The Real Reason the Arctic and Glaciers Are Melting So Fast
You know how dark cars get hotter than light cars? And dark clothes absorb heat from the sun more than light clothes?
The same thing may explain why the Arctic ice is melting so fast … and give a very hopeful solution.
The Economist noted last year:
Soot—also known as black carbon—heats up the atmosphere because it absorbs sunlight. Black things do. That is basic physics. But for years the institutions that focus on climate policy have played down the role of pollutants such as black carbon that stay in the atmosphere for a short time, and concentrated on carbon dioxide ….
On January 15th … the most comprehensive study of black carbon yet conducted was published in the Journal of Geophysical Research: Atmospheres. It concluded that the stuff was the second-most-damaging greenhouse agent after CO2 and about twice as bad for the climate as had been thought until now.
Black carbon is especially damaging to frozen regions, because when soot falls on snow and ice it increases the amount of light and heat they absorb. The new assessment may therefore help explain why the Arctic has been melting faster than anyone had expected.
Whereas CO2is long-lasting and an inevitable by-product of burning fossil fuels, soot drops out of the atmosphere within weeks.
The Christian Science Monitor points out:
Soot remains in the atmosphere for around seven days – a far shorter time than CO2, which remains in the atmosphere for centuries. This means efforts to reduce soot may apply an important brake to warming in the short term with quick results, the researchers suggest.
Initially, calls from some climate scientists during the past decade to focus first on reducing emissions of shorter-lived but powerful warming agents, such as methane or soot, have been met with polite nods and a resumption of heated debates over CO2 emissions. But the increasing recognition of the adverse health effects of soot, as well as the experience from efforts to control soot, are changing that, some researchers say.
Time wrote in 2009:
Unlike CO2, which can hang around in the atmosphere for centuries — CO2 that was emitted by the first coal-powered train is probably still in the air, warming the planet — black carbon has a relatively brief life span. It remains just a few weeks in the air before it falls to earth. That’s key, because if the world could reduce black carbon emissions soon, it could help blunt warming almost instantly. “You can wait a week or a month and the totals in the atmosphere can be significantly different,” says Eric Wilcox, an atmospheric scientist with NASA. Meanwhile, if we were to vastly reduce new CO2 emissions immediately, the billions of tons that already exist in the atmosphere would keep warming the planet for decades.
The Institute for Governance & Sustainable Development agrees:
Because black carbon only remains in the atmosphere for several days to weeks, reducing it can bring about almost immediate mitigation of warming, whereas decreases in temperature lag reductions in CO2 by 1,000 years or more.
The MAIN Cause of Global Warming?
One of the world’s leading crusaders against global warming – Dr. James Hansen – said in 2003:
Soot in snow and ice, by itself in an 1880-2000 simulation, accounted for 25 percent of observed global warming.
In fact – while most sources now list soot as the second most important cause of global warming – it may even be in first place … at least in the near-term. As the Christian Science Monitor reports:
Given the uncertainties in the estimates, black-carbon soot may even outpace CO2‘s warming effect, according to the 232-page study published today in the Journal of Geophysical Research–Atmospheres.
Indeed, the ability of soot to melt snow and ice is so well-known that, in the 1970s, scientists – including Obama’s top science adviser, John Holdren– proposed pouring soot over the arctic to melt the ice and so prevent the ice age which scientists feared.
And we’ve previously noted that soot has been discovered to be a leading cause of snow and ice melting in the Arctic and the Himalayas, soot has a much faster influence on temperature than CO2, and that it is relatively easy to reduce soot.
Why is it soot such a powerful ice melter? Because it is much darker than ice, and so absorbs much more heat from the sun. Specifically – as anyone who has ever been in snow knows – ice and snow reflect most of the sunlight back up towards the sky. But dark colors (think of black asphalt) get really hot in the sunlight.
Moreover, soot creates a feedback loop … as the ice and snow melt, the darker colored soil, ocean, or freshwater beneath are revealed. These – in turn – also absorb much more warmth from the sun.
The Most Important Short-Term Action
Dr. Charles Zender of the University of California at Irvine, told Congress:
Reducing Arctic [black carbon] concentrations sooner rather than later is the most efﬁcient way to mitigate Arctic warming that we know of.
We’ve previously noted:
Top climate scientists say that soot plays a huge role in the melting of snow and ice. The director of Stanford’s Atmosphere and Energy Program and professor of civil and environmental engineering (Mark Jacobson) believes that soot is the primary cause of melting arctic ice, and says:
Controlling soot may be the only way to significantly slow Arctic warming over the next two decades ….
Washington’s Blog spoke with Dr. Jacobson – the head of Stanford’s Atmosphere and Energy Program, who has written numerous books and hundreds of scientific papers on climate, and testified before Congress numerous times on soot, climate and related issues – to find out more about the issue.
Initially, Dr. Jacobson explained some of the main sources of soot, such as diesel exhaust, waste burning, forest and open savannah burning to clear land for farming, biofuel burning in developing countries, and jet fuel.
Dr. Jacobson then explained how simply rerouting arctic plane flights could quickly reduce the amount of soot that ends up melting arctic ice.
JACOBSON: Jet fuel actually has a super-impact because of cross-arctic flight paths, because that’s where you get the closest emissions to the arctic.
WASHINGTON’S BLOG: Have you done any studies on how much it would cost to reduce emissions from cross-arctic global flights?
JACOBSON: Yes. We did a study looking at how much it would cost to reroute the flights around the arctic circle. Rerouting would increase costs by about a hundred million dollars a year in higher fuel and operating costs. But that’s 47 to 55 times less than the global warming costs to the U.S. alone which would occur without doing so.
Black carbon gets removed faster, so there’s a significant reduction to loss of the arctic sea ice. The cost is about one-fiftieth of the climate costs.
WASHINGTON’S BLOG: Without tackling things like the burning of hydrocarbons in Asia, open pit fires and things like that, do you think we could really put a dent in the melting of ice if we reroute the flights alone?
JACOBSON: It would reduce the jet fuel emissions of black carbon by about 83% in the Arctic circle. And that would delay the loss of the Arctic sea ice.
It would also reduce warming worldwide – on a global average – by 2%. But a lot of the impact of global warming is over the Arctic. There’s much higher warming there than the average.
WASHINGTON’S BLOG: And is part of the reason that the Arctic is experiencing more ice loss than the Antarctic due to differential distribution of soot?
JACOBSON: The Arctic is closer to the melting point, so you get feedbacks because – when that ice melts – then you’re uncovering the dark surface below.
The Antarctic is harder to melt, so – even if you raise the temperature – it doesn’t change the albedo [the ability to reflect sunlight]. So there’s not this positive feedback.
WASHINGTON’S BLOG: Part of the debate between global warming believers and global warming skeptics is that Antarctic ice has increased during certain recent years recently.
Is that the explanation … that it doesn’t have the “warming feedback” you mentioned?
JACOBSON: There are two things operating. First, when you have global warming, you have a lot more water vapor in the air. And – in the polar regions – that water precipitates out as ice, if you’re at freezing temperatures. So if you’re not melting the ice, then you expect an accumulation with global warming.
You’d normally get an accumulation of ice at the North Pole. But since there’s a lot of melting there (because it’s closer to the melting point than the Antarctic), and the ice is very thin – it’s only one to three meters thick – compared to the Antarctic glaciers that are three kilometers thick.
So you’ve got this accumulation at both poles, but the accumulation in the Arctic is melting. Because you’re evaporating all this water from the oceans, that’s got to go somewhere, and once you get to subfreezing temperatures, it’s going to deposit it as ice or snow at the Antarctic.[Indeed, the mean summer temperature at the North Pole is right at the melting point (32 degrees Fahrenheit). In sharp contrast, the mean summer temperature at the South Pole is negative 18 degrees Fahrenheit. So any extra temperature in the Arctic could melt a whole lot of ice during the summer; but you’d need almost 50 degree higher summer temperatures in the Antarctic to get up to the melting point.]
