Paper Mac posted:

A1F1, which we're tracking at this point, takes us to 5 deg C by 2100 in the absence of any feedbacks and conservative assumptions about climate sensitivity. 7-10 deg C is usually a post-2100 scenario, not "by-2100" unless you postulate feedbacks, but there's sufficient fuels in the ground to take us there. In any case, I'm not sure who you've been talking to, but there's a consensus that 4 deg C above pre-industrial represents widespread disaster in terms of population health, social cohesion, etc. The 7-10 deg C warming scenarios I'm talking about are beyond imagination. We're in the process of baking in 4 deg C with our current emissions. Whether or not we get to 7-10 will depend on our emissions course over the next 50 years or so.

Squalid posted:

Well no poo poo duh we're all toast in a business as usual scenario. If we get to a point where we can't grow unirrigated corn in Ohio I'll probably be more interested in what I can pillage from the smoking ruins of Pittsburgh than peanut yields per hector in Niger or w/e.

Squalid posted:

However I disagree that adding human variables doesn't make systems less predictable. Especially when action may be contingent on large scale institutional action that is subject to the whims of a few individuals. The IPCC could produce a much more precise warming prediction if they could just replace the human economy nice, predictable CO2 making machines.

Squalid posted:

One of the things that causes me a lot of anxiety is what even a plateau in global per capita agricultural productivity could do to tropical forests. I just can't imagine the governments of Indonesia or Brazil resisting domestic pressure to develop tropical forests without massive payments from more developed nations, yet the amount of carbon that would be released by clearing the Amazon represents a planetary death sentence, just as certain as burning all the oil shale.

Trabisnikof posted:

Which is really my point. We'll never make meaningful action if our argument is "Do what I say or else the world will be doomed in +100 years". We sound just like a doomsday cult, and we'll have the same predictive accuracy.

Trabisnikof posted:

Widespread disaster and an end to global society and economics are two vastly different things. We've had widespread anthropogenic disasters for the last 200+ years and often it strengths global trade and institutions. We are talking about climate change undoing a large chunk of the advances in human quality of life, and that's going to be a dark age if we let it happen, but it won't destroy our human institutions.

Paper Mac posted:

Sorry, I need to be much more specific: the fact that humans have the technical capability to move water around does not make growing conditions much less predictable. We can make pretty reasonable predictions about how long particular aquifers can hold out at particular consumption rates under particular precipitation regimes. Generally speaking these answers are not encouraging if what you want to do in response to drought is to build out massive irrigation works. There may be other technical solutions to this problem, but one way or the other they're going to be subject to logistical models. You are of course right that above that there is a whole layer of political and institutional indeterminacy, but I'm speaking only to the question of "could technical solutions be used to overcome predicted drought conditions in eg. the Mississippi basin in 20-30 years" and as far as I can tell the answer to that is "maybe inconsistently mitigate".

Trabisnikof posted:

Look at this chart. This is all awful stuff we should prevent, but its not the collapse of the global economy.

IPCC 2013 posted:

Relative to the average from year 1850 to 1900, global surface temperature change by the end of the 21st century is projected to likely exceed 1.5°C for RCP4.5, RCP6.0 and RCP8.5 (high confidence). Warming is likely to exceed 2°C for RCP6.0 and RCP8.5 (high confidence), more likely than not to exceed 2°C for RCP4.5 (high confidence), but unlikely to exceed 2°C for RCP2.6 (medium confidence). Warming is unlikely to exceed 4°C for RCP2.6, RCP4.5 and RCP6.0 (high confidence) and is about as likely as not to exceed 4°C for RCP8.5 (medium confidence).
...
• Globally, it is likely that the area encompassed by monsoon systems will increase over the 21st century. While monsoon winds are likely to weaken, monsoon precipitation is likely to intensify due to the increase in atmospheric moisture. Monsoon onset dates are likely to become earlier or not to change much. Monsoon retreat dates will likely be delayed, resulting in lengthening of the monsoon season in many regions. {14.2}
• There is high confidence that the El Niño-Southern Oscillation (ENSO) will remain the dominant mode of interannual variability in the tropical Pacific, with global effects in the 21st century. Due to the increase in moisture availability, ENSO-related precipitation variability on regional scales will likely intensify. Natural variations of the amplitude and spatial pattern of ENSO are large and thus confidence in any specific projected change in ENSO and related regional phenomena for the 21st century remains low. {5.4, 14.4}
...
• It is very unlikely that the AMOC will undergo an abrupt transition or collapse in the 21st century for the scenarios considered. There is low confidence in assessing the evolution of the AMOC beyond the 21st century because of the limited number of analyses and equivocal results. However, a collapse beyond the 21st century for large sustained warming cannot be excluded. {12.5}
...
 Global mean sea level rise for 2081−2100 relative to 1986–2005 will likely be in the ranges of 0.26 to 0.55 m for RCP2.6, 0.32 to 0.63 m for RCP4.5, 0.33 to 0.63 m for RCP6.0, and 0.45 to 0.82 m for RCP8.5 (medium confidence). For RCP8.5, the rise by the year 2100 is 0.52 to 0.98 m, with a rate during 2081–2100 of 8 to16 mm yr–1 (medium confidence).These ranges are derived from CMIP5 climate projections in combination with process-based models and literature assessment of glacier and ice sheet contributions (see Figure SPM.9, Table SPM.2). {13.5}
 In the RCP projections, thermal expansion accounts for 30 to 55% of 21st century global mean sea level rise, and glaciers for 15 to 35%. The increase in surface melting of the Greenland ice sheet will exceed the increase in snowfall, leading to a positive contribution from changes in surface mass balance to future sea level (high confidence). While surface melting will remain small, an increase in snowfall on the Antarctic ice sheet is expected (medium confidence), resulting in a negative contribution to future sea level from changes in surface mass balance. Changes in outflow from both ice sheets combined will likely make a contribution in the range of 0.03 to 0.20 m by 2081−2100 (medium confidence). {13.3−13.5}
...
• A large fraction of anthropogenic climate change resulting from CO2 emissions is irreversible on a multi-century to millennial time scale, except in the case of a large net removal of CO2 from the atmosphere over a sustained period. Surface temperatures will remain approximately constant at elevated levels for many centuries after a complete cessation of net anthropogenic CO2 emissions. Due to the long time scales of heat transfer from the ocean surface to depth, ocean warming will continue for centuries. Depending on the scenario, about 15 to 40% of emitted CO2 will remain in the atmosphere longer than 1,000 years. {Box 6.1, 12.4,12.5}

Trabisnikof posted:

I'm sorry but there's not a research consensus to support global economic collapse in a 7-10˚F (no one seriously argues for a 7-10˚C model) scenario.

quote:

Our calculated global warming in this case is 16°C, with warming at the poles approximately 30°C. Calculated warming over land areas averages approximately 20°C. Such temperatures would eliminate grain production in almost all agricultural regions in the world. Increased stratospheric water vapour would diminish the stratospheric ozone layer.

More ominously, global warming of that magnitude would make most of the planet uninhabitable by humans. The human body generates about 100 W of metabolic heat that must be carried away to maintain a core body temperature near 37°C, which implies that sustained wet bulb temperatures above 35°C can result in lethal hyperthermia. Today, the summer temperature varies widely over the Earth’s surface, but wet bulb temperature is more narrowly confined by the effect of humidity, with the most common value of approximately 26–27°C and the highest approximately of 31°C. A warming of 10–12°C would put most of today’s world population in regions with wet a bulb temperature above 35°C.

TACD posted:

This is not quite true.


Not 'research consensus' but not some uninformed nutcase either.

IPCC 2013 Policymaker Summary posted:

Relative to the average from year 1850 to 1900, global surface temperature change by the end of the 21st century is projected to likely exceed 1.5°C for RCP4.5, RCP6.0 and RCP8.5 (high confidence). Warming is likely to exceed 2°C for RCP6.0 and RCP8.5 (high confidence), more likely than not to exceed 2°C for RCP4.5 (high confidence), but unlikely to exceed 2°C for RCP2.6 (medium confidence). Warming is unlikely to exceed 4°C for RCP2.6, RCP4.5 and RCP6.0 (high confidence) and is about as likely as not to exceed 4°C for RCP8.5 (medium confidence).

TACD posted:

This is not quite true.


Not 'research consensus' but not some uninformed nutcase either.

TACD posted:

This is not quite true.


Not 'research consensus' but not some uninformed nutcase either.

Uranium Phoenix posted:

"16°C" is for for the scenario of "burning all fossil fuels", and it's over a much longer time scale than the end of the century mark used by the IPCC report.

TACD posted:

That's true, I forgot the context of 'by 2100' in my quote. I don't think it's unreasonable to look at the effects of burning 'all fossil fuels' when that appears to be our default trajectory, though.

Kalenden posted:

I've recently received a newspaper article from a family member that raised some issues with the current climate change predictions.

Kalenden posted:

I've recently received a newspaper article from a family member that raised some issues with the current climate change predictions.

Since the newspaper is well respected but still a newspaper, I'm not sure how to interpret it, since it offers no statistics or sources.
Also, searching on the website of the newspaper I find contradictory statements.

Kalenden posted:

Basically, it asserts that temperatures haven't risen the past 10 years, in contrast to every climate model we have.
It also asserts that sea levels aren't rising abnormally fast, that any rise could be due to any number of reasons, etc.
It continues on to say that deserts aren't getting bigger and that the frequency of tropical storms isn't increasing, all in contrast to all the doomsday predictions of the common climate change views.

I've done some light googling but came up empty. Anybody know where and how they got that data and if it is in any way correct? The family member in question is a heavy climate sceptic and the newspaper is generally trustworthy so I'd appreciate any clear and concise scientific data about this.

Uranium Phoenix posted:

However, the models used for predicting climate are quite reliable.

Strudel Man posted:

Man, that's a pretty weak response. If the argument is "[Models] are full of fudge factors that are fitted to the existing climate, so the models more or less agree with the observed data," you can't exactly disarm it by saying that the hindcasting is accurate.

quote:

CAMPAIGN STRATEGIST JAMES Carville coined the phrase “It’s the economy, stupid” to focus the attention of campaign workers on the one key issue that would get Bill Clinton elected president in the 1992 U.S. election.

Alas, the authors of the Fifth Assessment of the Intergovernmental Panel on Climate Change (IPCC), which will be published on Friday (September 27), have no such sage to guide them. They’ll have to make do with me.

The 800-odd authors of the report are selected by their fellow scientists in the various disciplines relevant to climate change as the acknowledged leaders in their field of study. Their job was to review all 14,000 scientific papers on climate change published in the past five years. And they are doing this work at the behest of the world’s governments, not as some random pressure group; it is the Intergovernmental Panel on Climate Change.

Scientists are very cautious people. They won’t go one millimetre beyond what the evidence makes indisputable, knowing that they will be attacked by rival scientists if they do. They are much more comfortable talking about probabilities rather than certainties. They are, in other words, a nightmare for journalists who have to transmit their findings to the world.

Of the nearly 100 scientists I have interviewed on climate change over the past five years, not one doubted that global warming is a big and frightening problem. Indeed, there was often an undercurrent of panic in their remarks. But when it comes to writing official reports, they retreat into science-speak.

So the Second Assessment of the IPCC, published in 1995, said that it was more than 50 percent likely that human emissions of greenhouse gases were contributing to global warming. The Third Assessment, in 2001, raised the likelihood to 66 percent. The Fourth, in 2007, upped the ante to 90 percent, and the Fifth, this week, says 95 percent.

But how do you make a headline out of that? How much warming? How fast? And with what effects on human beings? The latest report will run, in its final version, to 3,000 pages, and the answers are buried among the statistics. What would Jim (Carville) do? He’d say: it’s the feedbacks, stupid.

Without the feedbacks, we could go on burning fossil fuels and cutting down the forests, and the average global temperature would creep up gradually, but so slowly that most of the inhabited parts of the planet would stay livable for a long time. But if we trigger the feedbacks, the whole thing goes runaway.

The feedbacks are natural sources of warming that we activate by raising the average global temperature just a modest amount with our own greenhouse gas emissions. The consensus number used to be plus 2 degrees Celsius, but some scientists now argue that the real threshold may be as low as +1.5 degrees C. There are three main feedbacks.

As the highly reflective ice and snow that covers most of the polar regions melts, the rate at which the sun’s heat is absorbed goes up steeply over a large part of the planet. We are creating a new warming engine that will shift the planet’s heat balance, and once it has started we can’t turn it off again.

There is reason to believe that it’s already too late to avoid this one. The protective covering of floating ice that has shielded the Arctic Ocean from solar heating for so long is now going fast, and we will probably see an ice-free Arctic Ocean in the August-September period as early as the 2020s. Mercifully, this is the smallest of the three major feedbacks in terms of its impact— but it triggers a bigger one.

The warmer air and water in the Arctic then starts to melt the permanently frozen ground and coastal seabed (permafrost) that extends over more than 10 million square kilometres of territory, a considerably larger area than Australia. This melting releases a huge amount of methane that has been locked into the ground for millions of years. Methane is a far more effective warming agent than carbon dioxide, and so we spin closer to runaway.

Finally the oceans, as they warm, release some of the vast quantities of carbon dioxide they absorbed in the past, simply because warmer water can contain less dissolved gas. Most of the excess heat in the Earth system has been going into the oceans in the past few decades, which is why the rise in land temperatures seems to have slowed down. But that is no real consolation: it just means that the biggest feedback is also being activated.

Those are the killer feedbacks. Earth has lurched suddenly into a climate 5-6 degrees C higher than now a number of times in the past. The original warming usually came from massive, long-lasting volcanic eruptions that put a large amount of CO2 into the atmosphere—but in every case it was feedbacks like these that carried the planet up into a temperature regime where there was a massive dieback of animals and plants.

We are the volcanoes now. Our own emissions would take a long time to get us up to really high average temperatures worldwide, but all we have to do is pull the trigger on the feedbacks. The rest is automatic.

Uranium Phoenix posted:

What are you talking about? Who is making that argument?

Kalenden posted:

I've recently received a newspaper article from a family member that raised some issues with the current climate change predictions.

Since the newspaper is well respected but still a newspaper, I'm not sure how to interpret it, since it offers no statistics or sources.
Also, searching on the website of the newspaper I find contradictory statements.

Basically, it asserts that temperatures haven't risen the past 10 years, in contrast to every climate model we have.
It also asserts that sea levels aren't rising abnormally fast, that any rise could be due to any number of reasons, etc.
It continues on to say that deserts aren't getting bigger and that the frequency of tropical storms isn't increasing, all in contrast to all the doomsday predictions of the common climate change views.

I've done some light googling but came up empty. Anybody know where and how they got that data and if it is in any way correct? The family member in question is a heavy climate sceptic and the newspaper is generally trustworthy so I'd appreciate any clear and concise scientific data about this.

Strudel Man posted:

The link in the quote?

Uranium Phoenix posted:

However, the models used for predicting climate are quite reliable.

Arkane posted:

That is a 3+ year old link featuring 8+ year old data.

Anyone trying to convince you that the models are "quite reliable" either is an idiot or thinks you are gullible. Do yourself a favor and don't rely on Google searches that land you on SkS pages. The models show exponentially increasing temperature. We're not even increasing at the moment, and the increase could very well even be logarithmic over time. The models have been diverging from observations for 13 years now to the point where we have exited the confidence intervals.

