The Idea of Anthropogenic Global Climate Change

March 6, 2010 4:35 PM

In 1896, Swedish physical chemist and Nobel laureate Svante Arrhenius calculated that doubling CO₂ in the atmosphere would raise Earth's temperature 5-6°C. The idea didn't get traction at the time, in part because many believed it impossible for humanity to affect the climate (sound familiar?), but Arrhenius might have been on to something. Historian and physicist Spencer Weart's history of the century-long scientific investigation and popular debate will re-frame your perspective on today's crisis and arm you to educate the uninformed. If you don't know the history, you are probably repeating it. [After I-don't-know-how-many years, my first FPP]
posted by guanxi (34 comments total)

For those having trouble, the link is to the abstract, but there are PDF/HTML links at the top.
posted by guanxi at 4:41 PM on March 6, 2010 [1 favorite]

Wonder if he conspired to hide the decline too?
posted by Sukiari at 4:49 PM on March 6, 2010

Yes, but he was probably being bankrolled by the Green-Industrial Complex. Recycled insulation is big business, you know.
posted by mccarty.tim at 5:26 PM on March 6, 2010

Great article.

I'm curious how the early pre-1950 calculations were done. Apparently the simple doubling of CO₂, ignoring any other effects, would only increase temperature 1.2°C accoring to IPCC. Even Manabe's first model including secondary effects only gave 2°C (p72 in the pdf).
posted by FuManchu at 6:38 PM on March 6, 2010

From the Wikipedia article:

Svante Arrhenius was one of several leading Swedish scientists actively engaged in the process leading to the creation in 1922 of The State Institute for Racial Biology in Uppsala, Sweden, which had originally been proposed as a Nobel Institute.[citation needed] Arrhenius was a member of the institute's board, as he had been in The Swedish Society for Racial Hygiene (Eugenics), founded in 1909.[citation needed] Swedish racial biology was world-leading at this time, and the results formed the scientific basis for the Compulsory sterilization program in Sweden.

Even assuming it was not uncommon for 'leading scientists' at that time to be proponents of Eugenics, this potted online bio makes no mention of it. Could it just be a nasty rumour or something the Nobel people would rather forget?
posted by evil_esto at 7:07 PM on March 6, 2010

What you forgot to mention is that Svante Arrhenius thought that higher CO2 is a very good thing.

"Arrhenius clearly believed that a warmer world would be a positive change. "
http://en.wikipedia.org/wiki/Svante_Arrhenius

Fixed that for you.


By the way, I wouldn't be surprised if climate is getting colder.
posted by yoyo_nyc at 8:41 PM on March 6, 2010

yoyo_nyc: What does that matter?
posted by guanxi at 9:21 PM on March 6, 2010

Arrhenius was a physical chemist who understood that CO2 is much more absorbent of IR radiation than it is of visible radiation and that increasing atmospheric CO2 would warm the earth. More than a century of research has shown that Arrhenius' estimate of climate sensitivity, how much the average global temperature will warm with a doubling of CO2, to be reasonably accurate. His climate sensitivity estimate was a first order estimate with large error bars. He did not know squat about ocean heat circulation and climate, the net effect of clouds on the earth's radiation budget, etc. More than a century of observations, experiments and modeling have led to a much better understanding of the climate system and reduced the error bars on the climate sensitivity estimates.

Like everyone else in 1896, Arrhenius had almost no knowledge of the impacts of climate change on ecosystems, agriculture, ocean circulation, sea level, etc. Whether he thought higher CO2 was good or bad is irrelevant to his understanding of the radiation balance of the climate system.

On preview, read guanxi's four word version!

