We’ve been a little preoccupied recently, but there are some recent developments in the field of do-it-yourself climate science that are worth noting.
First off, the NOAA/BAMS “State of the Climate 2009” report arrived in mailboxes this week (it has been available online since July though). Each year this gets better and more useful for people tracking what is going on. And this year they have created a data portal for all the data appearing in the graphs, including a lot of data previously unavailable online. Well worth a visit.
Second, many of you will be aware that the UK Met Office is embarking on a bottom-up renovation of the surface temperature data sets including daily data and more extensive sources than have previously been available. Their website is surfacetemperatures.org, and they are canvassing input from the public until Sept 1 on their brand new blog. In related news, Ron Broberg has made a great deal of progress on a project to use the much more extensive daily weather report data into a useful climate record. Something that the pros have been meaning to do for a while….
Third, we are a little late to the latest hockey stick party, but sometimes taking your time makes sense. Most of the reaction to the new McShane and Wyner paper so far has been more a demonstration of wishful thinking, rather than any careful examination of the paper or results (with some notable exceptions). Much of the technical discussion has not been very well informed for instance. However, the paper commendably comes with extensive supplementary info and code for all the figures and analysis (it’s not the final version though, so caveat lector). Most of it is in R which, while not the easiest to read language ever devised by mankind, is quite easy to run and mess around with (download it here).
The M&W paper introduces a number of new methods to do reconstructions and assess uncertainties, that haven’t previously been used in the climate literature. That’s not a bad thing of course, but it remains to be seen whether they are an improvement – and those tests have yet to be done. One set of their reconstructions uses the ‘Lasso’ algorithm, while the other reconstruction methods use variations on a principal component (PC) decomposition and simple ordinary least squares (OLS) regressions among the PCs (varying the number of PCs retained in the proxies or the target temperatures). The Lasso method is used a lot in the first part of the paper, but their fig. 14 doesn’t show clearly the actual Lasso reconstructions (though they are included in the background grey lines). So, as an example of the easy things one can look at, here is what the Lasso reconstructions actually gave:
‘Lasso’ methods in red and green over the same grey line background (using the 1000 AD network).
It’s also easy to test a few sensitivities. People seem inordinately fond of obsessing over the Tiljander proxies (a set of four lake sediment records from Finland that have indications of non-climatic disturbances in recent centuries – two of which are used in M&W). So what happens if you leave them out?
No Tiljander (solid), original (dashed), loess smooth for clarity, for the three highlighted ‘OLS’ curves in the original figure).
… not much, but it’s curious that for the green curves (which show the OLS 10PC method used later in the Bayesian analysis) the reconstructed medieval period gets colder!
There’s lots more that can be done here (and almost certainly will be) though it will take a little time. In the meantime, consider the irony of the critics embracing a paper that contains the line “our model gives a 80% chance that [the last decade] was the warmest in the past thousand years”….
@246: “Uncertainties do not change or challenge the overall picture, …”
That’s false. If that were true, a prediction that the Earth is warming at a rate of 100 degrees per decade (center), give or take 500 degrees per decade (uncertainty) would make sense and be scientifically interesting. It doesn’t and isn’t.
Uncertainties are critical part of any prediction.
CM,
“Well, the elapsed time in empirically observable reality is what we have to work with. Feel free to suggest a better way to test the projection that does not involve time travel, psychic powers, or substituting a straight line of your own fancy for the model projection.”
Good lord, do you really need to resort to hyperbole and appeals to ridicule to make your argument? First, it only makes me less likely to seriously consider anything you say. And second, it just makes you look irrational. But to the point, I already stated all that can be done about this problem. That is to test the models that we can (which suck) and to simply recognize that the other models are little more than a guess since they can’t be validated.
“Still, if you compare with a “no warming” null, even the 1990 projection doesn’t half suck so far. ”
The null hypothesis may be no warming, but there are alternative hypotheses which include lower amounts of positive feedback, etc. So we can do better than test it against no warming, we can test it against what has actually happened, and compare those test results between several models. You don’t just take any model that beats nothing, you take the best model. F=ma/2 would describe motion better than no equation at all, but F=ma is better.
“And yes, I do wonder why you are “skeptical” about addressing a risk just because it’s poorly bounded. Poorly bounded risk is not a happy thought.”
The concept of risk is poorly bounded CM, that’s why its risk. This risk just happens to be EXTREMELY poorly bounded, if you want to use that term. I know my risk of death in a car accident is on average, say 1/100,000, but how much does that change based on the car I drive? How about how I drive? Where I drive? Pooled risk might be better understood, by my individual risk is as you might say, poorly bounded. But just because its poorly bounded, doesn’t mean I ignore it. I generally obay the speed limit, I check my blind spot and use a blinker when changing lanes, I bought pretty much the safest car in my budget, I use my seat belt, I even took a highway driving class at Sears Point Raceway. But all those things are of fairly trivial marginal cost. The sears point thing was only a couple hundred bucks, was a ton of fun, and it saved me about as much as it cost on my insurance. It doesn’t cost me anything to drive 65 instead of 85, in fact it saves me money, nor does it cost anything to buckle a seat belt, and I was going to spend 20-24K on a car anyway, and the marginal safety improvement from other similar models was of negligable cost (and this car was again even safer than more expensive models). You can probably tell where this is, but with climate change, the purposed risk reductions are extremely expensive, so much so that they may even be worse than the problem itself. You’ve probably heard the term the cure is worse than the disease? Well, in this case, the disease is not even known to have negative effects, how bad those effects are, nor how likely it is we get the disease. Yet we do know that cutting back CO2 emissions to the scale required to make a serious dent will give extemely negative effects, and we don’t even know if we could do that with the continued development of the rest of the world. What kind of suffering will take place in just America if the cost of energy say, doubles, which is a very conservative estimate given the steps we’d likely need to take to get CO2 emissions just back to around 1980 or 1990 levels for the next century? What about the developing world? How many lives are you going to negatively effect by essentially preventing industrialization and modernization which requires so much energy? Sure maybe you can count on alternative sources of energy, but those currently aren’t going to solve this problem, and its far from certain it ever will. Unless, you support large scale construction of nuclear power all over the globe, which I do for many reasons outside of global warming.
Anyway, I could go on and on about the rational behind my skeptic stance, but I suppose you get the idea, and its quite likely I just get some terse ad hominem in responce anyway, so I’ll just stop.