Science generally works where you have a hypothesis (in this case, climate sensitivity), and you test the hypothesis. The initial test of the climate model hypothesis is failure. So either we are missing some gigantic & temporary unknown variable that is suppressing the temperature rise, or the modelers have bungled -- severely overestimated -- climate sensitivity. Trenbeth had the big paper about temperature increases in the ocean which is perhaps 'stealing' heat from the atmosphere, but this shouldn't necessarily be viewed as anomalous. The ocean is many magnitudes denser, so if the heat is being mixed into the deep ocean, that could work out amazingly for everyone.

quote:

"Leighton Steward is a geologist, environmentalist, author, and retired energy industry executive. He has written about the reasons for the loss of much of the Mississippi River delta (Louisiana's National Treasure) and has given advice on how the nation can achieve "no net loss" of wetlands in the future; advice that has been accepted by the EPA and U. S. Corps of Engineers. Leighton was lead author on a book about nutrition and health (Sugar Busters) that gave advice on how to lose weight and prevent and or treat diabetes. The book became a #1 New York Times Best seller for sixteen weeks and made a significant contribution to the changes that have occurred regarding the availability of no-sugar-added, higher fiber, and low-glycemic products in the super markets. More recently, he has written a book (Fire, Ice and Paradise) that is an endeavor to educate the non-scientist about the many causes of global climate change so that the reader will be better prepared to understand what they hear, see, and read about in the media and from the politicians. In recognition of his many environmental efforts, Leighton has received numerous environmental awards, including the regional EPA Administrator's Award for environmental excellence.

"He is Chairman of the Board of The Institute for the Study of Earth and Man at SMU, was Chairman of the National Wetlands Coalition, and was twice Chairman of the Audubon Nature Institute. Leighton currently serves on the boards or boards of visitors of the M. D. Anderson Cancer Center, EOG Resources, The Buffalo Bill Historical Center, the Southwest Research Institute, and is an emeritus member of the Tulane University board.

"Leighton's current interest lies in helping to educate the general public and the politicians about the tremendous benefits of carbon dioxide (CO2) as it relates to the plant and animal kingdoms and their related ecosystems and habitats, and the general health of humanity."

rivetz posted:

So torn...on the one hand, I get really tired of reading goony projections of various post-apocalyptic scenarios and welcome a return to discussion of more concrete science and projections (sorry, guys). On the other hand, the fact that we're about to go on a ride with Arkane is like finding out that after years of eating nothing but cotton candy, here's a big bowl of pancake batter just to change things up. I mean, it's nice to have something different, but ghhhhhhhhhgggh

Could we fast-forward through a couple talking points (I'm genuinely trying to save you having to retype these, dude)? Presumably it is still your contention that:

• Global surface temperatures have remained relatively flat for the last twelve years;
  
• We cannot verify 100% that the oceans are absorbing excess heat, so it's pointless to assume that they are (despite mounting evidence);
  
• Sea level rise to date is more or less to be expected, and there's nothing to indicate that it's out of the ordinary, nor is there any evidence to suggest rate of sea level rise will in the short term increase to the point that we should be concerned;
  
• AR4 overestimated everything and thus is not a particularly good resource for any projections;
  
• James Hansen overestimated everything and therefore is corrupted by politics and really doesn't know what he's talking about.

You can tear these up, I've tried to be pretty fair/accurate in summarizing your previous posts. I'm geniunely trying to save time here so we can get past everyone piling on you and you having to restate all this stuff. Are these relatively accurate? Have you found anything in AR5 that contradicts these positions?

Edit: it's lame to post these without some counterpoints, so in order:

• Saying that temperatures have remained flat completely disregards the longer warming trend going back one hundred years or more, and ignores the rise in ocean temps.
  
• There is to me sufficient evidence that the ocean is absorbing excess heat that we should proceed as if this is happening, vs. crossing fingers and hoping that virtually every accredited scientific organization on the planet is wrong, and Lord Monckton has shown us all the light.
  
• It is ignorant to project no change in sea level rise, given the very real melting of the West Antarctic ice sheet (and don't insult anyone's intelligence by pointing to the increase in sea ice because it's disingenuous as gently caress and I assume you know it)
  
• I see no point in tearing apart AR4 when we have AR5, but if you need to discredit five-year-old research to somehow postulate that current research must also be worthless, you can go there I guess
  
• Fine, Hansen went overboard, I don't at this point really give much of a poo poo what he said any more than Al Gore, or anyone who prioritizes PR like he does. I happen to think that James Hansen is plenty qualified to weigh in on the subject, given his education, accreditation and forty-plus years in the field, but if you want to toss his stuff out, fine; there are actually one or two other scientists out there who share his positions, and we can focus on them so you don't have to waste everyone's time including your own with the fancy graph showing how nutty he was with that thing he said once.