Just curious, yoyo_nyc, what do you propose is making the climate cooler, and over what time period is the cooling to take place?
posted by plastic_animals at 9:25 PM on March 6, 2010

Svante Arrhenius, On the Influence of Carbonic Acid upon the Temperature of the Ground (Philosophical Magazine, April 1896) [.pdf].
posted by washburn at 10:53 PM on March 6, 2010

I think what yoyo_nyc is trying to say is that he doesn't think we need to do anything about global warming. Either it's not happening; or if it is happening, maybe it'll be a good thing. He thinks it's just another example of political/media hype.

yoyo_nyc, I'm curious if you actually read the article or not. This isn't about politics, it's about science and technology, which our society is completely dependent upon. Look around you. Your computer doesn't work because people believe in electrons; the Internet doesn't work because people believe in packet switching.

The science of climate change isn't hard to understand. Carbon dioxide in the atmosphere traps heat (this is a good thing, as otherwise the planet would be much colder). By digging up and burning fossil fuels, we've raised the level of carbon dioxide in the atmosphere to the highest it's been in 15 million years. As the heat trapped in the atmosphere and the oceans continues to increase, the weather will get more and more unstable. That doesn't just mean warmer. Warm air holds more moisture, so we'll see more rain and snowfall as well as drought. "The last time carbon dioxide levels were apparently as high as they are today--and were sustained at those levels--global temperatures were 5 to 10 degrees Fahrenheit higher than they are today, the sea level was approximately 75 to 120 feet higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland."

So we have a big problem. What should we do about it?

Obviously, we depend on fossil fuels for power and transport. But we already have the technology to solve the problem. Battery technology has improved fast enough that plug-in hybrid vehicles are already here. We know how to generate additional electricity without emitting more carbon: hydroelectric dams, nuclear power plants, coal-burning power plants with carbon sequestration, renewables.

We can minimize the cost by replacing old equipment as it wears out. Scrapping a two-year-old car is expensive; scrapping a ten-year-old car isn't. The best policy to achieve this shift is a rising tax on fossil fuels, phased in over ten years or so. To avoid slowing economic growth, the revenue from this tax can be offset by matching cuts in other taxes, or refunded directly as a dividend.

The atmosphere is global, while any individual country can only set national policy. Therefore, we need agreement that each of the major industrialized countries will either bring in a carbon tax at comparable levels, or have some equivalent policy (like the European cap-and-trade system).

Of course politics is a slow process: it takes time to resolve conflicts between interests and to bring public opinion on board. What should individuals do in the meantime? We can behave as though a carbon tax were already in place. If gas prices were higher than they already are, and you know they were going to keep going up, what would you do? The next time you buy a car, you'd look at smaller, more fuel-efficient cars, or even a hybrid. The next time you need to move, you'd think about finding a place where you don't need to drive as much. If you run a business, you'd anticipate rising fuel prices. Etc.

There's some uncertainty in the science. Unfortunately, so far it looks like the IPCC's projections have underestimated the rate of change. The Arctic sea ice is shrinking faster than projected, for example. What this means is that we'll probably need to raise carbon taxes, and phase out fossil fuels, more rapidly than expected (and the later we start, the more painful it will be). If things start to get completely out of hand, the emergency solution is geo-engineering.

For a concrete example of damage caused by climate change, see British Columbia (where we just had the Winter Olympics). There's dead and dying pine trees all across the interior of the province, because the winters are no longer cold enough to kill the mountain pine beetle. Estimated economic damage to the BC forest industry is something like $30 billion.

BC brought in a revenue-neutral carbon tax more than a year ago (initially $10/tonne, rising $5/tonne each year). It was easy to implement (it's basically a sales tax), and although people didn't like it, the government survived the subsequent election.
posted by russilwvong at 11:23 PM on March 6, 2010 [7 favorites]

I am guessing from his user name that yoyo_nyc is making the argument that because it was snowy last month in the northeast of the United States, global climate change doesn't exist. But that might be an unfair assumption, so if he or she would like to cite something else... ?
posted by You Can't Tip a Buick at 12:15 AM on March 7, 2010 [2 favorites]

The science of climate change isn't hard to understand.

