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robert way at 22:02 PM on 1 October 2010An underwater hockey stick
Moberg not Mobert hahaResponse: It's been a long week :-( I fixed that error and while I was in there, I anti-aliased the text (it really bothered me that I'd missed that) and added some descriptive text to Figure 1 in case someone copies and pastes it out of context onto some other website. -
TOP at 22:01 PM on 1 October 2010The Asymmetric War on Climate Change: No Cause for Alarmism?
I thought checking the qualifications of the writers of paper on GW was one of the methods that was used to discredit various people's opinions on GW. Monckton comes to mind. For example this quote from the abstract:
The analysis considers two time periods — one during the time when the papers were found to be overstating challenges to then prevailing scientific consensus, and the other focusing on 2008, after the IPCC and former Vice-President Gore shared the Nobel Prize for their work on climate disruption, and before opinion polls showed the U.S. public to be growing more skeptical toward climate science once again.
This sentence could be written in a more neutral and informative way by stating the dates for the control period and another set of dates for the after period. The next few sentences could state the events that set those dates and the names of the papers used. Are winter and summer and 1998-2002 and 2008 and on so hard to write? Are New York Times, Washington Post, LA Times and WST so hard to write? My comment is no more vacuous than that of Freudenberg and Muselli:
Instead, Hirt emphasized that organized industrial interests -- often in alliance with relevant governmental agencies of that era, most notably the U.S. Forest Service-- tended not just to support lines of research that indicated higher levels of logging to be "sustainable", but also to hire the most skillful experts available to challenge or attack any research that might have suggested the need to reduce logging rates.
Muselli comes to mind as fitting this bill for environmental interests. -
Ned at 21:56 PM on 1 October 2010Climate Change: Past, Present, and Future
Way back yesterday, chriscanaris wrote: 1) CO2 has been rising 2) Temperatures have been rising 3) (1) very likely has made a substantial but not exclusive contribution to (2) As you know, I'm always grateful to see sceptics agreeing with these points. It's nice to know there is some common ground here. I will try to reciprocate (at least a little!) below. continuing... 4) We're not as confident that temperature rise is unprecedented - ie, we have some doubts about the palaeoclimate proxy record when it is 'spliced' onto the modern record I'm pretty confident that this is the warmest it's been in the past few millennia (and that unless we act soon we will exceed the peak warmth of the previous interglacial). But, from your perspective, can you explain why this question of "precedents" is important? I can see two possibilities. Some people seem to believe that if one or more previous intervals were as warm as today (for presumably "natural" reasons, ignoring Bill Ruddiman), then that would cast doubt on the anthropogenic origins of modern warming. An alternative reason for focusing on "precedence" is the idea that if societies and ecosystems survived an equally warm period in the past, the impacts of modern warming can't be too serious. IMHO there are obvious, serious flaws with the first alternative and more subtle issues with the second. (It's also possible you have some other reason for placing importance on the question of "precedents" that isn't obvious to me...) OK, back to chriscanaris: 5) We don't want to overlook the role of other feedbacks which may be important whether as exacerbating or mitigating factors I appreciate the way you worded this. It's important to keep in mind that the range of values for climate sensitivity (2 to 4.5 C per doubling) is intended to cover the uncertainty on both the high side and the low side, around a best estimate of 3 C. It is frustrating to me that so many sceptics focus exclusively on one half of this range of uncertainty while ignoring the other half. That seems like a dangerous (if all too human) irrational mindset. It is very easy to justify a low value for climate sensitivity if one hunts for all possible lines of reasoning that would support a low value while (not necessarily deliberately) avoiding thinking about those that would support a high value. This, to my mind, is a rather common theme in the writings of a great many "sceptics" on this site. chriscanaris continues his list: 6)We're not as confident of catastrophic outcomes even if temperatures and CO2 rises more or less as projected This, I think, is your strongest point, at least if you can guarantee that we don't switch over heavily towards burning coal or tar sands when the conventional oil starts to run out. The uncertainty on the question of impacts (economic and environmental) is real. To be perfectly honest, the tendency of many (most?) sceptical commenters to reiterate easily rebutted claims (yes, CO2 is a greenhouse gas; no, the CO2 rise is not coming from the ocean; no, there is no way that solar irradiance can explain modern warming) lets us supporters of the "mainstream climate science" position off the hook -- we get to provide easy answers, rather than discussing the more murky questions of impacts & consequences. I don't think the outcomes of a middle-of-the-road emissions scenario will be uniformly "positive" or "negative", but rather a mix of both depending on your location and your viewpoint. And although I use it myself from time to time, I'm not convinced that the "precautionary principle" argument is a really solid one. In balance, I think the costs of 21st century climate change will be greater than the benefits, but I recognize this is a purely qualitative interpretation on my part. Of course, there has to be a limit somewhere. We've burned around 300 GT of carbon since 1750. I agree that the impacts of this are likely mixed. The business-as-usual scenario would see us burning around 2000 GT carbon. If we burned all the reasonable coal reserves available, this would be 5000 GT carbon. I cannot imagine the impacts of the latter scenario being anything short of disastrous. Returning to chriscanaris's comments: 7)Even if our reservations in (4),(5), and (6) prove to be correct, becoming much less dependent on fossil fuel and decarbonising our economies and our emissions is a very good idea anyway for lots of other reasons. Thank you for including that. I think it would be really helpful if our society could focus on identifying common grounds for at least some action, and go ahead with those actions while we debate whether concerns about climate change justify further action. 8)However, we're much more likely succeed at (7) if we avoid a panicky response and scare the proverbial horses whilst triggering the laws of unintended consequences. I'll have to remain agnostic on this, I guess. We don't have parallel Earths to experiment on, so I guess we'll never know whether some hypothetical (different) approach to dealing with the energy/environment/climate nexus would have worked better. There is certainly a part of me that would like to believe that we've just handled this all badly and that our failure to take any significant steps on this issue is not a sign of inherent failings in human nature. Who knows? Anyway, thank you for your comments, chriscanaris -- as always they are a bit of a breath of fresh air after reading too many frankly silly dispatches from strangely unsceptical "sceptics" here and elsewhere. -
Vinny Burgoo at 21:39 PM on 1 October 2010It's not bad
'Severe consequences for over 60 million people dependent on ice and snow melt for water supply (Barnett 2005, Immerzeel 2010)' It's good to see that you update things, JC, but now you've understated the problem. Immerzeel et al's 60 million is related to ice-melt alone (not ice and snow) and is for only five river basins. Adding the inhabitants of the Tarim oases in NW China might take the number that'll eventually be threatened with food insecurity because of vanished glaciers up to 70 million. (I've never found a reliable number for the western China component. Thanks to Barnett et al, many sources say that 23% of China's population - all in Western China - relies on glacial melt but that's hooey. I suspect the claim originated with a journalist's ambiguous padding of a 2004 newspaper interview with Yao Tandong.) Adding a quota for ex-Soviet Central Asia might take you to... 100 million? The small populations outside Asia... Dunno, but a wild guess: 150 million in all. Or you could stick with ice *and* snow melt and reinstate Barnett's (dodgy) 1 billion. But at the moment you're using a partial number for ice and ascribing it to ice and snow, which is no better than the earlier problem (Barnett's billion all down to ice).Response: Thanks for the feedback. I've gone for "at least 60 million people dependent on ice melt" which is as weak as dishwater but Immerzeel is really the best estimate we've got so far, even if it only covers 5 river basins. Where does your figure for NW China come from? -
tobyjoyce at 21:26 PM on 1 October 2010An underwater hockey stick
The Ville, Yes, slow down!! But, maybe not. I keep leaving aside interesting posts to read later, but never get to them because another post just as interesting comes up!!! Congratulations, John, this side is easily the best climate science resource on the web. -
CBDunkerson at 21:14 PM on 1 October 2010IPCC Reports: Science or Spin?
