Wednesday, October 24, 2012
Global Warming: some unpleasant news for denialists
Two contentions:
1. Global warming is occurring, and AGW is an important factor. Since both statements are empirical, I might as well give in to my Bayesian side and put numbers on these: I put the odds at 90% that AGW is occurring.
2. I believe this because the evidence seems very strong, and most scientists seem to agree.
Evidence:
Here are a few pieces of evidence I find convincing, all of them well-documented by research scientists and non-controversial.*
A) Recorded global temperatures have increased rapidly of late. The magnitude of recorded temperature fluctuations is not unprecedented, but the rapidity seems to be.
B) The evidence from temperature data is further supported by long term climate records developed from ice core drilling.
C) Glaciers in both the northern and southern hemispheres are shrinking. This seems to be anomalous behavior; typical glaciation cycles seem to be driven by changes in earth's orbit with glaciers in one hemisphere tending to expand while those in the other shrink. Current patterns are consistent with general warming.
D) Climate change has led to great expansions in the range and populations of pine bark beetles, both in North America and Europe. Anyone who lives in the Rocky Mountain West has seen this first hand.
None of these prove global warming, of course, but anyone who expects proof has no understanding at all of epistemology or science. (My reference to Bayesianism was certainly lost on them, too.) There's other evidence, lots of it, but these are things I've looked at with some care and found convincing.
Additional support:
E) In addition there's theoretical support: the proposed mechanism for AGW -- a greenhouse effect from certain gases -- seems clear enough, and there's evidence to support it. I'm less impressed by climate models; my own experience with economic modeling suggest there's too much susceptibility to "assumptions in, assumptions out," and if these were the main argument for global warming I'd be quite skeptical, but they are not the main argument. (This isn't an argument against modeling, incidentally. Economic models and climate models have their places.)
F) One thing I keep in mind is that I'm economist, and most of the science relevant to studying climate change is outside my fields of expertise. So what do experts in these fields think? So far as I can tell, the great majority of scientists believe in global warming, and if we consider only climate scientists, over 95% believe in AGW. Unless I have good reason, I'm quite hesitant to dispute people who have studied something carefully.
Caveat:
G) As much as possible, I try to ignore popular debates on the subject of climate. The news media is incapable of good scientific reporting, and denialists and alarmists both treat the subject with religious fervor and hysteria. Just because I think AGW is real doesn't preclude me from recognizing that Al Gore is an idiot and a crook.
Here's a very nice, measured summary of the issue by economist Thomas Shelling.
_________________________________________________________________________________
* Non-controversial except among those who take climate change denial as a matter of faith, to be defended at all costs. I haven't provided links to my sources, but will mention them. My primary sources on temperatures are a series of articles and interviews in Scientific American including an interview with an ex-skeptic, a public lecture by a climate researcher from U. Michigan, and discussions with a couple of physicists I know. My sources on ice cores include the public lecture previously mentioned and discussions with a friend who participated in a drilling project in Greenland. My primary source on glacier cycles is a paper written by glaciologists at Ohio State University (I no longer have the link). My sources on pine beetles include personal observation, discussions with an entomologist friend, and several research papers by respected entomologists.
Comments:
<< Home
A)Recorded global temperatures have increased rapidly of late.
That's evidence that the climate changes only, it is not evidence that CO2 is the cause.
B) The evidence from temperature data is further supported by long term climate records developed from ice core drilling.
That's more evidence that the climate changes only, it is not evidence that CO2 is the cause.
C) Glaciers in both the northern and southern hemispheres are shrinking.
That's more evidence of climate changes only, not evidence that CO2 is the cause.
D) Climate change has led to great expansions in the range and populations of pine bark beetles, both in North America and Europe.
Again it is evidence that the climate changes only, it is not evidence that CO2 is the cause.
So what you have provided is evidence that climate change is occurring, but nothing to show that its anthropogenic.
So how did you really conclude 90% odds that it is human caused?
klem
That's evidence that the climate changes only, it is not evidence that CO2 is the cause.
B) The evidence from temperature data is further supported by long term climate records developed from ice core drilling.