You can prove anything with facts.
posted by Blazecock Pileon at 1:02 AM on March 7, 2010

It's interesting that the paper elides the fact that Arrhenius's later estimate of C02 sensitivity was 1.6 or 2.0 if there if positive water vapour feedback.
posted by sien at 2:47 AM on March 7, 2010 [1 favorite]

The book you might want to look at:

geological perspectives of global climate change

These are mostly geologists, not computational climate model guys. If you do not have time to read this, here is my summary:

1.) earth science is way more complicated than you can imagine;

2.) civilization is in far greater peril from an icehouse event than a greenhouse event.

(I am an agnostic if anybody cares.)
posted by bukvich at 5:34 AM on March 7, 2010 [1 favorite]

bukvich: you may be an agnostic, but the book you're flogging isn't.

The American Association Of Petroleum Engineers (AAPG), the publisher of this book, has a very specific axe to grind on this issue.
posted by sneebler at 6:19 AM on March 7, 2010 [2 favorites]

"By the way, I wouldn't be surprised if climate is getting colder.
posted by yoyo_nyc"

Here's a theoretical question, yoyo_nyc.

Let's say you were mixing, say... Manhattan for you and a friend. Dry. You get a shaker, add your whiskey, your vermouth... and a rather large, solid ice cube, surprisingly shaped like Greenland and the Artic ice sheet.

...but due to particular circumstances, that stubborn ice cube refuses to melt much. You do a couple quick stirs, strain the first Manhattan into a glass, and garnish with an olive.

Now imagine that circumstances change for that ice cube. It starts to melt and heat more rapidly than the rest of the shaker. It's not as solidly frozen anymore, and develops cracks and weaknesses, to the point of exposing more surface area to warming than would otherwise be exposed.

So, you start to mix a second Manhattan, adding the same amount of whiskey and vermouth. The weakened Greenlandesque ice cube melts rapidly this time around, to the point that it even slightly raises the level of your finished drink.

Let's assume you measured the temperature of your Manhattans, and found, to some surprise, that the second Manhattan, when served, was actually colder than the prior Manhattan, due to the increased melting of the Greenland-like ice cube.

So, let's assume you mixed additional Manhattans with that same, increasingly melting, shrinking ice cube, until the ice cube finally dissolved entirely...

What, kind of behavior, temperature-wise, would you expect the subsequent Manhattans to display?

Just because your Manhattan is colder right now, yoyo_nyc, that doesn't mean that your Greenland-shaped ice cube isn't melting. In fact, it could very well mean that it's rapidly warming, even while your Manhattan is surprisingly cold, right?!
posted by markkraft at 7:04 AM on March 7, 2010 [3 favorites]

bukvich: to be a bit less dismissive, Google Scholar turns up only five references to the book. Here's a 2006 presentation by Lee Gerhard. All the graphs end before 2000, while temperatures have been continuing to increase, providing stronger and stronger evidence for the CO2 "signal". BBC article on the Arctic temperature record:

"The most pervasive signal in the reconstruction, the most prominent trend, is the overall cooling that took place for the first 1,900 years [of the record]," said study leader Darrell Kaufman from Northern Arizona University in Flagstaff, US.

"The 20th Century stands out in strong contrast to the cooling that should have continued. The last half-century was the warmest of the 2,000-year temperature record, and the last 10 years have been especially dramatic," he told BBC News. ...

The root cause of the slow cooling was the orbital "wobble" that slowly varies, over thousands of years, the month in which the Earth approaches closest to the Sun.

This wobble slowly decreased the total amount of solar energy arriving in the Arctic region in summertime, and the temperature responded - until greenhouse warming took over.

"The 20th Century is the first century for which how much energy we're getting from the Sun is no longer the most important thing governing the temperature of the Arctic," said another of the study team, Nicholas McKay from the University of Arizona.

posted by russilwvong at 7:16 AM on March 7, 2010

sneebler:The American Association Of Petroleum Engineers (AAPG)

That is American Assoc Petroleum Geologists.