After our interview, I found a good 2012 New York Times report on Jacobson’s research:
Air traffic is the biggest source of pollution in the Arctic. Ever since cross-polar flights became commonplace in the late 1990s, flights crossing the Arctic Circle have risen steadily, surpassing 50,000 in 2010.
While cross-polar flights account for only a tiny percent of total global emissions from aviation, the standard cruising altitude for commercial planes in the Arctic is the stratosphere, an extremely stable layer of the atmosphere. Black carbon and other emissions get trapped in this layer and as a result remain in the atmosphere longer, causing far more damage than emissions from flights at lower latitudes, scientists say.
But with some creative detours, airlines can buy a little more time for Arctic sea ice, a new study suggests.
Writing in the journal Climatic Change, Mark Jacobson, an atmospheric scientist at Stanford University, and other researchers report that rerouting planes around the Arctic Circle could help delay the advent of a tipping point after which the ice would eventually disappear.
The research team gathered emissions data from 40,399 cross-polar flights in 2006 and used computer simulations to compare what would happen over the next 22 years if those flights skirted the Arctic rather than following their current routes.
Good News: We Can Reduce Soot Without Selling Our Souls
The Economist notes:
Stop putting it there and it will rapidly go away—a potentially easy win.That win is made easier still by the fact that about 70% of emissions in Europe and the Americas come from diesel engines. Better exhausts, to trap carbon particles before they are emitted, and the scrapping of old, highly polluting vehicles could make an immediate impact. In other countries the problem is more often inefficient stoves and dirty fuel—again, things that are easy to deal with, at least in principle.
Reducing soot will be cheaper than the “decarbonation” which many policy-makers have proposed. And it would increase the health of millions of people worldwide.
The New York Times also notes the cost-effectiveness of reducing soot:
Decreasing black carbon emissions would be a relatively cheap way to significantly rein in global warming — especially in the short term, climate experts say …
The Monitor provides more good news:
“There are clear options” to cut soot emissions, Ramanathan says.
In California, for instance, black-carbon soot emissions fell by half between 1990 to 2008 in response to tighter air-quality regulations affecting diesel emissions, according to a study Ramanathan and colleagues from Scripps and Argonne National Laboratory published in early 2011.
The decline occurred even as “diesel consumption has increased significantly,” he adds. The soot pollution “has come down to almost nothing” statewide.
The study on global black-carbon soot released Tuesday notes that focusing initially on diesel sources “appears to offer the most confidence in reducing near-term” warming.
Another opportunity lies in supplying cook stoves that burn biofuels like wood or dung more efficiently, Ramanathan adds.
Moreover – while Noam Chomsky and James Lovelock (environmentalist and creator of the “Gaia hypothesis”) have both said that they would be okay with a fascist approach to tackling global warming – we don’t need to go fascist to reduce soot.
Indeed, University of California at San Diego researchers point out that climate issues can more effectively be tackled on the local level:
Action on soot and ozone can transform the politics of climate change because controlling these pollutants doesn’t just benefit the climate. It also delivers tangible local benefits. Even the governments that are skittish about spending money for global benefits can see real local advantages in this new strategy.”
Similarly, the Economist writes:
Dealing with them is also cheaper than cutting CO2 emissions and does not need global agreement, because the local benefits would be the main point, so no one could free-ride on the emission-cutting efforts of others. Instead, the good of the climate would be free-riding on local self-interest.
In other words, reducing soot in our communities will improve our standard of living (think smog in Beijing) and prevent millions of deaths from lung disease every year.
Ironically, however, a growing international consensus is forming on soot. As UC San Diego notes:
In February, six countries (including the United States) formed a coalition devoted to promote practical changes that could control emissions of global warming agents such as soot and ozone.
Postscript for global warming skeptics: This essay is for people who are worried about Arctic ice melting. If you’re not, you’re of course welcome to (1) skip this essay or (2) read it as an attempt to compromise with those who believe in global warming, because the actions recommended here are much less harmful than most of the hairbrain “fixes” being proposed by global warming believers (and see this) … such as nuclear power, geoengineering, cap-and-trade, or the imposition of fascism in order to combat climate change.