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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Cedders at 07:32 AM on 31 October 2016

Extreme weather isn't caused by global warming

Some non-expert comments to Giancarlo and Terry, in lieu of a more informed response.

Giancarlo - yes, it'd surprise me a litle if increased drought hasn't been unambiguously detected, although it has been unambiguously projected. Would be interested to take that figure 5 in Hao up to present and see if the trend is positive yet. I find examples of projections in the USA in the National Climate Assessment, and in Cook, B. I., Ault, T. R. & Smerdon, J. E. Sci. Adv. 1, e1400082 (2015) covered here and here. Cook also detects extreme drought in the Levant. It does seem there has been differences of emphasis in the literature recently. Sheffield et al 'Little change in global drought over the past 60 years' seems like a downward estimate compared to the usual measure (PDSI) of past drought, and is put in context by John Holdren in an article reproduced on this site. He also refers to a summary in research by Schwalm et al that 'severity and incidence of climatic extremes, including drought, have increased'. Spinoni et al (2013) finds a small increase in each of global drought frequency, duration and severity from 1951-2010, but big regional variations that are disruptive.

Responding to Terry's graph, this is nice work, but I'm sure someone must looking at this professionally, who you may be able to contact. The increase in thunderstorms you show is so dramatic it must surely be an artefact, maybe of increased reporting? Secondly, a correlation between two time series each of which are increasing may well come to >90% (even more so if smoothed), but be misleading since both are dependent on time.

It strikes me that new measures may be useful for examining trends in 'extreme' weather rather than total weather, for example, maximum hourly rainfall, variance of rainfall, or collating data on water tables and aquifers. Not sure how realistic or expensive that would be.

Tom Curtis at 05:50 AM on 31 October 2016

Welcome to Skeptical Science

curiousd@31, apparently Chris Colose joined NASA GISS just this month, and consequently has a new email address. For that he deserves congratulations. For the rest, I am not a correspondent with any of the people listed, and am finding the email addresses by google search. If I were you, and if the email address you have is current, I would make Dr Pierrehumbert the first point of contact. My experience in contacting scientists is that so long as you remember that any help they provide you is a courtesy by them, not a right of yours; they tend to bend over backwards to help honest enquirers. Given that all three of the people I recommended, and SOD, have a history of trying to help explain AGW, I very much doubt that they would be different in this regard; and Dr Pierrehumbert would be acknowledged by the three others as the most expert on this topic, not to mention best informed about what he meant when he wrote his text book. Here is a more recent email address for him.

ubrew12 at 02:55 AM on 31 October 2016

Climate change could push risk of ‘megadrought’ to 99% in American southwest

LaughingMan@4: Unless the beavers have a wicked 'rain dance', I don't think they're going to be as helpful as you imagine in many places.

ubrew12 at 02:52 AM on 31 October 2016

Climate change could push risk of ‘megadrought’ to 99% in American southwest

bjchip@1: Maybe one form of how Earth will 'Ring' was anticipated in the 1972 film 'Silent Running'. Bruce Dern plays a biologist who maintains a spaceship filled with the last natural plants from Earth, and responds with rebellion when he's asked to clear them out for cargo. I don't think many natural ecosystems can respond quickly enough to avoid catastrophe; for them, 'Ringing' brings fracture. I think humans can respond more rapidly (but probably after much difficulty), and may have to act forcefully to prevent species extinction in a few decades or so.

ELIofVA at 00:11 AM on 31 October 2016

Global weirding with Katharine Hayhoe: Episode 2

I asked a few weeks ago after Katharine Hayoe's earlier videos featured on this web site how as a Evangelico Christian she resolves the contradictions between the Bibilical version of creation and the physical evidence of much longer time frame. In this video, when she speaks of much longer time frames than the Bible, she is siding the the physical evidence. I presume that many Christains take the Bible as a metaphor more than a historical document. I hope she can speak to these Christian believers to support Climate Change believers so that we can work together to solve the problem.

BaerbelW at 23:02 PM on 30 October 2016

Over 31,000 scientists signed the OISM Petition Project

Just found a new entry on Snopes about this:

Not All Climatologists

Acouphène at 22:29 PM on 30 October 2016

CERN CLOUD experiment proved cosmic rays are causing global warming

New paper from CERN experiment : "A significant fraction of nucleation involves ions, but the relatively weak dependence on ion concentrations indicates that for the processes studied variations in cosmic ray intensity do not significantly affect climate via nucleation in the present-day atmosphere."

http://science.sciencemag.org/content/early/2016/10/26/science.aaf2649

curiousd at 16:44 PM on 30 October 2016

Welcome to Skeptical Science

Hi Tom Curtis,

I have attempted to contact everyone on your list except Dr. Pierrehumbert and either get no response or find that the listed e mail address does not work. I am not on Facebook nor Twitter! Do you know of a more recent e mail address for Gavin Schmidt? I would prefer to check with another expert before contacting Dr. Pierrehumbert.

Sincerely,

Curiousd

RedBaron at 10:50 AM on 30 October 2016

Climate change could push risk of ‘megadrought’ to 99% in American southwest

It is a pity that LaughingMans post was so inflamatory. Because that is in fact one leg of a 3 pronged approach, ecosystem restoration. And none better than keystone and engineer species like beaver to start restoring vast areas and using them as carbon sinks, as well as mitigating drought. Beavers are the stereotypical ecosystem engineer because of the effects their dams have on channel flow, geomorphology, and ecology. The ecological cascade that follows is profound and spreads far beyond the beavers' habitat.

Unlike LaughingMan, I don't see this as a stand alone solution. But it certainly can be a significant part of the solution.

ed leaver at 09:11 AM on 30 October 2016

Debunking climate myths with Leonardo DiCaprio's Before The Flood

Hi John, your contributions are appreciated. Could you possibly attribute the concluding figure of your last "We have all the technology..." bullet? It appears to be Figure 2 from The Solutions Project's: 100% Clean and Renewable Wind, Water, and Sunlight (WWS) AllSector Energy Roadmaps for 139 Countries of the World Jacobsen, Deluchi, et al. 24 October 2016.

Thanks!

LaughingMan at 03:30 AM on 30 October 2016

Climate change could push risk of ‘megadrought’ to 99% in American southwest

I would argue that the occurrence is normal as well.

The likelihood of climate change itself having the effect its always had vs. Human influence is illogical. A permanent drought has been effect in Western US since the 1930s, the Grapes of Wrath even addresses this issue with no recourse. The water wars are in full effect and the EPA made it illegal for water conservation to occur. So if water management has been outlawed by Obama, then the only conclusion will be no water for consumption later.

I have a solution though! While the EPA might regulate human use to exhaust what watersheds might be left, it would be advantageous to farmers and land owners to bring in beavers from Canada to restore the watersheds.

The beaver has proven its ability in Texas and is the ultimate watershed manager. It can engineer the development of green savannah if allowed to carry out its functions.

Obama tried really hard to exterminate the US population in a quiet unobvious way. First he stripped people of their rights, then he stripped them of their jobs, then he quietly took away their access to water and food.

If the watershed in your area is under threat of drying up, you need beavers now to fix it. Beavers, often thought to be a nuisance, a pest, a horrible animal to have near you is actually a clever watershed engineer. They can be effectively communicated with, they can be an effective ally.

The key is the research conducted in Gatineau Quebec Canada by the Government of Canada.

The beaver was interfering with run off, road construction, and was deemed a pest. When the lead researcher used tape recorders with tapes playing running water sound, the beaver started to build dams near the sound. The effect was mind blowing. The beaver started to build where the tape recorders were.

Thus saving the government millions in road construction costs. Plus, the ability to get the beaver to perform vital construction better than any human construct in water was amazing too! Overall, the Canadian watersheds depend on beavers to manage a lot of it. We didn't know until about 5 years ago. Now we rely on beavers to help keep watersheds managed effectively.

This will work in California and the western US as well. But first, the farmers need to tell the EPA to get lost, collect rain water without penalty, stop exhausting or taxing ground water and ease up on archaic farming principles.

If all the areas are properly addressed the solution to the problem should fix itself.

We cannot hope for better outcomes without addressing best practices.

That includes watershed management, responsible use, responsible legislation, policy and procedure, as well as due diligence.

To simply blame climate change is a cop out. Its easier to blame stupidity and ignorance and greed. If I take a five hour shower every day, flush the toilet 50 times a day, open a fire hydrant and flood a street every other day, and generally waste water that's on me. But if the EPA says you can't legally collect rainwater, you have to use your water allotments from the watershed or lose them, and make water management impossible, that's on the government.

This isn't about climate change. The climate always changes. This is about stupidity. If you still think the climate change is at fault, you should also blame the rain spirits for not showing mercy. And the water elves for not bringing moisture and the Eskimos for not bringing ice. Yeah, blame everything else first, shake fingers and further the problem. Or find a trickle of a stream, two inches wide, 1 inch deep, order some beavers, and quietly correct the problem! Within two years you will have your watershed back.

Moderator Response:

[JH] This post violates multiple prohibitions contained in the Sks Commnts Policy including No sloganeering, No accusations of deception, and No profanity or inflammatory tone.

Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

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Ger at 23:10 PM on 29 October 2016

Climate change could push risk of ‘megadrought’ to 99% in American southwest

Sauerj@2: 'ringing' or Gibbs phenomenon: https://en.wikipedia.org/wiki/Gibbs_phenomenon. The result from a step function/pulse on a second (or higher) order system

sauerj at 20:06 PM on 29 October 2016

Climate change could push risk of ‘megadrought’ to 99% in American southwest

Nice comment. Curious, could you explain a bit more the concept of "ringing". That is one I haven't heard before. Thanks!

dred at 13:36 PM on 29 October 2016

So what's really happening in Antarctica?

How the ice age commencing ~3 million years ago may have been caused (several angles follow:)

a) There are different hypothesis that have been tested in global cooling model simulation to check their potential importance in the glacial inception of the Northern Hemisphere. One of the major hypotheses is the closure of both the Indonesian (~3-5 Ma, Cane and Molnar, 2001) and Panama seaways (~3 Ma, Bartoli et al, 2005). The closure of the Panama isthmus, which began 13 Ma, was very slow. When the connection between the Pacific and the Atlantic Oceans closed, it intensified the thermohaline circulation in the Atlantic intensifying the heat transport from the equator toward high latitudes. Such hypotheses tested in GCMs circulation show that, even if a larger heat export could bring more precipitation and lead to the built of an ice sheet, the difference in ice sheet volume accumulated between an “open” or “closed” isthmus is small (Klocker et al., 2005; Lunt et al., 2008). On the contrary, the closure of the Indonesian seaway stopped the warm waters from the South Pacific from flowing into the Indian Ocean. This increased the amount of the North Pacific cold waters involved in circulation into the Indian Ocean and thus reduced the heat transport from the tropics toward the higher latitudes, finally triggering a global cooling (Cane and Molnar, 2001). http://www.climatescienceandpolicy.eu/2011/01/the-three-million-years-ago-dilemma-the-beginning-of-the-ice-ages/

……………………………………..

b) The collision of India and southern Asia began between 50 million and 40 million years ago, during the Eocene Epoch, and continues today. The collision produced two main geologic results. First, it began to block the westward-flowing Tethys seaway near the Equator, a process completed with the junction of Africa and Asia near present-day Iran roughly 16 million to 14 million years ago. Second, the creation of the Himalayas and the Plateau of Tibet, which resulted from the collision, altered global climates by changing patterns of weathering (and thus the transfer rate of carbon to the atmosphere) as well as wind circulation. India’s collision with southern Asia also altered patterns of oceanic productivity by increasing erosion and thus nutrient runoff to the Indian Ocean.

Principal Cenozoic faunal migration routes and barriers.
Encyclopædia Britannica, Inc.
The present-day Mediterranean Sea is a geologically recent descendant of a portion of the Tethys seaway. About six million years ago, during the Messinian Age, the western remnant of the Tethys seaway was subject to a brief paroxysm, known as the Messinian salinity crisis, that lasted approximately 270,000 years and saw the entire basin virtually isolated from the wrld ocean. The basin experienced severe desiccation and the precipitation of vast deposits of evaporites (such as salt and gypsum) up to several kilometres in thickness. The Atlantic Ocean subsequently refilled the basin from the west at the beginning of the Zanclean Age. Geologic evidence suggests that water rushing through a channel cut near Gibraltar filled some 90 percent of the Mediterranean Sea within two years. Some scientists contend that sea levels may have risen 10 metres (about 33 feet) per day within the basin during the period of peak flow. The Mediterranean basin has undergone significant geologic evolution during the most recent five million years. About one million years ago this part of the Tethys was transformed into the Mediterranean Sea by the elevation of the Gibraltar sill. Consequently, the Mediterranean basin became isolated from deep oceanic bottom waters, and the present-day pattern of circulation developed. …

The Bering land bridge which united Siberia and Alaska served as a second connection between Eurasia and North America. This link seems to have been breached by the Arctic and Pacific oceans between five and seven million years ago, allowing the transit of cold water currents and marine faunas between the Pacific and Atlantic oceans. The Atlantic and Pacific were also linked by the Central American seaway in the area of present-day Costa Rica and Panama. This seaway, extant since the first half of the Cretaceous Period, prevented the interchange of terrestrial fauna between North and South America; however, for a brief interlude during the Paleocene, a land connection may have existed between North and South America across the volcanic archipelago of the Greater Antillean arc, and some scholars have argued that land bridges between the two continents may have existed for short periods during the Late Cretaceous and again during the late Miocene. The seaway was closed by the elevation of the Central American isthmus between 5.5 million and 3 million years ago. This event had two significant geologic results. … Second, the emergence of the isthmus deflected the westward-flowing North Equatorial Current toward the north and enhanced the northward-flowing Gulf Stream. This newly invigorated current carried warm, salty waters into high northern latitudes, which contributed to increased rates of evaporation over the oceans and greater precipitation over the region of eastern Canada and Greenland. This pattern eventually led to the formation and development of the polar ice cap in the Northern Hemisphere between 4 million and 2.5 million years ago. https://www.britannica.com/science/Tertiary-Period

………………………………………………..

More angles: ("Ice age" is differentiated from "periodic glaciation".)

c) For several million years the Earth has experienced regular galciations followed by shorter warmer periods roughly every 100,000 years. What causes this seemingly regular climate oscillation ? The textbook answer is that they are initiated by changes in the Earth’s orbit and axis tilt called Milankowitch cycles and are then enhanced by a CO2 feedback effect. However the details are complex. For the last 1 million years Ice ages have occurred more or less every 100,000 years which corresponds to the change in eccentricity of the Earth’s orbit around the sun. Looking at the detailed effects on changes to incident solar radiation we find:

1. A 41,000 year variation in the tilt of the Earth’s axis to the sun. This effects the severity of winters and summers during the year.

2. A 23,000 year precession of the same axis of rotation which changes the season within the year. 13,000 years ago Winter in the Northern hemispheer was in June.

3. A 100,000 year oscillaton in the elipticity of the Earth’s orbit around the sun. Most important is the change in elipticity of the Earth’s orbit which changes the distance from the Sun during the year. So when winter in the northern hemisheper corresponds to a large distince from the sun we can expect more severe cold winters. http://clivebest.com/blog/?p=2732

…….

antarctica: 40 million years ago to present

How Antarctica got its ice sheets–In the continual movement of Earth’s tectonic plates, Antarctica was severed from the southern tip of South America about 34 million years ago, creating the Drake Passage. Antarctica became completely surrounded by ocean. The powerful Antarctic Circumpolar Current began to sweep around the continent, isolating Antarctica from the warmth of the global oceans and provoking large-scale cooling. Illustration by Jack Cook. http://www.whoi.edu/services/communications/oceanusmag.050826/v42n2/haug-en1.html
…………

e) 3-22-04 How could the Gulf Stream–which transports not only moisture but also heat to the North Atlantic–lead to major Northern Hemisphere cooling and the formation of ice?
Neal Driscoll and Gerald Haug proposed one solution. They postulated that moisture carried northward by the Gulf Stream was transported by prevailing westerly winds to Eurasia. It fell as rain or snow, eventually depositing more fresh water into the Arctic Ocean–either directly, or via the great Siberian rivers that empty into the Arctic Ocean.

The added fresh water would have facilitated the formation of sea ice, which would reflect sunlight and heat back into space. It would also act as a barrier blocking heat stored in the ocean from escaping to the atmosphere above the Arctic. Both these phenomena would further cool the high latitudes. In addition, Arctic waters flowing back into the North Atlantic would have become less cold and salty–short-circuiting the efficiency of the Ocean Conveyor belt as a global heat pump to North Atlantic regions.

These preconditions–moisture plus an Arctic nucleus for cooling–would have made the climate system highly susceptible to ice sheet growth. Even modest changes in the global environment would have been sufficient to tip the scales and lead to the onset of major Northern Hemisphere glaciation.

Just such a change occurred between 3.1 and 2.5 million years ago, as Earth’s axis fluctuated so that the planet’s tilt toward the sun was less than today’s angle of 23.45 degrees. Less tilt to the Earth would have reduced the amount and intensity of solar radiation hitting the Northern Hemisphere, leading to colder summers and less melting of winter snows.

The onset of Northern Hemisphere glaciation also affected the Subarctic Pacific. It led to the formation about 2.7 million years ago of a freshwater lid at the surface of the ocean, called a halocline. This Arctic halocline would have created a barrier to upwelling, which blocked deep carbon-dioxide-rich deep waters from rising to the surface. The “leak” of heat-trapping carbon dioxide into the atmosphere was stemmed, further cooling the planet.

Many other ocean-atmosphere feedback mechanisms, resulting from the opening and closing of oceanic gateways, remain imperfectly understood. http://www.whoi.edu/services/communications/oceanusmag.050826/v42n2/haug.html

………..

f) Their case rests on temporal correlations between tectonic and climatic phenomena. Particularly impressive is the correlation at 50 Ma of the Indian–Asian collision and the consequent shutdown of what they call the “carbon factory” during the climate optimum, which is immediately followed by the temperature decline of the Middle and Late Eocene and the transition to a glacial state. Correlations do not necessarily imply causation, but they are strongly suggestive when linked in the manner that Kent and Muttoni (1) do. http://www.pnas.org/content/105/42/16061.full

………..

III. The mechanisms behind sudden climate transitions.

It is still unclear how the climate on a regional or even global scale can change as rapidly as present evidence suggests. It appears that the climate system is more delicately balanced than had previously been thought, linked by a cascade of powerful mechanisms that can amplify a small initial change into a much larger shift in temperature and aridity (e.g., Rind and Overpeck, 1993). At present, the thinking of climatologists tends to emphasize several key components:

III.1. North Atlantic circulation as a trigger or an amplifier in rapid climate changes.

The circulation of the north Atlantic Ocean probably plays a major role in either triggering or amplifying rapid climate changes in the historical and recent geological record (Broecker 1995, Keigwin et al., 1994, Jones et al., 1996; Rahmstorf et al., 1996).

II.2 Carbon dioxide and methane concentration as a feedback in sudden changes.

Analysis of bubbles in ice cores shows that at the peak of glacial phases, CO2 was about 30% lower than during interglacial conditions (e.g., Jouzel et al., 1993). We do not at present know whether the lower glacial CO2 levels were a cause or merely an effect of the ice ages.

III.3 Surface reflectivity (albedo) of ice, snow and vegetation.

The intensely white surface of sea ice and snow reflects back much of the sun’s heat, hence keeping the surface cool. Presently, about a third of the heat received from the sun is reflected back into space, and changes in this proportion thus have the potential to strongly influence global climate (e.g., Crowley and North, 1991). In general the ice cover on the sea, and the snow cover on the land, have the potential to set off rapid climate changes because they can either appear or disappear rapidly given the right circumstances.

III.4 Water vapour as a feedback in sudden changes.

Water vapour is a more important greenhouse gas than carbon dioxide, and as its atmospheric concentration can vary rapidly, it could have been a major trigger or amplifier in many sudden climate changes.

III.5. Dust and particulates as a feedback in sudden changes.

Particles of mineral dust, plus the aerosols formed from fires and from chemicals evaporating out of vegetation and the oceans, may also be a major feedback in co-ordinating and amplifying sudden large climate fluctuations.

III.6. Seasonal sunlight intensity as a background to sudden changes.

A major background factor in pacing climate switches on timescales of tens of thousands of years seems to have been the set of ‘Milankovitch’ rhythms in seasonal sunlight distribution or insolation (Imbrie and Imbrie, 1992; Imbrie et al., 1992, 1993). Although the insolation values change gradually over thousands of years, they may take the earth’s climate to a ‘break point’ at which other factors will begin to amplify change into a sudden transition. http://www.esd.ornl.gov/projects/qen/transit.html

…………

h) Last but certainly not least in this list of factors causing the last ice age is that the continent of Antarctica moved to its locale near the South Polar Axis, via continental plate drift.

8-27-09 According to calculations by geologist Professor Christopher Scotese of the University of Texas, Antarctica could
move significantly away from its current location and become at least partially ice-free again within the next 50 million years. http://www.sciencefocus.com/qa/antarctica-moving-away-south-pole

bjchip at 05:44 AM on 29 October 2016

Climate change could push risk of ‘megadrought’ to 99% in American southwest

It is often a point claimed by some who are uninterested in actually reasoning clearly, that thousands of years ago California and its environs experienced droughts that spanned centuries.

Their illogical point is that because the droughts before there was a CO2 issue the CO2 cannot be the cause of droughts.

That was in the period closest to the holocene optimum. It was then as warm as it is currently (though we have raised temperatures more suddenly).

It is, I always point out, utterly illogical to expect a different result from the same temperatures. We are returning (briefly, as it appears we are merely passing through them on the way to something much warmer) to the conditions of the climate optimum.

There are two questions only. The first one is how high will it finally go, as it is clear that we're aimed for something significantly in excess of anything our civilization evolved in.

The second is the effect of the rate of change. It is a complex system and we hit it with a step function change of input. Will it "Ring"? What would ringing look like?

Keep up the good work.

curiousd at 15:38 PM on 28 October 2016

Welcome to Skeptical Science

Thank you Tom,

Attempting to contact Chris Colose.

Curiousd

Rob Honeycutt at 13:28 PM on 28 October 2016

Tracking the 2°C Limit - September 2016

It's a little challenging to get statistical significance with 10 years of data. The point is, the trend over the past decade is running warmer than the long term trend.

denisaf... This is an ongoing series I've been doing posting this chart showing where we are relative to the 2C limit. And no, the 2C limit dates back to the original UNFCCC in Rio and that doesn't state "2C by 2100." The idea is that we need to limit global temperature to 2C, period. And now there are even more aggressive proposals to limit warming to 1.5C.

Harry Twinotter at 13:20 PM on 28 October 2016

Tracking the 2°C Limit - September 2016

It is clear the data shows that there is a good chance the decadal warming trend is accelarating. But the trend is only borderline statistically significant, to 2-sigma anyway? That is Steve L's point?

I am just playing contrarian here.

denisaf at 09:08 AM on 28 October 2016

Tracking the 2°C Limit - September 2016

Why calling it 'Tracking the 2 C Limit' when the discussion is about the various measures of the rising temperature. The 2 C Limit discussed at the Paris Conference is a hypothetical value when in actual fact the temperature will continue to rise although the rate trend will depend on how rapidly the global rate of greenhouse gas emissions decreases. The original referral was to '2 C by 2100' not to '2 C Limit'

bjchip at 08:03 AM on 28 October 2016

Global weirding with Katharine Hayhoe: Episode 2

http://qz.com/817354/scientists-have-been-forecasting-that-burning-fossil-fuels-will-cause-climate-change-as-early-as-1882/

Those darned Chinese have been trying to hoax us for a longgg time...

...or someone isn't competent to be a dog-catcher.

:-)

Moderator Response:

[PS] Fixed link and excess white space

ubrew12 at 01:30 AM on 28 October 2016

Global weirding with Katharine Hayhoe: Episode 2

Excellent video! I like the way she anticipates denier arguments and innoculates her listeners with the truth before the 'doubt is our product' crew can infect them. I just found out about Eunice Foote yesterday: amazing bit of history.

