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One Planet Only Forever at 10:01 AM on 21 December 2014What happens if we overshoot the two degree target for limiting global warming?
wili,
The current CO2 levels have not locked in endless increase in temperature. What has been locked-in is a long-term feedback response system which will raise temperatures for several decades before a balance condition is reached. The current CO2 levels will not lead to an endless always increasing temperature, just like the 280 ppm level over the past 1000 years had not caused endlessly increasing global average temepratures.
So curtailing the addition of CO2 by curtailing the burning of buried hydrocarbons is the most important thing to do. And once humans stop adding CO2 from that activity the eventual maximum global average impact will have been established, and it will be reached several decades later as the feedbacks collectively develop a new balanced condition. However, other changes of human activity can actually reduce atmospheric CO2 levels by things like:
- reforesting to increase the locking in of carbon into trees
- CO2 capture and storage applied to biofuel burning (CO2 capture on coal burning reduces CO2 emissions but is still adding CO2).
A more difficult thing to evaluate is the potential for the feedbacks to collectively lead to very significant additional rapid changes resulting in the new balanced point being extremely magnified beyond the simple additional CO2 impact. Mann and others have repeatedly tried to raise awarenss of this concern so that policy makers do not get the idea that it is OK to shift to a higher target of human impact if we don't want to limit things to 2.0 degrees C.
The lack of action by the biggest impacting humans since 1990, when there was no doubt about the need to reduce the human impacts, resulted in a limit of 1.5 C being virtually unachievable by 2009. As much as I agree with the point that a continued lack of concern by current generations resulting in 2.0 C being unachievable would be no reason to stop trying to limit the impact, it is very dangerous to imply that it would be reasonable and decent or acceptably 'pragmatic' (a work I despise being applied to the knuckle-dragging done by many 'leaders' regarding this issue), for a current generation to decide 'it is too hard' for them to do what 'needs' to be done. The real problem is that the need is a future need. The current socioeconomic system encourages too many people to only care about their current 'desires' even making some people believe the 'desires' are 'needs'.
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wili at 09:31 AM on 21 December 20142014 SkS Weekly News Roundup #51B
Second word of second title needs to be corrected: "Aboriginal kowledge could unlock climate solutions"
Moderator Response:[JH] Done. Thank you.
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MA Rodger at 07:31 AM on 21 December 2014Arctic sea ice has recovered
Responding to off-topic comment here (as is #68 & #69 above).
The David Rose item in the Rail on Sunday of 30/8/14 basically does the usual Rose trick of "hiding his bogus decline" in AGW predictions by making such predictions as extreme as possible and then proving them to be in error. Sadly, and Rose is a real saddo, he is unable to do this without misrepresenting those extreme positions and his proofs.
To debunk his 30/8/14 piece would take a while to write out. But it would likely start something like this.
☻ Rose misrepresents what Gore said in 2007. Firstly Gore was reporting what others had said and secondly he mentioned two predictions for an ice-free summer - 7 years and 22 years. Rose usually plays an extremly strong game misrepresenting AGW comment.
☻ The 25th August date is a bit of a cherry-pick. A couple of days earlier and it would have been "since 2009" not since "since 2006" because 2009, 2013 and 2015 SIE were very similar through the height of the melt season.
☻Rose mischaracterises the period 2012-14. Most of the SIE increase (90%) occurred 2012-13. His comment about 'consentrations' is likewise a mischaracterisation. Most of the SIA increase (95%) occurred 2012-13. So his news story is a year out-of-date. SIV is however more even between the two years.
☻ Judy Curry is more a denialist blog-mom these days and no longer a pukka climatologist. Her assertion that the "death spiral" is (or will be) entering a reversal which will last decades is air-headed lunacy of her own creation.
And on and on and on. -
MA Rodger at 07:25 AM on 21 December 2014Antarctica is gaining ice
alan2112drums @371.
I think the writings of David Rose of the Daily Mail on the subject of AGW are usually requiring "rebuttal" rather than "peer review". Even the IPCC have found it necessary to carry out such corrections, as SkS posted here.
I will add comment on this particular serving of gobshite from Rose on the same thread linked @373 & 375.
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John Cook at 07:01 AM on 21 December 2014My AGU talk on tackling climate myths in a free online course
Shoyemore: am very familiar with Kahneman's fast and slow thinking, which is extremely relevant to how people think about climate change. Very insightful and influential work.
BTW, I've uploaded the slides for my talk in PDF form (link at the top of the OP).
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Daniel Bailey at 06:50 AM on 21 December 2014Antarctica is gaining ice
I have replied to that nonsense about Al Gore and Arctic Sea Ice demise by such-and-such date, here.
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Daniel Bailey at 06:47 AM on 21 December 2014Arctic sea ice has recovered
In reality, Gore echoed Wieslaw Maslowski's prediction.
Maslowski's prediction, originally made in 2006, was that Arctic sea ice would decline to <1,000,000 square kilometers extent (with no ice at the North Pole) by the end of the September melt by 2016, +/- 3 years. So 2013-2019. [Source, slide 6]
But that truth is always inconvenient to deniers, who revert to their preferred idiom of mendacity, prevarication and lies indiscriminately, without pretext needed.
