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gallopingcamel at 14:12 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
scaddemp (#56), TOPEX is providing really accurate measurements. Currently the rate of sea level rise is averaging ~3.2 +/- 0.4 mm/year. The rate of rise is not showing any kind of "Hockey Stick" tendency that should be evident if sea levels are to rise by 1,900 mm (AR4 worst case) in the next 90 years (21 mm/year). -
scaddenp at 14:11 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
Climate is not single-variable. Try the extremely strong correlation between temperature and all forcings. eg Benestad & Schmidt for an example of a statistical approach but the models are even better. The science has worked hard to estimate the size of all feedbacks and so far any globe-saving negative forcing has been extremely illusive. John Cook's summary on why GHG is the dominant forcing acting now is mighty good summary. If you have data to dispute this, then please post and continue the argument in the relevant place. So far this is a long way from your opening gambit that greenland's melting ice is a good thing. -
johnd at 13:49 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
Phila at 12:05 PM, if anyone does follow up with a post perhaps they could illustrate it by using the Global Land Index, figure 2 above, with the base period set as 1880-1890. I don't know what period is used at present, I'm guessing 1960-70 as that was used for figure 3. A graphic illustration should be easier to demonstrate what difference, if any, different base periods make. -
gallopingcamel at 13:45 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
scaddenp (#54), The world is in an "Ice Age" as we still have polar ice caps. Currently we are fortunate to be experiencing an "Interglacial" period characterised by relatively high temperatures. Over millennia, sustained high temperatures cause ice to melt and oceans to rise. Hopefully we are in agreement up to this point. When you say that we are causing temperatures to rise by generating GHGs I still agree with you. When it comes to quantifying humanity's contribution to the undeniable "Global Warming" that has occurred since 1850 we may diverge. While basic physics can show that a doubling of CO2 concentration should increase global temperatures by ~1.2 degrees Celsius, there is the question of feedback. Do other natural processes increase or diminish the effect of radiative forcing? Given the poor correlation of global temperature with CO2 concentration I consider it likely that natural effects are overwhelming the "Anthropogenic" influence. -
scaddenp at 13:11 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
"Mother nature" is a very confusing term. Global sealevel responds to changes in temperature. I dont think you can postulate any other causes on time scale of million years or so. Do you seriously contest that temperature is NOT the cause of global sealevel temperatures? Since we are causing temperatures to rise thanks mainly to our GHG emissions, then of course we are influencing sea level. -
gallopingcamel at 13:03 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
Phila (#45), I can't prove that it is "impossible" to influence the rate of rise of sea levels. To the contrary, Mother Nature does it all the time, proving that it is possible. Can mankind control sea levels? I don't believe we can but I am open to persuasion if you can explain how to do it. -
gallopingcamel at 12:54 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
The Ville, (#40), As you say, the consequences of rising sea levels will be "huge". I got a feel for this issue while living in Rotterdam on a street 7 meters below mean sea level. Today I live in Florida, less than 5 meters above mean sea level. At the present rate it will take 1,000 years for the seas to rise 3 meters. If that rise happens, our distant ancestors will have plenty of time to move to higher ground.Response: The key point is that sea level will not remain at the current rate - ice sheet melt is accelerating and past history tells us the ice sheets are very sensitive to sustained warmer temperatures. The latest peer-review analyses of future sea level rise, using various independent methods, predict sea level rise of 1 to 2 metres by 2100 (and don't forget that sea level rise will continue after 2100). -
nautilus_mr at 12:36 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
Further to that topic, when I first got into the climate change issue, one of the things I initially found confusing was the term "temperature anomaly". Anthony Watts' site was one of the first that I read, which undoubtedly added to my confusion. For about the first 6 months, I was deeply skeptical about the temperature record. My background is in biology and philosophy of science, but I had to work very hard to grasp statistical principles. Once I got my head around the issues, I realised the whole approach of Watts et al is confused. The issue isn't whether a given weather station is close to buildings, while another one is in a forest. Obviously the first will be affected by urban heat production. What matters is whether the temperature trends differ widely, or indeed whether there is no trend at all. When the trend is similiar across a wide variety of stations, then there is clearly a general influence that is greater than the local, variable influences. You must explain the data, and the urban heat island effect just doesn't do it. That realisation was one of the first major steps for me in satisfying my skepticism. Watts' famous photos of weather stations are total red herrings. And let's think about this - if the actual trends in weather station data were chaotic, the skeptics would have been all over it like a rash. He really is dumbing down the debate. I suspect the use of temperature anomalies is actually inherently conservative, because it compares the current year's temperature to the average of the last century. As real temperatures increase, the average must increase slightly, thereby modestly reducing the difference between the two. I remember reading a study showing that, if we separate out the rural and urban weather stations, the rate of temperature change is almost identical. I don't have the article saved -perhaps somebody can help with a link..?Response: How urban heat island has little effect on temperature trends is examined in Does Urban Heat Island effect add to the global warming trend? -