Tom Curtis at 15:50 PM on 27 October 2016

Welcome to Skeptical Science

curiousd @27 and 28, I am fairly sure the formula you are using is incorrect. Unfortunately I am not sure as to the correct formula. The HITRAN database gives S_ij and γ_air for each line, where S_ij and γ_air are illustrated by this diagram:

The values given are for a reference temperature of 296 K, and 1 atmosphere pressure. S varies based on temperature, and γ based on temperature and pressure. As a result both Pierrehumbert in Principles of Planetary Climate (PoPC) and HITRAN give formulas for making the appropriate adjustment. For adjusting γ you use PoPC formula 4.61 and HITRAN formula 6. For adjusting S you use PoPC formula 4.62 and HITRAN formula 4. At least, that is as best I understand it. However, these formulas differ, probably based on assumptions about the shape of absorption pattern (shaded area above), which is not strictly known. There is a brief discussion of this in PoPC pages 227 and 228.

The actual absorption coefficient in each spectral line is not determined by S alone, but by S and γ as per formula 4.63 (PoPC) and HITRAN formula 10.

Even if I have misunderstood this, I am certain your formula is incorrect in not taking account of doppler and pressure broadening, which I understand to be very important.

At this stage I am again going to recommend you consult somebody with significant experience with these formulas.

Rob Honeycutt at 14:33 PM on 27 October 2016

Tracking the 2°C Limit - September 2016

Tom, My sense of the TLT data is that it's sort of a worst of all worlds. While you're right, it is probably the satellite product most similar to the surface data, the channel still peaks well above the surface, plus is measuring a significant portion of the upper troposphere.

It seems to me it's probably better to look at satellite data and surface data as apples and oranges, and use them to communicate the different aspects of the climate system each is measuring. And for that, TTT is probably the superior channel over TMT or TLT.

Rob Honeycutt at 14:15 PM on 27 October 2016

Tracking the 2°C Limit - September 2016

Fixed. Thanks for pointing that out, Bob.

Rob Honeycutt at 14:05 PM on 27 October 2016

Tracking the 2°C Limit - September 2016

I suspect you're right, Bob. Not sure what I did there.

Will do an update. Thx!

Bob Tisdale at 09:08 AM on 27 October 2016

Tracking the 2°C Limit - September 2016

Hi Rob. You may want to check your decadal trends. Based on the raw GISS LOTI, HADCRUT4 and Berkeley Earth (land+ocean) data, they appear to be too high for the last 120 months. As determined by EXCEL, for the past 120 months of data, the raw data present the trends of:

0.312 deg C/decade for Berkeley

0.314 deg C/decade for GISS

0.306 deg C/decade for HADCRUT4

I suspect you're presenting 9-year (108-month) trends.

Cheers

curiousd at 08:47 AM on 27 October 2016

Welcome to Skeptical Science

I believe I am correct with the above expression for SMASS, but that somehow the data published in Fig. 4.7 of P-H is as if it were at higher resolution than what I get from the Spectral Calc version of HITRAN. Except for the sharp fundamental around 670 wn, the other features I get agree with P-H pretty well, agreement which yields a check on my expression for SMASS.

A few years back, someone on this site told me how to make graphs and publish them cheaply or maybe free with an associated URL. There is some website that does this. Could someone remind me how this works?

Tom Curtis at 06:44 AM on 27 October 2016

Tracking the 2°C Limit - September 2016

While the RSS TTT may be more representative of the troposphere as a whole, the TLT channel remains the best (though far from perfect) comparison with surface temperatures. Unfortunately it has not been updated in line with the new method for determining the TMT (from which it is derived).

Dcrickett at 06:27 AM on 27 October 2016

'The atmosphere is being radicalized' by climate change

I do not agree 100% with the essay or any of the comments. I loved them all; this is a necessary conversation. Thanks, everybody!

scaddenp at 06:19 AM on 27 October 2016

The True Cost of Coal Power

If you are using up a finite resource, then you dont have "sustainable farming" without using a definition of "sustainable" that would differ a long way from any conventional usage. Why is solar not an option? What part of the world is this?

LaughingMan at 05:53 AM on 27 October 2016

The True Cost of Coal Power

Now that this is real, the co op rural movement is where I'm at. Sustainable farming is the name of the game. How do we power a sustainable farming indoor vertical growing system? We have no coal power come next month. Our only means of power generation is oil, natural gas, and gasoline. Air power and solar are not options. We don't have hydrogen systems and the Nitinol engine doesn't exist here yet. We have no rivers so to speak, and no alternatives that will provide the megawatts we need for our communities. I'm tempted to go back to coal or using biomass burnable products that are comparable. Anyone have a suggestion? Oil is abundant. We can burn crude oil by the thousands of barrels and not put a ding into production one bit.

Thanks!

Laughing Man

Steve L at 03:32 AM on 27 October 2016

Tracking the 2°C Limit - September 2016

La Niña comment is out of date. Good for you for printing the error along with your 2 sigma errors along with the midpoint trend estimate. By this you can see that the RSS trend isn't statistically different from zero. Some of the others aren't highly significant and may become insignificant with 11 years of data (depending on the strength of the coming La Niña).

