Note: Please see this post of mine for more on the project, my sources, and potential sources for bias.
I have written a couple of blog posts on my understanding of climate forecasting, climate change, and the Anthropogenic Global Warming (AGW) hypothesis (here and here). I also laid down the sources I was using to inform myself here.
I think one question that a number of readers may have had is: given my lack of knowledge (and unwillingness to undertake extensive study) of the subject, why am I investigating it at all, rather than relying on the expert consensus, as documented by the IPCC that, even if we're not sure is correct, is still the best bet humanity has for getting things right? I intend to elaborate on the reasons for taking a closer look at the matter, while still refraining from making the study of atmospheric science a full-time goal, in a future post.
Right now, I'm curious to hear how you formed your views on climate change. In particular, I'm interested in answers to questions such as these (not necessarily answers to all of them, or even to only these questions).
- 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?
- 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").
- 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.
- 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?
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 whe... (read more)
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.
In many issues like this, my opinion is formed automatically without my conscious will or any kind of deliberate reasoning. I don't have opinions on highly technical issues I don't really care about, but on highly publicized issues like global warming it's hard for me not to develop any kind of preference to one direction or another. I had a certain feeling about global warming before I even knew enough about all the relevant facts and the science behind it, and this feeling was probably formed using very straightforward subconscious heuristics. So the question then is not "should I form an opinion on this", but rather "should I trust my gut feeling enough to call it an opinion and make it a small part of my identity" or "should I investigate this more to get a better feeling on the subject".
But this is just me, I'm not sure how other people's minds work. So do you mean you don't have even a slight preference to either direction? Or do you mean that this preference is not on such a firm ground that you should pay attention to it?
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.
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 cha... (read more)
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.
It does seem extremely unlikely that global temperatures are optimized for human welfare, but not as hard to believe that human welfare is optimized for current global temperatures.
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:
The answer to the first question... (read more)
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 wa... (read more)
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 (... (read more)
OK now I have to quote this:
(Note I don't mean this is an intentional strategy as applied to climate change, even one operating at a subconscious level within individuals. Given a range of skeptics with different opinions, it could be that different ones are coming into the spotlight so that the "most defensible" argument for doing nothing appears at the appropriate time. I just thought the parallel was funny.)
I am extremely skeptical of AGW alarmism. Here are some reasons:
I'm skeptical of various parts of AGW (e.g., Climategate) but I believe the reaction to the field has become a hate death spiral. (Hence, considering it in its separate parts rather than a single phenomenon.)
Accordingly, I find some of your reasons unconvincing.
Fully general counterargument.
IPCC Scientific Assessment
Regarding the confirmation of the second and third assessments (that is, they failed to be falsified, which implies that they were in fact falsifiable):
"Comparing climate projections to observations up to 2011"
You don't find any falsifiable predictions if you never look for them.
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 u... (read more)
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.
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.... (read more)
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 ... (read more)
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.... (read more)
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 i... (read more)
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 ser... (read more)
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 wit... (read more)
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 ... (read more)
To a significant extent I defer to the IPCC and other bodies on whether AGW exists. But as Holden Karnofsky says: