[QUESTION]: What are your views on climate change, and how did you form them?

Based on my appreciation of the scientific method and my research into the weaknesses of models and experts, I take the median IPCC estimate as correct, but assume the uncertainties are greater than they claim. This is somewhat scary, as uncertainties cut in both directions, and moderate climate change is something we can cope with, but extreme climate change is very much worse.

I am highly confident that anthropogenic warming is occurring, with some concern that institutional pressures will tend to exaggerate the amplitude of warming predictions. As an aspiring geologist (master's level, for now), I'm unusually well-informed on the issue; I have spent considerable time discussing climate changes with geoscientists of various specialties (in particular, chemical oceanography, isotopic geochemistry, paleobotany, regional weather forecasting, and geobiology), and I have the education to read the primary literature comfortably. Working in the same labs as the experts has been especially helpful, since they have universally been happy to discuss complexities and uncertainties as I encounter them in my own studies. It's worth pointing out that my own work is not directly related to modern climate change, so my own 'insider status' is questionable.

I was less confident when I first entered the sciences than I am now, although I didn't ever qualify as a 'climate skeptic' except insofar as I was a skeptic with thoughts about the climate. The increase in confidence has been ongoing, with many causes- I recall a particularly visceral shift in perspective came when I saw researchers working with the concept of global reservoirs, a framework that clarified some issues for me and satisfied on an analytical level. (i.e. quantified global carbon budgets )

The up-close experience has also given me a good view of the structural distortions caused by scientific praxis generally and the enormous quantity of global warming funding in particular. The challenge in publishing negative results is well known; in the case of climate modeling, this tends to create a situation where researchers are constantly discovering that 'climate change may be even worse than we thought!!!!' and we never seem to hear 'actually, increased evapotranspiration may promote cloud cover and increase Earth's albedo, as a negative feedback loop to warming trends'. It's less clear to me that the extraordinary funding incentives are silencing doubtful researchers or skewing results towards a particular conclusion; the primary effect I've seen in the acadame has been some strained explanations about why the circulation patterns of epicontinental seas in the Pennsylvanian era are going to teach us about anthropogenic climate change. It's rather ironic that my concerns about the amplitude of IPCC predictions have more to do with broad scientific habits than with the politicization of the field.

If any of the climate researchers I worked with had reservations about the consensus in their field, they didn't say so publicly, or provide any hints I could detect.

[This is a first post, so I apologize for any formatting errors or breaches of protocol.]

I don't have any.

I know next to nothing about climatology and I have no way of determining which experts are trustworthy. I don't think that trying to form an opinion on it would be a worthwhile use of my time: I have no need for one, and it wouldn't be a very useful source of data either way -- I don't think there are any meta-level lessons I could learn from its truth or falsity. Developing a belief would create a very significant risk of forcing me into one of two camps, with decidedly negative consequences for me either way, whereas if I don't develop one, that only makes me elthedish to the people who believe that everyone ought to have an opinion on it, and I don't mind that at all.

What are your current beliefs on climate change? Specifically, would you defer to the view that greenhouse gas forcing is the main source of long-term climate change? How long-term? Would you defer to the IPCC range for climate sensitivity estimates?

Based on asking UCSD scientists when I've met them at parties, I'd parrot them and say human emissions are maybe about 1/2 of the source of long term climate change. I would not defer to the IPCC or to anybody without giving them careful reads. The issue is too politicized to trust anyone merely because of fancy or scientific sounding titles.

What were your beliefs on climate change when you first came across the subject, and how did your views evolve (if at all) on further reading (if you did any)? (Obviously, your initial views wouldn't have included beliefs about terms like "greenhouse gas forcing" or "climate sensitivity").

When I first heard of global warming I thought it was ludicrous because I could remember a number of years ago reading about the coming ice age and all the evidence for that. The idea that we should bring CO2 emissions to a halt is ludicrous to me even in the face of real climate change because there are so many cheaper ways to cool the earth than to stop emitting CO2. The idea that we should stop emitting CO2 because it is emissions of CO2 that got us here is simplistic, and, I suspect, essentially reflecting a religious impulse of "purity," the same kind of thing that leads to strange dietary restrictions and proscriptions against associating with menstruating women. I was very influenced by Michael Crichton (a denier, more or less, but a damn smart one) and I accept the steady stream of obviously real experts who say we have nowhere near enough reason to think that trillion dollar changes like stopping burning fossil fuels is likely to be any more effective than solutions that cost a millionth as much. A good source of these experts is to look at the guests on "econtalk" hosted by Russ Roberts.

What are some surprising things you learned when reading up about climate change that led you to question your beliefs (regardless of whether you changed them)? For instance, perhaps reading about Climategate caused you to critically examine your deference to expert consensus on the issue, but you eventually concluded that the expert consensus was still right.

I was surprised that there is still no measurable ocean level change even as every hurricane or blizzard that passes by is claimed to be a sign of the changes that have already occurred. I was surprised to learn that there are easily worked out things that can be done that could cool the earth at a cost of a few billion US$ or less. I was surprised to learn that glaciers really are melting.

If you read my recent posts linked above, did the posts contain information that was new to you? Did any of this information surprise you? Do you think it's valuable to carry out this sort of exercise in order to better understand the climate change debate?

I started reading them, they seemed OK, just didn't have the energy to get through them at the moment.

other comments

The real question is not "what is really happening" but "what is the best thing to do now." Intelligent study is certainly a thing to do now and fortunately there is no shortage of that, even though the politicization will make it really hard to dig through and find reasonable descriptions of results as they are developed.

I am also fascinated by the idea that a slow rise in sea level is described as a catastrophe. It is not. The sea has always eroded the coast and houses and other structures last a finite time in many of these places. Oh Well. When I suggest that a sea level rise slow enough that "we can walk away from it" is not particularly frightening, I am warned that poor countries with no hills could see millions die... of drowning? It is not clear. The hypothesis is that since they are poor they can't figure out how to move somewhere else. So the solution is to turn off all the engines in the world to help keep Bangladesh above sea level? It would be simpler and cheaper to buy a few million square miles in Africa an pay to move all interested Bangladeshi's there. Oh but that is not politically realistic? But turning off all the engines is?

The usage of fossil fuels has not only NOT declined worldwide, it continues to grow as fast as it has ever grown. No matter at what rate renewable energy comes on line, more fossil fuel energy comes on line faster. " Solving" CO2 by having Americans and Europeans buy Tesla's is like "solving" population growth by having American's and Europeans use condoms. In each case, if you do not change what China, India, and Africa are doing you are for all intents and purposes doing nothing but rendering the US and Europe less important and powerful in the future of earth.

I think that the Earth will get warmer in the same way that I think exercise is good for longevity. I'm not competent to evaluate the arguments or even evaluate the people who evaluate the arguments, but there seems to be enough evidence from different sources to make me reasonably confident.

I have no idea what climate change's impact will be on people. Are current global temperatures optimized for human welfare? Probably not. Will making temperatures warmer be an overall gain or loss to human welfare? I have no clue. Is the cheapest way to avoid harms reducing CO2 emissions, or building levees, or moving everyone 10 miles inland, or putting mirrors in the stratosphere, or something else? Again, no clue.

I am encouraged that people are taking the welfare of humans hundreds of years in the future seriously. I am discouraged that the discussion on climate change is dominated by if it real, not what will its effects be and how can we optimize the upside and minimize the downside.

I don't care, because there's nothing I can do about it. It also applies to all large-scale problems, like national elections.

I do understand, that that point of view creates 'tragedy of commons', but there's no way I can force millions of people to do my bidding on this or that.

I also do not make interventions to my lifestyle, since I expect AGW effects to be dominated by socio-economic changes in the nearest half a century.

I would probably get a "sceptic" label stuck onto me.

Global warming is not a single yes/no issue (even though a lot of mindkilled people like to pretend it is). Roughly I think it breaks down into five major questions:

• Has Earth been warming up during the last several decades?
• To what extent the warming is caused by anthropogenic factors?
• How will the climate change proceed in the future and how certain we are of the forecasts?
• What will be the consequences of the change in climate?
• What should be done about it?

The answer to the first question is clearly "yes". There is a lot of data and it is pretty unambiguous.

The answer to the second question, I think, is "some". It is not 100% and it is not 0%.

The third question is probably the one where my sceptic attitude is the most pronounced. I believe that the climate models looking several decades ahead greatly overstate their confidence in the results and a lot of them are junk. My belief is based on the impression that we don't understand long-term climate mechanisms well (and so can't model them well), on the results of the out-of-sample testing that we have so far, and on peeking inside the sausage factory via the Climategate documents (hint: it's not pretty).

The fourth question is complicated -- there obviously are both positive and negative consequences. As far as I remember it is usually held that the positive consequences (e.g. better harvests, etc.) overwhelm the negative until the about +2 degrees C rise in the temperature, but it's all very uncertain.

The fifth question, the most interesting of them all, is not in the domain of the climate scientists at all. It is essentially a social and a political question the answers to which are driven by values and trade-offs.

Overall, I feel the climate science has been hijacked by fearmongers who use the hysteria to push their agenda and/or just to get money. There is a huge publication bias and my prior for media publications on climate change is that they have zero useful information.

I don't have any problems with the physics of climate change, that seems pretty clear.

I am worried about drawing conclusions about policy from predictive models. Causal modeling of time series data is very hard (according to at least some stats folks I asked who work with time series data). I don't know much about it, myself. I also don't know much about climate modeling.

1) The Earth is presently warming. I estimate that greenhouse gas emissions are a very significant component (~70%) of the long-term (100 years) climate change and a significant component (~30%) of short-term climate change (20 years). I think the IPCC is right, though this is largely because of their wide error bars (wide error bars should also be applied to my estimates above!)

2) It was presented as simple fact, and I accepted it. As I studied physics, my understanding became more nuanced, but nothing I found contradicted the initial impression. There was a period when I had a much higher estimate of the probability of massive cascading ice-slides that would eventually (not soon) raise the sea level noticeably over a short period. Recently I have attended a number of climate-related talks at APS conferences. That filled in certain gaps in my understanding (of course, I still have large remaining gaps)

3) The data since 1998 had been steadily decreasing my confidence since about 2004. Then I found out about the deep-sea temperature increases, and my confidence was restored most of the way (unfortunately - I'd been hoping we were missing an important effect that made GHG not matter so much).

Also, though it changed my expectations, it didn't really change my beliefs: I found out that CO2 emissions have been dropping.

Climategate's impact: Very little. If someone looked through my old email they'd find similar shorthand that might with an uncharitable reading look like I was basically making up my results, or applying very biased filters to them (I wasn't). Yeah, I 'questioned' my beliefs when I first read about it, but if this were a courtroom, the defense only had to cross-examine to acquit.

4) The recent posts contained some new information, but not that much. I don't know how useful this is.

Current beliefs on climate change: I would defer to the IPCC.

I would have first came across the subject while I was at school about 25 years ago (probably not at school, or at least only in passing). I think I accepted the idea as plausible based on a basic understanding of the physics and on scientific authority (probably of science popularisers). I don't remember anyone mentioning quantitative warming estimates, or anyone being particularly alarmist or alarmed.

My current views aren't based on detailed investigation. I would say they are based mostly on (a) things on climate change I come across in general scientific reading e.g. I have read most abstracts of articles and letters (and try to struggle through full text of all climate-related ones) in Nature in the last 7 years or so, and more sporadically in the last 20 years; and (b) the Azimuth blog of John Baez et al, who seem genuinely interested in what you can and can't get out of climate models.

One thing I learned on reading your posts (if I got the right impression) is that "respectable skeptics" agree about the C02 increase, that it is human-caused, that there is some warming, that the warming is C02 caused, but they disagree about the magnitude and confidence of future projections. I did not know this.

I am extremely skeptical of AGW alarmism. Here are some reasons:

• I am intrinsically contrarian.
• My understanding of AGW is superior to the large majority of people of I talk to about it. For example, very few people understand basic concepts of temperature, blackbody radiation, and Wien's law. Very few people understand why C02 molecules are worse than 02, N2 or CO molecules for warming, or why methane molecules are much worse (the reason is that C02 has many rotational degrees of freedom, which allow it to absorb IR radiation emitted by the Earth). The small minority of people who understand it better than me tend to be extremely cautious (anti-alarmist) in their statements.
• Simple arguments are morely likely to be true than complex ones. A simple environmentalist argument is: species are disappearing because of the destruction of wilderness habitats. Therefore, we should act to preserve wilderness habitats. I fully endorse this argument and would be happy to sacrifice large amounts of money on its basis. The argument for AGW action is more complex by many orders of magnitude: the world is warming (true), C02 emissions are the cause (probably true), increased temperatures are going to be bad (not at all obvious), and the increase in temperature is going to be large (untrue and unscientific in my view).
• Building on the above point, if half of contemporary research results are wrong, then the likelihood that the complex multipart AGW argument is wrong is very high.
• Climate scientists have never made a public falsifiable prediction.
• Climate alarmists constantly depict their opponents as "shills" or tools of the oil/automotive/etc industries, as a strategy for undermining their legitimacy. I consider this offensive, but more relevantly, as a misreading of the socioeconomic forces at play. The only industry that should really be strongly opposed to AGW advocacy is the coal industry. Oil is cleaner than coal, so if C02 emissions are restricted, the oil industry will probably benefit. The nuclear industry will benefit significantly, as will the natural gas industry. The automotive industry might have to do some work to improve efficiency, but they can just pass those costs along to the customers.

The cause of my original beliefs on climate change is my parents' politics.

In my larval form, I had many more common misconceptions about how the greenhouse effect was supposed to work. The most wrong, and also the only one that I actually changed because of an anti' web site, was that the cycle of historical CO2 was a cause of historical climate changes, rather than an effect. Otherwise, I learned much more from RealClimate than I did the antis.

There was a distinct moment when I figured out that global warming was a physics problem that I could actually understand simple models of. Without these simple models, I would not actually understand the physical mechanism behind global warming. Most people still don't - people arguing on both sides don't know what they're arguing for/against.

The experts are basically right.

I'm an economist and think that the challenge of macroeconomic forecasting tells us something about the difficulties of creating mathematical models of the climate. I don't think we have the ability to make accurate mathematical models of complex systems where we can not conduct experiments to calibrate our models. But I recognize that I know little about climate models and so am not highly confident of my beliefs.

What are your current beliefs on climate change? Specifically, would you defer to the view that greenhouse gas forcing is >the main source of long-term climate change? How long-term?

I have no particular opinion about that. I think any specific predictions are more likely wrong then true, especially predictions about climate change economic effects, and catastrophic predictions are almost certainly wrong. I strongly oppose emissions cut policies.

What were your beliefs on climate change when you first came across the subject, and how did your views evolve (if at >all) on further reading (if you did any)?

I thought that climate change is an obvious scam (that is default position in my country). No I don't.

What are some surprising things you learned when reading up about climate change that led you to question your beliefs >(regardless of whether you changed them)?

The most suprising thing is that there is any science involved at all, not just political propaganda.

What are your current beliefs on climate change? I think it most likely that the experts have it roughly correct: the climate is warming, there's a lot of noise on short timescales, a big influence on overall temperature is how much CO2 there is in the atmosphere, a big influence on that is emissions from human activity like burning coal, etc. I would not be greatly surprised to find that the current consensus is a factor of 2 out either way in magnitude (nor, I think, would the experts) but I would be surprised by a factor of 10.

What were your beliefs on climate change when you first came across the subject? I don't remember. and how did your views evolve (if at all) on further reading? I haven't made much attempt at understanding the science for myself. Most of the "further reading" I have done is looking at popular-audience stuff written by both affirmers and deniers. My bullshit meter pings a lot more loudly on the deniers' material. Since I don't remember how my opinions started out, it's hard to be sure how they've changed, but I think my confidence that the expert consensus is at least somewhere in the vicinity of the truth has increased.

What are some surprising things you learned when reading up about climate change? I've seen it claimed that there's a startlingly large overlap between people and institutions that are arguing against anthropogenic climate change now, and people and institutions that were arguing against the link between tobacco-smoking and cancer a couple of decades ago. I haven't checked this, but it would be rather interesting if true.

If you read my recent posts linked above ... Sorry, I didn't. (Not because of any particular fault in them.)

What are your current beliefs on climate change? Specifically, would you defer to the view that greenhouse gas forcing is the main source of long-term climate change? How long-term? Would you defer to the IPCC range for climate sensitivity estimates?

I'm fairly confident about the sign, but not the magnitude of climate change. I'm not sure that greenhouse forcing is the principle component. IPCC estimates seem pretty reasonable since they were scaled down a while back.

What were your beliefs on climate change when you first came across the subject, and how did your views evolve (if at all) on further reading (if you did any)?

I didn't have much of an opinion at first. I saw that warming was believed by scientists and believed it. Then I saw a bunch of politicization and became somewhat contrarian. I went seeking out information to confirm or disprove my contrarianism and found a whole bunch of uncertainty. I became confident that people who were confident about the area were wrong. I investigated economic analysis of best and worst case scenarios and concluded it wasn't worth paying attention to.

What are some surprising things you learned when reading up about climate change that led you to question your beliefs

Climate sensitivity and public choice issues in climate science. Climate science was my first exposure to a scientific field in disarray with money flowing based on politics rather than truth seeking. This eventually lead me to being more skeptical of claims in lots of other fields as I studied public choice and statistics.

If you read my recent posts linked above, did the posts contain information that was new to you?

No, but this exercise of tracking beliefs was good.

When I was young I was quite the environmentalist, but I grew out of it around age 7 or so(~1992, when it was still fairly new). Didn't have much of a rational basis for it(truth be told, the moment I remember was reading a book by a lady named Harms, and thinking that didn't make any sense for someone named Harms to be doing something I so strongly associated with helping, so I drifted off to other things to geek out about instead - yes, I was a strange kid). I sort of dropped AGW with all the other baggage of that era for many years.

Didn't think about it much until I got into political debate again around 2001. I was a hard-line libertarian by then, and hung out in a pretty sarcastic circle, so seeing AGW as a big-government plot was easy. Defaulted to that for a little while, but then I took a spectroscopy class in university and a simple look at the absorption spectrum of CO2 makes it clear that it is, in fact, a greenhouse gas, so the theory must have some truth.

It was still a second-tier issue for a long time - Iraq took up most of my political debate time for years. The next moment I remember was reading Bjorn Lomborg in about 2005, and thinking that there was finally someone who I thought really made sense on the topic. AGW is real, but it's not a catastrophe waiting to happen - if it was, it'd have happened at some point in our planet's history, so negative feedback has to exist. It'll raise temperatures, which will have both positive and negative effects, and while the cost of the negatives outweighs the benefits of the positives, the present value of the sum is far too small to be worth worrying about.

My views largely haven't changed since then. AGW is scientifically real(though somewhat overblown, and I don't have a lively confidence in the accuracy of their pretty bad models), but worrying about it is economically silly. And the economic studies seem to back me up - the ones that say it's bad use ridiculously low discount rates, which is about the only number that matters over that time scale. I favour some mild mitigation efforts - a revenue-neutral carbon tax for example, since it has no real societal cost - and research into how to geoengineer for cooler temperatures if we hit the black swan and have to worry about a catastrophe, but put the real money into bigger problems.

Meta: I don't think questions need to have "[QUESTION]" in the title. That's what the question mark does.

I used to just trust the word of the experts, because I am not an expert and had no incentive to become one. I didn't have a lot of faith in such a politicized science, but reasoned it was probably better than anything I could come up with. I trusted the IPCC reports, but after reading about Climategate thought they were exaggerated a bit as a means to gain political power.

Recently I've started to consider investing in alternative energy. Given that most alternative energy (especially with the fracking and shale oil revolutions) is based on AGW being a serious problem, I thought it deserved a real look.

I was appalled to see a non-experimental science call something as complex as the Earth's climate to be "settled", and how even the scientists seemed to degenerate into name-calling ("deniers" and "alarmists"). The issue was even more politicized than I first thought. I was unable to find real public debate between skeptics and supporters, but did come to understand that the disagreement is over feedbacks, specifically the change in water vapor, which respond to an increase in temperature from CO2 emissions.

I was most appalled at the lack of reporting of the global warming pause. I did not find a single supporting scientist seriously reconsider his views in light of the pause. One would think admissions such as "our models were clearly wrong, but AGW may still be a problem because the heat is probably going into the oceans/arctic/whatever" would be commonplace.

To me the "science" of climatology seems very similar to economics: experiments are impossible and it is very politicized. I enjoy and respect economics greatly, but recognized that progress in it has been very slow relative to the harder, experimental sciences.

As a result my faith in climatologists is at an all-time low. If I had to guess, I'd take a shot in the dark and say the feedbacks are being exaggerated by the IPCC, and warming will continue at about 0.10 degrees C per decade. Actually I'd say this whole experience has lowered my faith in politics and made me more libertarian as a result. I am used to people doing and believing disgusting things for power, but something about perverting science especially offends.

So I came here to read some (hopefully) more rational reports on AGW.

I would really like to see a study of the Earth's energy budget - can't we measure radiation lost to space with satellites? Everything else seems rather immaterial (unless the nuclear energy output of the Earth's core varies significantly).

I just read the OP's articles. There is a supporting argument in them which makes me think my sensitivity estimates are too low: the idea that sensitivity can be estimated from any source of forcing (of which there are many), and not just CO2. This would seem to suggest that we have more evidence on climate sensitivity (even if its all proxy records) than I'd of first guessed. However, unless proxy records can cover all significant forcings, I would doubt their usefulness. Do we have a proxy record of cloud cover, for example?

What are your current beliefs on climate change?

I'll skip talking about my own general beliefs about climate change because there's little reason to think they're of much more interest than those already posted.

Instead I'll point to the results of the last LW survey, where hundreds of us answered the question, "What is the probability that significant global warming is occurring or will soon occur, and is primarily caused by human actions?" The question isn't very specific and is somewhat subjective, but the answers to it can be correlated with the survey's other answers (on demographics, politics, and so on).

If you read my recent posts linked above, did the posts contain information that was new to you?

Some of the fine details were new to me, but the only substantial bit of information I hadn't seen before was Armstrong & Green's allegation that climatologists don't hew to forecasting principles closely enough.

Did any of this information surprise you?

Not particularly.

Do you think it's valuable to carry out this sort of exercise in order to better understand the climate change debate?

Do I think it's valuable for you to have made these posts? Yeah, a bit; it's been interesting to see how an intelligent, Less Wrong-y person with some mathematical training thinks about the topic when they're prompted to investigate it as part of a more general project about forecasting.

Do I think it's valuable for people in general to do this? If they get into arguments about climate change a lot, they probably ought to read into the topic in some detail. Otherwise, realistically, there's not much reason to put lots of time into honing one's beliefs here (and my advice would be to just flick through the relevant sections of the IPCC reports as & when one feels like it).

Obviously, your initial views wouldn't have included beliefs about terms like "greenhouse gas forcing"

In my case this is wrong. Carbon dioxide absorbs infrared? Duh. The only change in my views since the beginning has been learning that the role of clouds is unclear (they may contribute some negative or positive feedback, depending on which types increase or decrease in prevalence). That increases the error bars for magnitude of warming, but that's in line with IPCC forecasts. Since solar forcing seems unlikely to change that much in the next few decades or centuries, anthropogenic changes to the atmosphere will be the main drivers of climate.

As to what to do about it, geoengineering looks like the best first line of defense, though that's an opinion I hold with great uncertainty. Unfortunately, ocean acidification won't be helped by (e.g.) making more clouds at sea (which could stabilize global temperature).

To a significant extent I defer to the IPCC and other bodies on whether AGW exists. But as Holden Karnofsky says:

I generally find it very hard to formalize and explain what “outside views” I am bringing to a decision, how I am weighing them against each other, and why I have the level of certainty I do in each view.