gallopingcamel at 12:34 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
Since debating this subject with Ned on another thread I posted a response relating to the station drop off problem in the Canadian Arctic: http://www.skepticalscience.com/news.php?p=2&t=81&&n=164 The above post is based on correspondence with Environment Canada and NOAA/NCDC that demonstrates John Cook made an incorrect statement at the head of this thread when he said: "The physical number of weather stations that are reporting temperature data has diminished......" There are 37 stations to GCN/WMO standards reporting in the Canadian Arctic. The data from all of them is available to the NCDC but only Eureka appears consistently in GHCN v2. I still don't know why the number of stations in the Canadian Arctic has fallen dramatically so I am planning a trip to NCDC in Asheville next month. If I learn anything I will let y'all know. If you still think that a very thin data set does not affect published results take a look at what happened on July 13, 2009 and March 29, 2010 (thank you, Berenyi Peter): [LINK] A temperature anomaly of 4 degrees Celsius for March 2010 should raise a few eyebrows!
Moderator Response:[DB] Shortened link breaking page formatting.
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Phila at 12:05 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
#13 "Why is it that so many people simply don't understand what temperature anomalies are?" I suspect it's simply because so many people aren't used to them. They have a certain commonsense expectation of how temperatures should be measured; when actual scientific practice doesn't match that expectation, some people will get confused, and others will conclude that there's something underhanded going on. I don't think it's too late to do anything about it, though. Perhaps there could be a post on it here (or on arguments that exploit this misunderstanding). -
Jeff Freymueller at 10:59 AM on 29 April 2010Why are there fewer weather stations and what's the effect?
Why is it that so many people simply don't understand what temperature anomalies are? Is it something about the name? too late to do anything about it now, I suspect, but misconceptions abound. -
Tom Dayton at 09:20 AM on 29 April 2010Why are there fewer weather stations and what's the effect?
johnd, it doesn't matter what the base period is when you're interested in the trend in anomalies from the base period--the change in the anomalies over time. That's not an assumption, it's a mathematical fact. You can demonstrate it yourself, simply by adding or subtracting any number from all the anomalies and observing that the shape of the line over time is unchanged. The line merely moves up or down. -
johnd at 08:49 AM on 29 April 2010Why are there fewer weather stations and what's the effect?
HumanityRules at 19:25 PM, regarding your comments about the correlation from the 50's onwards. One of the problems? advantages? of plotting anomalies against one another is that they will naturally show good correlation at around the time of the base period selected. The base period is not shown on the graphs used here, it should be. A bit of digging indicates that a base period of 1960-1970 was used by one of the other analysis referenced, I haven't determined what base period was used by the others. First one has to assume that the same base period was used for both anomalies on each chart. Secondly one has to wonder why that particular period was selected. It is not the mid point of the time span. It however is the mid point of the post WW2 global cooling period. Would that be significant? Why not choose a period during the rapid warming pre WW2, or at the beginning of the time span. If that was done, then correlation would have been shown as best early on and getting worse as time progressed. Lastly, the use of anomalies against one another gives the impression that the raw data matches closely. However the two sets of data could shown differences of say 10 degrees, and the anomalies would still appear interwoven. -
kdkd at 07:50 AM on 29 April 2010Tracking the energy from global warming
Ken, You've hit the nail on the head there (unable to draw strong conclusions). You're right, we can't draw strong conclusions from the OHC/TOA data at this point, for all of the reasons mentioned previously. However there is a vast wealth of other data available that shows us the nature of the problem and it's magnitude. One small divergence of data and theory based on too little data does not a paradigm shifter make. -
scaddenp at 07:17 AM on 29 April 2010A visual depiction of how much ice Greenland is losing
"The sea levels are going to do whatever Mother Nature wants them to do and we need to stop whining about it. " Um, why do you think sea level rises? Mother Nature suddenly makes more water? There is nothing we can do about tectonic subsidence but this is local. However, sea level rises or falls globally in response to temperature change. Do you seriously dispute that there is no credible scientific evidence to support this? And we surely can change the main forcing in temperature change (GHGs). And are you still insisting that no rate of change in temperature is not dangerous? -
Phila at 07:12 AM on 29 April 2010A visual depiction of how much ice Greenland is losing
#45 "At the risk of upsetting some of you I consider that idea to be nonsense with no credible scientific basis." This would seem to be an example of argument by assertion. Presumably, if it's impossible that "mankind can influence the rate of rise of sea levels," there is some physical mechanism that makes it impossible. What might that mechanism be? -
Flowers blooming earlier now than any time in last 250 years
John, I added that article link under "It's not happening".Response: Much appreciated, thanks! The more peer-reviewed links we can include in the Global Warming Links directory, the more useful a resource it is. -
Riccardo at 05:47 AM on 29 April 2010Has Arctic sea ice returned to normal?
A few more points on sea ice and salinity. The layer below newly formed sea ice initially gets more saline but then tend to sink due to an increase in density. This contributes to the stratification of the Arctic Ocean. The solidification temperature of sea water decreases by about 0.28 °C for every 5 PSU increase in salinity.
Sea ice melting may play a role as a CO2 sink. When ice melts the resulting water is depleted in CO2 and then can absorb more of it from the atmosphere.
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Jacob Bock Axelsen at 05:31 AM on 29 April 2010Are we too stupid?
embb for individuals there is a higher authority, namely the state, that can punish defection and reward cooperation, Consider the fig tree/fig wasp symbiosis. If the female wasp invades an immature fig, the tree responds by cutting the fig off and thus both the fig and larvae perish. Tit-for-tat works because the defecting genes are purged and symbiosis is perpetuated. It was evolved thousands if not millions of years ago, and it does not involve an executive power. Taxes would not work if the state collected taxes only to avoid an uncertain catastrophe in 100 years Are there certain catastrophes? The tax would of course be used to further sustainable energy sources - immediate payoff in terms of environment and security. Your descendants will certainly appreciate it as it is evolutionary favourable. Examples would be the chemotaxis behavior of E. Coli or the sporulation of B. Subtilis both involving benefits only to future generations. Both mechanisms are extremely simple, stunningly robust and have been evolved millions of years ago. What I have are doubts. I am in this discussion to clear them You still have doubts, in spite of my reference to the fact that clever taxation and regulation have lead californian power plant companies to ask users to minimize their consumption? Please do not take offense, but your incapacity to quench these specific doubts seems suspicious and fits perfectly into Kingsley Davis' definition of someone who wish to obstruct reforms (from Hardin, 1968): "(...) worshippers of the status quo sometimes imply that no reform is possible without unanimous agreement, an implication contrary to historical fact. Hardin continues: (...) automatic rejection of proposed reforms is based on one of two unconscious assumptions: (i) that the status quo is perfect; or (ii) that the choice we face is between reform and no action; if the proposed reform is imperfect, we presumably should take no action at all, while we wait for a perfect proposal." So I ask, do you have any interest in maintaining status quo? If not, what is the best way to get states, individuals, companies etc. to cooperate about mitigating climate change? Please, do not be modest and claim that you cannot imagine it. -
CBDunkerson at 04:41 AM on 29 April 2010Has Arctic sea ice returned to normal?