You don't read too good, do you?

They have 1000's members. I assure you they have the full spectrum believers, deniers, agnostics.
posted by bukvich at 8:10 AM on March 7, 2010

OK I read Weart's article. It is very good. There is a ton more information at his website. I downloaded his list of references. The sucker is 88 pages long. Fine post guanxi. It isn't every day I get the opportunity to look at good relevant research published in 1896. And Arrhenius references Fourier 1827!
posted by bukvich at 10:11 AM on March 7, 2010

Oh look, a global-climate-change denying commenter... from Houston, TX! I'm shocked. This is my shocked face.
posted by hincandenza at 10:24 AM on March 7, 2010

Note: Help maintain a healthy, respectful discussion by focusing comments on the
issues, topics, and facts at hand—not at other members of the site.

Dismissing bukvich because he lives in Houston isn't helping the discussion.

bukvich: I assure you they have the full spectrum of believers, deniers, agnostics.

But this is science, not aesthetics. The question isn't, "What's your favorite color?" There's only one right answer: either human activity is causing significant climate change, or it isn't. If the believers and deniers are both looking at the same evidence, they can't both be right.

I'm curious: is it just petroleum geologists who are skeptical, or geologists in general? Steven Dutch, a geologist at the University of Wisconsin who says he's politically conservative:

... we have increases in a gas known to trap solar heat, and indications of climatic warming. Straightforward cause and effect reasoning suggests the one caused the other. If you woke up uncomfortably hot in the middle of the night and found someone had put an extra blanket over you, you'd logically conclude the blanket caused the warming. You wouldn't argue that your getting warm caused the blanket to appear on the bed, or that the two events were unrelated, or that there was no reason to connect the blanket and the warming.

So people who doubt the cause and effect link have work to do:

* If they don't believe carbon dioxide traps heat, what's their evidence? Give step by step physical justification for the claim that increasing carbon dioxide will not warm the earth.
* If they give more credence to studies that doubt global warming, why? Specifically, why are those particular studies more credible than studies that support global warming?

posted by russilwvong at 11:11 AM on March 7, 2010

> But this is science, not aesthetics.

The science is computational modeling. The last time I looked at one of these papers there were over 50 co-authors. This is not like special theory of relativity. The scope of this particular science problem is beyond a single human's understanding.

What makes me unconvinced of the finality of the argument is the cell size they are computing on. The last paper I read closely had cells that were larger than the Strait of Gibraltar, and they had an explicit "Strait of Gibraltar fudge factor" variable in their model, without which their model would not fit their data. I am not saying the one hundred percent consensus is fabricated and I am not saying anthropogenic global warming is bogus. I have no opinion on the subject yet. It's above my pay grade.

I printed about a 100 pages of Weart's book and look forward to reading it, perhaps eventually all of it. So far I like what I am reading.
posted by bukvich at 11:51 AM on March 7, 2010

It's easy to understand why the American Association of Petroleum Geologists may not be offering an objective and rational analysis of anthropogenic climate change, no? They seem to have a bit of a conflict of interest.
posted by mek at 12:20 PM on March 7, 2010

I'm not a "denier" but god, you people really have a hair-trigger for the torches and pitchforks, don't you?
posted by nasreddin at 3:21 PM on March 7, 2010

Let's burn down the observatory so this never happens again!
posted by mek at 5:22 PM on March 7, 2010

bukvich: The science is computational modeling.

Not really. The key scientific finding is that atmospheric CO2 traps heat (according to Weart, this was discovered by Gilbert Plass in 1956). To quote Dutch again: "In the case of global climate change, we have an atmospheric gas, carbon dioxide, that is known to be effective at trapping solar heat. You can shine infrared light through carbon dioxide and measure the absorption. You can fill a transparent vessel with carbon dioxide, put it in the sun, and compare its temperature with an equivalent vessel of air."

