As the evidence has gotten more clear that the global climate is, in fact, warming, I have heard the arguments made by certain blogs and think tanks (and several of my more conservative friends) shift from “there’s no evidence of global climate change” to “there’s no evidence of anthropogenic climate change”.
But my friends have been somewhat stumped when I’ve responded to this new argument with “so what”?
My argument to them is fourfold: (i) humanity has (at least economically) adapted to a certain climate; (ii) regardless of cause, that climate is changing, to humanity’s (at least economic) detriment; (iii) humanity has the capability to at least mitigate the climate change through control of greenhouse gas emissions; and (iv) from what I’ve read (your reading/mileage may vary), control of said emissions will cost less than the damage that will be inflicted by unabated climate change.
What is the counterargument? If climate change is a “natural cycle”, how does that affect the issue of whether we should combat it, if we can?
Whenever I’ve seen this point raised, the response is typically (IME) this:
“Global warming is natural, and the amount of greenhouse gases we’re putting into the atmosphere isn’t affecting it. Following this logic, there’s probably nothing that we can do to combat it - we just need to adapt.”
Or something along those lines. Hopefully, someone will come by and provide a reasoning that is better than this.
LilShieste
Because it’s one more delay, deflection, and diversion.
My own bet is the next fallback position will be “Sure, we have determined that it’s anthropogenic, but we don’t know which portion of it is anthro and which portion is non-anthro”.
Well, for one thing, it definitely impacts the issue of whether we’re able to combat it, and what strategies will be effective.
If our hefty anthropogenic increases in atmospheric greenhouse-gas concentrations are in fact warming the earth—as basic atmospheric physics predicts that they should, and most of the world’s climate scientists agree that they are—then we know that reducing and/or counteracting our greenhouse-gas emissions should be a key part of our anti-global-warming strategy.
If, on the other hand, there’s some yet-unexplained physical phenomenon preventing our emissions from warming the planet by the predicted greenhouse-effect mechanism…and the observed warming is coming from some other yet-unexplained physical phenomenon…then it’s harder to know what we need to do to combat it.
Unfortunately for this line of argument, no AGW (anthropogenic global warming) skeptic has yet put forth a convincing scientific explanation of why the global warming that we’ve observed in recent decades is “natural”. The AGW explanation favored by the vast majority of climate scientists is certainly far from perfect, but so far it’s a more consistent and evidence-based explanation than any of the alternatives suggested by the AGW skeptics.
I don’t know how much of the current warming is anthropogenic and I’ve read enough on the internet that I don’t think anyone knows the answer to that for certain. I do think most reputable scientists believe we have contributed to global warming, and that global warming is in fact happening. Across the scientific spectrum you do run in to some debate about precisely how much global warming has happened, and precisely what has caused it.
While the answers to those questions are important scientifically, policy-wise they aren’t important. We know that the climate is changing, and we’ve identified it will be a bad thing to deal with (at least in the short term–and I use that in the geologic sense, meaning hundreds of years.) So we should be doing things to scale back our contributions to the problem.
However, I tend to be a pessimist. I think humans are helping global warming along but I think it’s likely the world is moving out of the current ice age, or is at least moving into a relatively warm interglacial period. Meaning I think even if we all do our best, we’re going to see serious warming and while that doesn’t mean we should give up trying to limit GHG emissions (for reasons beyond just global warming, actually), I do think people need to realize that global warming is happening, is going to continue happening, and even if we do our best it’s going to get worse and we’ll have to deal with it.
Yep. If we’re not causing it, how are we going to prevent it from happening? It would seem impossible (or economically impossible) to do something *else *on the scale of the combined output of our global use of fossil fuels.
I don’t understand. AFAICT, it is pretty well accepted by climatologists that we are already in a warm interglacial period, and have been for the last ten thousand years or so. We are not “moving out of the current ice age”: there is no ice age at the moment. The most recent ice age ended several millennia ago.
Where are you getting your inference that natural orbitally-based climate cycles ought to be causing increasing global temperatures at the current time, independent of anthropogenic global warming?
Well, first you’ve misdefined ice age (cite.) Everything I’ve read indicates Ice Ages have two distinct states, glacial and interglacial. During a glacial period of an ice age, you will see significant glaciation (like was common more than 10,000 years ago) during an interglacial period, you see less glaciation and the recession of glaciers. But it is still an ice age. My understanding is, the definition of ice age is “a period if ice sheets in the northern and southern hemispheres.” Last I checked, the Antarctic ice sheet was still there, as was the Greenland ice sheet. To be truly out of an ice age, there are no ice sheets. The idea that ice sheets are always around is false, during many periods of Earth’s history there have been no ice sheets. For a long time it was presumed that during periods with no glaciation, the far northern reaches of the world which are currently “arctic” had a climate not dissimilar from the Pacific Northwest. But recent studies have suggested that that may have been a conservative estimate, and that outside of ice ages the arctic regions may have had a subtropical climate (cite.)