Mike_Allen, sea ice is 'fresh water'... the salt is forced out during the freezing process. Thus, the melting of large amounts of sea ice can decrease the overall salinity of the underlying ocean water. I know cold water acidifies more quickly / to higher concentrations than warm water, but not how that impacts freezing point. -
chris at 03:12 AM on 29 April 2010Tracking the energy from global warming
Ken Lambert at 23:23 PM on 28 April, 2010 re your comment:If you can't draw strong conclusions against climate change based on warming from CO2GHG from *this* data, then neither can you draw strong conclusions *for* it
Well yes Ken, but I don't think anyone is drawing "strong conclusions" for climate change from this small snippet of temporal evolution of the climate system. I'm sure people here are very interested in what it might mean in detail. No doubt in a few years we'll be somewhat better informed about the apparent misaccounting of the Earth's energy budget; we may well know whether it's real or an artefact of measurement problems.... ... and of course "Strong conclusions about climate change" follow from the vast wealth of scientific knowledge and empirical observations, and a recognition of the nature of unceretainties. -
chris at 03:00 AM on 29 April 2010Tracking the energy from global warming
Ken Lambert at 22:21 PM on 28 April, 2010 We're probably geting into the "arguing fruitlessly" stage, which often an indication that the data under discussion is inconclusive (not surprising when assessing temporal evolution of observables with large inherent stochastic short term variability and relatively large measurement error bounds). I'll just make two points: (i) numerology. Of course the first law of thermodynamics is obeyed (a "scientific fact"!). The "numerology" relates to playing with tentative numbers as if they were perfect representations of the phenomena of interest and then drawing incorrect conclusions. We've been here so often before (e.g. with apparently solid evidence that the troposphere wasn't warming c/o Spencer/Christy; that the troposphere would dry as atmospheric [CO2] increased c/o Lindzen...). It's usually best to lay off making profound conclusions (e.g. Peter's "the climate system is not gaining energy, but losing it") until the measurements are solid, or if one feels compelled to look at the numbers, to do so with a recognition of the uncertainties. (ii) Your comments re Topex/Jason sea level measurements are apposite. I'm clearly looking at the graph (my post 76 above) with different eyes than you!. If the 60 day smoothed delta mean sea level (MSL) was around 5 mm in 2002 and looks likely to cross the 2010 line at a delta MSL near 25-30 mm at 2010, then it's difficult to argue that sea levels haven't risen during the last 8 years. Overall they've continued to rise something like (30-5)/8 mm.yr-1; i.e. around 3 mm.yr-1. That's really difficult to square with Peter's conclusion. If Peter was right we'd have to assume that the rise was solely due to the mass component (melting ice); however we are pretty certain that's not true. Somethng is wrong with Peter's argument, beautiful numbers notwithstanding. Incidentally, the sea level rise did seem to flatten for a while ( from around 2006ish to 2008ish). That's interesting, yes? Does it, as Peter infers "bring havoc to standard greenhouse theory"? Not really.. and it would be surprising if the solar cycle down-turn and extended solar minimum didn't have some effect in reducing the rate of increase of thermal energy into the climate system. -
Where is global warming going?
suibhne, did you read my reply on G&T on the "Is CO2 a pollutant?" thread? You did not respond there. I took the time to read their article thoroughly, which was... rather painful. G&T display an appalling lack of understanding of the physics of thermodynamics, particularly radiative equilibrium - a concept dating to 1791, well understood and acknowledged as a scientific consensus. The core of their paper uses a strawman argument conflating convection blocking greenhouse effects with radiative greenhouse effects (not true, demonstrable in any freshman thermodynamics class), and from that stating that since they are not the same thing, radiative greenhousing doesn't exist. That's a pure logical fallacy. They make (by my estimate) ~2 errors, logical fallacies, or outright physics howlers (I'll refrain from labeling them lies, but it's hard to understand how such basics are misunderstood) per page. I'll enjoy further comments from people with better physics skills than mine, but IMO G&T isn't worth the paper it's written upon. I put some references to radiative equilibrium in my previous post (linked above) - I would strongly recommend them, as they're important elements of what we disagreed upon in the CO2 thread. -
Flowers blooming earlier now than any time in last 250 years
An article on Washington DC seasonal creep is described in Abu-asab et al, where they studied 100 species; 89 bloomed earlier over the recorded period (1970-1999), 11 bloomed later, with cherries blossoming 6 and 7 days earlier in '99 than in '70. They also provide precipitation data, with no significant correlation found between precipitation trends and first-flowering dates. They do point out that increasing CO2 levels might have an effect, and do not have an explanation for the 11 species that bloom later - but the earlier bloom dates correlate closely with the temperature changes. -
Chris G at 01:36 AM on 29 April 2010A visual depiction of how much ice Greenland is losing
#39 gallopingcamel, "For the last 2,000 years sea levels have been rising by less than 0.3 meters/century. " Yes, substantially less than 0.3 m/century. Over the last 2,000 years, up until recently, there has been negligible change. Over 20 centuries, anything close to that rate would have caused approximately 6 meters of rise. That hasn't happened. Here is a summary http://commons.wikimedia.org/wiki/File:Holocene_Sea_Level.png -
JulianRGP at 01:09 AM on 29 April 2010Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
The "Post a Comment" box does not appear for the most recent post which is "Why are there fewer weather stations and what's the effect?" I'm logged in OK and obviously the Post a Comment box appears in this article otherwise I would unable to post this comment! Can someone check/fix it? Thanks!!Response: Now fixed. The last comment had some dodgy HTML. -
Chris G at 00:36 AM on 29 April 2010A visual depiction of how much ice Greenland is losing
@#34, I really like the river and lake comparisons. The cubic volume that John has in nice, but the numbers are too large to get a good feel for. However, I think your math is a little off. I get Mississippi 12,743 m^3/s = 0.000012743 km^3/s *60 // minute *60 // hour *24 // day *365.25 // year = 402 km^3/year // 1 Gton ~= km^3 water, neglecting temperature and sediments Flow rate from http://en.wikipedia.org/wiki/Mississippi_River, which is derived from USGS measurements. So, to keep things simple, the net loss of water (ice flow + melt) off of Greenland is about 3/4 of the Mississippi river at present. If the two measurements above are directly comparable, that means that the flow increased from 1/3 of a Mississippi to 3/4 in a 6 year span. Wow. -
Paul D at 00:14 AM on 29 April 2010A visual depiction of how much ice Greenland is losing
Gallopingcamel said: "Your "rate" argument is nonsense. At the end of the last Ice Age, sea levels rose at an average rate of more than 1.2 meters/century. About 7,000 years ago the rates started to fall. For the last 2,000 years sea levels have been rising by less than 0.3 meters/century. There is no big mystery about this. The main continental ice sheets melted long ago and all we have left is the Antarctic, Greenland and relatively few glaciers." OK by your own figures and checking some others seas rose about 110 metres between the last ice age and 7000 years ago. Not surprising. Humankind was mobile and used to a harsh life, plus the human population was tiny by comparison with today. No major static cities or other developments. eg. Sea levels rising 1.2 metres per century wasn't a big deal for the population at the time, especially if populations had to deal withj much more severe problems. However Now is not the past. Most populations today live in static locations and invest a lot of time and effort building infrastructures that they expect to be preserved for many centuries. Hence the consequences of the remaining ice melting is huge and you are underestimating the impacts. -
Paul D at 00:02 AM on 29 April 2010A visual depiction of how much ice Greenland is losing
Re: @45. There are a lot of reasons why land falls below or rises above sea levels over time. Most of which are red herrings when viewing the global perspective of what is going on. Some parts of the UK are now land locked where as in the past they were on the coast, other parts are underwater where as in the past they were above sea level. The reasons for changes are numerous, but it doesn't impact on the global picture of what is going on. More often than not they are simple diversions. -
gallopingcamel at 23:50 PM on 28 April 2010A visual depiction of how much ice Greenland is losing
Jeff Freymueller (#41), While I generally agree with what you say, it is worth noting that the remains of stone buildings have been found "beneath the waves" in many places, for example in the Mediterranean and Black seas. The submersion in some cases may have been caused by rising sea levels rather than seismic activity. The folks on this blog generally seem to believe that mankind can influence the rate of rise of sea levels. At the risk of upsetting some of you I consider that idea to be nonsense with no credible scientific basis. The sea levels are going to do whatever Mother Nature wants them to do and we need to stop whining about it. -
Ken Lambert at 23:23 PM on 28 April 2010Tracking the energy from global warming
kdkd #83 No it is not clear now. The starting point of John Cooks blog is the OHC graph and discussion of the 'missing heat' over the last 5-6 years. Your argument is that this whole discussion is worthless without longer timescales (up to 30 years) and more annual data. If you can't draw strong conclusions against climate change based on warming from CO2GHG from *this* data, then neither can you draw strong conclusions *for* it. -
kdkd at 22:58 PM on 28 April 2010Tracking the energy from global warming
Ken #82 Nobody is trying to dispute the first law of thermodynamics. However, it seems to be logically invalid to try to draw strong conclusions from the small amount of TOA/OHC data available. This is because the TOA/OHC data is only available for a small number of annual cycles, it represents measurements from a large, complex (and chaotic) system with an estimated measurement error or around 30%. So until either more data is available, and if possible the measurement error is reduced, it is not possible to reach strong conclusions about anthropogenic global warming from the OHC/TOA data. Is that clear now? -
nautilus_mr at 22:22 PM on 28 April 2010Why are there fewer weather stations and what's the effect?
Now..is this it? Kundzewicz paper If it is the paper to which you refer, I would be cautious about citing a slide show intended to accompany a lecture, without knowing how the speaker intended to use the information. In any case, the graphic on page 7 shows temperature, not the rate of temperature change (temperature anomaly). Naturally, we expect absolute temperatures to be higher in urban areas. Temperature anomaly measures the underlying trend in temperature, irrespective of the urban heat island effect. If urban power use were a significant climate forcing, the trend would differ from region to region, but it is precisely this trend that turns out to be quite homogeneous around the world. It actually doesn't even matter whether the density of stations varies from continent to continent, because the global trend is indicated quite uniformly. This can only be explained by a well mixed, general effect in the atmosphere - urban power consumption is not such a generalised effect, but CO2, which disperses very widely, is clearly the best explanation for the evidence. -
Ken Lambert at 22:21 PM on 28 April 2010Tracking the energy from global warming
Chris #80 Forcings in W/sq.m are both positive and negative energy fluxes (power) which when summed; produce a theorized imbalance. If you integrate the forcing 'imbalance' WRT time you get the total energy over that time period added to or subtracted from the earth - atmosphere - ocean system. First law of thermodynamics says that this energy (Joules) must show up somewhere in the system either by warmer or cooler land, atmosphere, water; or phase changes into ice, melting ice and evaporation or condensation of water. This is not 'numerology'; it is long established scientific fact. If we see flattening of temperatures over the last 5-6 years or more, then less energy is being added to the system or due to thermal lags, this reduction has already happened some tme ago. Tell us Chris how long these lags (response times) are? If you look at your sea level graph, the Topex data follow the 3.2mm/year slope until 2002, and the Jason data follow a lesser constant slope from 2002-10 or if you stop linearizing a non-linear system - a curve fit would show pronounced flattening from 2005 onward. This is real evidence that sea level rise has slowed or flattened, and being such a giant reservoir of heat energy, indicates a reduced or non-existent uptake of heat. When the observation goes against the theory of increase forcing imbalance and greater energy uptake, have a hard look at the theory as well as trying to bolster the observation with better data. -
nautilus_mr at 22:01 PM on 28 April 2010Why are there fewer weather stations and what's the effect?
re # 8, Would you kindly provide a link to the Kundzewicz paper please? -
Arkadiusz Semczyszak at 21:21 PM on 28 April 2010Why are there fewer weather stations and what's the effect?
re#7: Just compare the map on page 7, "Climate change and extreme events - the Central European perspective," Z. Kundzewicz (IPCC expert - COP 14, 2008) the population density of Europe; to accept - at least the possibility of existence - the European UHI (covering and villages) . The same is true in SE China, Japan, and other. Only in the U.S. there is a sufficient number of truly rural stations. Among other things, hence the temperature change in the U.S. differ greatly from those in Europe and worldwide. -
neilrieck at 20:58 PM on 28 April 2010The significance of past climate change
Good presentation but here is a much more straight-forward method when presenting to non-scientists. <<< Point #1 >>> The primary mover of Earth's overall climate is Milankovitch Cycles (the main one being changes in the orbital shape from circular to elliptical then back). http://en.wikipedia.org/wiki/Milankovitch_cycles When the orbit is circular like now, we experience interglacial periods which average 20,000 years in length. When elliptical, we experience glacial periods which average 100,000 years in length. This is verified by ice cores from Greenland (Century Station), Antarctica (Vostok Station), as well as deep sea cores from the Indian Ocean (Vema 28-238). <<< Point #2 >>> Effects from volcanoes, thermohaline circulation, atmospheric currents, storms systems, and feedbacks from greenhouse gases add or subtract from the Milankovitch cycles. <<< Point #3 >>> During the previous interglacials, warming always occurred first which then triggered the release of dissolved CO2 from the oceans. This caused the release of other greenhouse gases like methane and water vapor (to only name two) which the forces Earth's climate hotter. In our current interglacial which started 11,700 years ago, industrial humans released CO2 