Glenn Tamblyn at 20:35 PM on 26 October 2016

'The atmosphere is being radicalized' by climate change

denisaf

"They cannot provide the liquid fuels required by most forms of transport. "

Where liquid fuels are not required:

Electric cars can currently meet daily commuting type range, which is the vast majority of personal car usage.
Electric trucks, buses etc can similarly do daily delivery range tasks now.
Electric heavy gauge rail does not need liquid fuels.
Light Rail/Trams can currently operate electrically and do not need liquid fuels.
Similarly, electric trolley buses are common in Eastern Europe - no liquid fuel required.
Stand-alone electric buses that us inductive or overhead charging at stops are being trialled in Europe - no liquid fuels.
Short range aviation with batteries is possible.

Where liquid fuel might be required:

Longer range aviation. Hard to see an alternative.
Shipping. Solar and wind can contribute to reducing the energy demands of a ship, but unlikely to supply more than a modest fraction
Long distance personal car use. Battery recharge en route can meet this need but requires longer 'recharge stops'. Liquid fuels only needed if we want fast turn-around time at 'refueling stops'
Long distance road transport. Similar. Time vs convenience/cost trade off.

So aviation and shipping need something like liquid fuels Long distance land trasnport only needs it if we value time more highly than other factors.

So if we are willing to wear longer long distance land journeys, we only need liquid (or compressed gas) fuels for aviation and shipping. And we can source those from renewables via electrolosys, chemical synthesis, biofuels etc.

nigelj at 10:36 AM on 26 October 2016

'The atmosphere is being radicalized' by climate change

I just think radicalising the atmosphere is a bit sensationalist. Maybe restructuring the atmosphere has the right sound. And we all know how restructuring ends, not always very well.

nigelj at 10:32 AM on 26 October 2016

'The atmosphere is being radicalized' by climate change

Michael Sweet @5, as you say in about 100 years oil will be used up. This is one of the things that persuades me that we might as well go ahead with alternative energy, because we will run out of oil eventually. Climate change is sort of a trigger that has come unexpectedly. Its not a major factor that persuades me, but all these things do add up.

If by some miracle global warming is not as bad as predicted (just to be clear I think we have a big problem), the oil will always be in the ground if we need it. Our options will always be open, in terms of energy sources. But if we warm the climate, that will be a one way trip, and very hard to reverse.

However new technologies like renewable energy are dropping in price and becoming attractive on an economic basis, regardless of the global warming issue. And another thing with new technology: it often has numerous unpredictable advantages and uses. Witness how microprocessors have revolutionised phones. When contemplating choices relating to climate change, it pays to factor in all the potential benefits from new technology, because its highly probable there will be many.

I find the argument that electricity can’t resolve all transport problems rather frustrating. It can reduce a huge percentage of fossil fuel reliance. Surely that's what counts.

Aircraft emissions are more challenging, but can be offset by growing forests or some other non- carbon based fuel source could be used like ammonia, or some completely new form of fuel.

Tom Curtis at 09:40 AM on 26 October 2016

Global warming continues; 2016 will be the hottest year ever recorded

Digby Scorgie @11, yes - and thanks for the catch.

Tom Curtis at 09:39 AM on 26 October 2016

'The atmosphere is being radicalized' by climate change

denisaf @3, solar systems and wind farms can straight forwardly provide hydrogen as a fuel through electrolysis. More importantly, there are a variety of methods to convert CO2 into useful fuels, including:

CO2 to Jet Fuel (Electricity)

CO2 to Methanol (Heat)

CO2 to Ethanol (Electricity)

CO2 to Methane (Sunlight)

CO2 to Jet Fuel (Sunlight)

CO2 to diesel (Biological)

The first three can be driven by solar systems and wind farms; while the hydrogen (from electrolysis) is a key ingredient in some of the others. None of these methods is commercial yet, but there is every reason to think at least some of them will be. The first process (or a similar more efficient process) is currently planned to by the US Navy as a future supplier of jet fuel for naval operations, with electricity drawn from nuclear reactors in air craft carriers, so we can expect that process to be developed to a commercial stage. In addition, Space X is planning to use solar power plus CO2 to generate fuel at Mars for return trips in its projected Mars program.

In short, while renewable energy is only capable of supplying 100% of land, stationary energy (including for electric trains, and recharging batteries for electric cars) with todays technology, it is not constrained to that role by physics, but by current, and temporary technological limits.

Digby Scorgie at 09:35 AM on 26 October 2016

Global warming continues; 2016 will be the hottest year ever recorded

Tom Curtis @10

In your item (b) don't you mean 2038, not 1938?

michael sweet at 09:32 AM on 26 October 2016

'The atmosphere is being radicalized' by climate change

Denisaf,

Jacobson 2015 shows that renewable energy can supply 100% of all power. Jacobson won the 2015 Cozzarelli Prize from the National Academy of Science for best paper in the PNAS for this work.

Your wild, unsupported claim that renewable energy cannot supply all energy is simply false. The comments policy requires links to peer reviewed data that supports your claims. Please provide links to support your wild claim that renewable energy cannot provide all power.

In 100 years fossil fuels will run out if we do not stop using them today. What do you expect to take their place when cheap liquid fuels are no longer available? Why can't we build out WWS as Jacobson describes now, instead of waiting for fossil fuels to run out. Already coal is becoming uneconomic in competition with wind and solar. Your argument does not withstand the most basic evaluation.