The Ville, I wouldn't say Spencer is indecisive so much as 'conflicted'. He has religious ('creationism is more logical than evolution') and political ('environmentalists want to wreck the economy') beliefs which are at odds with observed reality. Over time the scientist in him has given more and more ground to reality, but he still clings to core beliefs in any case where he can construct possible doubt in his own mind. That said, his calls (along with others) for a sort of 'anti IPCC' which would receive large amounts of funding to 'find evidence against AGW' is inherently anti-scientific. It is a continuation of the 'skeptic' myth that AGW findings are all due to scientific bias and efforts to get funding. They suggest that without funding 'scientists' dedicated to the view that AGW is false we can't get an accurate picture. Which is nonsense because true scientists look at reality and make conclusions... not make conclusions and then try to fit 'reality' to them. This is why climate scientists are constantly finding things which don't immediately add up; the area around Antarctica is warming... but sea ice there is increasing, sea levels are rising... but the measured increases in ocean heat content and land ice melt are too low to explain this sea level rise, earlier OHC measures actually showed cooling... until errors in the instruments were discovered, et cetera. The REAL skeptics are already reporting contradictory findings and searching for alternative explanations... within the bounds of consistency and reason. Spencer straddles the line... drifting back and forth between skeptic and 'skeptic'. -
JMurphy at 21:03 PM on 1 October 2010Climate Change: Past, Present, and Future
chriscanaris, you know very well that there are many so-called skeptics out there (including self-appointed auditors) who are obsessive about proving a global MWP. Why do you think that is ? And, don't forget that another self-appointed blog expert has only this year brought out a book referring once again to the 'hockey-stick'. Finally, you have only to read the threads about the 'hockey-stick' on this site, to see so-called skeptics claiming that Mann has been 'proved wrong' (which seems to suggest that, therefore, AGW is also proven false) and that McIntyre, etc. are heroes who have proved...well, who knows, but they keep coming up for adoration by some on here. Why the obsession ? -
Ned at 21:02 PM on 1 October 2010An underwater hockey stick
Nice post, John. Also, I like the use of the francophone spelling in the Y-axis of the graphs. -
Riccardo at 20:49 PM on 1 October 2010An underwater hockey stick
The Ville, John Cook is trying to show what overwhelming evidence means ;) -
SRJ at 20:46 PM on 1 October 2010New temperature reconstruction vindicates ...
@80 Mathew and 85 kdkd Regarding the trend for 1990-2000 vs. 2000-present: I made a plot showing the trend for the last period August 2000-August 2010 and for the period August 1990- August 2000, with confidence intervals (with and witout AR1 correction) for the trendlines:
It shows that the trends are not different from each other in a statistical signicant manner. Correcting for AR1-noise, they are not statistical significant on their own.
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Paul D at 20:38 PM on 1 October 2010An underwater hockey stick
I can't keep up with all the posts on this site. Slow down! (not). -
Paul D at 20:34 PM on 1 October 2010IPCC Reports: Science or Spin?
Actually on a similar note, the Royal Society here in the UK has been forced to change it's document about climate science by a minority of members that suggested it didn't make clear what the uncertainties are. Some of the members complaining are members of Nigel Lawsons political climate change skeptic group. Lawson is pro fiscally neutral taxation regimes, so he doesn't like the idea of 'green' companies getting tax breaks. eg. it's a case of the science having to fit his political ideology. -
Paul D at 20:27 PM on 1 October 2010IPCC Reports: Science or Spin?
Spencer is really naive in my opinion. It is irresponsible to just effectively say 'science should just be a direction-less talking shop'. The IPPC was set up to assess the science and give advice. The 'goal' would change as the science changes. Maybe his indecisive personality is reflected in the fact that he mixes religion and science. Really his whole philosophy is that people can choose what to believe. Does he actually get things done? Or does he argue with himself all day trying to decide whether to mow the lawn or not? -
Paul D at 20:13 PM on 1 October 2010Newcomers, Start Here
It isn't just adaptation to climate that is a problem. Changing climate also results in changing diseases and vulnerabilities to other changes, which are indirect issues. eg. species of tree may be able survive a changed climate, but they may be susceptible to a disease that climate brings with it or other invasive species. Polar bears have led a relatively isolated existence, warmer conditions may wipe them out because of a lack of immunity to invasive disease carried by other species that migrate into Polar bear territory. Humans have a high track record of introducing invasive species that wipe out complete populations of native species. Climate change can do the same thing. -
ProfMandia at 20:12 PM on 1 October 2010IPCC Reports: Science or Spin?
Let me repeat myself: Despite strong political reasons for them not to endorse, the following countries endorsed the IPCC 2007 reports because the science was undeniable: United States of America - Fossil fuel-based economy, strong lobby efforts opposed to regulating fossil fuel emissions Saudi Arabia - World's largest producer/exporter of oil China - Rapidly industrializing using coal-fired power plants India - Rapidly industrializing using coal-fired power plants The IPCC WGI Report (2007) concluded: “Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” 130 countries endorsed the reports, and since 2007, no scientific body of national or international standing has maintained a dissenting opinion. Politics? Hardly. Spencer, as a scientist, should know that one cannot make such grand claims without supporting evidence. -
adelady at 18:12 PM on 1 October 2010Climate Change: Past, Present, and Future
As for "a clear MWP hotter than today", that *would* be the final nail in the coffin of the idea that climate sensitivity is a small or manageable number. The last thing anyone wants is this or any other confirmation that climate sensitivity is on the much higher side rather than the lower. -
adelady at 18:07 PM on 1 October 2010Climate Change: Past, Present, and Future
Chris, the discussion was about agriculture. I very much doubt anyone with any brains would use goats for anything but reclaiming degraded growing areas. They're particularly good for areas within a farm infested with blackberry and the like. (Though I personally think pigs are better for this.) I know of no grain crop that grows under forest cover, especially not native forest. -
Riccardo at 17:25 PM on 1 October 2010Newcomers, Start Here
johnd, the word adaptation is used both in the sense of evolutionary adaptation or of adaptive capacity of the individuals. The former is a very slow process, it is passed to offspring and it takes many generations for small gradual changes; fast reproduction and short lifecycle would be an advantage. The latter is much faster but it is not passed to offspring. Polar bears cannot count on evolutionary adaptation, it's much too slow. Also, they are a very specilized and occupy a narrow ecological niche. Theese facts strongly limit their capability to adapt. In any case it's a race with time, the faster the change the less the odds that a specie will survive a change. And don't forget that climate change adds to other stresses. -
johnd at 15:23 PM on 1 October 2010Newcomers, Start Here
It seems to me that the problem facing polar bears is not so much their supposed inability to adapt to a changing, warmer climate, but trying to maintain an environment, any environment, that puts some distance between themselves and humans. I don't think those who fear the inability to adapt fully appreciate just how rapidly most species can adapt to new completely different environments. Unless there is some special genetic makeup within the polar bear DNA that gives it an inability to adapt, it should be able to adapt as many other species have adapted in the past, and are still doing so, moving from one region to another transported over land or shipped by sea, or now days at times by air. Is there any accumulated evidence where the polar bear has demonstrated a special inability to adapt to different climatic conditions or is it just supposition?Response: "...it should be able to adapt as many other species have adapted in the past"