ahead of the main warming trend. So a run-away warming effect could be right around the corner. reference (see the second graphic): http://www.southwestclimatechange.org/climate/global/past-present <<< Point #4 >>> Heat doesn't always immediately increase temperature. By definition: one calorie of heat will raise the temperature of one cc of water by one degree Celsius. However 80 calories of heat are required to convert one cc of zero degree ice into zero degree water. Question: what happens when all the ice is melted? Answer: heat will begin to raise water temperature. http://en.wikipedia.org/wiki/Enthalpy_of_fusion 70% of the Earth's surface is water. When it is heated, atmospheric and ocean currents move this excess energy toward the poles. So why is the arctic melting much faster than the antarctic? Answer: The Arctic is mostly an ice structure at sea level where it is exposed to oceanic heat. The Antarctic is an ice covering over a continent with an average elevation of 2300 m (which is the largest of all contents). As everyone already knows, higher elevation means cooler temperature. But higher elevation also means less exposure to warm oceanic water. Most people already know that ice reflects 90% of incoming sunlight while water absorbs 90%. This albedo change (hysteresis) is another snap-action feedback. <<< Optional-Speculative Point 5 >>> Has Earth always been effected by glaciations this way? Scientists don't think so. Major changes to Earth's climate occurred after geological forces formed the Panama land bridge 3 million years ago (joining North America to South America). This blocked east-west ocean currents between the Pacific and Atlantic. Many believe that this triggered changes in Atlantic currents which caused warmer temperatures to be delivered to Europe. (London England is warmer than Labrador while Glasgow is warmer than Moscow). Since it now seems that ocean currents are more important than previously thought, we now need to wonder what will happen if climate change disrupts the thermohaline current or even the gulf stream. If this happened, global warming could actually cool Europe while melting Russia's Arctic (I'm sure Russians would think this a benefit) -
nautilus_mr at 20:42 PM on 28 April 2010Why are there fewer weather stations and what's the effect?
re#4: Is this the de Laat article to which you refer? (pdf version here- http://www.knmi.nl/~laatdej/EOS2008.pdf) I have to say it makes a pretty underwhelming argument, consisting of little more than innuendo. It makes no predictions in order to engage with data - but there are obvious predictions it should make: namely that if human energy consumption is a significant forcing of global temperature, we should observe the rate of warming to vary dramatically by region. As we all know -and as is spelled out elsewhere on this site, for example- the rate of warming is remarkably consistent across the globe. -
sleepership at 20:18 PM on 28 April 2010Flowers blooming earlier now than any time in last 250 years
Actually last winter we where a Zone 7- lowest temperature was 1 degrees in my north central/eastern Connecticut location. Boston & Providence where a few degrees warmer (Bostons low was actually 10 degrees-making it a borderline zone 8- and Providence at 6 degrees making it a solid zone 7. -
HumanityRules at 19:25 PM on 28 April 2010Why are there fewer weather stations and what's the effect?
John can you just clarify a few points. 1) Have the "dropped stations" stopped recording temperature or have they been dropped from the set of stations that go into the GHCN series? 2) Has the data from the "dropped stations" that was collected before they were dropped been dropped from the GHCN series? Just from the 3 graphs you show the looks to be good correlation from 1950's onwards but earlier decades look very different. Any thoughts why? -
JMurphy at 19:19 PM on 28 April 2010Why are there fewer weather stations and what's the effect?
I'm still amazed that there are people out there who will cite Watts as a source for anything but humour and laughter. His beliefs about the Darwin station have been dismissed and disregarded by all but those most in denial. Just by reading one blog (The Way Things Break) I was able to get access to two official sources (BOM, Australia & NOAA) which show why Watts is mistaken - as usual. It even led to a pertinent REALCLIMATE comment which summed up the situation very nicely : "Second, just because the writer can't work out why something changed, it does not mean it was 'manually adjusted'". As for UHI, you should read more of the articles on SKEPTICAL SCIENCE, especially here and here -
Mike_Allen at 19:18 PM on 28 April 2010Has Arctic sea ice returned to normal?