And we know by direct measurement that we're raising atmospheric CO2 levels. Here's a visualization showing atmospheric CO2 measurements taken by the Atmospheric Infrared Sounder on the NASA Aqua spacecraft.

So we're increasing the heat trapped by the atmosphere. This is known.

The computational models are just trying to quantify the effects. So far they seem to be underestimating the effects; see this graph of Arctic sea ice projections versus the actual measurements.

People seem reluctant to accept that this is a real problem because they imagine that we'll need to go through some drastic lifestyle change to tackle it. But like I said, we already have the technology. Do people really care whether their car runs on gas or electricity? Or whether their electricity is generated by burning coal or by nuclear fission?
posted by russilwvong at 9:18 PM on March 7, 2010 [2 favorites]

I'm not a "denier" but god, you people really have a hair-trigger for the torches and pitchforks, don't you?

SCIENCE!!
posted by russilwvong at 9:26 PM on March 7, 2010

I'm not a "denier" but god, you people really have a hair-trigger for the torches and pitchforks, don't you?

She blinded me with science. And a poke in the eye.
posted by Blazecock Pileon at 8:06 AM on March 8, 2010

To borrow a phrase from William Whewell, there is a ‘consilience of evidence’ when it comes to the science of climate change: multiple, independent lines of evidence converging on a single coherent account. These forms of evidence are both observational (temperature records, ice core samples, etc) and theoretical (thermodynamics, atmospheric physics, etc). Together, these lines of evidence provide a conceptual and scientific backing to the theory of climate change caused by human greenhouse gas emissions that is simply absent for alternative theories, such as that there is no change or that the change is caused by something different.
posted by sindark at 12:01 PM on March 8, 2010 [2 favorites]

For those who think that anecdotal information about how cold it is this winter is a reason to believe that global warming isn't a reality, might I suggest going to Greenland or Kamchatka this winter? You know... the place with melting glaciers, leaking deposits of trapped CO2 and methane, and increasingly more exposed ground, absorbing heat rather radiating it back?

Because those are the areas where the problem is manifesting itself most radically, and, ironically enough, those are the areas that are currently experiencing a surprisingly warm winter.

It's ultimately not about what temperatures are like in the US that matters at this point. It's whether or not we're getting close to a tipping point in the arctic, where the ice melts, trapped greenhouse gasses escape, coastal flooding is inevitable, and the entire planet starts to seriously heat up for a very, very long stretch of time.
posted by markkraft at 10:57 AM on March 9, 2010

> You can fill a transparent vessel with carbon dioxide, put it in the sun, and compare its temperature with an equivalent vessel of air.

This is true, and it is evidence. It is not much. The earth's carbon is contained within a system vastly more complex than that. The best model I have seen.

As to why earth scientists may be skeptical or conservative (I prefer the word agnostic) I wrote something which is too long to post in this thread. Link.

The guy who made the carbon system diagram (Mackenzie) has 250 scholarly publications listed on his home page, for those of you who like to tally up publication citation numbers.
posted by bukvich at 2:00 PM on March 9, 2010

The earth's carbon is contained within a system vastly more complex than that. The best model I have seen.

Sorry, I'm not following what you're saying. Are you saying, how do we know that the CO2 from burning fossil fuels is ending up in the atmosphere, and not getting stored somewhere by the carbon cycle? By looking at carbon isotopes.

Yes, it's ending up in the atmosphere. That it traps solar heat is a simple physical property. We can see clearly that the Arctic is heating up. As Steven Dutch says, it's pretty hard to argue that maybe the two aren't related.

Regarding agnosticism: Dutch suggests that you ask yourself if there's any amount of evidence you would regard as convincing. (It looks like he has a whole collection of pseudoscience pages devoted to people who don't believe in the moon landing, etc.)
posted by russilwvong at 3:43 PM on March 9, 2010

> As Steven Dutch says, it's pretty hard to argue that maybe the two aren't related.

Earth scientists are capable of arguing darn near anything, and no, it is not pretty hard; it is routine, what guys do 8 hours a day daily.