This seems to be a common misconception - that animals will simply adapt to climate change. Throughout Earth's history, there have been periods where climate has changed so abruptly, animals have not been able to adapt quickly enough. These periods are known as mass extinctions. In the Permian mass extinction, between 80–95% of all marine species went extinct. In the Triassic mass extinction, around 80% of all land quadrupeds went extinct. Virtually no large land animals survived the Cretaceous mass extinction 65 million years ago (this is famous for the demise of the dinosaurs). Our current period is being described as the 6th mass extinction in Earth's history. -
chris1204 at 15:11 PM on 1 October 2010Climate Change: Past, Present, and Future
Doug's right, we are off topic but adelady @ 27 writes: Goats are brilliant at clearing weed infested land, but finding enclosures that are both movable and secure enough would be an issue. Goats are brilliant at clearing weed infested land because they rip plants out by the roots, ie, they literally eradicate. Consequently, they can be a huge problem with regard to deforestation. Coming back on topic, JMurphy @ 29: Identifying a clear MWP hotter than today would not be the final nail in anything. While it would change the parameters of our debate around climate sensitivity and forcings, I'd like to think that most of us who participate in these discussions do so not to score points but to come to a better understanding of the fascinating intricacies of the workings of the world in general and climate in particular. AWG may have been the catalyst to our musings but the science is never *settled* if you are a genuine scientist! :-) -
Doug Bostrom at 15:05 PM on 1 October 2010Models are unreliable
Tom, thanks, and that link does appear to work for us in the Great Unwashed Masses. Vardi makes an excellent point. -
Matthew at 14:13 PM on 1 October 2010IPCC Reports: Science or Spin?
I heard somewhere else that a good amount of the "old" or year to year sea ice within the arctic has recovered some since 2007. Is that true?Response: There was a slight rebound in the 1 to 2 year old ice but a continued drop in the 2+ year old ice:
The result is that Arctic sea ice volume (eg - the total amount of ice) reached record low levels in 2010:
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ginckgo at 13:59 PM on 1 October 2010Newcomers, Start Here
What the "polar bears will just adapt" crowd seem to not understand about evolution, is that adaptation to a changing environment is far from guaranteed. The major mass extinctions in the past have all occurred when environmental change was too rapid and/or environmental stress was too strong. This is what we're seeing today. Plus, mass 'extinction' is perhaps a misnomer, as some events are marked by extinction rates dramatically elevated above background levels, while others are marked by dramatically reduced speciation rates. I think our double wammy of human encroachment and environmental change is causing both to occur at the same time. -
Tom Dayton at 13:21 PM on 1 October 2010Models are unreliable
A good, short, essay on the role of computer models in science is in the journal Communications of the ACM, the September 2010 issue, page 5. I can see it on line for free, but I don't know if that's because I'm an ACM member: Science Has Only Two Legs. -
archiesteel at 11:58 AM on 1 October 2010Newcomers, Start Here
@CW: that's your rebuttal? Weak. Changing light bulbs (preferabley to LEDs) and driving hybrid/electric cars is just smart, regardless of the overwhelming amount of evidence supporting AGW theory. Oil is too valuable to use as fuel. -
DSL at 11:44 AM on 1 October 2010Newcomers, Start Here
Ignoring Doug's correction, what you say is right, CW: we should go ahead and take these poor ------s out in the next 50 to 100 years with our paltry 3-7 C warming, because there's no way they could continue to evolve over the next 20,000-30,000 years as insolation slowly creeps toward max. Why stretch it out for them? Indeed, let's go ahead and make that choice for all the other species we couldn't possibly be affecting by our slight changes to the biosphere. Who needs em? What a work is man! How infinite in reason! Or was it density or greed or something like that . . . -
Doug Bostrom at 11:27 AM on 1 October 2010Newcomers, Start Here
I believe you're mixing up BP w/AD, CW. -
ClimateWatcher at 11:23 AM on 1 October 2010Newcomers, Start Here
By the way, if you can repress the memory of the HCO ( the peak just prior to the blue dot which marks the present ), and are still convinced that changing your light bulbs ( or as Nissan would sell you, driving a 'Leaf' ) will have any bearing whatsoever on the Ursus Maritimus ( polar bears ), do reflect that nature is going to irradiate the Arctic with greater summer sunshine than present for most of the next fifty thousand years:
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David Horton at 10:59 AM on 1 October 2010IPCC Reports: Science or Spin?
