a faster rate than the disaster rate. But the biggest thing is there incremental choices they picked for determining a disaster. From 1980 it was $25 million. In 1990 it was $40 million. In 2005 it was $50 million. The overall rate of determining a disater rose 50% in 25 year or at a rate of 2% a year. From 1990 to 2005 the rate of increase would only be 1.3% a year. The criteria to become a disaster was rising at a much slower rate than property values. The logic here is that events that did not count as disasters, because they did not cause enough damage, but were close, suddenly became disasters as the property values rose past the trigger mechanism. This logic explains the high rate of disasters for the US, and other advanced systems with much higher property values. It also shows that the Munich Re graph would be valuable as an insurance tool but may bear no reflection on the actual state of climate change or more dangerous weather events. US home price rate increase. Also your chart is a global one. The property values in China and India have gone up in the last 15 years. What the data may be showing you is a reflection of inflation in the growth rate. You would have to admit it would be the most valuable type of data for an insurance company. There bigger concern would be the financial cost of a disaster. Since
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