For whatever reason, in pop culture ice age seems to be synonymous with the “glacial period” of an Ice Age, one in which large ice sheets are seen over significant parts of Eurasia and North America; I’m not glaciologist, but everything I’ve seen written by them indicates the presence of ice sheets is a key definition of what an ice age is. The absence of ice sheets would indicate that it was not a period defined as an “ice age.”
The problem with the BBC article you linked is, the person who wrote it confuses interglacials as being separate from ice ages, which isn’t the case. Interglacials are periods within ice ages periods which are not interglacial are glacial. (I was certainly aware that we’re currently in a warm interglacial period, since there isn’t a massive ice sheet covering Europe; however the fact that glaciers still remain convince me that we can, in fact, continue get warmer. I may be going too far in saying the ice age will actually end in the next few thousand years, but that may not be totally out of the question.)
This seems like you are trying to rewrite history, the conservative main line was (and still may be), that man is not responsible for changes in climate. The earth is not cooling because of man, it is liberal BS to try to have government take control of your life, then went to the earth is not warming due to man, it’s liberal BS to try to get you our of your SUV.
I’d like to add a side note to this. It would not necessarily be that we can’t do anything to combat it, but reducing greenhouse gas emissions will not reduce global warming if they don’t create it in the first place.
While I think reducing CO2 emissions is the right thing to do, it wouldn’t surprise me in the slightest to get a report 10 years from now proving that our CO2 emissions account for 2% of total global warming, which is mostly caused by <insert technobabble>.
The real question is: HOW do you get India and China , to agree to limitations on CO2 emissions? Given China’s record on contaminated food, one would noyt expect too much cooperation on this. China and india need energy-and they have chosen to use coal. So what is the solution? Build them nuclear power plants? Or boycott Chinese-made goods?
I don’t see any solutuons. Remember the CFCs (airconditioning freons)? The USA and the EU banned their production and use-while india and china kept on making 9and exporting to the West) air conditioners containing the banned compounds.
I don’t think it is quite a nitpick to say that humanity has adapted to a number of different climates. So it may not be accurate to imply that humanity as a whole is locked to this particular set of circumstances. Isn’t that what the head of NASA said recently? (I can dig up a cite if anyone really needs it).
Well, yes, the climate seems to be changing. But (AFAICT) the world is getting warmer, wetter, and has more CO[sub]2[/sub]. This is, overall, good for plant growth. Again, going from memory, I believe there was a recent UN report that made this point. Yes, desertification will increase, in some regions, and coastal flooding in others. But that does not mean that all humanity is necessarily doomed, or even would be significantly disadvantaged.
That’s the part (as otherwise mentioned) that I don’t know about. If we aren’t the major cause of it, then what leads to the conclusion that we can stop or reduce it?
Well - maybe. But it may be more cost-effective to spend the same amount of money on dealing with GW rather than trying to stop it. This would be especially true if GW is not anthrogenic. If indeed we are in some natural cycle of warming, and/or if it is really caused mostly by factors beyond our control, it would be foolish and counter-productive to spend trillions trying to stop it. Spend the same trillions on economic development so that we can afford to deal with those effects of GW that are disadvantageous.
This is not the same as saying “fuck the environment; I’ve got mine”. It is to address a problem that I perceive with some environmental causes of the last thirty years or so, which is a reluctance to consider cost-benefit analysis as a basis for policy. Maybe it would be best to spend enormous amounts on implementing the Kyoto protocols, and try to figure out some way (as ralph124c mentions) to deal with the fact that those who are expected to be the greatest contributors to GW may not play along. Or maybe it would be best to spend the same amount on air conditioners and flood control (to take a trivial example). IYSWIM.
Not that we shouldn’t (perhaps) have a big push to reduce our energy footprint overall, or increase our dependence on nuclear power, or do research on fuel cells and fusion and so forth. But before we spend gigantic sums on trying to prevent GW, we ought (in my opinion) to have some reasonable assurance that it will do more good than harm. And wasting all that money would be, to me, more harm than good. YMMV.
Well, actually, it has been generally agreed that the Montreal Protocols and subsequent agreements have been very successful in decreasing the release of stratospheric-ozone-destroying compounds into the atmosphere (see here and here). Now, we just have to wait for a while (on the order of 50 years) for the compounds and the resulting stratopheric chlorine ions to be removed from the atmosphere and the ozone to recover.
Just on the surface of it, it seems rather unlikely that we just so happen around now to be naturally coming out of the ice age period (as you define it) that we have in fact been in for 2 or 3 million years. [It is unlikely in a statistical sense, plus there may be more reasons why it is unlikely in a mechanistic sense…i.e., presumably when the earth does come out of the ice age period it will be for an identifiable mechanistic reason.]
Furthermore, even the change from glacial to interglacial seems to have had an average rate of warming of around 0.1 to maybe 0.2 C per century whereas the current rate of warming is close to 0.2 C per decade.
