Greening of the Desert: Open Climate Models (1)
Greening of the Desert: Open Climate Models (1)
A couple of years ago a student of mine brought me the following problem. He described a project where desalinization plants would be built off of the West Coast of Africa. The water would be used to irrigate the Western Sahara for agriculture. The project proposer realized this would change, in a fundamental way, the surface of the Earth. Presumably it would change from white reflective sand to green absorbing leaves. And there would be huge changes in the water.
The person proposing the project knew that there was a relation between the Sahara and hurricanes in the North Atlantic. The question posed was whether or not there might be a weakening of the hurricanes, and perhaps, the project might engender support because of this. Of course there would also be the possibility of increased risk, and opposition to project.
Figure 1. Schematic of African Easterly Waves that I use in dynamics class, but I forget where I got it originally.
In a general sense, this is not a crazy question. The Sahara is an important ingredient of regional climate. There is enough heating in the Sahara that the normal condition of temperature decreasing as you move away from the equator is reversed during the summer, leading to the conditions that cause African easterly waves, which do influence the generation of hurricanes. But there are other influences of the Sahara that are more direct. Even the Romans talked about dust from the Sahara influencing Europe. Therefore, a large regional agricultural or energy project that altered the surface of the Sahara is likely to have regional, perhaps even global, climate effects. There might be benefit, or damage, or risk, or liability.
If we are to imagine alternative energy sources like wind and solar being built to large enough scales to displace fossil fuels, then that will require huge alterations to the surface of the Earth. In 2005 David Keith investigated changes that would occur if wind farms were placed near population centers in the Northern Hemisphere; these covered 10% of the land surface. Nathan Lewis on his web site talks about the scale of the projects needed for alternative energy projects.
The Keith et al. paper referenced above is the type of simulation that is needed when preparing for climate change, new energy systems, and providing energy and food for increasing population. That is, we have to alter the surface of the Earth in some significant way, and then compare, for example, the costs and risks of wind energy, to using other types of energy, including continued emissions of carbon dioxide from burning fossil fuels. Regional climate impacts also need to be investigated fully.
If you compare this sort of simulation to weather forecasting there are several differences. While there have been studies of weather modification in the past, for the most part we think of weather forecasting as defining with observations what the atmosphere looks like at a particular time and then projecting forward for a few days what the atmosphere will look like. Climate projections are, however, mostly about how the forcing of the climate changes. Forcing? How is the energy budget being changed? What changes absorption and reflection? How does the surface change?
We often focus on how will the greenhouse gases like carbon dioxide change? While this is the most important global problem, when we think about what I will call large-scale adaptation, major energy projects that cover the Earth’s surface with windmills and solar panels, these land-use changes might be more important. And their importance might be in terms of local changes to the weather. Going back to the question posed at the beginning of this entry, benefits, risks, and liability for a specific project, I imagine the desire, the need, maybe even the requirement to do climate impact assessment studies.
Such an assessment study would necessarily be a set of model simulations with changes to the land-surface. There would need to be experiments designed to extract any possible signal from what is bound to be significant noise – variability within the system. New analysis techniques would be required. Given the need to evaluate specific projects, project designers would need access to and the ability to change climate models. This means that the ability to configure, run and evaluate climate simulations needs to exist outside of government laboratories and universities. Compared with weather forecasting, where we are pretty settled on the idea of collections of observations of the current state of the atmosphere, followed by prediction of the future, this is an enormous change. That is, there are few people who have the vested interest to want to play around on the insides of a weather model, but there are potentially many people with the interest and desire to play around with the insides of a climate model.
With this as introduction, the next articles will be a series on the challenges of how to address this potential need: the need for communities other than scientists to have access not just to the results from climate models, but the ability to configure climate models for particular changes to the Earth and investigate the impact of those changes.
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Pakistani Flood Relief Links
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MERLIN medical relief charity
U.S. State Department Recommended Charities
The mobile giving service mGive allows one to text the word "SWAT" to 50555. The text will result in a $10 donation to the UN Refugee Agency (UNHCR) Pakistan Flood Relief Effort.
Portlight Disaster Relief at Wunderground.com
An impressive list of organizations
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(11-28) 04:00 PST Chersky, Russia --
The Russian scientist shuffles across the frozen lake, scuffing aside ankle-deep snow until he finds a cluster of bubbles trapped under the ice. With a cigarette lighter in one hand and a knife in the other, he lances the ice like a blister. Methane whooshes out and bursts into a thin blue flame.
Gas locked inside Siberia's frozen soil and under its lakes has been seeping out since the end of the last ice age 10,000 years ago. But in the past few decades, as the Earth has warmed, the icy ground has begun thawing more rapidly, accelerating the release of methane - a greenhouse gas 23 times more powerful than carbon dioxide - at a perilous rate.
Some scientists believe the thawing of permafrost could become the epicenter of climate change. They say 1.5 trillion tons of carbon, locked inside icebound earth since the age of mammoths, is a climate time bomb waiting to explode if released into the atmosphere.
"Here, total carbon storage is like all the rain forests of our planet put together," says the scientist, Sergey Zimov - "here" being the endless sweep of snow and ice stretching toward Siberia's gray horizon, as seen from Zimov's research facility nearly 350 kilometers (220 miles) above the Arctic Circle.
Climate change moves back to center stage Monday when governments meet in Cancun, Mexico, to try again to thrash out a course of counteractions. But U.N. officials hold out no hope the two weeks of talks will lead to a legally binding accord governing carbon emissions, seen as the key to averting what is feared might be a dramatic change in climate this century.
Most climate scientists, with a few dissenters, say human activities - the stuff of daily life like driving cars, producing electricity or raising cattle - is overloading the atmosphere with carbon dioxide, methane and other gases that trap heat, causing a warming effect.
But global warming is amplified in the polar regions. What feels like a modest temperature rise is enough to induce Greenland glaciers to retreat, Arctic sea ice to thin and contract in summer, and permafrost to thaw faster, both on land and under the seabed.
Yet awareness of methane leaks from permafrost is so new that it was not even mentioned in the seminal 2007 report by the Intergovernmental Panel on Climate Change, which warned of rising sea levels inundating coastal cities, dramatic shifts in rainfall disrupting agriculture and drinking water, the spread of diseases and the extinction of species.
"In my view, methane is a serious sleeper out there that can pull us over the hump," said Robert Corell, an eminent U.S. climate change researcher and Arctic specialist. Corell, speaking by telephone from a conference in Miami, said he and other U.S. scientists are pushing Washington to deploy satellites to gather more information on methane leaks.
The lack of data over a long period of time casts uncertainty over the extent of the threat. An article last August in the journal Science quoted several experts as saying it's too early to predict whether Arctic methane will be the tipping point.
"Arctic Armageddon Needs More Science, Less Hype," was its headline.
Studies indicate that cold-country dynamics on climate change are complex. The Arctic Monitoring and Assessment Program, a scientific body set up by the eight Arctic rim countries, says overall the Arctic is absorbing more carbon dioxide than it releases.
"Methane is a different story," said its 2009 report. The Arctic is responsible for up to 9 percent of global methane emissions. Other methane sources include landfills, livestock and fossil fuel production.
Katey Walter Anthony, of the University of Alaska Fairbanks, has been measuring methane seeps in Arctic lakes in Alaska, Canada and Russia, starting here around Chersky 10 years ago.She was stunned to see how much methane was leaking from holes in the sediment at the bottom of one of the first lakes she visited. "On some days it looked like the lake was boiling," she said. Returning each year, she noticed this and other lakes doubling in size as warm water ate into the frozen banks."The edges of the lake look like someone eating a cookie. The permafrost gets digested in the guts of the lake and burps out as methane," she said in an interview in Amsterdam, en route to a field trip in Greenland and Scandinavia.
More than 50 billion tons could be unleashed from Siberian lakes alone, more than 10 times the amount now in the atmosphere, she said.
But the rate of defrosting is hard to assess with the data at hand.
"If permafrost were to thaw suddenly, in a flash, it would put a tremendous amount of carbon in the atmosphere. We would feel temperatures warming across the globe. And that would be a big deal," she said. But it may not happen so quickly. "Depending on how slow permafrost thaws, its effect on temperature across the globe will be different," she said.
Permafrost is defined as ground that has stayed below freezing for more than two consecutive summers. In fact, most of Siberia and the rest of the Arctic, covering one-fifth of the Earth's land surface, have been frozen for millennia.
During the summer, the ground can defrost to a depth of several feet, turning to sludge and sometimes blossoming into vast fields of grass and wildflowers. Below that thin layer, however, the ground remains frozen, sometimes encased in ice dozens or even hundreds of meters (yards) thick.
As the Earth warms, the summer thaw bites a bit deeper, awakening ice-age microbes that attack organic matter - vegetation and animal remains - buried where oxygen cannot reach, producing methane that gurgles to the surface and into the air.
The newly released methane adds to the greenhouse effect, trapping yet more heat which deepens the next thaw, in a spiraling cycle of increasing warmth.
Curbing man-made methane emissions could slow this process, said Walter Anthony.
"We have an incentive to reduce our fossil fuel emissions. By doing so, we can reduce the warming that's occurring in the Arctic and potentially put some brakes on permafrost thaw," she said.
The U.S. National Oceanic and Atmospheric Administration, in its 2010 Arctic Report Card issued last month, said the average temperature of the permafrost has been rising for decades, but noted "a significant acceleration" in the last five years at many spots on the Arctic coast.
One of those spots would be Chersky, an isolated town on the bank of the Kolyma River at the mouth of the East Siberia Sea.
The ground in this remote corner of the world, 6,600 kilometers (4,000 miles) east of Moscow, has warmed about 2 degrees Celsius (3.6 Fahrenheit) in the last five years, to about minus 5 Celsius (23 Fahrenheit) today, says Zimov, director of the internationally funded Northeast Science Station, which is about three kilometers (two miles) from town.
The warming is causing the landscape to buckle under his feet.
"I live here more than 30 years. ... There are many (dirt) roads in our region which I used or built myself, but now I can't use anymore. Now they look like canyons," he says.
Buildings, too, collapse. The school in Chersky, a Soviet-era structure with a tall bronze statue of Karl Marx on its doorstep, was abandoned several years ago when the walls began to crack as the foundations gave way.
The northern Siberian soil, called yedoma, covers 1.8 million square kilometers (700,000 square miles) and is particularly unstable. Below the surface are vertical wedges of ice, as if 15-story-high icicles had been hammered into the soft ground, rich in decaying vegetation, over thousands of years.
As the air warms, the tops of the wedges melt and create depressions in the land. Water either forms a lake or runs off to lower ground, creating a series of steep hillocks and gullies. During summer, lakeside soil may erode and tumble into the water, settling on the bottom where bacteria eat it and cough up yet more methane.
The process takes a long time, but Zimov has done a simulation by bulldozing trees and scraping off moss and surface soil from 1 hectare (2.5 acres) of former larch forest, rendering it as if it had been leveled by fire.
Seven years later the previously flat terrain is carved up with crevices 10 to 15 feet (3 to 5 meters) deep, creating a snowy badlands.
Gazing across a white river to the apartment blocks on a distant hill, Zimov said, "In another 30 years all of Chersky will look like this."
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Posted by Eben Harrell Monday, November 29, 2010 at 3:30 pm
Submit a Comment • Related Topics: Cancun, Carbon Policy, Climate Negotiations , Greenpeace, HFCs, Hydrofluorocarbons
As the next round of international talks about climate change begin in Cancun tomorrow, optimism is low that the talks will lead to a major breakthrough among countries trying to cut emissions. But ahead of the summit, environmentalists applauded an initiative by a consortium of around 400 private companies to ban Hydrofluorocarbons—another contributor to global warming—in their refrigeration.
Attention at climate talks tends to focus on carbon dioxide. But there are other, short-lived gases that are even more potent, although there is less of them. Hydrofluorocarbons, or HFCs, are currently being used by many companies for refrigeration. The warming effect of these HFCs is at least 1,000 times that of carbon dioxide.
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