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New analysis shows that without proper regulation, biofuels programs aimed at curbing greenhouse gases could do just the opposite

A global push toward production of biofuels, advocated by many as a measure to curb greenhouse gas emissions, could have exactly the opposite effect unless adequate controls are put in place, a new study has found. Because forests, which remove carbon dioxide from the atmosphere, could end up being cut down to create new cropland as a result of intensive agriculture for fuels, a gallon of biofuel could ironically end up being responsible for twice as much greenhouse gas emission as a gallon of gasoline.

This indirect impact from biofuels production is "an inescapable effect" unless regulations control it, but it cannot directly be measured, says John Reilly, associate director of the MIT Joint Program on the Science and Policy of Global Change. Reilly, along with five other MIT researchers, is a co-author of the new study published Oct. 23 in Science. The lead author is Jerry Melillo of the Marine Biological Laboratory in Woods Hole, Mass.

The study found that a massive campaign to substitute biofuels for petroleum could result in a net doubling of the amount of land devoted to agriculture worldwide - and that, perhaps surprisingly, there is enough land available to sustain that. But this change in land use, unless coupled to regulations that either specifically protect forestland, or that tax the destruction of forest sufficiently to render that uneconomic, would lead to a net increase in carbon emissions. In addition, the increase in intensive agriculture would require an enormous addition of nitrogen fertilizers to the soil, producing emissions of nitrous oxide, a much more potent greenhouse gas than CO2. Together, these two effects could double the overall emissions attributable to land use. However, with proper controls in place, the use of biofuels instead of petroleum could reduce carbon emission by almost four-fifths, Reilly says.

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A new analysis shows that even moderate carbon-reduction policies now can substantially lower the risk of future climate change. But without prompt action, extreme changes could soon become much more difficult, if not impossible, to control.

Analysis shows climate change to yield more extreme rainfall — Heavier rainstorms lie in our future. That's the clear conclusion of a new MIT and Caltech study on the impact that global climate change will have on precipitation patterns. But the increase in extreme downpours is not uniformly spread around the world, the analysis shows.

Overall, previous studies have shown that average annual precipitation will increase in both the deep tropics and in temperate zones, but will decrease in the subtropics. However, it's important to know how the magnitude of extreme precipitation events will be affected, as these heavy downpours can lead to increased flooding and soil erosion. It is the magnitude of these extreme events that was the subject of this new research, which will appear online in the Proceedings of the National Academy of Sciences this week. The report was written by Paul O'Gorman, assistant professor in the Department of Earth, Atmospheric and Planetary Sciences at MIT, and Tapio Schneider, professor of environmental science and engineering at Caltech. (View article.)

Model simulations used in the study suggest that precipitation in extreme events will go up by about 5 to 6 percent for every one degree Celsius increase in temperature. Separate projections published earlier this year by MIT's Joint Program on the Science and Policy of Global Change indicate that without rapid and massive policy changes, there is a median probability of global surface warming of 5.2 degrees Celsius by 2100, with a 90 percent probability range of 3.5 to 7.4 degrees.

Specialists in the field called the new report by O'Gorman and Schneider a significant advance. Richard Allan, a senior research fellow at the Environmental Systems Science Centre at Reading University in Britain, says, "O'Gorman's analysis is an important step in understanding the physical basis for future increases in the most intense rainfall projected by climate models." He adds, however, that "more work is required in reconciling these simulations with observed changes in extreme rainfall events."

The reason the climate models are less consistent about what will happen to precipitation extremes in the tropics, O'Gorman explains, is that typical weather systems there fall below the size limitations of the models. While high and low pressure areas in temperate zones may span 1,000 kilometers, typical storm circulations in the tropics are too small for models to account for directly.

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Fed by MIT data, display shows extent of human-caused emissions

The latest ominous number to appear on the side of a New York building is a real-time count of the tons of carbon dioxide (and equivalents of other greenhouse gases) emitted each day, based on MIT calculations. The 70-foot-tall display, unveiled last week by Deutsche Bank outside New York's Madison Square Garden, is modeled after the familiar Times Square Debt Clock, which keeps a running tally of the U.S. national debt. The new display's rapidly rising red digits are based on data collected and analyzed by MIT's Joint Program on the Science and Policy of Global Change, using a global network of monitoring stations. The display not only shows the level of greenhouse gases entering the atmosphere but also underscores how businesses and financial institutions are starting to grow concerned about the economic impacts of climate change. More...
 

New analysis shows warming could be double previous estimates.

The most comprehensive modeling yet carried out on the likelihood of how much hotter the Earth's climate will get in this century shows that without rapid and massive action, the problem will be about twice as severe as previously estimated six years ago — and could be even worse than that. The study uses the MIT Integrated Global Systems Model, a detailed computer simulation of global economic activity and climate processes that has been developed and refined by the Joint Program on the Science and Policy of Global Change since the early 1990s. The new research involved 400 runs of the model with each run using slight variations in input parameters, selected so that each run has about an equal probability of being correct based on present observations and knowledge. Other research groups have estimated the probabilities of various outcomes, based on variations in the physical response of the climate system itself. But the MIT model is the only one that interactively includes detailed treatment of possible changes in human activities as well — such as the degree of economic growth, with its associated energy use, in different countries.

Study co-author Ronald Prinn, co-director of the Joint Program and director of MIT's Center for Global Change Science, says that, regarding global warming, it is important "to base our opinions and policies on the peer-reviewed science," he says. And in the peer-reviewed literature, the MIT model, unlike any other, looks in great detail at the effects of economic activity coupled with the effects of atmospheric, oceanic and biological systems. "In that sense, our work is unique," he says.

The new projections, published this month in the American Meteorological Society's Journal of Climate, indicate a median probability of surface warming of 5.2 degrees Celsius by 2100, with a 90% probability range of 3.5 to 7.4 degrees. This can be compared to a median projected increase in the 2003 study of just 2.4 degrees. The difference is caused by several factors rather than any single big change. Among these are improved economic modeling and newer economic data showing less chance of low emissions than had been projected in the earlier scenarios. Other changes include accounting for the past masking of underlying warming by the cooling induced by 20th century volcanoes, and for emissions of soot, which can add to the warming effect. In addition, measurements of deep ocean temperature rises, which enable estimates of how fast heat and carbon dioxide are removed from the atmosphere and transferred to the ocean depths, imply lower transfer rates than previously estimated.

Prinn says these and a variety of other changes based on new measurements and new analyses changed the odds on what could be expected in this century in the "no policy" scenarios — that is, where there are no policies in place that specifically induce reductions in greenhouse gas emissions. While the outcomes in the "no policy" projections now look much worse than before, there is less change from previous work in the projected outcomes if strong policies are put in place now to drastically curb greenhouse gas emissions.

Without action, "there is significantly more risk than we previously estimated," Prinn says. "This increases the urgency for significant policy action. [...] There's no way the world can or should take these risks," Prinn says. And the odds indicated by this modeling may actually understate the problem, because the model does not fully incorporate other positive feedbacks that can occur, for example, if increased temperatures caused a large-scale melting of permafrost in arctic regions and subsequent release of large quantities of methane, a very potent greenhouse gas. Including that feedback "is just going to make it worse," Prinn says.

The lead author of the paper describing the new projections is Andrei Sokolov, research scientist in the Joint Program. Other authors, besides Sokolov and Prinn, include Peter Stone, Chris Forest, Sergey Paltsev, Adam Schlosser, Stephanie Dutkiewicz, John Reilly, Marcus Sarofim, Chien Wang and Henry Jacoby, all of the MIT Joint Program on the Science and Policy of Global Change, as well as Mort Webster of MIT's Engineering Systems Division and David Kicklighter, Benjamin Felzer and Jerry Melillo of the Marine Biological Laboratory at Woods Hole.

Prinn stresses that the computer models are built to match the known conditions, processes and past history of the relevant human and natural systems, and the researchers are therefore dependent on the accuracy of this current knowledge. Beyond this, "we do the research, and let the results fall where they may," he says. Since there are so many uncertainties, especially with regard to what human beings will choose to do and how large the climate response will be, "we don't pretend we can do it accurately. Instead, we do these 400 runs and look at the spread of the odds."

Because vehicles last for years, and buildings and powerplants last for decades, it is essential to start making major changes through adoption of significant national and international policies as soon as possible, Prinn says. "The least-cost option to lower the risk is to start now and steadily transform the global energy system over the coming decades to low or zero greenhouse gas-emitting technologies."

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Early detection may permit 'nipping it in the bud' — A gas used for fumigation has the potential to contribute significantly to future greenhouse warming, but because its production has not yet reached high levels there is still time to nip this potential contributor in the bud, according to an international team of researchers. Scientists at MIT, the Scripps Institution of Oceanography in San Diego and other institutions are reporting the results of their study of the gas, sulfuryl fluoride, this month in the Journal of Geophysical Research. The researchers have measured the levels of the gas in the atmosphere, and determined its emissions and lifetime to help gauge its potential future effects on climate.

Sulfuryl fluoride was introduced as a replacement for methyl bromide, a widely used fumigant that is being phased out under the Montreal Protocol because of its ozone-destroying chemistry. Methyl bromide has been widely used for insect control in grain-storage facilities, and in intensive agriculture in arid lands where drip irrigation is combined with covering of the land with plastic sheets to control evaporation. "Such fumigants are very important for controlling pests in the agricultural and building sectors," says Ron Prinn, director of MIT's Center for Global Change Science and a co-author on the new paper.

Prinn adds that "fumigation is a big industry, and it's absolutely needed to preserve our buildings and food supply." But identifying the greenhouse risks from this particular compound, before many factories have been built to produce it in very large amounts, would give the industry a chance to find other substitutes at a time when that's still a relatively easy change to implement. "Given human inventiveness, there are surely other alternatives out there," says Prinn. He describes this approach as "a new frontier for environmental science — to try to head off potential dangers as early as possible, rather than wait until it's a mature industry with lots of capital and jobs at stake." More ...

An MIT ocean microbiologist and a Caldecott Award-winning author and illustrator have teamed up to produce a lavishly illustrated children's book that explains how the sun creates life on Earth through photosynthesis. Penny Chisholm, the Lee and Geraldine Martin Professor of Environmental Studies in the Department of Civil and Environmental Engineering, provided the science background for "Living Sunlight: How Plants Bring the Earth to Life," which was co-authored and illustrated by Molly Bang. The book is designed to help children grow up with a better understanding of how plants use the sun's energy to photosynthesize, turning water and carbon dioxide in the air into carbohydrates and releasing the oxygen that makes it possible for humans—and countless other creatures—to exist. "Photosynthesis is arguably the most important phenomenon on Earth," Chisholm says, "Yet few people understand it. I've been on a mission [to educate the public about] how life works for some time, and decided the best way to get the word out—besides teaching ecology at MIT—is through a set of children's books. Molly was eager to take on the challenge." More ...

A leading economist explains why a carbon tax is the best strategy for cutting greenhouse gases and the use of fossil fuels. — Many economists argue that painful though it might be to consumers, the best way to address climate change is to put a "price" on carbon dioxide and other carbon-based emissions, thereby making fossil fuels more expensive and alternative energy sources more competitive. Over the last several years, Gilbert Metcalf, an economist at Tufts University [and research associate of the MIT Global Change Program], has calculated the costs and consequences of such a policy. In the January/February issue of Technology Review he explains why a carbon tax is a good idea. More...

Will putting a price on carbon increase the use of renewables? — The cheapest way to reduce carbon dioxide emissions is probably to put a price on them. One way to do that is a direct tax. Another is a cap-and-trade system, where the government sets an overall cap on emissions, but indi­vidual businesses trade emission allowances. But surprisingly, a carbon penalty may do little to increase reliance on renewable energy or reduce petroleum consumption.

Putting a price on carbon would certainly reduce the use of conventional coal-fired power plants. Coal emits more carbon dioxide than other fossil fuels, and its price would more than double. But natural gas would see only a modest change in price: in the short term, it would probably replace coal as the chief source of power. Oil prices wouldn't change much, either.

But unless the costs of wind and solar power come down or nuclear energy proves politically viable, the cheapest way to reduce emissions in the long term would be to capture carbon dioxide from coal plants and sequester it underground, according to a study by MIT's Joint Program on the Science and Policy of Global Change. If the goal is to increase the use of renewable energy, says Sergey Paltsev, principal research scientist at the MIT joint program, governments may have to mandate its use.

More... in the January/February 2009 issue of Technology Review

'Partial capture' of emissions could be near-term move — Construction of new coal-fired power plants in the United States is in danger of coming to a standstill, partly due to the high cost of the requirement -- whether existing or anticipated -- to capture all emissions of carbon dioxide, an important greenhouse gas. But an MIT analysis suggests an intermediate step that could get construction moving again, allowing the nation to fend off growing electricity shortages using our most-abundant, least-expensive fuel while also reducing emissions. Instead of capturing all of its CO2 emissions, plants could capture a significant fraction of those emissions with less costly changes in plant design and operation, the MIT analysis shows. More...