Trying to predict the future is hazardous, not only because of the conjunction fallacy, but because there are so many factors involved. Even if you’re careful to avoid the mistake of thinking that A, B, and C happening are more likely than A and C, it’s not easy to estimate what will happen when you’ve got factors A through Z involved, and complicated chains of relationships like “if D and E, but not F, and G is stronger than expected, then H”. Misjudging the likelihood of a factor, or misunderstanding a relationship, or omitting factors or relationships, can make an apparently solid set of predictions completely worthless.
That’s not to say that it’s impossible, of course. If you restrict yourself to asking what will happen if we push on a physical system, and throw the world’s best scientists at the problem for decades with millions of dollars and powerful supercomputers at their disposal, then they can actually model what inputs will cause what outputs with probabilities attached. The existence of anthropogenic global warming is a fact, just as the existence of evolution and atoms is a fact, and it’s clear that all else being equal (note 1), basically everyone would prefer for the Earth’s climate to be original recipe instead of extra crispy. The problem is, we don’t know what the inputs will be, and it’s trying to guess what the inputs will be that’s especially hazardous. It’s a lot harder to model what one Congress will do, let alone many. (Modeling the mind-killer is a headache.)
When faced with this sort of problem, I find it useful to instead think about possible end states, which are typically easier to envision and enumerate, and ask how likely it is we’ll end up there, through any path whatsoever. And Stein’s Law is usually helpful: “If something cannot go on forever, it will stop.”
Anthropogenic global warming can’t go on forever, so it’ll stop. How will it stop? I can think of several ways—this is a non-exhaustive list:
We discover a novel feedback loop, Earth’s atmosphere becomes like Venus’s, and everyone dies. It’s pretty clear that this isn’t a possibility, we hope, although it should be considered before being rejected (note 2).
We collectively come to our senses, and do all the right things right now to keep the problem from getting any worse, and to fix as much as physically possible of the damage that’s already been done. It’s also pretty clear that this will not happen.
A technological breakthrough substantially solves the problem for us. For example, we solve a bunch of engineering problems, and leapfrog from ITER to cheap and plentiful commercial nuclear fusion in just a couple of decades, without having thrown 100 billion dollars at the problem (as that would be shading into the “come to our senses” scenario). The probability of this one is hard to judge—we get stuck by some problems for a while before eventually solving them—but hope is not really a plan.
The nasty consequences of global warming keep getting worse and worse, until advanced civilizations are wrecked back into more primitive states, where they’re unable to keep dumping carbon into the atmosphere. It looks to me like this one is unlikely too—advanced nations will be able to cope at significant cost. It’s just poor nations that are boned.
We run out of coal (note 3), oil, and natural gas to burn. They’re finite, so this is guaranteed to happen—the question is whether it happens before anything else. A more precise question is, when will our rates of production stop increasing—combined with inelastic demand, this will cause significant price increases that force us to consider previously more expensive (or ionizing), but non-carbon-emitting, sources of energy. This is the scenario that I judge as most likely. Unfortunately, it looks like the result will be extra crispy at a minimum.
Something else—increasing food/water/resource scarcity leads to increasing conflict, and eventually to global thermonuclear war—we know that one is perfectly capable of wrecking technological civilization. Hopefully unlikely (there’s that word again).
My conclusion is that because many people are already working on both sides of this issue, this community’s time would be better spent elsewhere.
Note 1: The “all else being equal” part is key. The ultimate problem isn’t that some people want to seriously modify the Earth’s climate in and of itself, or for the lulz, or because they’re supervillains. It’s because fucking money is at stake, and like Mafia bosses in movies, people want their fucking money and they want it now. This wouldn’t even be a problem, except that carbon is an unpriced negative externality.
Note 2: Just as igniting the Earth’s atmosphere was considered and rejected before the Trinity test. Note that many popular accounts of how this possibility was considered are completely wrong. The worry was never that a nuclear weapon could ignite a global chemical fire in the atmosphere—it was that it could ignite a global nuclear fire. (Follow Wikipedia’s citation.) Fortunately for us, the physics don’t work out that way.
The nasty consequences of global warming keep getting worse and worse, until advanced civilizations are wrecked back into more primitive states, where they’re unable to keep dumping carbon into the atmosphere. It looks to me like this one is unlikely too—advanced nations will be able to cope at significant cost. It’s just poor nations that are boned.
One thing I noticed about predictions of nasty consequences of global warming, is that they’re always about 5 to 10 years from the present, with the date always being updated. See here, for a discussion of a recent example.
It all started back in October 2005 when the U.N. flatly stated, “by 2010 the world will need to cope with as many as 50 million people escaping the effects of creeping environmental deterioration.” They forecast “this new category of ‘refugee.’” In 2008 the Srgjan Kerim, president of the U.N. General Assembly, upped the doomsday prediction, saying there would “between 50 million and 200 million environmental migrants by 2010.” Environmental activist Norman Myers, a professor at Oxford University predicted that climate change could force to 200 million climate refugees.
The U.N. specifically identified Pacific and Caribbean populations that would be ravaged by climate change. Gavin Atkins, writing for Asiancorrespondent.com reports “a very cursory look at the first available evidence seems to show that the places identified by the UNEP as most at risk of having climate refugees are not only not losing people, they are actually among the fastest growing regions in the world.” Atkins reports that all of China’s “threatened” cities –Shenzzen, Dongguan, Foshan, Zhuhai, Puning and Jinjiang — are the fastest growing cities in the world.
Atkins also looks at other endangered locations, the Bahamas, St. Lucia, the Seychelles and the Solomon Islands. None have refugees and all have enjoyed healthy population growths.
This is by no means the only example of a global warming doomsday prediction failing to come true and being quietly forgotten.
I’m surprised to find statements here such as “the existence of anthropogenic global warming is a fact”. I’m new here, haven’t read all the sequences, and this may seem obnoxious. But I’m testing my beliefs and willing to change my mind.
Let’s start with the article linked to by the OP. It says that 4 degrees of warming is likely and bad. I’ll concentrate on likely.
The argument for athropogenic global warming goes something like this:
1) carbon dioxide levels have increased since pre-industrial times
2) increased carbon dioxide levels in the atmosphere will cause a small amount of warming
3) we have measured a large amount of warming (since, say, 1880)
4) there may be feedback effects that mean that the small amount of warming caused by CO2 could lead to a large amount of warming
5) if we build a computer model of the atmosphere including supposed feedbacks, and tweak it until it predicts past events correctly, then it predicts a large amount of warming in the future
1 and 2 are uncontroversial.
3 is difficult to measure. For example land based thermometers are only accurate to, say, 1C, and we are extracting a signal that varies by tenths of a degree. Or we are using proxies like tree rings that are difficult or impossible to calibrate. The signal we do extract is not linear, to say the least. For example warming stops at times even as CO2 increases, so we know there are large variations not accounted for by CO2 which makes it hard to determine the influence of CO2 alone. The signal looks very different depending on what timescale one looks at, hence arguments about natural variation, decadal oscillations, the medieval warm period and so on.
The feedback effects in (4) are not well understood, which means that the models in (5) do not necessarily reflect how the real climate system works.
And if a model does not include important parts of the system, even if it correctly predicts past events that does not mean it can predict future events. I could build psuedo-random-number generators until I find one that happens to match closely the observed past temperature signal, but it will not predict future temperatures.
All this does not add up to a high level of certainty that additional CO2 will lead to any particular amount of warming. The sensitivity of climate to doubling of CO2 is not known with any degree of certainty. In short, climate is not as well understood as evolution and atoms.
The OP speaks of “meaningful climate reform and legislation” which means redirecting lots of resources to change the amount of CO2 emitted. Resources that could generate more utility elsewhere.
So what is going wrong? Possibilities:
a) I am wrong about 1-5 -- I haven’t linked to any sources for them partly because I have built this picture by reading around a lot and filtering everything through whatever untamed cognitive biases I have. I think I will explore this more.
b) I am not being rational
c) I or other commenters are making poor certainty estimates outside their area of expertise
d) other commenters are assuming that the majority is right
e) other commenters have discounted climate skepticism after having seen poor climate skeptic arguments without having seen the good ones; or I have made the opposite error
run out of coal (note 3), oil, and natural gas to burn. They’re finite, so this is guaranteed to happen—the question is whether it happens before anything else
Running out is not likely to happen any time soon at expected usage growth rates. The cost of extracting coal, oil, and natural gas will (possibly) increase over time but new technologies may depress the price of each (see the current state of natural gas). The estimates for potentially extractable reserves gives a figure such that if ways are found to extract such reserves oil and coal will be in continual usage (at present growth rates) for over another hundred years in the future.
Further, there are ways of producing oil substitutes that become feasible as oil hits certain price points. As these get implemented large scale it is likely that economies of scale and incremental improvements will kick in so that even though there will still be oil being produced most ways that we currently use oil will be changed over to the new technologies. Oil just happens to be the lowest cost alternative currently but as demand increases and cost of production increase then the other alternatives will be used.
Trying to predict the future is hazardous, not only because of the conjunction fallacy, but because there are so many factors involved. Even if you’re careful to avoid the mistake of thinking that A, B, and C happening are more likely than A and C, it’s not easy to estimate what will happen when you’ve got factors A through Z involved, and complicated chains of relationships like “if D and E, but not F, and G is stronger than expected, then H”. Misjudging the likelihood of a factor, or misunderstanding a relationship, or omitting factors or relationships, can make an apparently solid set of predictions completely worthless.
That’s not to say that it’s impossible, of course. If you restrict yourself to asking what will happen if we push on a physical system, and throw the world’s best scientists at the problem for decades with millions of dollars and powerful supercomputers at their disposal, then they can actually model what inputs will cause what outputs with probabilities attached. The existence of anthropogenic global warming is a fact, just as the existence of evolution and atoms is a fact, and it’s clear that all else being equal (note 1), basically everyone would prefer for the Earth’s climate to be original recipe instead of extra crispy. The problem is, we don’t know what the inputs will be, and it’s trying to guess what the inputs will be that’s especially hazardous. It’s a lot harder to model what one Congress will do, let alone many. (Modeling the mind-killer is a headache.)
When faced with this sort of problem, I find it useful to instead think about possible end states, which are typically easier to envision and enumerate, and ask how likely it is we’ll end up there, through any path whatsoever. And Stein’s Law is usually helpful: “If something cannot go on forever, it will stop.”
Anthropogenic global warming can’t go on forever, so it’ll stop. How will it stop? I can think of several ways—this is a non-exhaustive list:
We discover a novel feedback loop, Earth’s atmosphere becomes like Venus’s, and everyone dies. It’s pretty clear that this isn’t a possibility, we hope, although it should be considered before being rejected (note 2).
We collectively come to our senses, and do all the right things right now to keep the problem from getting any worse, and to fix as much as physically possible of the damage that’s already been done. It’s also pretty clear that this will not happen.
A technological breakthrough substantially solves the problem for us. For example, we solve a bunch of engineering problems, and leapfrog from ITER to cheap and plentiful commercial nuclear fusion in just a couple of decades, without having thrown 100 billion dollars at the problem (as that would be shading into the “come to our senses” scenario). The probability of this one is hard to judge—we get stuck by some problems for a while before eventually solving them—but hope is not really a plan.
The nasty consequences of global warming keep getting worse and worse, until advanced civilizations are wrecked back into more primitive states, where they’re unable to keep dumping carbon into the atmosphere. It looks to me like this one is unlikely too—advanced nations will be able to cope at significant cost. It’s just poor nations that are boned.
We run out of coal (note 3), oil, and natural gas to burn. They’re finite, so this is guaranteed to happen—the question is whether it happens before anything else. A more precise question is, when will our rates of production stop increasing—combined with inelastic demand, this will cause significant price increases that force us to consider previously more expensive (or ionizing), but non-carbon-emitting, sources of energy. This is the scenario that I judge as most likely. Unfortunately, it looks like the result will be extra crispy at a minimum.
Something else—increasing food/water/resource scarcity leads to increasing conflict, and eventually to global thermonuclear war—we know that one is perfectly capable of wrecking technological civilization. Hopefully unlikely (there’s that word again).
My conclusion is that because many people are already working on both sides of this issue, this community’s time would be better spent elsewhere.
Note 1: The “all else being equal” part is key. The ultimate problem isn’t that some people want to seriously modify the Earth’s climate in and of itself, or for the lulz, or because they’re supervillains. It’s because fucking money is at stake, and like Mafia bosses in movies, people want their fucking money and they want it now. This wouldn’t even be a problem, except that carbon is an unpriced negative externality.
Note 2: Just as igniting the Earth’s atmosphere was considered and rejected before the Trinity test. Note that many popular accounts of how this possibility was considered are completely wrong. The worry was never that a nuclear weapon could ignite a global chemical fire in the atmosphere—it was that it could ignite a global nuclear fire. (Follow Wikipedia’s citation.) Fortunately for us, the physics don’t work out that way.
Note 3: Fucking coal.
One thing I noticed about predictions of nasty consequences of global warming, is that they’re always about 5 to 10 years from the present, with the date always being updated. See here, for a discussion of a recent example.
This is by no means the only example of a global warming doomsday prediction failing to come true and being quietly forgotten.
I’m surprised to find statements here such as “the existence of anthropogenic global warming is a fact”. I’m new here, haven’t read all the sequences, and this may seem obnoxious. But I’m testing my beliefs and willing to change my mind.
Let’s start with the article linked to by the OP. It says that 4 degrees of warming is likely and bad. I’ll concentrate on likely.
The argument for athropogenic global warming goes something like this:
1) carbon dioxide levels have increased since pre-industrial times
2) increased carbon dioxide levels in the atmosphere will cause a small amount of warming
3) we have measured a large amount of warming (since, say, 1880)
4) there may be feedback effects that mean that the small amount of warming caused by CO2 could lead to a large amount of warming
5) if we build a computer model of the atmosphere including supposed feedbacks, and tweak it until it predicts past events correctly, then it predicts a large amount of warming in the future
1 and 2 are uncontroversial.
3 is difficult to measure. For example land based thermometers are only accurate to, say, 1C, and we are extracting a signal that varies by tenths of a degree. Or we are using proxies like tree rings that are difficult or impossible to calibrate. The signal we do extract is not linear, to say the least. For example warming stops at times even as CO2 increases, so we know there are large variations not accounted for by CO2 which makes it hard to determine the influence of CO2 alone. The signal looks very different depending on what timescale one looks at, hence arguments about natural variation, decadal oscillations, the medieval warm period and so on.
The feedback effects in (4) are not well understood, which means that the models in (5) do not necessarily reflect how the real climate system works.
And if a model does not include important parts of the system, even if it correctly predicts past events that does not mean it can predict future events. I could build psuedo-random-number generators until I find one that happens to match closely the observed past temperature signal, but it will not predict future temperatures.
All this does not add up to a high level of certainty that additional CO2 will lead to any particular amount of warming. The sensitivity of climate to doubling of CO2 is not known with any degree of certainty. In short, climate is not as well understood as evolution and atoms.
The OP speaks of “meaningful climate reform and legislation” which means redirecting lots of resources to change the amount of CO2 emitted. Resources that could generate more utility elsewhere.
So what is going wrong? Possibilities:
a) I am wrong about 1-5 -- I haven’t linked to any sources for them partly because I have built this picture by reading around a lot and filtering everything through whatever untamed cognitive biases I have. I think I will explore this more.
b) I am not being rational
c) I or other commenters are making poor certainty estimates outside their area of expertise
d) other commenters are assuming that the majority is right
e) other commenters have discounted climate skepticism after having seen poor climate skeptic arguments without having seen the good ones; or I have made the opposite error
f) something else…
Running out is not likely to happen any time soon at expected usage growth rates. The cost of extracting coal, oil, and natural gas will (possibly) increase over time but new technologies may depress the price of each (see the current state of natural gas). The estimates for potentially extractable reserves gives a figure such that if ways are found to extract such reserves oil and coal will be in continual usage (at present growth rates) for over another hundred years in the future.
Further, there are ways of producing oil substitutes that become feasible as oil hits certain price points. As these get implemented large scale it is likely that economies of scale and incremental improvements will kick in so that even though there will still be oil being produced most ways that we currently use oil will be changed over to the new technologies. Oil just happens to be the lowest cost alternative currently but as demand increases and cost of production increase then the other alternatives will be used.