> please don’t suggest that someone … might not have had statistics 101
Nobody’s asking you personally to disclose that. You decide where to begin, based on what you know.
We’re readers like you, not here to “win any favors” from you.
The science assumes some statistics; if you don’t have that background or, like me, learned it a third of a century ago, it’s helpful to read at least something like Grumbine on trends for the basic idea.
A lot of resources on using Excel for climate point to old topics at Tamino’s blog that are currently unavailable, for example this page:
http://processtrends.com/toc_trend_analysis_with_excel.htm (which is still worth a look; I just found it this minute, not a recommendation yet).
I see some readers at Tamino’s have found and maybe archived some of the missing material. That will help.
Tim Chase’s explanation of how to search for cached topics from Tamino’s: http://tamino.wordpress.com/2010/07/01/on-thin-ice/#comment-43321
“Yes, we also know that we should probably expect at least some warming (say 0-2 degrees/100 years).”
How do we know this?
“What we disagree about is the confidences surrounding how much warming and what that means we should do.”
Wrong wrong wrong wrong wrong. Try again.
We /know/ what the impact of forcing on temperature is. This is called ‘climate sensitivity’. We DO NOT need models to know this.
See http://julesandjames.blogspot.com/2006/03/climate-sensitivity-is-3c.html
“So you ask suppose they are right?”
So this isn’t a question. Because we /know/ climate sensitivity, so we don’t need models to tell us the temperature impact of GHG emissions.
“I still don’t think we understand the Earth’s climate well enough to know if over the whole this “catastrophic” warming will even be bad.”
Great. Try reading the IPCC AR4. Here are a bunch of people who /do/ know what the impacts will be. They are experts. You are not. Learn something.
“Sure some people will likely be hurt in a myriad of ways, but it would be completely naive to not also study and consider posible benefits.”
Strawman. Costs and benefits are analysed
“Yet, I don’t think very many people are looking at such things, do you?”
Wrong.
“Oo, ok, lets suppose they are right, despite any convincing proof that they are, now convince me I need to do something about it.”
Convincing proof already exists. You don’t appear to have read any.
– We know climate sensitivity is 3 degrees (+/- 1.5 deg)
– We know what current GHG emissions are
– We know what proportion of current GHG emissions end up in atmosphere
– We know, therefore, what future emissions will do to atmosphere, and hence what they will do to T
– We have done a LOT of studies of benefits and negatives of increasing T
– You /don’t/ need to do something about it. This won’t effect you since you are rich, and probably too old to really be impacted. However, if you don’t do anything about it, you leave a legacy for your children and grandchildren that they may be utterly incapable of dealing with.
Any questions?
Wally, ocean pH change is better understood and faster than climate change:
http://www.nature.com/nature/journal/v425/n6956/abs/425365a.html
http://www.nature.com/cited/cited.html?doi=10.1038/425365a
@253: Good lord, skip lectures on the importance of statistics. They are totally uncalled for. We know that “science assumes some statistics” and that understanding statistics is important. Please post when you have something valuable to say, eg, when you have links for your resource, otherwise you are just cluttering the discussion (so do I in this post, but I will keep it short and will never post on that topic again).
Martin Vermeer @250 – “The agreement seems to suggest that you are ignoring the autocorrelation present (right?), which is significant for monthly data and should be accounted for.”
Thank you for your response, and yes, you’re correct, I hadn’t considered autocorrelation. Quick calculation shows the lag-1 autocorrelation in the monthly GISTEMP data is very high (0.761)… which I suspect is more than enough to invalidate the calculated significance of a simple OLS regression. I hadn’t anticipated this issue, and will look at ways to correct for it. Suggestions are welcome. (Ah the joys of ‘doing it yourself’…)
“On a more general note, the test you are doing (the most appropriate one being against the B scenario) kicks over the straw man that the model outputs are “perfect”. Of course they are not.” I don’t expect the models to be perfect. I expect every model prediction will be “precisely wrong” but aims to be “generally right”.
My issue is that two people with different axes to grind can still manage to look at the same model prediction and the same observed data and disagree over whether the model is “generally right” or not because both sides will set different arbitrary, self-serving thresholds for what constitutes “generally right”. Statistics would appear to be the objective way to put such disputes to rest, and I personally try to be as objective as possible.
And yes, I’m aware that Hansen (1988) used a higher estimate for climate sensitivity than is currently popular. That’s why I suspect those predictions came out on the high side. I don’t see this as justification for discrediting modeling, rather for better understanding some of the factors that go into models. If the predictions came out on the low side, that would be equally informative.
Wally, are you aware that computer models are used successfully for many, many applications where we have no ability to run a full-scale test? Whether it’s simulating the explosion of a nuclear bomb, modelling the failure modes of a hydroelectric dam, or ensuring an aeroplane is safe to fly – we use models all the time.
Climate models are among the better validated models, since we have over 30 years of data from our 1:1 model so we don’t have to rely entirely on back casting. Your claims that the models don’t perform well are simply wrong. If your “null hypothesis” is a constant warming (which is a really stupid thing to do, which is why the scientists didn’t use that as a null) – but assuming you are that stupid, then do you understand that this means that you have just assumed that the world is constantly warming, and that you have no explanation for why? Consequently, we still need to act to deal with this warming – but of course, we don’t know what is causing it, so we don’t know how to tackle it? But you aren’t that stupid, of course. You do, however, need to go and look up what a null hypothesis actually is – because currently, you have it wrong.
Your arguments about the cost of reducing carbon to the developing world are just shocking. Climate change will hit developing countries hardest, since those countries are already at the limit of liveability. They are also countries which can really benefit from investment is a completely carbon-free economy. The risks of action and inaction may be still an area of active research, but the current conclusions are utterly different to what you seem to think.
And you evidently haven’t been paying attention, because those serious about tackling climate change are in favour of using nuclear power where appropriate.
Looking through your rambling post, I’m struggling to find any position of yours that isn’t based on a misconception. Get the facts straight, then the conclusion follows easily.
“Anyway, I could go on and on about the rational behind my skeptic stance”
Nothing you have said so far is in agreement with the facts, so I look forward to a clearer explanation of your rationale after you have re-examined the evidence.
252 (Wally),
This is unnecessarily alarmist. Do you have any citations for these statements?
First, everything I’ve read says that professional economists estimate the cost at between 1% and 3% of GDP, which is pretty minor. No skyrocketing costs. Just retooling, and jobs/economy involved in the process.