If I was arguing against anthropogenic global warming, (I am not; it would be above my pay grade) I would begin with solar radiation influx variation (Milankovitch cycles), then to relative greenhouse gas power of different components (particularly water and increased cloud cover with heat retention), then to various feedback subsystems, and we could be here for weeks. There are dozens variables and far more data than anybody could comprehend for a final exam preparation, let alone an internet discussion.

What we are observing in the climate in 2010 is not that much. At an icehouse maximum there are glaciers in Kansas City and the sea level is over a hundred meters lower. We are currently warm, but not near geological historical greenhouse peaks. The earth physics system is a hugely huge beast we only partially understand.

Are there dangers in burning carbon willy nilly?

Absolutely.

Do we have a mature reliable science regarding these dangers?

I am curious to know.
posted by bukvich at 8:25 PM on March 9, 2010

Earth scientists are capable of arguing darn near anything, and no, it is not pretty hard; it is routine, what guys do 8 hours a day daily.

If I was arguing against anthropogenic global warming, (I am not; it would be above my pay grade) I would begin with solar radiation influx variation (Milankovitch cycles), then to relative greenhouse gas power of different components (particularly water and increased cloud cover with heat retention), then to various feedback subsystems, and we could be here for weeks. There are dozens variables and far more data than anybody could comprehend for a final exam preparation, let alone an internet discussion.

Right. You'd construct a climate model which matches reasonably well with past climate observations, and show that in the model, it's not the increasing atmospheric CO2 which is causing the warming, but other factors.

Obviously this would be way too much work for an Internet discussion, but it's the kind of work you'd expect to appear in the peer-reviewed scientific literature. But as far as I know, there aren't any solid climate models in the scientific literature in which increasing atmospheric CO2 doesn't lead to warming. Since we already know that CO2 traps heat, that's not too surprising.

You mentioned Fred Mackenzie earlier. I did a quick search and found a half-hour video from a conference presentation that he did in 2005. Global Warming: Fact or Fiction?

We are currently warm, but not near geological historical greenhouse peaks.

I think it's worth taking a step back and thinking about what we ought to consider to be "dangerous." Geological greenhouse peaks? At past geological greenhouse peaks (hundreds of millions of years ago), there were dinosaurs running around! "Being able to support some form of life" is not the same as "not dangerous for human beings", especially not modern human society!

I think there may be a mismatch in timescales here. From a geological perspective, a million years is barely any time at all. You can't count on climate being stable, in another million years it's likely to have changed dramatically anyway, so why worry about the next hundred years? Life will continue to flourish; some form of life, anyway.

But from a human perspective, a million years is basically infinity, and our societies are dependent on a stable climate. Anatomically modern human beings have only existed for 100,000 years; human civilizations based on agriculture have existed for less than 10,000 years. In this context, destabilizing the climate in the course of 100 years or less is a huge deal, likely (at the very least) to kill a lot of people.

As noted earlier, we've already raised atmospheric CO2 levels to a point last seen 15 million years ago, when sea levels were at least 75 feet higher. And they're continuing to rise sharply, because we continue to depend on fossil fuels. We can argue about how solid the existing climate models are, but basically the models are just a way of predicting what's going to happen. We can see by direct observation of things like the Arctic sea ice that they're already changing rapidly (and faster than the models have predicted).

As I said earlier, what we need to do is pretty clear: use a rising carbon tax or equivalent policy to shift from gasoline-powered cars to electric cars, and to shift from coal- and gas-fired power plants to carbon-free power plants (whether using nuclear, carbon sequestration, or renewables), over a period of 10 years or so. The longer we delay, the more painful it will be.

This isn't to say that fossil fuel extraction will come to a dead stop. We'll still need petroleum for jet fuel, for example. But it should be easier to manage the diminishing supply of petroleum once we've stopped burning it for urban commuting.
posted by russilwvong at 11:36 PM on March 9, 2010 [1 favorite]