That's more evidence that the climate changes only, it is not evidence that CO2 is the cause.
C) Glaciers in both the northern and southern hemispheres are shrinking.
That's more evidence of climate changes only, not evidence that CO2 is the cause.
D) Climate change has led to great expansions in the range and populations of pine bark beetles, both in North America and Europe.
Again it is evidence that the climate changes only, it is not evidence that CO2 is the cause.
So what you have provided is evidence that climate change is occurring, but nothing to show that its anthropogenic.
So how did you really conclude 90% odds that it is human caused?
klem
# posted by 
: 11:01
: 11:01
Thanks for your questions.
The rapidity of these various changes is what is unusual, and apparently unprecedented. Other likely causes, e.g. shifts in earth's rotation, seems to operate on a much longer time frame. The one other factor that might operate on this time frame is solar activity, but I understand from several specialists that observed solar activity can't account for what we've observed.
Sudden increases in greenhouse gases (not just CO2, btw) seem to be the most likely factor, and these are indeed strongly linked with human activity, hence AGW. I've listened to a number of lectures (e.g. the UM climate researcher I mention, others as well) and discussed this with several of the scientists I mentioned, and find the arguments on these lines compelling.
Why am I only 90% convinced? Well, that's obviously a subjective estimate; I arrived at the number first because I find the arguments largely convincing, but also don't discount the more informed critics -- 90% is a roughly reasonable of my degree of uncertainty. It also roughly corresponds to the percentages of believers & disbelievers among scientists. That isn't really measure of *my* uncertainty, but makes 90% seem like a reasonable focal point.
The rapidity of these various changes is what is unusual, and apparently unprecedented. Other likely causes, e.g. shifts in earth's rotation, seems to operate on a much longer time frame. The one other factor that might operate on this time frame is solar activity, but I understand from several specialists that observed solar activity can't account for what we've observed.
Sudden increases in greenhouse gases (not just CO2, btw) seem to be the most likely factor, and these are indeed strongly linked with human activity, hence AGW. I've listened to a number of lectures (e.g. the UM climate researcher I mention, others as well) and discussed this with several of the scientists I mentioned, and find the arguments on these lines compelling.
Why am I only 90% convinced? Well, that's obviously a subjective estimate; I arrived at the number first because I find the arguments largely convincing, but also don't discount the more informed critics -- 90% is a roughly reasonable of my degree of uncertainty. It also roughly corresponds to the percentages of believers & disbelievers among scientists. That isn't really measure of *my* uncertainty, but makes 90% seem like a reasonable focal point.
Whether or not AGW is real I feel is wholly outside the real question. The real question is whether or not our governmental institutions will allow the free market to design solutions to this problem. I have a lot of faith that if this evolves into a tangible crisis that entrepreneurs should be on the front lines, not bureaucrats and clunky regulations.
# posted by : 11:02
: 11:02
A note on Scientific American: there is nothing scientific about that magazine anymore. It is little more than a propaganda instrument of the academic left. I used to subscribe but cancelled when I realized they're not even trying to write about serious science anymore.
My breaking point was when they interviewed a sociologist who decided (literally, he said that) that he is also a geneticist and argued that no genetic causes for differences in heart attack rates between blacks and whites exist, and that it is only a matter of stress caused by persecution of blacks by whites.
By the way, Scientific American is not even American magazine anymore. They are now owned by the super-leftist Nature Publishing Group, a British conglomerate that publishes the prestigious journal Nature.
I hate to agree with denialist idiots, but Scientific American is really not a source to be taken seriously.
My breaking point was when they interviewed a sociologist who decided (literally, he said that) that he is also a geneticist and argued that no genetic causes for differences in heart attack rates between blacks and whites exist, and that it is only a matter of stress caused by persecution of blacks by whites.
By the way, Scientific American is not even American magazine anymore. They are now owned by the super-leftist Nature Publishing Group, a British conglomerate that publishes the prestigious journal Nature.
I hate to agree with denialist idiots, but Scientific American is really not a source to be taken seriously.
I just saw that minutes after posting my previous comment, so I had to include it.