Second, it also addresses other problems, like peak oil and strategic dependence on oil and coal rich countries. We have to get off of fossil fuels eventually, so why not do so in a comfortable, controlled fashion, instead of under the gun of “oh my God, there’s so little left!”
Third, the world has transitioned in the past from horses and sailing ships to steam ships to more, and from broad sheets to telegraph to radio to television to the Internet. Change happens, and it’s not by default bad and expensive.
Fourth, if we wait and then find out that the problem is big, the expense will then be huge. Then we have to put the brakes on faster, and worry about having reached a CO2 level that is already dangerous and can’t be undone. We really will then be in the situation you’re trying to avoid, causing economic pain and suffering when it all could have been avoided with an earlier but more conservative approach.
Fifth, no free market democracy, no matter what is done, is going to implement policies that strangle the economy and cause the sort of damage you’re describing. In the worst of cases, politicians that try to do so would be voted out of office. That sort of behavior could not come about until climate change itself was so damaging and indisputable that the populace was panicking, which will be too late.
So you are promoting a complete lack of action to avoid what is nothing more than the illusion of dangerous action, and in the end will result in the sort of chaos and suffering that you use as the basis for your argument.
David Archer’s classes:
http://www.youtube.com/view_play_list?p=FA75A0DDB89ACCD7
“PHSC 13400: Global Warming
This 10-week course for non-science majors focuses on a single problem: assessing the risk of human-caused climate change. The story ranges from physics to chemistry, biology, geology, fluid mechanics, and quantum mechanics, to economics and social sciences. The class will consider evidence from the distant past and projections into the distant future, keeping the human time scale of the next several centuries as the bottom line. The lectures follow a textbook, “Global Warming, Understanding the Forecast,” written for the course. For information about the textbook, interactive models, and more, visit: http://forecast.uchicago.edu/ ”
Hat tip to Lionel Smith for the pointer, in a comment here:
http://scienceblogs.com/deltoid/2010/09/steven_schneider_and_the_skept.php?utm_source=mostactive&utm_medium=link#comment-2785002
Adding to Hank’s link:
http://www.statsoft.com/textbook/multiple-regression/
Russ R. @235 — Thank you.
I now have a more realistic, but still very simple, model which will make short range “predictions” if youn supply future net forcings and also future values for the AMO, an index of internal variabilty, also SOI, another indexc of internal variability. Since neithr is predicatable in a deterministic sense, one would need to sample against an ARMA-type model for both. For SOI there is enough data available to construct one; this is much more problematic for the AMO.
Nonetheless, his would give approximate 10–20 year predictions with appropriate error intrvals.
Bob,
I’m sorry, 1-3% of GDP yearly is minor? This is effect of basically going into a recession every year. Over a few years this would have the effect of legislating ourselves into another great depression. Your belief that 1-3% of GDP is minor is simply an indication of your ignorance.
Sources for energy cost increase for purposed cap and trade legislation are litterally all over the place. Here’s a piece from the Heritage: http://www.heritage.org/research/testimony/the-economic-impact-of-the-waxman-markey-cap-and-trade-bill
Which, is estimated at loosing about ~1M jobs, a three thousand dollars/household yearly, and about $400B in GDP yearly. That is not by any means minor.
Other points:
“Second, it also addresses other problems, like peak oil and strategic dependence on oil and coal rich countries.”
Whether we use oil for commerce/industry is going to ultimately be irrelevant for peak oil or defense. F-22 are never going to be solar powered. We’ll always need to protect our oil supplies.
“Third, the world has transitioned in the past from horses and sailing ships to steam ships to more, and from broad sheets to telegraph to radio to television to the Internet. Change happens, and it’s not by default bad and expensive.”
This is a complete red herring and an awful analogy to boot. Have we ever transitioned from a cheaper, more efficient, more easily harvested fuel, to something that is more expensive, and more difficult to use? That’s what we’re considering when going from coal/oil to solar/wind. This change is bad and expensive. What other changes have been before has absolutely ZERO barring on the current technologies and resources available.
“Fourth, if we wait and then find out that the problem is big, the expense will then be huge. Then we have to put the brakes on faster, and worry about having reached a CO2 level that is already dangerous and can’t be undone.”
This may be true, but its only an argument from ignorance. You’re essentially trying to tell me because we don’t know if A will happen we should protect ourselves from A at pretty much an unquantifiable cost, because well, it MIGHT be worse later, but you can’t tell me what kind of chances are around that might. Quite illogical.
“So you are promoting a complete lack of action to avoid what is nothing more than the illusion of dangerous action”
I regect your conclusion based on the false assumption that the action is not “dangerous,” yearly lose of 1-3% of GDP from something like cap and trade alone would be devastating.
Nick Rogers, your reply to Adelady is certainly right: “Uncertainties are critical part of any prediction.” I’d guess that when she wrote @246 “Uncertainties do not change or challenge the overall picture” she meant that greater uncertainty doesn’t move the midrange, it widens both extremes — it is a reason to worry more, rather than less, about the worst case.
If you’re, say, the Nick Rogers who’s written several climate books, don’t take simple answers personally. We don’t know who you are (you can put a URL into the “Website” field if you want more known).
Pointers to basic statistics get given here repeatedly, because later readers may find them useful. No offense meant.
To #258:
“Your claims that the models don’t perform well are simply wrong.”
“Nothing you have said so far is in agreement with the facts.”
It is telling that instead of “simply” showing why exactly the claim (which applies to specific models, see previous page) is wrong or what exactly in the post is not in agreement with the facts (I take “nothing” for what it is – a pose), you have chosen to write 6 paragraphs of invective.
Nick Rogers @257 — Unfortunately this method of communications requires a superabundance of repitition. Learn to deal with it, possibly by just scanning quickly over comments (thoughtfully) offered to others less knowledgable than you.
Thank you.
Wally (#252), your advice is well taken. Hyperbole is best avoided. That goes also for your claim that the testable models suck and the ones not yet testable are little more than guesses.
I think Hargreaves (2010) has a more reasonable take. Already the Hansen (1988) forecast had skill. Lately, it’s turning out to be high, but for reasons that are largely understood. From what we now know about oceans and aerosols, and on current best estimates of climate sensitivity, we’d expect it to be too high. Since current climate models take this knowledge into account, we’d expect them to do at least as well.