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Daniel Bailey at 06:44 AM on 21 December 2014Antarctica is gaining ice
I have placed some updated information on Polar Bears here.
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Daniel Bailey at 06:42 AM on 21 December 2014Polar bear numbers are increasing
Polar Bear populations are declining.
In 2005, the IUCN Polar Bear Specialist Group (PBSG) classified the Polar Bear as a vulnerable species. In 2009, they reported that of the 19 subpopulations of Polar Bears:
8 are declining
3 are stable
1 is increasing
7 are without sufficient dataThis compares with, in 2005:
5 declining
5 five stable
2 increasing
7 data deficient[Source]
· A decline in survival of female polar bears of all age classes, from 1194 to 806, between 1987 and 2011 in western Hudson Bay was due to earlier sea ice break-up in the spring and later freeze-up in the autumn.
· In 2010, polar bear numbers in the southern Beaufort Sea appeared to stabilize at 900 bears following a period of low survival during 2004-2006 that led to a 25-50% decline in abundance. However, survival of sub-adult bears declined during the entire period.
· Polar bear condition and reproductive rates have also declined in the southern Beaufort Sea, unlike in the adjacent Chukchi Sea, immediately to the west, where they have remained stable for 20 years. There are also now twice as many ice-free days in the southern Beaufort Sea as there are in the Chukchi Sea.
· Genetic studies indicate that polar bears have been through long and dramatic periods of population decline during the last one million years, and that during periods with little sea ice there have been multiple episodes of interbreeding between polar bears and brown bears.
[Source]
"The primary habitat for polar bears and their prey, sea ice, is declining rapidly in extent in all seasons, and particularly in summer, with concurrent and even more dramatic reductions in total volume (Laxon et al. 2013). Since the satellite record began in 1979, minimum sea ice extent has declined 13.3% per decade (see the essay on Sea Ice). Given the close association between polar bears, their primary prey and sea ice, climate warming remains the most significant threat to the long-term survival of this species (Stirling and Derocher 1993, Amstrup et al. 2008, 2010)."
[Source]
The evidence is clear: Polar Bear populations are declining.
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wili at 05:35 AM on 21 December 2014What happens if we overshoot the two degree target for limiting global warming?
OPOF, what is the source for your last claim. It would seem to contradict recent work by MacDougal et al. and other papers that take carbon feedback into account, unlike most earlier models.
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shoyemore at 05:18 AM on 21 December 2014My AGU talk on tackling climate myths in a free online course
I watched the Muller video and it reminded me of this book:
Thinking Fast and Slow by Daniel Kahneman
Kahneman is an Israeli psychologist and Professor at Yale who won a Nobel Prize in Economics. The book is about what he calls Fast Thinking ("heuristics" or short cuts), and Slow Thinking which is more logical but mentally draining and demanding, but more likely to give right answers.
Fast Thinking has its place in time of crisis "fight or flight", but as humans we over-use it in a lazy fashion.
It seems to me Miller is saying that to teach physics, or probably any science, you need to engage Slow Thinking. Bit off-topic, but you might find Kahneman's book enlightening, John, if you have not already read it.
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wili at 05:06 AM on 21 December 2014Two degrees: Will we avoid dangerous climate change?
The second sentence in section 5: "In order to meet limit warming to two degrees the world must..." has something wrong. I think you want to drop "meet."
(But of course the whole section is essentially saying that we need to rely on fairy dust. How did we go so very far down such a very wrong road?)
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Composer99 at 04:35 AM on 21 December 2014Antarctica is gaining ice
alan2112drums:
I have responded here to the point raised by the Daily Mail about sea ice. Perhaps others will offer additional perspectives.
I must leave it to others to address the polar bear matter - although the on-topic post I have shared does, too.
(I have to get to cleaning a bathroom. Fun times.)
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Composer99 at 04:33 AM on 21 December 2014Arctic sea ice has recovered
alan2112drums:
Further to your comment on the Antarctic thread, please see the original post and review the findings on sea ice.
You may also wish to review the behaviour of the sea ice relative to the IPCC AR4 projections (here) - note that this information is only from 2009, so it doesn't show the record low set in 2012 - or the behaviour of the sea ice over the last (not quite) 1,500 years (here).
Basically, Arctic sea ice has fallen off the proverbial cliff. Al Gore got that right, at any rate.
Arctic sea ice minimum in 2014 (September) was 5.02 million km², which NSIDC reports is the 6th lowest on record. Arctic sea ice maximum in 2014 (March) was 14.8 million km², which NSIDC reports is the 5th lowest on record.
Arctic sea ice behaviour year-over-year is not monotonic, and as far as I can see the Daily Mail is taking advantage of this fact to form a narrative that casts doubt on the science, when in fact what is seen is merely the result of stochastic fluctuation.
Just to be clear, what I perceive the Mail as doing is:
- Provide quote from Al Gore (despite Gore emphatically not being a climate scientist, "spokesperson" for climate science, or otherwise generally a source of information used by scientists), possibly omitting contextual remarks (and definitely ignoring Gore's own inclusion of uncertainty - note the words "could" and "in as little as seven years", which allow that an ice-free summer could be more than 7 years away, too) to maximise dramatic effect.
- Contradict Gore with very careful framing (notice how much the Mail emphasises the degree to which Arctic sea ice has increased relative to 2012, despite the general irrelevancy of that information).
- This allows a reader who wishes to dismiss the actual science to do so - "Well, if Gore got it so wrong in 2007, why should we take climate scientists so seriously now?" - without the Mail taking responsibility for making false claims.
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michael sweet at 04:02 AM on 21 December 2014Examining Hansen's prediction about the West Side Highway
Roger,
Have you gone to WUWT and asked them to correct al the other posts they have with errors? It will be a long post since you will have to correct virtually everything they have. Why are you so concerned that SkS is perfect when the bulk of WUWT is in error?
In examining your link they still claim that Hansen is wrong. Why should SkS change their article when WUWT has not changed their claim? You need to correct WUWT before you try to get the post here changed.
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Composer99 at 03:56 AM on 21 December 2014Antarctica is gaining ice
alan2112drums:
I believe you can simply share the link (which you did at the bottom of your post - unless that's for a related post) and either paste/quote relevant highlights or paraphrase what you think are the key points, rather than copy/pasting the entire article - especially since the Daily Mail still has copyright on its own content.
Please note that this original post & thread are meant to discuss the behaviour of Antarctic ice, and as such remarks about either the Arctic sea ice or polar bear populations - which appear to be the main poitns of contention raised by the Daily Mail article - are off-topic.
Threads for further follow-up (including responses):
- Arctic sea ice
- Polar bear populations
- There may be other appropriate threads following a search.
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alan2112drums at 03:17 AM on 21 December 2014Antarctica is gaining ice
I am not a scientist, merely a layman that discusses politics and current events with my 20 year old son studying engineering, physics and math at the University of Waterloo in Canada. He supports the claim that climate is changing and the polar ice cap is shrinking. I am a right wing skeptic so I am searching for more info on this claim. Our only right wing media (Sun News) regularly scrutinizes these and other topics with in depth reports and documetaries. I find them extremely interesting and much more balanced than what I see on main stream media, (hence my skepticism). I found this article from "mail online", also called "Daily Mail" and was hoping this forum could do a "peer review" of sorts on it. (I'm sorry to have copied & pasted the entire document but I knew no other way to share it here).
Read more: http://www.dailymail.co.uk/sciencetech/article-2738653/Stunning-satellite-images-summer-ice-cap-thicker-covers-1-7million-square-kilometres-MORE-2-years-ago-despite-Al-Gore-s-prediction-ICE-FREE-now.html#ixzz3MSUzouTW
Moderator Response:[Rob P] Please don't copy/paste screeds of text. I have removed it but, in the future, a simple link will suffice. Also, note the correct threads for this are the Arctic sea ice and polar bear myths - as Composer99 points out.
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BillEverett at 02:41 AM on 21 December 2014My AGU talk on tackling climate myths in a free online course
@bouke Thanks for the link. I had not seen that TED Ed talk, but I had seen D. Muller's video "Khan Academy and the Effectiveness of Science Videos" at https://www.youtube.com/watch?v=eVtCO84MDj8, which presents basically the same message, and I downloaded his thesis to read from the link in the YouTube video description. "Start with the misconception." People don't learn from being told; they learn from thinking (mental effort).
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John Cook at 02:32 AM on 21 December 2014My AGU talk on tackling climate myths in a free online course
Yes, I have seen his work and watched his online talks (which are very good). We discussed interviewing him when we were at UNSW interviewing climate scientists but apparently he's abroad at the moment.
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bouke at 01:59 AM on 21 December 2014My AGU talk on tackling climate myths in a free online course
I wonder if you're familiar with the work of Derek Muller; he did a PhD on how to teach physics. Your approach reminded me of his work, but watch for yourself:
https://www.youtube.com/watch?v=AcX3IW00nuk
Moderator Response:[PS] Fixed link
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Joel_Huberman at 00:34 AM on 21 December 2014Rising air and sea temperatures continue to trigger changes in the Arctic
I've just looked at the full report. The word "permafrost" is mentioned only four times in the report, and never in depth. The word "methane" is not mentioned at all. This year's report contains ten substantive chapters, each dealing with a different aspect of Arctic conditions. None of the chapters in this year's report was targeted at permafrost, sea level, or coastline stability. Perhaps those subjects will be addressed in future reports.
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Roger Knights at 21:31 PM on 20 December 2014Examining Hansen's prediction about the West Side Highway
In March 2011, perhaps in reaction to this March 10 SkS thread, Watts updated his original 2009 story to correct the record and concede that 40 years was the correct number. He wrote, “So I’m happy to make the correction for Dr. Hansen in my original article, since Mr. Reiss reports on his original error in conflating 40 years with 20 years.”
See the updated first pages at: http://wattsupwiththat.com/2009/10/22/a-little-known-but-failed-20-year-old-climate-change-prediction-by-dr-james-hansen/
SkS should update its head post by mentioning Watts’s update. As-is, it can be read as implying that Watts is continuing to make a debunked claim. (It says, “One climate myth found on the internet, propagated by Anthony Watts, is that James Hansen erroneously predicted . . . .”) In addition, “previously” should be inserted before “propagated.”