Here's this week's editorial of Nature, the world's leading scientific journal: "A vote for science: In support for science and environmental issues, Barack Obama and the Democrats have a clear advantage over Mitt Romney and the Republican Party."
http://www.nature.com/news/a-vote-for-science-1.11634
Here's this week's editorial of Nature, the world's leading scientific journal: "A vote for science: In support for science and environmental issues, Barack Obama and the Democrats have a clear advantage over Mitt Romney and the Republican Party."
http://www.nature.com/news/a-vote-for-science-1.11634
Greg: I mostly agree. That's why I took care to separate this discussion from the discussion of libertarianism. Of course, whether a problem is real or not does matter for policy, but in this post I'm not discussing policy.
PL: I quit subscribing to SA b/c of the high fluff content and the economic & political nonsense. It's mostly drivel. But the particular GW discussions I referenced seemed pretty fluff-and-propaganda-free and were simply interviews & contributions by climate scientists of note.
PL: I quit subscribing to SA b/c of the high fluff content and the economic & political nonsense. It's mostly drivel. But the particular GW discussions I referenced seemed pretty fluff-and-propaganda-free and were simply interviews & contributions by climate scientists of note.
Also to Greg: Let's assume AGW is real. One enormous obstacle to solving it is that it's global in nature. Getting China & India, for example, to cooperate in solving it is an enormously difficult problem. Some of the earlier work by Thomas Shelling (I link to his Liberty Library entry at the end) on Kyoto showed it was useless as a solution, and he's done a nice job in general of analyzing the difficulties of such negotiations. It's clear govts would have a role, but I think it would have to be in better defining property rights such that incentives exist to mitigate the problem. Central planning OTOH is an inane approach.
"One enormous obstacle to solving it is that it's global in nature. Getting China & India, for example, to cooperate in solving it is an enormously difficult problem..."
But that is exactly what carbon taxes and Cap&Trade were designed to do, they can be used to control other countries. In other words, if China has no carbon controls on their manufactured goods, you can simply slap a carbon duty on their products, forcing them to adopt a carbon scheme. If a country want to control US products, they will simply slap carbon duties on US products, services, airlines, shipping lines, tourists, basically anything they want to really. Once that carbon scheme is in place, governments can manipulate it anyway they want, toward any outcome they want.
He who controls carbon, controls life.
klem
But that is exactly what carbon taxes and Cap&Trade were designed to do, they can be used to control other countries. In other words, if China has no carbon controls on their manufactured goods, you can simply slap a carbon duty on their products, forcing them to adopt a carbon scheme. If a country want to control US products, they will simply slap carbon duties on US products, services, airlines, shipping lines, tourists, basically anything they want to really. Once that carbon scheme is in place, governments can manipulate it anyway they want, toward any outcome they want.
He who controls carbon, controls life.
klem
# posted by : 12:04
: 12:04
klem, I suppose you have evidence that carbon taxes & C&T were invented to do this? Cite it, please.
Control carbon, control life? Control of information, or monetary system, or guns, or the oceans and skys, those I might believe. Carbon is very, very, very far down on the list of such tools.
Economist Ed Dolan has a great post on his blog debunking the idea that high energy prices are an important economics problem. Very worthwhile.
Control carbon, control life? Control of information, or monetary system, or guns, or the oceans and skys, those I might believe. Carbon is very, very, very far down on the list of such tools.
Economist Ed Dolan has a great post on his blog debunking the idea that high energy prices are an important economics problem. Very worthwhile.
There's so much overwhelming support for the case of climate change, it seems very hard to ignore it as a serious issue that must be tackled. I personally believe that a lot of the denialists are possibly funded by corporations who don't wish to be curtailed in terms of their operations and their ability to neglect environmental obligations. A lot of corporations must see climate change as a serious threat to their profits. For political parties to offer subsidies for renewable energy technology from companies like WDS Cardiff, I think that there must be something more important on the agenda than simply offering government policies in favour of those that gave campaign contributions.
Post a Comment
# posted by : 03:54
: 03:54 << Home