RedBaron at 08:38 AM on 26 October 2016

'The atmosphere is being radicalized' by climate change

@3 denisaf,

Actually I believe a lot of transportation can be replaced by stored electric vehicles. However your point is well taken. Probably not all. That's why I have posted multiple times on various threads here that a 3 pronged approach is probably best. Here and here are a couple examples.

denisaf at 07:05 AM on 26 October 2016

'The atmosphere is being radicalized' by climate change

Solar systems and wind farms use weak enegy income to intermttedly provide some electricity during their limited life times. They cannot provide the liquid fuels required by most forms of transport. These are facts that determine 'renewable' energy systems can only fill a niche role in the operation of industrialized civilization, despite the views of many people who do not understand that physical reality.

Cooper13 at 04:17 AM on 26 October 2016

'The atmosphere is being radicalized' by climate change

I realize this gets 'off topic' from the typical climate discussions, however, I think it's important to identify also the perspectives that climate change and potential mitigations (e.g. renewable energy) will have in other areas - two in particular.

1. Energy (fossil fuels) and terrorism money - the US absolutely has the potential to produce all its energy needs from wind and solar. It is an infrastructure and cost issue, not a 'capability' issue.

Doing so (and other world nations following suit) means fossil fuels lose value - rapidly (stranded assets). This means entities such as Saudi Arabia, Iran, Russia, etc. are all at risk of losing their primary sources of national revenues - it also means that none of the money spent on fossil fuels purchased from these nations can be filtered into radical religous sects or terrorist groups. Mitigating climate change won't "solve" terrorism, but one aspect of it (shifting away from oil resources) may certainly alter whether these radical groups can get any funding, and where that funding will come from.

2. U.S. 'green energy' and trade - we have a massive trade deficit in the US, because we import from areas where labor costs are cheap, and fossil fuels used to ship those products globally are 'cheap'.

If 'renewable energy' were tied to international trade costs (e.g. 'true' costs of fuels for shipping; carbon 'tariffs' or taxes on products produced using fossil fuels), and the US develops a 'green' energy grid, you immediately gain better cost-competitiveness for things 'made in USA' (or made locally or anywhere they are produced and shipped using carbon-free energy).

The entities that have large infrastructure investements in maintaining the status quo (fossil fuel producers/nations; companies and nations with factories and 'on the ground' investments where labor is cheap) stand to lose out with a carbon tax or any form of trade tariffs on products made with carbon-based energy. It's not only the "Exxons" of the world.

Climate change, as temperatures continue to rise, is going to be disruptive.

Upsetting the 'norm' of a worldwide economy and worldwide infrastructure that's been designed to run off carbon based energy for over a century, is also going to be disruptive.

The real challenge we have as a society is figuring out which political leaders can craft transitional laws and framework to minimize the economic disruptions as we shift away from fossil fuels, and recognizing the benefits and opportunities that will be available and really helping some of these heavily 'carbon-energy embedded' companies and entities to benefit from the new 'rules', rather than making them out as 'the enemy' and as 'those who will lose out'. When these entities believe they will lose out, they are going to dig in their heels, and continue to fund climate-denial groups to maintain their status-quo revenue streams for as long as possible.

curiousd at 02:30 AM on 26 October 2016

Welcome to Skeptical Science

I want to back off to something more basic, and if this also is considered too technical for Skeptical Science than I would feel better about contacting someone like Gavin Schmidt. What is the formula that relates the HITRAN tabulated cross section I will call STAB to the corresponding mass absorption coefficient I call SMASS? Here is how I do this.

1. multiply STAB (cm²/molecule) by 10^-4 m²/cm²to give STAB in m²/molecule.

2. PV = NkT where k is Boltzmann's constant. And so N/V = P/kT.

Then multiply equation 1 by P/kT so that (m²/molecule) x (molecules/m³⁾

gives SLIN, the linear absorption coefficient in reciprocal meters.

3. Now one has SLIN = STAB x 10^-4 x P/kT ; units m^-1

4. One now needs SMASS = SLIN/mass density of atmosphere

5. PV = nRT where n is the gas constant and n is the number of moles per cubic meter. I next divide by n/V = P/RT to obtain

6. STAB x 10^-4x (P/kT)/(P/RT); the Ps and Ts cancel to yield

7. STAB x 10^-4(R/k) x (1/n) where n is the number of moles per cubic meter.

8. The mass of gas per mole is 0.029 kg.

Then n (moles/cubic meter) x 0.029 (kg/ mole) = kg / cubic meter

9. SMASS = STAB x 10^-4 x (R/k) x (1/0.029) (m² / kg)

The most intense line in the CO₂ bending mode part of the IR spectrum is close to

STAB = 3 x 10^-19 cm²/ molecule. Inserted into equation 9 above I get something between 600 and 700 m² / kg. I think this may be somewhat too small looking at Fig. 4.12 in Pierrehumbert.

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