Yes, nicely done Graham. Worth noting too that whatever "political pressure" may be operating on the IPCC in a general sense is operating in the direction of toning down warnings, as a result of countries such as the US and Saudi Arabia being determined that nothing will be allowed to slow down the profit stream from oil. And that there will be none of this regulation nonsense getting in the way of [polluting] business as usual. Since there has to be consensus this results in only the lowest threat levels being acceptable to all. Whenever individual climate scientists are able to speak without political pressure (and this pressure operates within countries too, again the US being a prime, though not the only, example) their real views are much more gloomy than the IPCC consensus position. -
Doug Bostrom at 09:48 AM on 1 October 2010Newcomers, Start Here
CW's chart is from NOAA, Rob. They've got an interesting discussion of paleoclimate information available. It's a little long in the tooth, last updated 2006. For some fresher Arctic paleo information, see History of sea ice in the Arctic (Polyak et al, 2010) and Temperature and precipitation history of the Arctic (Miller et al, 2010)
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Rob Honeycutt at 09:25 AM on 1 October 2010Newcomers, Start Here
ClimateWatcher (#6)... BTW, where does that diagram come from? What's the source of the data? Robert Way would know far better but the numbers look a little fishy to me. And it's always a red flag if there is no source referenced. -
kdkd at 09:25 AM on 1 October 2010Newcomers, Start Here
While the comment about the bear de-evolving it's white coat is silly (it would require a change in the bear's phenotype which would take a very long time indeed to evolve) the previous comments about the Hudson Bay population are interesting. This appears to be an example of learned behaviour which is quite different from evolved behaviour (or evolved physical characteristics). So it's quite possible that the bears will learn to adapt to ice free summers where possible as they are intelligent long-lived animals. However this has absolutely nothing to do with evolution. -
Doug Bostrom at 09:22 AM on 1 October 2010NASA-GISS: July 2010-- What global warming looks like
Not to reignite the flames of controversy over whether 145 x 10^20 Joules per year of increased energy per year retained on Earth must certainly remain invisible to us but rather just to follow up on the original topic, here are are a couple of items looking back on this past summer, from NASA-GISS: 2010 — How Warm Was This Summer? How Warm Was Summer 2010? -
Doug Bostrom at 09:01 AM on 1 October 2010New temperature reconstruction vindicates ...
KR: ...long term sequestration of CO2 involves plants that are not then burnt, eaten, or rotted away. Also foraminifera, coccolithophores, diatoms. C in C02 ends up in hydrocarbons, carbonates. Of course we're short on enormous shallow seas these days. -
Rob Honeycutt at 08:59 AM on 1 October 2010Newcomers, Start Here
fydijkstra... What I believe you are also pointing out with your comments is that it takes many thousands of years for evolution to allow these species to adapt. They are not going to readapt to an ice free environment over the course of a few generations. It's important to protect species for obvious reasons, but I keep saying that polar bears are the canary in the coal mine. They should be a sign to us that something serious is afoot. ClimateWatcher (#6)... I would point out that what you are claiming here does not account for any further rise in temperature. By this chart you might not conclude that the HCO was warmer than today. But that placed aside, what we are looking at is a rise of another 2-3C in global average temps (more in high latitudes) in this century. As a species polar bears have very definitely never seen such conditions. -
kdkd at 08:56 AM on 1 October 2010New temperature reconstruction vindicates ...