Moderator Response:[JH] Your concerns have been duely noted.
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One Planet Only Forever at 15:11 PM on 20 December 2014What happens if we overshoot the two degree target for limiting global warming?
denisaf,
You are correct about the damage to the ocean due to excess CO2 being absorbed. And the ocean is taking in a large amount of heat energy, however, because it is such a large mass it has not gotten very much warmer. A very small amount of ocean warming represents a huge amount of energy. However, the temperature will not continue to rise is humans curtail the creation of excess CO2 acummulation in the atmosphere.
The extra CO2 simply absorbs more infrared radiation that is being emitted by the planet surface. There is always a balance point when the warmer surface is emitting enough extra infrared to balance with the incoming solar radiation.
Though the excess CO2 that has accumulated in the atmosphere (most of the excess is being absorbed in the oceans), is expected to persist as excess for a very long time before it naturally gets lowered, the global average surface temperature will reach a 'balanced energy state' (balancing solar energy in with emitted energy getting out through the thicker CO2 'blanket'), at any level of CO2. It is expected to take at least 10 years for the 'balanced state' to be established for any level of CO2. However, if the excess CO2 concentration stops increasing the global average is expected to also stop increasing. So it is possible for human activity to change in ways that will reduce the future impact.
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denisaf at 14:53 PM on 20 December 2014What happens if we overshoot the two degree target for limiting global warming?
The current atmospheric concentration level of greenhouse gases has put in place a blanket that is causing irreversible global warming. The objective of the so-called 2 degree of warming is meaningless.The degree of warming will coninue to increase even if the rate of greenhouse emissions slow down due to decisions made and implemeted by governments. Ironically, the absorption of heat by the oceans will only slow the atmospheric heating down slighlty while the absorption of some of the greenhouse gases is causing the damaging ocean acidification.
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One Planet Only Forever at 09:56 AM on 20 December 2014What happens if we overshoot the two degree target for limiting global warming?
shastatodd@6,
The amount of climate difference resulting from only the 0.4 C cooling that occurred during the time of the Mauder Minimum is indeed significant. It does suggest that a 2.0 C increase would result in very significant changes. That is indeed the concern.
A recent SkS item here presents the case that 2.0 degrees C should be considered an increase of significant concern and be the upper limits of impacts resulting from policy makers decisions of actions to be taken. Earlier reports have indicated that even a 1.5 C increase would lead to significant and difficult to forecast rapid changes of regional climate. Those changes could be difficult to effectively adapt to regionally since they would be changing so rapidly. At Copenhagen in 2009 global leaders had to admit that the lack of action by the already developed highest impact people, including the increased impacts of a dastardly few who already were very fortunate, had made a 1.5 C limit virtually impossible to achieve.
So 2.0 C is not just a concern it is a serious concern. Exceeding it is not considered to be decent, however, as has been stated, it would be even less acceptable to declare that since the impacts to date are so significant there is no reason for any attempts to reduce the impacts that the highest impact people of this generation have on future generations.
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Riduna at 09:52 AM on 20 December 2014Rising air and sea temperatures continue to trigger changes in the Arctic
Interesting Report Card.
Thank goodness the effects of Arctic Ampilification have, apparently, had no effect worth mentioning on carbon release from thawing permafrost, instability on foundations of buildings or infrastructure, no effect on average global sea level and no effect on erosion of Arctic Ocean coastlines.
Some might think the report incomplete.
Moderator Response:[JH] Please note that the OP is only a news release summary of the full report.
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scaddenp at 05:44 AM on 20 December 2014What happens if we overshoot the two degree target for limiting global warming?
Further to Rob's comment, I dont know what you are using as your source of information on the LIA, but I would strongly recommend you read the chapter in the IPCC report (paleoclimate) for a summary of the science to date on the LIA. It is more accurate to say that the maunder minimum contributed to the LIA than caused it. To get a better idea of the effect of the Grand minimum alone, then it would be best to look at the Southern hemisphere climate in the LIA.
You can see here to comment on what a Grand minimum would bring. +2 is no picnic but projecting from LIA is too extreme.
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Rob Honeycutt at 05:31 AM on 20 December 2014What happens if we overshoot the two degree target for limiting global warming?
shastatodd... A new Maunder minimum is highly speculative, but even if it were to occur, it would likely have only a small influence on global temperature trends. Radiative forcing for solar is on the order of 0.05W/m2, whereas the change for anthropogenic forcing is >2W/m2.
Solar barely registers relative to man-made causes.
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shastatodd at 04:12 AM on 20 December 2014What happens if we overshoot the two degree target for limiting global warming?
it is speculated that the sun is entering another "maunder minimum"... in doing some online research about that event, the associated "little ice age" was caused by an estimated -.4 C degree cooling, from decreased solar output.
if -.4 C created that much change, how is that +2 degrees C is considered acceptable? -
jja at 03:41 AM on 20 December 2014Rising air and sea temperatures continue to trigger changes in the Arctic
Twice the Global Average, not "anywhere on earth".