I have a trip to make, so I’ll leave the discussion there.
Nick #251, good grief! If projections were contrary to observations then we’d have to re-examine them. As we’re not projecting anything like your suggestion, or any other outlandish possibility, I don’t see your point.
My worry about the projections is that we seem to have understated several things. The Arctic melt is the obvious one at the moment, but methane seems to be bubbling up around both poles and that doesn’t seem outlandish to me. It’s worrying.
Wally, you’re comparing the cost of taking action to — what? Your assumption that nothing could go wrong with business as usual?
Seriously, look for something you can read about the costs of going on in the direction we’re headed. Example:
Estimates of the long-term US economic impacts of global climate change-induced drought. – 2010 –
http://www.osti.gov/bridge/servlets/purl/984152-0fKpjM/984152.pdf
“This report quantifies some of the potential economic impacts of a subset of potential consequences of global climate change, namely changes in domestic agricultural productivity, changes in water available for consumption to large consumers of water, and changes in hydroelectric power consumption caused by global climate change-induced drought in the United States…. this report examines a range of realizable outcomes of different severities to gain a better understanding of the range of possible economic consequences…..”
Or, Wally, read some of the science.
This is — or should be — an eye-opener.
http://www.nature.com/ismej/journal/v4/n9/full/ismej2010107a.html
Commentary
The ISME Journal (2010) 4, 1090–1092; doi:10.1038/ismej.2010.107; published online 8 July 2010
Dangerous shifts in ocean ecosystem function?
Nick Rogers, Tell ya what. We’ll quit emphasizing the importance of proper statistical analysis as soon as you guys actually start doing it. Deal?
Didactylos
“Wally, are you aware that computer models are used successfully for many, many applications where we have no ability to run a full-scale test? Whether it’s simulating the explosion of a nuclear bomb, modelling the failure modes of a hydroelectric dam, or ensuring an aeroplane is safe to fly – we use models all the time.”
Uh, Mr. didactylos, we absolutely have full scale tests for all of those things. People don’t just jump right on a plane that has never been test flown and only undergone some sort of simulated flight. Similarly our hydroelectric models, have how many real world dams to build off of? Do you think we went straight from E=mc^2 to Hiroshima? These models where of course varying degrees of accurate upon their first conception, and as time has passed models for building “aeroplanes” in silico have improved greatly thanks to repeated real world experimentation, but real world tests are essential for every model. Eventually this will be true of climate science as well, both time passes and technological improvements make it easier to run actual experiments.
The rest of your post is utter gibberish, blindly throwing around insults and making grand claims of “limits of livability” with out any grounding in fact. I suppose India is at the “limits of livability?” Please, show me that research piece.
BPL ““How does “harvests failing around the world due to massive increases in drought” grab you?”
Maybe I did not make myself entirely clear. I won’t be scared into believing you, you need to post large and exhaustive set of studies on how the climite change will effect basically everything” Wally — 9 September 2010 @ 9:29 AM
google scholar search for global+warming+drought
Dai, Aiguo, Kevin E. Trenberth, Taotao Qian, 2004: A Global Dataset of Palmer Drought Severity Index for 1870–2002: Relationship with Soil Moisture and Effects of Surface Warming. J. Hydrometeor, 5, 1117–1130. Cited by 328
“Together, the global land areas in either very dry or very wet conditions have increased from 20% to 38% since 1972, with surface warming as the primary cause after the mid-1980s. These results provide observational evidence for the increasing risk of droughts as anthropogenic global warming progresses and produces both increased temperatures and increased drying.”
Constraint to Adaptive Evolution in Response to Global Warming, Science 5 October 2001: Vol. 294. no. 5540, pp. 151 – 154 DOI: 10.1126/science.1063656
“Despite genetic variance for traits under selection, among-trait genetic correlations that are antagonistic to the direction of selection limit adaptive evolution within these populations. Predicted rates of evolutionary response are much slower than the predicted rate of climate change.”
Translocation experiments with butterflies reveal limits to enhancement of poleward populations under climate change. S. L. Pelini, J. D. K. Dzurisin, K. M. Prior, C. M. Williams, T. D. Marsico, B. J. Sinclair, and J. J. Hellmann (2009) PNAS 106, 11160-11165
“…we have evidence that facilitation of poleward range shifts through enhancement of peripheral populations is unlikely in either study species.”
Keeping Pace with Fast Climate Change: Can Arctic Life Count on Evolution? Oxford Journals Life Sciences Integrative and Comparative Biology Volume44, Issue2 Pp. 140-151.
Dominique Berteaux, Denis Réale, Andrew G. McAdam and Stan Boutin
“Our conclusion is that evolution by natural selection is a pertinent force to consider even at the time scale of contemporary climate changes. However, all species may not be equal in their capacity to benefit from contemporary evolution.”
Science 15 August 2003: Vol. 301. no. 5635, pp. 929 – 933 DOI: 10.1126/science.1085046 Climate Change, Human Impacts, and the Resilience of Coral Reefs
Flattening of Caribbean coral reefs: region-wide declines in architectural complexity, Proc Biol Sci. 2009 Aug 22;276(1669):3019-25. Epub 2009 Jun 10.
“In the Caribbean and elsewhere, reef-building corals now face new threats from climate change, particularly in the form of thermally induced coral bleaching and mortality, which are becoming increasingly frequent and extensive as thermal anomalies intensify and lengthen.”
Science 20 August 2010: Vol. 329. no. 5994, pp. 940 – 943 DOI: 10.1126/science.1192666 Drought-Induced Reduction in Global Terrestrial Net Primary Production from 2000 Through 2009 Maosheng Zhao* and Steven W. Running
“The past decade (2000 to 2009) has been the warmest since instrumental measurements began, which could imply continued increases in NPP; however, our estimates suggest a reduction in the global NPP of 0.55 petagrams of carbon. Large-scale droughts have reduced regional NPP, and a drying trend in the Southern Hemisphere has decreased NPP in that area, counteracting the increased NPP over the Northern Hemisphere. A continued decline in NPP would not only weaken the terrestrial carbon sink, but it would also intensify future competition between food demand and proposed biofuel production.”
Science 22 February 2008: Vol. 319. no. 5866, pp. 1080 – 1083 DOI: 10.1126/science.1152538 Human-Induced Changes in the Hydrology of the Western United States
“The results show that up to 60% of the climate-related trends of river flow, winter air temperature, and snow pack between 1950 and 1999 are human-induced. These results are robust to perturbation of study variates and methods. They portend, in conjunction with previous work, a coming crisis in water supply for the western United States.
Science 25 June 2010: Vol. 328. no. 5986, pp. 1642 – 1643 DOI: 10.1126/science.1186591 Climate Change: Dry Times Ahead
“In the past decade, it has become impossible to overlook the signs of climate change in western North America. They include soaring temperatures, declining late-season snowpack, northward-shifted winter storm tracks, increasing precipitation intensity, the worst drought since measurements began, steep declines in Colorado River reservoir storage, widespread vegetation mortality, and sharp increases in the frequency of large wildfires.”
“All of these changes, as well as dramatic warming and drying elsewhere in the region and deep into Mexico, are consistent with projected anthropogenic climate change, but seem to be occurring faster than projected by the most recent national (2) and international (3) climate change assessments…”
Projected changes in drought occurrence under future global warming from multi-model, multi-scenario, IPCC AR4 simulations, J Sheffield, EF Wood – Climate Dynamics, 2008 – Springer
“Recent and potential future increases in global temperatures are likely to be associated with impacts on the hydrologic cycle, including changes to precipitation and increases in extreme events such as droughts.”
Global Warming and the Water Crisis, ]S Kanae – Journal of Health Science, 2009
“… Less water availability and increased drought due to global warming cannot be fully mitigated by high-tech measures such as desalination, even if we neglect the fact that such measures consume much fossil fuel.”
doi:10.1016/j.foreco.2009.09.001 A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests, Forest Ecology and Management Volume 259, Issue 4, 5 February 2010,
“Although episodic mortality occurs in the absence of climate change, studies compiled here suggest that at least some of the world’s forested ecosystems already may be responding to climate change and raise concern that forests may become increasingly vulnerable to higher background tree mortality rates and die-off in response to future warming and drought, even in environments that are not normally considered water-limited.”
http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=155952, Responses of Wheat Varieties Released since 1903 to Increasing Atmospheric Carbon Dioxide
“…newer varieties did not show a stronger carbon dioxide response when growth and yield were compared at a common CO2 concentration of 290 and 370 ppm.”
“In addition, the newer varieties showed a strong decrease in protein content and baking quality…”
Footprint of temperature changes in the temperate and boreal forest carbon balance, Geophysical Research Letters (GRL) paper 10.1029/2009GL037381, 2009
“The authors show that while current mean annual temperatures do not correlate well with current NEP[net ecosystem productivity}, temperature changes spanning the recent past (1980–2002) may be important factors that influence current carbon balance. In particular, changes in past springtime temperatures seem to have had the greatest effect on current annual NEP, the authors find. Their results also suggest that if global warming continues, forests will not continue to be carbon sinks in the future but may instead become carbon sources.”
Wally: “People don’t just jump right on a plane that has never been test flown and only undergone some sort of simulated flight. ”
me: see Test pilot.
Wally: “Eventually this will be true of climate science as well”
me: see hindcasting.
Didactylos: “modelling the failure modes of a hydroelectric dam”
Wally: “we absolutely have full scale tests for all of those things”
Me: Really, full scale tests of failures of dams. Wow.
Wally, is there anything in the world that you know anything about?
“Your belief that 1-3% of GDP is minor is simply an indication of your ignorance.” Wally — 9 September 2010 @ 1:33 PM
According to http://www.tradingeconomics.com/Economics/GDP-Growth.aspx?Symbol=USD
“From 1947 until 2010 the United States’ average quarterly GDP Growth was 3.31 percent reaching an historical high of 17.20 percent in March of 1950 and a record low of -10.40 percent in March of 1958.”
Using their chart tool, From January 1993 to january 2001, the average GDP growth rate was 3.81 percent/yr. From January 2001 through January 2009, the GDP growth rate was 1.75 percent/yr.
According to wikipedia “Another proposed definition of depression includes two general rules: 1) a decline in real GDP exceeding 10%, or 2) a recession lasting 2 or more years.[3][4]” and “Production as measured by Gross Domestic Product (GDP), employment, investment spending, capacity utilization, household incomes, business profits and inflation all fall during recessions;” Depending on whether the actual number is 1% or 3% of GDP, and what the economic climate is, it probably wouldn’t cause a recession,let alone a depression.
“Whether we use oil for commerce/industry is going to ultimately be irrelevant for peak oil or defense. F-22 are never going to be solar powered. We’ll always need to protect our oil supplies.” Wally
For FY 2009, Federal spending was 28 % of GDP, Department of Defense spending was 4.8% of GDP. http://www.census.gov/compendia/statab/2010/tables/10s0459.pdf
“…yearly lose of 1-3% of GDP from something like cap and trade alone would be devastating.” Wally
According to https://www.cia.gov/library/publications/the-world-factbook/geos/us.html, 2009 US GDP was 14.14 trillion dollars.
According http://www.eia.doe.gov/emeu/perfpro/news_m/index.html?featureclicked=3&, nineteen major energy companies reported revenues of 260.6 billion for the second quarter of 2010; ~1.0 trillion for the year, or ~7.4% of GDP.
Replacing fossil fuel expenditures with renewable expenditures wouldn’t be a loss, and it would be less devastating than the current fossil fuel and military expenditures in the Mideast.
Brian,
“Using their chart tool, From January 1993 to january 2001, the average GDP growth rate was 3.81 percent/yr. From January 2001 through January 2009, the GDP growth rate was 1.75 percent/yr.”
Right, so you’d basically stagnate growth at least, or slap it negative, which would be devastating as your population continues to grow.
“Depending on whether the actual number is 1% or 3% of GDP, and what the economic climate is, it probably wouldn’t cause a recession,let alone a depression.”
Uh, did you just look at your facts? Through a 9 year period we averaged 1.75 percent growth. If we assume a 1-3% range of depression of growth and that more recent growth is better indicator or future growth than that of pre-2000, you basically have a a 50-50 chance at positive or negative growth. So….its quite possible this would lead to a recession or even a depression. Especially since growth is never linear. Lets say we entered the most recent recession, yet we had this extra 1-3% drag from cap and trade…TADA! Recession turns to depression.
[Response: Completely OT, no more please. Jim]
273 Wally sez: “Do you think we went straight from E=mc^2 to Hiroshima?”
WHat does the one have to do with the other? You might want to learn some physics and history of physics.
Wally 249,
I’m about to have a paper published on the subject. In the meantime, I recommend reading these:
Battisti, D.S., and R.L. Naylor 2009. “Historical Warnings of Future Food Insecurity with Unprecedented Seasonal Heat.” Science 323, 240-244.
Dai, A., K.E. Trenberth, and T. Qian 2004. “A Global Dataset of Palmer Drought Severity Index for 1870–2002: Relationship with Soil Moisture and Effects of Surface Warming.” J. Hydrometeorol. 1, 1117-1130.
Wally #277, you’re holding the wrong end of the stick on this… the 1-3% should be subtracted from the GDP itself, not from the growth rate. From consumption, not investment. Read about it in the IPCC’s WG3 report… what 3% of GDP means is that we’ll still be getting richer all the time — only a year or two later.
During the Vietnam war, U.S. military spending went as high as 10% of GDP, while the economy just went on growing… you’re seriously underestimating the robustness of the US (and Western countries’) production system. All this depression talk is alarmism of the worst kind.
Wally 252: we do know that cutting back CO2 emissions to the scale required to make a serious dent will give extemely negative effects,
BPL: And how do we know that, precisely?
Wally 264: I’m sorry, 1-3% of GDP yearly is minor? This is effect of basically going into a recession every year.
BPL: You and he both have it wrong. That’s a projection of how much lower GDP will be in 2030 compared to if we take no action, and assuming AGW doesn’t cause any further damage.
Your basic mistake is assuming we’ll be just fine if we do nothing. We won’t be.
Dear Wally: *sigh*
I didn’t really expect you to go away and learn anything, but I hoped so all the same.
It’s not what you don’t know – it’s the vast ocean of knowledge that you aren’t even aware exists. You don’t know how much you don’t know.
For example: the test ban treaty means modelling is now the only method available for nuclear testing. Planes are expensive. Manufacturers do conduct destructive tests, but only the absolute minimum that they are required to do. Thousands more scenarios are run completely virtually, and validated by the full scale tests.
I could go on, but if you aren’t interested in learning then evidently I am wasting my time.
Your odd claim that we will be able to do real world climate experimentation in the future is just bizarre. It’s another clear indicator that you are deeply, truly out of your depth. We already do many real world tests, which are the basis of our models. But we can never do full-scale climate simulations because we only have one Earth-like planet, and we can only run it at 24 hours per day.
That’s quite a major limitation, and destructive testing is severely contra-indicated.
You mention liveability in India. Why you picked a country with one of the highest rates of malnutrition in the world is beyond me. And another example of your inability to find out the first thing about what you are talking about. It’s not difficult. All you need to do is click. And continue to learn.
“I regect your conclusion based on the false assumption that the action is not “dangerous,” yearly lose of 1-3% of GDP from something like cap and trade alone would be devastating.”
Wally – If you’re going to argue the economics, do so ready.
Go away and read the Stern review.
Very short summary
“Using the results from formal economic models, the Review estimates that if we don’t
act, the overall costs and risks of climate change will be equivalent to losing at least
5% of global GDP each year, now and forever. If a wider range of risks and impacts
is taken into account, the estimates of damage could rise to 20% of GDP or more.
In contrast, the costs of action – reducing greenhouse gas emissions to avoid the
worst impacts of climate change – can be limited to around 1% of global GDP each
year.”
‘Cap and trade alone would have a tiny impact on the US economy. Obviously depends on where you set the cap, but the suggestion that it could cost 1% of US GDP is based on … nothing.
Wally, Had you been paying attention, you would have seen that:
1)increasing temperatures decrease yields of rice and many other important food crops
2)increase (along with increasing CO2) survivability and vigor of noxious weeds such as poison ivy
3)increase drought
4)increase severe weather events
And all of this as human population increases to 10 billion by mid century. What is more, you assume that all of the investment in mitigation is lost, when in reality,
1)the development of a non-fossil fuel economy is essential even in the absence of climate factors due to the finitude of fossil fuels
2)Investment in technology pays dividends down the road.
264 (Wally),
I’ll ignore the % of GDP issue, since everyone else is hammering you with it.
This is silly. Obviously we will need oil for certain critical things for a long time, which is all the more reason to be more careful with it. Using our reserves up so you can drive to the mall three times a week is a huge waste.
It’s a perfect analogy. What, the only good analogy would be to point to that time in 1520 when we converted from fossil fuel use to zorgon power? The point of the analogy is that the world changes. It always has and always will. When the world changes that doesn’t instantly make everyone poorer. Quite the opposite, it creates jobs, new opportunities, and ultimately frees people up to focus on other things.
To be honest, when I look at the complexity involved in harvesting oil reserves (locate, drill, extract, transport, refine, transport, and also clean up the inevitable mess) compared to something like wind (build a tower and power grid, then maintain it) I don’t know what you can be thinking by claiming that a FF infrastructure is so wonderful.
You also twisted the argument. You ignored the point that the world has revamped its infrastructure many times in the past, to instead argue that a change to wind and solar power “is bad and expensive.” Based on what? Your personal opinion? One hundred years from now people are going to wonder why the heck we wasted more than a century on FF use.
Note that your argument is also equivalent to “human civilization is doomed.” If we can’t safely get off of FF use now, with the benefits of FF to ease the transition, how are we going to do so when it’s completely gone? Are you saying that when FFs run out, it’s going to be the dark ages for all time?
Except it’s not “might”, it’s “almost certainly.” It’s also not an unquantifiable cost, although ignoring the problem may be. As far as being unable to tell you what kind of chances… well, you know you just made that up. What did you think the IPCC AR4 report was for?
Alarmism, and in a far worse and more incorrect form than when that term is used for those people that (correctly) recognize that climate change is a problem. You have no basis for your argument, except for emotional assertions.
The economy is the denier’s polar bear. It’s the emotional symbol that is used to appeal to people’s fears, to get them to stop thinking and ignore the facts.
264 (Wally),
I do want to add one point on the GDP issue. When the money is spent, that does not mean that it simply vanishes, which is how you are behaving. The money goes to people, to perform labor, and to the owners of various resources (land, metals, vehicles, tools), to construct something new. It’s not very different from what happens now, except that different people are going to receive the money for doing different, new things.
That new thing is replacing an old thing which will eventually wear out anyway. If the money isn’t spent on the new thing, it must instead be spent maintaining and replacing the old, worn out thing. Old oil tankers get decommissioned and replaced by new ones. Old refineries need parts continuously fixed and replaced. Oil wells run dry and are abandoned, and new ones must be built.