Follow up from #85 Of course there's an easy way of assessing the significance of the difference between the trends - correlate the difference between the 1990s and the 2000s against the position in the series. This gives a correlation coefficient of -0.07, 95% confidence interval of -0.67 to +0.58. As this confidence interval intersects zero (and as I indicated previously is a very wide interval) there's clearly no significant difference between trends in the 1990s and the 2000s as measured by the annualised satellite data. For this analysis to be statistically significant the correlation would have to be (0.58 - 0.67)-1 = 0.91 which would be very difficult to achieve with this system, even if we were seeing clear evidence of runaway global warming (or cooling) over such a short time frame. -
Nick Palmer at 08:42 AM on 1 October 2010New temperature reconstruction vindicates ...
#81 johnd at 06:47 AM on 1 October, 2010 wrote: "If we look at the carbon cycle where the the natural sources and sinks exceed anthropogenic emissions by a factor of 30, and those natural sinks each year sequester approximately half of the man made emissions" Perhaps you might like to consider the difference between short and long term sequestration. I was referring to the digging up of (semi-)permanently sequestrated carbon. -
New temperature reconstruction vindicates ...
johnd - My point was that seasonal CO2 variations due to the growing season are very definitely not the trend - and that you cannot count on large seasonal variations to take care of a multi-decade CO2 increase. -
adelady at 08:29 AM on 1 October 2010Newcomers, Start Here
fydijkstra "So what's wrong with adaptation of the polar bear? If it does not need its white color any more, so what?" And how long did that earlier adaptation take? 50 generations, 100 generations, 1000 generations? This kind of evolution does not happen in the space of a few years or a few generations. Nobody's suggesting that we should stand in the way of natural evolution. The kind of time scale our emissions are imposing is not conducive to natural evolution. -
johnd at 08:29 AM on 1 October 2010New temperature reconstruction vindicates ...
KR at 08:09 AM, the rate at which CO2 is being moved deeper in the oceans will be tied to the rate at which the heat also absorbed at the surface is redistributed and moved deeper, and that, whilst subject to great discussion, is more reflective of shorter rather than longer term circulation. -
Albatross at 08:20 AM on 1 October 2010New temperature reconstruction vindicates ...
Matthew @80, I concur with kdkd, or rather Hansen does ;) "Contrary to a popular misconception, the rate of warming has not declined. Global temperature is rising as fast in the past decade as in the prior two decades, despite year-to-year fluctuations associated with the El Nino-La Nina cycle of tropical ocean temperature. Record high global 12-month running-mean temperature for the period with instrumental data was reached in 2010." From: Hansen, J., R. Ruedy, Mki. Sato, and K. Lo, 2010: Global surface temperature change. Rev. Geophys., in press, doi:10.1029/2010RG000345. -
kdkd at 08:14 AM on 1 October 2010New temperature reconstruction vindicates ...
Matthew #80. "Kdkd 2000-2009 warmed about .15c, which is below the 1990's. Is that true? Nope. Firstly you can't really assess trends properly over such a short time period in isolation due to a lack of statistical power. The difference in trend is almost certainly not statistically significant even before correcting for autocorrelation. The calculation for actual statistical significance is fiddly so I'm not going to do it, but with 10 paired data points it would require quite a large difference in correlations to be significant (probably greater than r=0.6 from memory) - the observed difference in correlation is only 0.15 which is definitely not statistically significant for 10 paired observations. Looking at the satellite data for 1990-1999 and comparing it to the satellite data for 2000-2009, the mean anomaly for the 2000s is 0.25 deg C greater for the 2000s period than for the 1990s period (95% confidence interval: 0.095-0.40). -
New temperature reconstruction vindicates ...