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MA Rodger at 20:41 PM on 19 December 2014CO2 lags temperature
davytw @447.
I have to say that your denialist has a pretty poor graph. There is a far better one, also from Wood-for-trees, up-thread @391.
As folk here describe, there is a tiny CO2 effect due to rising global temperature but also due to ENSO which wobbles temperature & CO2 both, small (or perhaps more correctly very small) effects when compared with the direct anthropogenic inputs of CO2.
These tiny wobbles are used by some, with added smoke and mirrors, to 'demonstrate' that rising CO2 is natural. I think Murray Salby takes the saddo prize in these works of lunacy as he has actually managed to line all his mirrors up to link this modern-day lagging of CO2 with the measured lags in CO2 in the ice core data. (If you can cope with such madness, there is a 68 minute video of his presentation here. I think it helps if you wear tin-foil hat, just to get into the spirit of the thing.)
Encountering such mind-blowing nonsense once too often prompted me to produce this graphic (usuallt 2 clicks t 'download you attachment'). I forget whose equasion it was, possibly Humlum's. And I'm pretty certain there is a SkS version as well, somewhere.
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localis at 18:22 PM on 19 December 2014What happens if we overshoot the two degree target for limiting global warming?
The latest C02 levels are now very close to passing the 400 ppm level again which may mean that 2015 could be the first year that remains above that level throughout. This seems to indicate that C02 levels are still increasing at an accelerating rate. Quite how we can even consider achieving a limit on future warming seems more based on optimism than science until we can stabilize C02 levels at their current level.
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Tom Curtis at 16:25 PM on 19 December 2014CO2 lags temperature
davytw @447, you have three excellent responses so far. Let me add that it is often worthwhile taking denier cherry picks or other selective data at face value. If you do in this case, for example, you see that the lag shown is about 1 year. So, assume CO2 lags temperature by one year, and assume also, as per denier dogma, that there has been a pause in global temperatures. It follows that from one year after the pause started (1995 and 1998 seem to be the preffered values) there has been a pause in the rise of global CO2 concentrations. If your interlocuter cannot show you that pause the raw CO2 data, then it follows that either:
There has been no pause in global temperatures; or
CO2 does not simply lag global temperatures and the graph has been deceptively constructed to show an appearance that is not real; or both.
In other words, even at face value combined with the raw data, the claim refutes itself.
On a more subtle point, the partition of CO2 between the three main surface reservoirs (atmosphere, ocean and terrestial biosphere) is governed by temperature. In particular, increased temperatures will shift CO2 from the ocean to the atmosphere. If there are no other relevant factors, this is the primary short and medium term controller of CO2 concentration, and given the size of the effect relative to the increase in global temperature, dominates CO2 concentrations at sub decadal time scales. However, anthropogenic emissions over a decade or more far exceed the variation in CO2 concentration caused by small temperature effects so that anthropogenic emissions control almost completely the long term rise.
Long term temperture trends (such as occur at the start and end of glacials) can result in long term changes in CO2 concentration. However, taking the graph your denier interlocuter provided, the ratio appears to be 1 ppmv of CO2 increase for every 2.5 C increase in temperature. (Again the advantage of face value. Your interlocuter must either admit that figure or something very close, or admit the graph has been deceptively constructed.) Based on that figure, the approximate 1 C temperture increase since the preindustrial can only be responsible for about 0.5 ppmv increase on CO2 concentration ;)
Of course that figure is way to low, because the graph is deceptively constructed. Using the ratio between temperature and CO2 concentrations in the glacial, the actual increase in CO2 due to the 1 C increase in temperature may be as much as 20 ppmv. Of course, that increase is itself no more natural than the warming.
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dvaytw at 16:14 PM on 19 December 2014CO2 lags temperature
As usual, fellas, your help is much appreciated!
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One Planet Only Forever at 14:32 PM on 19 December 2014What happens if we overshoot the two degree target for limiting global warming?
Unfortunately the discussion of the science and the clearly indicated required changes of how people can enjoy their life appears destined to lead to an insufficient response from leadership in current society.
Levermann's end of comment "... but that is for society to decide." is the crux. How can the future global society that will have to deal with these consequences influence the decisions made by today's society? The problem is the lack of consequences to the leaders of the current global powerful and wealthy societies (leaders of politics, industry, and finance).
The science has been strong and continues to get stronger. Yet people who are undeniably aware of the science continue to attempt to increase profit taking from activities known to need to be curtailed. As a result, the 'target' temperature will increase until there are meaningful consequences for the powerful people in a current society who knowingly deny and resist the need to act more decently.
Continued development of the science will strengthen the case for penalties against those who willfully try to benefit in ways they understand they should not (including carbon taxes). Hopefully some of the worst actors will be penalized retroactively for past actions. When that first such 'significant penalty' is effectively applied to a wealthy and once powerful person the motivation for more decent behaviour will grow and we can then begin meaningfully forecasting the likely maximum global temperature.
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CO2 lags temperature
Looks like one of the heavily massaged graphs that Smokey/dbs/dbstealey, WUWT moderator and sock puppet extraordinare keeps posting. Congratulate your guy, he's (re) discovered that atmospheric CO2 varies with the growth and die-off of global seasonal vegetation. Which we already knew.
The short term and the use of 'isolate' are the give-aways; removing the long term rise in CO2 and ignoring mass-balance, isotope, oxygen level, and all the other evidence demonstrating an anthropogenic cause for rising CO2.
It's simply amazing how much deliberate effort goes into these denial graphs. At best (!) confirmation bias, searching for a combination that confirms what they believe despite the evidence, or at worst, flatly attempting to lie with a misrepresentation of the data. Really no way to tell which, unless the person presenting this junk is a known lobbyist...
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scaddenp at 13:02 PM on 19 December 2014CO2 lags temperature
Pure misinformation. Go to that link and take off the detrend on the CO2 and look at the picture. When you detrend, all you have left is the short-term seasonal wiggle in CO2 caused by the change in winter/summer vegetation primarily in the Northern hemisphere. Southern hemisphere doesnt have same effect (way less land vegetation) so his plot looks like lag. Try it with Northern hemisphere instead. How much effort do you suppose went in constructing such a story and do you think that some could find that accidentally? If the guy created this himself, then I think you are dealing someone who is delibratedly intending to misled with the full knowledge of what they are doing.
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Composer99 at 12:34 PM on 19 December 2014CO2 lags temperature
I'm suspicious of the 'detrend' term written into the CO2 time series, and the fact that your interlocutor is using the HadCRUT3 unadjusted southern hemisphere temps, instead of global.
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dvaytw at 12:28 PM on 19 December 2014CO2 lags temperature
I'm arguing with a couple guys in the comments under George Marshall's excellent video presentation, How to Talk to a Climate Change Denier
One fellow there keeps pointing at this one graph as irrefutable smoking, gun proof that CO2 lags temperature:
I speculate that this is pretty short-term and in any case we know the source of atmospheric CO2, but can anyone suggest anything more to say about this?
Moderator Response:[RH] Shortened url that was breaking formatting.
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Trevor_S at 10:19 AM on 19 December 2014What happens if we overshoot the two degree target for limiting global warming?
With emissions accelerating faster than they are now for the next few decades, global temperature rise in RCP8.5 reaches five degrees by about 2120 and six degrees by 2150. This is a worst-case scenario, says Levermann, but that doesn't mean it's not a possibility.
As Professor Richard Alley states in seversl lectures of his I have watched on Youtube... the uncertianty is on the upside and it is not our friend. We should be mitigating because we might get 4C+, the thought of actually hitting 4C+ is... nearly unimaginable.
Professor Wanless from Miami U>
Wanless says a two-metre rise in sea level by 2100 is likely, but says it’s also plausible it could be as much as five metres by the end of the century, and it will continue rising for centuries after that
and yet some places (In Australia, Queensland and New South Wales) aren't doing infrastructure planning for any rise at all by 2100 and some for only 0.8.. We should be planning for 4m. If you plan for 4m and you 2m, no issue, if you plan for 0.8m and you get 2m ... well... You will want to take a whole lot of tax to undo your planning "incompetence."
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jhint at 07:17 AM on 19 December 2014What happens if we overshoot the two degree target for limiting global warming?
I look forward to a response to this seemingly very important question. I don't see where the unacceptable repetiton occurs, that the moderator JH has admonished dagold for.
Moderator Response:[JH] Ooops! My comment was meant for another commenter, not dagold. My bad!
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Stephen Baines at 06:31 AM on 19 December 2014There is no consensus
"The enormous evidence base that you cite does not preclude other factors causing the most recent warming."
Actually, it does preclude them as that list is really rather small. It would have to be something that affected the net heat balance of the earth by affecting incoming radiation (solar inputs, aerosols, clouds), the reflectivity of the earth (ice caps, land use changes) or the ability of the surface to cool (greenhouse gases). The only thing that has been changing in a way that should increase global heat balance over the last 40 years are greenhouse gases.
Your equivalent of H pylori would be to discover a new way for heat to be produced, absorbed or lost by the atmosphere in a large enough quantity to challenge the importance of those other factors. I'd argue the likelihood that such a missing component of the heat budget exists and has not been seen is virtually nil, because we can close the heat budget now.
"and whilst you are right that there is a lot of knowledge about paleo climate I have yet to see anything that comes close to proof that C02 changes are the main factor in those. "
First, what explains variations in paleo climate does not have to be the same thing that explains current climate change. I.e., The glaciations were not initiated by CO2, but they were exacerbated by feedbacks that increased CO2. Current warming is only really related to changes in greenhouse gases though.
Second, we will always know less about what drives paleo climate because we know less about the key factors that drive global heat balance in the distant past than we know about the present, for which we have precise measurements. The lack of certainty about past climate variations does not undercut what we have learned by studying current conditions. Still, there have been puzzles raised by past climate conditions that have seemed to challange the consensus, which has generated futher research to understand the factors underlying the energy budget better for those periods. I can't think of a current case in paleoclimate, however, that hasn't been reconciled with the accepted role of CO2 in climate once more was understood about conditions affecting the earth's energy balance.
"As I said before icecaps existed at both poles when C02 concentrations were 100 times the current levels."
A case in point. Actually, the high CO2 concentrations during large glaciations in the paleozoic were discovered by scientists trying to understand how the earth became deglaciated after essentially freezing over. Glaciation of the earth should have been hard to overcome because a white earth reflects a lot of sunlight, and therefore greatly reduced incoming energy. That lead many to doubt evidence that the earth was actually glaciated — because it still would be.
But, the glaciations alsostopped processes that typically removed CO2 from the atmosphere, allowing it to build up, which heated the earth and allowed the glaciers to melt. So paradoxically, the phenomenon you hold up as challenging a role for CO2 in climate, is actually understood by scientists to reinforce the idea that CO2 is important in climate.
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Tom Curtis at 06:01 AM on 19 December 2014Human CO2 is a tiny % of CO2 emissions
MA Rodger @264, I believe the figure originally came from calculations of the residence time of CO2 in the atmosphere made from measurements of the rate at which the C14 spike from nuclear testing dissipated. From such measurements it was determined that approximately 203 gigatonnes of Carbon in the form of CO2 (GtC) leaves the atmosphere each year. Given a total atmospheric reservoir of 829 GtC, the average duration of a carbon atom in the atmosphere is just over four years. Ergo, for a year n years ago, the approximate fraction remaining in the atmosphere is 0.75^n. Even with an assumed constant emissions of 8 GtC per annum, that means only approx 24 GtC in the atmosphere was emitted from an anthropogenic source, and has never left the atmosphere since emission. That turns out to be 2.9% of the atmospheric concentration. (Obviously the figure will vary slightly with more exact calculation.)
Taking a simple ratio of annual gross natural emissions to annual anthropogenic emissions gives you a ratio of 4.1% if you only include fossil emissions, but 4.7% if you include emissions from land use change and 17.5% if you include all anthropogenic emissions including outgassing due to global warming.
Both calculations assume that any emissions from the ocean or plants and animals cannot have come from fossil sources. That is, of course, absurd. Indeed, it is assumed by both methods that most anthropogenic emissions are stored in either plants or the ocean as a result of the rapid exchange of CO2 between atmosphere and the other surface reservoirs of carbon. It follows that a certain proportion of the "natural emissions" are emissions of carbon that until a few hundred years ago (and in most cases a decade ago or less) was stored in a fossil reservoir. A rough calculation of the proportion of CO2 in the atmosphere that was recently in a fossil reservoir is then given by the ratio of the sizes of the combined reservoirs to the cumulative emissions. That works out to approximately 12% excluding the deep ocean and soil (for which exchange is slow). The actual number may be lower than that, but not by much. (It may also be higher given the average life span of trees.)
All this, however, is as you note, beside the point. The real question is how much of the increase in atmospheric emissions is due to anthropogenic emissions. To that the answer is 100%. Ergo, 30% of the current atmospheric concentration would not have been in the atmosphere without anthropogenic emissions. That is the case regardless of whether or not any individual atom was recently in a fossil reservoir for the approximately 20% of atmospheric CO2 that would not have been there without emissions, but whose carbon was not recently in a fossil reservoir has merely displaced CO2 whose carbon was recently in a fossil reservoir due to equilibrium exchanges.
(Note, all figures calculated using values from Fig 6.1 of AR5 WG1.)
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There is no consensus
Peter Lloyd - The consensus on AGW, although very consistently measured in the high 90%'s, is not immutable.
In the early 20th century the consensus on climate was that natural causes predominated. There were early researchers like Tyndall Fourier, and Arhennius who made some quite prescient predictions, but until the mid-20th century there was no general opinion that anthropogenic factors were important. But then things changed due to new evidence. Callendar in the 1930's (AGW a factor in early 20th warming), Plass (radiation balance) and Revelle (oceans won't absorb all anthropogenic CO2) in the 1950's, Keeling measuring CO2 in the 1960's, Manabe and others in the 1970's modelling GHG effects, etc - all contributed to the body of evidence.
And over the 1960's-1980's, the scientific consensus on climate changed, to the currently held view that AGW is the dominant factor in recent warming, accounting for ~100% of it (with natural factors such as insolation providing negative contributions).
The consensus changed due to evidence and how it is viewed by those who have studied these topics. It could certainly change again - but that would require a considerable amount of new (and contrary) evidence to that effect. There's no sign of such whatsoever - just inconsistent, contradictory and unsupported claims (it's the sun, it's a cycle, cosmic rays, it's not happening at all, there's a grand conspiracy toward a 'World Order', etc), claims that appear, quite frankly, loony.
Now, as to the meaning of such a strong scientific consensus - that's important because laypeople (quite wisely) will take expert opinions into consideration when deciding public policy.
You've claimed uncertainty where it doesn't exist. And your comments simply don't hold up in the face of the evidence.
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Rob Honeycutt at 05:19 AM on 19 December 2014There is no consensus
Peter... The point isn't that it took so long. Once actual evidence was presented scientists changed their position based on the evidence. The previous position was one where there was little active research that made up the basis of the consensus position.
AGW is not a case where little research is being done and scientists are just accepting what has been assumed.
This is an issue that has been actively researched for 100 years. There are thousands of papers coming out every year on various aspects of man-made climate change. It's a field of intensive research.
In the past 100 years there have been various challenges to the core idea that increasing greenhouse gas concentrations will warm the planet. Each of those challenges have been shown to be wrong. And in the meatime, more and more research is being published confirming the consensus position.
The comparison to H. pylori is just not a valid.
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MA Rodger at 05:09 AM on 19 December 20142014 will be the hottest year on record
robert way @16.
It's not really cherry-picking as it's not just the NOAA (NCDC) that is set for the hottest year on record. The Jan-Nov NASA GISS average is also above the hottest calendar year on record, as is the HadCRUT4 Jan-Oct average. Likely BEST will show similarly.
The satellite records, UAH & RSS, wobble far more with ENSO so the 'warmest year' is more to do with the size of El Ninos than rising global temperature. And today we remain without an El Nino, which is added reason for considering the surface temperatures worthy of note.
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Peter Lloyd at 04:58 AM on 19 December 2014There is no consensus
645. I think we are at cross purposes here. Neither of us doubt that there was a, let's call it strong, or established if you like, consensus prior to the discovery of the effect of H. pylori. Neither of us disagrees that new evidence did change the consensus although I would argue that the fact that it took as long as it did illustrates that medics were very keen to hold on to their previous consensus view.
Where we would probably disagree is on whether there is sufficient scientific proof underlying the consensus on the degree of man-made global warming and the degree to which that consensus is reflected correctly in the statements made at the top of this thread.
I think that looking at the science and its credibility is important and that the use of "consensus" is being corrupted to give a false impression of certainty
644. No. I am arguing that there is ignorance and you seem to be in denial of it! It is freely admitted by paleo-climatologists that they know a lot about many of the factors involved but not enough to know the exact reasons behind paleo-climatic changes.
Taking your Tom Curtis conclusion from Marcot et al:
"Global temperature, therefore, has risen from near the coldest to the warmest levels of the Holocene within the past century, reversing the long-term cooling trend that began ~5000 yr B.P.
and your conclusion from it:
"In other words, little temperature wiggles up-and-down notwithstanding, human emissions are the only cause of the current sustained warming trend."
The conclusion you draw cannot logically be made from that Marcot statement. There maybe many reasons for the cooling and for the most recent warming of which human emissions are likely to be a contributory factor.
The enormous evidence base that you cite does not preclude other factors causing the most recent warming and whilst you are right that there is a lot of knowledge about paleo climate I have yet to see anything that comes close to proof that C02 changes are the main factor in those. As I said before icecaps existed at both poles when C02 concentrations were 100 times the current levels.
...."Unless you care to suggest that, say, plate tectonics, quantum electrodynamics, gravity-as-distortion-of-spacetime, and evolution of biological organisms are also "guesswork"."....
I don't care to say it because they are all demonstrably true and repeatedly proven by observation and / or experiment. The theories and mechanics behind them have been, and are, still subject to many different "consensuses". But none of those causal theories are held as unshakeable truth in the way, say for example, that the movement of crustal plates is, via something described as plate tectonics. This will not be falsified.
The same cannot be said for the claim that man-made emmissions of C02 are causing 100% (ish) of temperature increases on earth.
Moderator Response:[JH] You are now skating on the thin ice of excessive repetition which is banned by the SkS Comments Policy.
Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.
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dagold at 04:46 AM on 19 December 2014What happens if we overshoot the two degree target for limiting global warming?
A question: The World Bank commissioned report from 2012 about the prospects of a 4C warmer world states: "Even with the current mitigation commitments and pledges fully implemented, there is roughly a 20 percent likelihood of exceeding 4°C by 2100. If they are not met, a warming of 4°C could occur as early as the 2060s." You cite "the most extreme scenario" as being a 4C rise by 2100 at the earliest. This is quite a discrepancy - almost a 'halving' of the time period (from 2012) for such a rise. What is the disrepancy....is it possible that it is due to an inherently conservative nature of the IPCC projections? (that is, assuming the mitigation commitments are NOT met, something that the world has amply demonstrated to be a possible if not probable outcome).
Moderator Response:[JH] You are now skating on the thin ice of excessive repetition which is banned by the SkS Comments Policy.
Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.
Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
The above was meant for another commenter. My bad and my apologies!
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MA Rodger at 03:52 AM on 19 December 2014Human CO2 is a tiny % of CO2 emissions
CBDunkerson @263.
The 0.006 value being quoted is probably ppm CO2 by weight which is roughly 1.5x the 'by volume' value for dry air.
The 2%-7% is probably that derived from the relative size of CO2 fluxes into the atmosphere, from man-made sources and from natural sources, a particularly stupid value to use as the natural fluxes are bi-directional while the man-made ones only go one way.
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Rob Honeycutt at 02:45 AM on 19 December 2014There is no consensus
Peter Lloyd... "You don't show in what way my H. plyori story has "little basis in fact" or isn't relevant."
You stated that there was an unshakable consensus. I quoted for you the words of one of the researchers who discovered the H. plyori saying it only took a few years for his work to become accepted. That means, in actuality, that previous consensus was very quickly overturned by presenting the research.
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