Kuhn posted:

This genetic aspect of the parallel between political and scientific development should no longer be open to doubt. The parallel has, however, a second and more profound aspect upon which the significance of the first depends. Political revolutions aim to change political institutions in ways that those institutions themselves prohibit. Their success therefore necessitates the partial relinquishment of one set of institutions in favor of another, and in the interim, society is not fully governed by institutions at all. Initially it is crisis alone that attenuates the role of political institutions as we have already seen it attenuate the role of paradigms. In increasing numbers individuals become increasingly estranged from political life and behave more and more eccentrically within it. Then, as the crisis deepens, many of these individuals commit themselves to some concrete proposal for the reconstruction of society in a new institutional framework. At that point the society is divided into competing camps or parties, one seeking to defend the old institutional constellation, the others seeking to institute some new one. And, once that polarization has occurred, political recourse fails. Because they differ about the institutional matrix within which political change is to be achieved and evaluated, because they acknowledge no supra-institutional framework for the adjudication of revolutionary difference, the parties to a revolutionary conflict must finally resort to the techniques of mass persuasion, often including force. Though revolutions have had a vital role in the evolution of political institutions, that role depends upon their being partially extrapolitical or extrainstitutional events.

The remainder of this essay aims to demonstrate that the historical study of paradigm change reveals very similar characteristics in the evolution of the sciences. Like the choice between competing political institutions, that between competing paradigms proves to be a choice between incompatible modes of community life. Because it has that character, the choice is not and cannot be determined merely by the evaluative procedures characteristic of normal science, for these depend in part upon a particular paradigm, and that paradigm is at issue. When paradigms enter, as they must, into a debate about paradigm choice, their role is necessarily circular. Each group uses its own paradigm to argue in that paradigm’s defense.

The resulting circularity does not, of course, make the arguments wrong or even ineffectual. The man who premises a paradigm when arguing in its defense can nonetheless provide a clear exhibit of what scientific practice will be like for those who adopt the new view of nature. That exhibit can be immensely persuasive, often compellingly so. Yet, whatever its force, the status of the circular argument is only that of persuasion. It cannot be made logically or even probabilistically compelling for those who refuse to step into the circle. The premises and values shared by the two parties to a debate over paradigms are not sufficiently extensive for that. As in political revolutions, so in paradigm choice—there is no standard higher than the assent of the relevant community. To discover how scientific revolutions are effected, we shall therefore have to examine not only the impact of nature and of logic, but also the techniques of persuasive argumentation effective within the quite special groups that constitute the community of scientists.

"The Structure of Scientific Revolution", Thomas Kuhn, Vol. 2, No. 2, pages 93-94

hobbesmaster posted:

Well, good news is if we can reproduce those numbers on Mars we might have at least one habitable planet in the solar system.

Arkane posted:

Arkane posted:

Going backwards on your list, I think Hansen still has a lot of credibility even if pretty much everything he has predicted except for GHG emissions has been awful. Overall his sentiment that the Earth is going to poo poo very quickly is sort of the theme of this thread. He is a crackpot as far as I am concerned. His sea level projections are very, very wrong (his most recent prediction is 5m by 2100, which is 400% higher than the absolute highest level in the IPCC report). His temperature forecasts are very, very wrong (we're below his 0 emissions scenario forecast and his predictions just keep getting bigger the more wrong he is). His hurricane scare tactics are wrong. This guy is like the reverse Inhofe.

a lovely poster posted:

http://www.ted.com/talks/james_hansen_why_i_must_speak_out_about_climate_change.html

What's more unreasonable here, what he's saying about the future of the climate, or his solution to fix it. I don't understand how anyone can watch that video and say anything other than "wow, that's a really good idea". A revenue-neutral carbon tax that's redistributed from large fossil fuel corporations to the people. This is the nightmare we're scared of?

StarMagician posted:

Hell, I think global warming is a load of crap and I still support the idea.