In answer to the OP more generally, I always find the assumption made by people that we may get a substantial warming but it may not be our fault to be rather ill-informed: There is no known reason why we would have a substantial warming at these sorts of rates for natural reasons. If the cause of the current warming is mainly natural, it is very unlikely to continue (in fact, it is not even possible for us to explain why it has continued this long). The logic of the IPCC predictions for warming in the coming centuries is not “We think it is going to warm 1.4 to 5 C but we are not sure about the cause.” Rather, it is, “We think that the increases in greenhouse gas levels in the atmosphere that we produce will warm the earth 1.4 to 5 C.”
First, as I noted, historically even in going from glacial to interglacial, the average rate of warming globally has generally been an order of magnitude or so less than the warming rates we have been seeing over the last 30 years.
Second, the temperature proxy evidence, while not perfect, does suggest that Northern Hemispheric temperatures are likely higher than they have been in at least 1000 years. We are likely approaching the temperatures that were seen at the peak of the current interglacial. And, it wouldn’t be too much longer (I’m not sure when…but pretty certainly within the next century) at the current rate of warming that we would likely pass the warmest temperatures seen in any of the several past interglacials.
Third, we don’t know of any natural mechanism that ought to be causing such a strong warming. In fact, our best estimates are that natural factors alone should have led to pretty much steady temperatures over the last 30 years or so.
Martin, thanks for the clarification on your use of “ice age” (i.e., multimillion-year-long major global cooling period comprising many glaciation/interglacial cycles) versus “glacial period of an ice age” (which is what most people mean when they say “ice age”). However, I’m still confused as to why you think that natural climate cycles, independent of anthropogenic climate change, are likely to be causing the currently observed warming trend.
As jshore noted, the orbital oscillations which have caused us to shift back and forth between glacial and interglacial periods in a fairly well-defined pattern for at least the past several hundred thousand years don’t give us any reason to expect such an anomalous warming trend now. Why do you “think it’s likely the world is moving out of the current ice age” (i.e., the third major Cenozoic cooling period) which has prevailed for the last two or three million years, without any known orbital mechanism to produce that change at the present time or any known statistical pattern to predict it?
I agree that it may not be “totally out of the question” that we might be confronting some anomalous natural climate phenomenon that’s causing sudden warming. But only in the sense that climate is so complex that it’s hard to rule anything totally out of the question.
In terms of current theories of climate science and geology, AFAICT, the idea that we’re now suddenly seeing the beginning of the end of the current multimillion-year cooling period has essentially zero scientific support. Why would you believe that hypothesis rather than the comparatively (only comparatively, still far from perfectly) well-understood and evidence-backed hypothesis of present-day warming caused by anthropogenic climate change?
This may be true. Transitioning out of an ice age would be an enormous change for the world, transitions to ice ages and out of ice ages tend to result in massive extinctions, because these warm and cool periods last many millions of years (the current ice age has been going on for around 70m years) and because of that, organism have adapted significantly to either being in an ice age or a non-ice age climate. The transition itself takes an extremely long time, but usually they happen faster than animals can adapt and thus you have mass extinctions.
My opinion that maybe we’re moving out of an ice age is simply a guess. Nothing more, nothing less. I feel comfortable in presenting said guess because climatologists who have spent decades of their life studying these things, don’t know for sure what causes the earth to move in and out of ice ages, or in and out of glacial/interglacial periods within ice ages. We understand certain basics of global climate very well.
For example, we know that the primary determinant of Earth’s climate is the amount of radiation we receive from the sun. This radiation can be altered in three primary ways:
By changing the solar radiation received (through changes in Earth’s orbit or changes in the Sun itself)
By changing the fraction of solar radiation that is reflected (called albedo) by changes in cloud cover and/or atmospheric particles
By altering the longwave radiation from Earth back towards space (by changing greenhouse gas emissions.)
Because we know these are the three ways to change climate, we know pretty much for sure that increasing greenhouse gas emissions or decreasing them will have an effect on global climate.
That’s why people who believe GHG emissions don’t contribute to global warming are more or less dumb.
I agree. However, your conclusion is “we have no explanation for the current warming naturally, so it is entirely human doing” is different from my conclusion.
As I’ve said, I’m fairly pessimistic. The optimist would want to believe that the entirety of global warming is being caused by humans; because that means we could definitely, without a doubt, stop it. I tend to think people overestimate how important we are, and overestimate our power to stop climate change.
You can agree with everything the IPCC puts out and still believe that there are enormous unknowns; because the IPCC admits as much. What we do know, and this is basically a fact, is that increasing GHG emissions can increase global temperature. For that reason alone, we should work to limit them. I disagree with John Mace, I believe that there is a definite contribution to global climate change occurring that is not man-made in origin. However, I see no reason why we should work towards a complete understanding of what causes climate change (something that will take many more decades) when we do know, right now that increasing GHG emissions does cause warming.