johnd - Seasonal variation is cyclic; what goes in comes out. Actual long-term sequestration of CO2 occurs through rock weathering, subduction in ocean zones, and the formation of those hydrocarbons we're so rapidly burning. The long term trend is what's important, currently +2ppm/year, not seasonal variations. The only long term sequestration of CO2 involves plants that are not then burnt, eaten, or rotted away. That's a pretty small portion. -
Same Ordinary Fool at 07:37 AM on 1 October 2010Newcomers, Start Here
The story of polar bears coping without sea ice has already been filmed. Several years ago I saw an hour long show about a mother and cub who missed the departing sea ice. They were stuck on shore for the rest of the summer. They missed the salmon run, because they didn't know about it. They did find the berries. Mom was pretty gaunt by the end of the summer. Unlike in the Arctic, the Hudson Bay sea ice disappears completely during the summer. So entire subpopulations there are forced onto land. The good news is that the polar bears have evolved the ability to survive a summer long fast. The bad news is that in a warming world the time on shore is getting longer. Ironically, when the multi-year ice becomes even thinner, there will be some new areas that the polar bears can move into. These are areas where the ice is now too thick for the seals to maintain their breathing holes. fydijkstra @ 5:59Am.....The other evolved traits that make it the perfect maritime bear, work against it on land. Its big and slow. Its calorie requirements that are currently met by seals (an adult polar bear eats only the fat) can't be met on shore. And, most importantly, its the grizzly bears that win in fights with polar bears (if only the polar bears learned to use their nose butt...). -
johnd at 07:31 AM on 1 October 2010New temperature reconstruction vindicates ...
KR at 07:14 AM, the CO2 sequestration of the oceans and the plants and soil are divided roughly equal. The drop in CO2 levels that coincide with the seasonal growing periods in each hemisphere show that the plants and soil are a significant destination for CO2 with a capacity that is only partly utilised for a portion of each annual cycle. -
New temperature reconstruction vindicates ...
johnd - Actually, much of the anthropogenic emissions are going right into acidifying the oceans. It takes quite some time for that absorbed CO2 to move deeper. The rate required to be absorbed by the environment and not change ocean pH would be much much smaller than 50% of current emissions. -
johnd at 06:47 AM on 1 October 2010New temperature reconstruction vindicates ...
Nick Palmer at 03:20 AM, regarding your comment of digging up CO2 that took millions of years to sequester. If we look at the carbon cycle where the the natural sources and sinks exceed anthropogenic emissions by a factor of 30, and those natural sinks each year sequester approximately half of the man made emissions, then one could make a case showing that in fact man is only releasing carbon in one year that took two years to get down there. -
Matthew at 06:35 AM on 1 October 2010New temperature reconstruction vindicates ...
Kdkd 2000-2009 warmed about .15c, which is below the 1990's. Is that true? -
kdkd at 06:32 AM on 1 October 2010New temperature reconstruction vindicates ...
KL #74. We've been through the scientific argument many many times. You seem to claim that the ocean heat content data is capable of falsifying the remaining evidence for anthropogenic global warming. You do not seem to have any other 'evidence' to support this position. A large and important part of your position is the need to maintain the pretence that the existing measures of ocean heat content are accurate enough to draw strong conclusions. It has been demonstrated to you many many times that it is not. As you have no other argument to support your position, you maintain the position regardless of the evidence presented to you (like the 'flattening of temperature post 1998' claim that you cling to as well), I think that repetitive rubbish is a fair comment which summarises your argument well. -
Positive feedback means runaway warming
hadfield - Your statement "a system with positive feedback is by definition unstable" is incorrect, a system with a gain < 1 is stable, as discussed at some length here, and in better detail on the advanced version of this page. Total stable increase for a particular gain (g<1) and forcing (f) is, if you work the math: V = f / (1-g) The oft-quoted 3oC increase for a doubling of CO2 (forcing = 1oC) represents a gain of 0.666. This, incidentally, works for negative feedbacks as well - gains with an absolute value < 1.0 are always stable. Differing time constants may cause some oscillation before settling, but systems with |g| < 1.0 are always stable. Gains > 1 don't tend to exist in natural systems (as they would require infinite energy!); they're pretty common in electronics, amplifying values until you hit the limits of the power supply.
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