All of this is part of the necessary expense of maintaining the existing, but not eternal and unchanging and “cheap,” FF infrastructure. There is a huge, huge expense behind fossil fuels.
So spending some amount of money on wind, solar, hydro, nuclear and other power sources is merely a choice not to put some or all of that same money back into continued fossil fuel use.
The money doesn’t just vanish. No harm whatsoever will come to the economy. Period. In fact, once we are invested in that path, my own personal prediction is that once we get some momentum it will be historically viewed as something of a New Renaissance, the time when the world got cleaner and smarter and better organized, and abandoned a dirty, failing, clumsy and inevitably short term power source.
The only real difference here, if we do things methodically and rationally, is that the poor, rich, Texas oil barons aren’t going to be as rich. Which is why they’re fighting it tooth and nail… just like every other owner of an obsolescent technology has fought change throughout human civilization.
[Response: Let’s get back on topic please]
I’m not entirely sure this is “back on topic” in the strictest sense, but it’s in the spirit of DIY, I think–DIYers always steal from the pros. . .
August GISS anomaly is now online, reported at .74 C. That’s a 2-way tie for 3rd-warmest ever, behind (you may have guessed it) August 1998 (.76 C.) Didn’t check/don’t remember the confidence intervals on the monthly anomalies, but clearly this was an August just as toasty globally as it was here in the Southeast.
UAH had a (predictably) lower, but still warm .51 (of course, that’s for the lower troposphere, not the surface.) We’ll see what NCDC says in a few days.
Wow, way to much to tackle here, but I’ll try.
“I do want to add one point on the GDP issue. When the money is spent, that does not mean that it simply vanishes, which is how you are behaving. The money goes to people, to perform labor, and to the owners of various resources (land, metals, vehicles, tools), to construct something new. It’s not very different from what happens now, except that different people are going to receive the money for doing different, new things.”
True that money doesn’t “vanish” but if you’re putting money to less productive use, the marginal difference in that efficiency does effectively vanish. If we us X dollars to make Y power now, but in the future you need X+Z dollars to make Y power because of cap and trade or what ever legislation, you’ve lost the ability to use Z dollars for other kinds of investments or consumption. Effectively Z dollars are now gone from the new system compared to the old system. Further, this will happen every year this system is in place. So it will continually slow growth, not simply slow growth for a few years until we return to some sort of normal growth as one poster claimed above.
“The point of the analogy is that the world changes. It always has and always will. When the world changes that doesn’t instantly make everyone poorer. Quite the opposite, it creates jobs, new opportunities, and ultimately frees people up to focus on other things. ”
That depends on the kind of change Bob. That was my point, and you ignored it. If we transition to more expensive, less efficient fuels, that’s change for the worse. We’ll use our current wealth to create new wealth less efficiently. That’s the point.
“You ignored the point that the world has revamped its infrastructure many times in the past, to instead argue that a change to wind and solar power “is bad and expensive.” Based on what?”
Cost per unit energy.
>Except it’s not “might”, it’s “almost certainly.”<
No, it isn't "almost certainly," that's what we've been attempting to discuss until the GDP discussion started, and no one has been able to prove such a thing.
"1)increasing temperatures decrease yields of rice and many other important food crops
2)increase (along with increasing CO2) survivability and vigor of noxious weeds such as poison ivy
3)increase drought
4)increase severe weather events"
I won't bother to go into a lot of detail, as neither has this poster even attempted to prove such things, but every one of these issues has been debunked.
"1)the development of a non-fossil fuel economy is essential even in the absence of climate factors due to the finitude of fossil fuels"
True, but that doesn't mean we have to make painful top-down legislation. As fossil fuels become more scarce, the price will go up naturally, and the alternatives will become more competitive. Plus, by that point, the alternatives might actually have improved as well.
"2)Investment in technology pays dividends down the road."
Depends on technology and the amount of investment. We could likely dump billions into cold-fusion and never get anything productive. Similarly what's the point of using up X dollars just to make the technology if you'll never actually be able to save at least X dollars in the future with it? These kinds of statements are far to simplistic to be at all useful or constructive.
"Using the results from formal economic models, the Review estimates that if we don’t
act, the overall costs and risks of climate change will be equivalent to losing at least
5% of global GDP each year, now and forever."
So you've now combined the results from climate models with dubious validity with economic models? I see expanding error bars….
"Obviously depends on where you set the cap, but the suggestion that it could cost 1% of US GDP is based on … nothing."
Silk, its based on increased power costs, which are pretty straight forward to evaluate.
"Your basic mistake is assuming we’ll be just fine if we do nothing. We won’t be."
This hasn't been established, as much as you'd like it to be. You can neither prove the magnitude of warming, much less its effects on the entirety of world and human actions.
And this one is too rich to pass up:
"273 Wally sez: “Do you think we went straight from E=mc^2 to Hiroshima?”
John: "WHat does the one have to do with the other? You might want to learn some physics and history of physics."
First, you're talking to some one that holds a BS in physics among other things. Second, the idiocy of your comment is self evident, so I'll let it speak for itself. Good laugh though John. Next time think before you cast an insult, you might just make yourself look like a fool again.
> a BS in physics
I’ll believe that, but I’d bet it was more than 30 years ago. Much has been learned since. Have you read Spencer Weart’s history? First link under Science sidebar.
Wally may need to consider the RealClimate PhDs have kindly indicated to him that this is not the place for those “other things”.
Re: Silk (284)
Stern released an update:
Source here.
The Yooper
Wally, maybe you didn’t notice, but your “answer” failed to actually answer anything.
Which really has been our complaint all along. Now, stop appealing to your own imaginary authority, and go and seek some knowledge.
We’ll wait.
Kevin, I see 0.53 – where are you looking?
0.53 is identical to July, and in line with the end of El Nino.
There are two basic tactics used by those who profit enormously from fossil fuels and who therefore wish to obstruct and delay the urgently needed phase-out of fossil fuels:
1. Deny that the problem exists. Everyone here is familiar with the various forms of AGW denial.
2. Deny that alternatives to fossil fuels exist. This includes denigration and disparagement of alternative energy sources, exaggeration of the importance of fossil fuels (e.g. without fossil fuels we will live in caves and wear animal skins — just like people in the 19th century did, I guess), exaggeration of the cost of transitioning from a fossil fuel economy to a wind/solar based economy, etc.