I have a question about sea ice formation. How does salinity effect the sea ice. How much salt remains in the sea ice, does the layer below the ice become more saline? Does this affect the temperature of ice formation? What about acidification and ice? I can't test this in my freezer it just won't do -20C. I'm thinking about optimal conditions for sea ice growth. -
Arkadiusz Semczyszak at 18:24 PM on 28 April 2010Why are there fewer weather stations and what's the effect?
There is no sufficient argument to deny the existence of the current warming relying on data from rural stations, but ... ... the scale of the current warming is questionable. For example, data from rural stations in Europe may not be reliable. All Europe Central and Western Europe is (in all likelihood) a great sub-continental UHI (de Laat, ATJ, 2008: Current Climate Impact of Heating from Energy Usage). There is also the problem of homogenization of data from different time periods. Anthony Watts wrote about it (for example: the Darwin station in Australia). -
Chad at 17:50 PM on 28 April 2010Why are there fewer weather stations and what's the effect?
johnd, Calculating a global average of temperature as opposed to temperature anomaly would seriously bias the analysis. For example, losing spatial coverage at high northern latitudes would cause the global average to spike when it shouldn't. By converting the station data to anomalies the fact that the tropics is much warmer than higher latitudes and that stations are being lost in those colder regions becomes much less a serious concern. The difference in anomalies is much smaller than the difference in temperatures between those two regions so the potential for bias is much lower. Like John Cook pointed out, losing stations at high latitudes (which have experienced the largest warming) will depress the warming trend a bit. -
A visual depiction of how much ice Greenland is losing
#39 gallopingcamel, You mention plants growing from pole to pole, but never explain exactly how long you think this would take. I assure you new ecosystems do not sprout up overnight. In the meantime, our society could be going through some severe economic and environmental turmoil. It is of little comfort to say that 2000 years from now our problems may not seem so bad. It's also interesting you noted potential agriculture improvements in Canada and Siberia, but neglected to mention any other possible effects. There are other places in the world after all. How would lower latitude countries be affected? Did you weigh the negative effects vs. the positive to come up with your conclusion that warming will be a "blessing", or did you just cherry pick the details that support your conclusions? That's an intellectually lazy approach, and you'll need to do better if you want to make a convincing argument. If you are interested in knowing more about the predicted effects of global warming, both positive and negative, this post is a great start. The IPCC and EPA also go into more detail on the subject. -
johnd at 17:24 PM on 28 April 2010Why are there fewer weather stations and what's the effect?
Is there any chance of getting graphs that compare the calculated temperatures rather than comparing the anomalies? Only then can we be sure that there is no basic bias. -
qball17 at 16:08 PM on 28 April 2010CO2 effect is saturated
so the atmosphere is infinitely large is it? so what is the better model? can you show me some solid evidence that debunks the saturated greenhouse effect and proves that CO2 drives climate? -
robert way at 16:06 PM on 28 April 2010Why are there fewer weather stations and what's the effect?
I know that in my region the GHCN has dropped some stations which still operate. The stations take only daily recordings and have them online in the climate.gc archive for all of canada. Turns out GHCN only downloads the monthly data which results in leaving out a lot of available data. In a related story, the two stations I looked at in particular that they dropped are rural stations which have undergone incredible warming in the last two decades (2-3 degrees) -
robert way at 15:58 PM on 28 April 2010A visual depiction of how much ice Greenland is losing
Chris G, I wouldn't call it a nitpick at all. This individual spent so much time on skeptic blogs looking up his argument that he forgot that you need the overall knowledge of the issue at hand also. It is not as though we were referring to some abstract type of specialist. Glaciologists are very well known today and not taking the time to learn who it is that studies these things, and then talking in a manner as if he/she were an expert is not something which I am willing to defend. You look up the core literature and gain the core knowledge before you make accusations about the existence of AGW or not. I don't want to be rude to the individual in any shape or form but it does get a little annoying when comments are made with such certainty and yet such ignorance all at once. -
scaddenp at 13:43 PM on 28 April 2010A visual depiction of how much ice Greenland is losing
The "rate" question relates to the ability of our society to cope with change. Past rates are of no relevance but some projections exceed 1.2m/century. While there is less ice to melt now, the rate of temperature is higher, much much higher. Ice leaves behind outwash and rock, not past soils. Plant colonisation is rapid but a productive soil, especially compared to delta, very slow.
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