What Wally is offering here is the second tactic. I don’t accuse him of deliberate dishonesty; I have no reason to doubt that he has embraced in all innocence and good faith the obstructionist propaganda that has been spoon-fed to him — and to a great many people — by those who wish to protect the billion-dollars-per-day profits of the fossil fuel corporations at any cost.
The facts are, that the AGW problem is FAR WORSE than most people realize, including (I believe) some climate scientists; and on the other hand, the solution is FAR EASIER than most people realize, if they are not paying close attention to ongoing developments in renewable energy and efficiency technologies.
We have a very horrible problem, that we can solve rather quickly, easily and inexpensively if we choose to do so. The obstacles are not technical or economic; the only real obstacle is the vast, entrenched power and wealth of the fossil fuel corporations which has enabled them for a generation to obstruct solutions.
Sea Surface Temperatures in the Atlantic’s main hurricane development region had warmest August on record, 1.23C above normal: http://bit.ly/JeffMWB
“”1)increasing temperatures decrease yields of rice and many other important food crops
2)increase (along with increasing CO2) survivability and vigor of noxious weeds such as poison ivy
3)increase drought
4)increase severe weather events”
I won’t bother to go into a lot of detail, as neither has this poster even attempted to prove such things, but every one of these issues has been debunked.” Wally — 10 September 2010 @ 12:48 PM
For those who might be interested in some details from the literature –
(1)
Global scale climate–crop yield relationships and the impacts of recent warming, stacks.iop.org/ERL/2/014002
“For wheat, maize and barley, there is a clearly negative response of global yields to increased temperatures. Based on these sensitivities and observed climate trends, we estimate that warming since 1981 has resulted in annual combined losses of these three crops representing roughly 40 Mt or $5 billion per year, as of 2002.”
Rice yields decline with higher night temperature from global warming, http://www.pnas.org/content/101/27/9971.full
“We analyzed weather data at the International Rice Research Institute Farm from 1979 to 2003 to examine temperature trends and the relationship between rice yield and temperature by using data from irrigated field experiments conducted at the International Rice Research Institute Farm from 1992 to 2003. Here we report that annual mean maximum and minimum temperatures have increased by 0.35°C and 1.13°C, respectively, for the period 1979–2003 and a close linkage between rice grain yield and mean minimum temperature during the dry cropping season (January to April). Grain yield declined by 10% for each 1°C increase in growing-season minimum temperature in the dry season,”
“Relationships between grain yield and temperature or radiation were evaluated by using yield data from field experiments conducted under irrigated conditions with optimal management at the IRRI Farm from 1992 to 2003.”
Nonlinear temperature effects indicate severe damages to U.S. crop yields under climate change, http://www.pnas.org/content/106/37/15594.abstract
“We find that yields increase with temperature up to 29° C for corn, 30° C for soybeans, and 32° C for cotton but that temperatures above these thresholds are very harmful. The slope of the decline above the optimum is significantly steeper than the incline below it.”
“Holding current growing regions fixed, area-weighted average yields are predicted to decrease by 30–46% before the end of the century under the slowest (B1) warming scenario and decrease by 63–82% under the most rapid warming scenario (A1FI) under the Hadley III model.”
Radically Rethinking Agriculture for the 21st Century, Science 12 February 2010: Vol. 327. no. 5967, pp. 833 – 834 DOI: 10.1126/science.1186834
“Climate change also has important implications for agriculture. The European heat wave of 2003 killed some 30,000 to 50,000 people (3). The average temperature that summer was only about 3.5°C above the average for the last century. The 20 to 36% decrease in the yields of grains and fruits that summer drew little attention.”
(2)
Biomass and toxicity responses of poison ivy (Toxicodendron radicans) to elevated atmospheric CO2. Proc Natl Acad Sci U S A. 2006 Jun 13;103(24):9086-9. Epub 2006 Jun 5.
“In this 6-year study at the Duke University Free-Air CO(2) Enrichment experiment, we show that elevated atmospheric CO(2) in an intact forest ecosystem increases photosynthesis, water use efficiency, growth, and population biomass of poison ivy. The CO(2) growth stimulation exceeds that of most other woody species. Furthermore, high-CO(2) plants produce a more allergenic form of urushiol. Our results indicate that Toxicodendron taxa will become more abundant and more “toxic” in the future, potentially affecting global forest dynamics and human health.”
Response of an allergenic species, Ambrosia psilostachya (Asteraceae)[ragweed], to experimental warming and clipping: implications for public health (American Journal of Botany. 2002;89:1843-1846.)
“Warming increased ragweed stems by 88% when not clipped and 46% when clipped.” “Although warming caused no difference in pollen production per stem, total pollen production increased by 84% (P < 0.05) because there were more ragweed stems."
Changes in biomass and root:shoot ratio of field-grown Canada thistle ( Cirsium arvense), a noxious, invasive weed, with elevated CO2: implications for control with glyphosate, Weed Science, 52:584–588. 2004
"…the study indicates that carbon dioxide–induced increases in root biomass could make Canada thistle and other perennial weeds that reproduce asexually from belowground organs harder to control in a higher [CO2] world." "At the time of herbicide application, growth at elevated [CO2] had resulted in a small but significant increase in shoot biomass in both years but a larger, significant increase in root biomass (2.5- to 3.3-fold) relative to am bient [CO2]."
There is some good news – "Production of morphine in wild poppy (Papaver setigerum) (Ziska et al. 2008b) (Figure 1) showed significant increases with both recent and projected CO2 concentrations." http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2649213/
Didactylos, #294–
This is what I was looking at. Seems like it’s the correct table, but let me know if I’ve missed something.
http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt
Hank,
It was going on six years ago now. And how much has BS level physics really changed in the last, I don’t know 20 years, at least? All the basic courses, quantum mech, thermo, electromagnetism are pretty much unchanged. Some of the elective type class may have been improved upon, update, and even rotated out of fashion, but undergrad physics is probably one of the most static majors as far as content goes out of all the sciences over the last 50 years. Compare to say, biology. We change what we teach undergrads almost yearly.
Secular,
You’re creating strawmen. Most of us in the skeptic camp do agree with AGW, we disagree with catastrophic AGW.
Second, we don’t deny no alternatives exist, we point out they are not currently practical and/or expensive.