planetary meltdown

The predicament of global warming is like a frog, a stove and a pot of water. Boil the water before you drop in the frog, and it will jump out of the pot to safety in a flash. But place the frog in water heated gradually, and it will never jump out. The frog will never be able to determine the crucial moment when the heat simply becomes too high. It will die.\nIf that pot of water is the earth, and we are the doomed frogs, how will we know when it is time to bail out? \n "The answer is -- we don't," said Kenneth Richards, an IU professor of public and environmental affairs. "Gradual change makes it difficult to predict."\nGlobal warming, the gradual heating of the earth's surface temperature by an accumulation of greenhouse gases like carbon dioxide in the atmosphere, has been out on the proverbial discussion table for years. It is hardly a small problem. Measurements made at the Mauna Loa Observatory in Hawaii last year showed atmospheric carbon dioxide levels at an all-time high. Scientists blame global warming for rising sea levels, extreme rainfall and even the strength of last year's hurricanes, according to the Environmental Protection Agency and the United Nations Intergovernmental Panel on Climate Change. Global warming is typically treated as one of those vague, gee-we-should-do-something-about-that-soon items that get pushed aside in favor of more immediately solvable problems. But last year, a smattering of articles popped up about the issue, published everywhere from most major newspapers to Business Week. In fact, Discover named global warming its No. 1 science issue of 2004, demoting the wildly popular launch of SpaceShipOne to the sixth spot on the list. \nSomehow, the word is out. \nAnd the buzzword about what to do about global warming is a mouthful: carbon sequestration.\nBecause cars and power plants are major producers of carbon dioxide and other greenhouse gases that accumulate in the atmosphere, carbon sequestration is a kind of nemesis. Carbon sequestration involves diverting and "capturing" the carbon dioxide and other greenhouse gases, typically as they roll out of a factory smokestack, and storing them somewhere. Storage facilities might include places under the soil, deep in the ocean or in a secure container. The idea of sequestration, as Richards thinks of it, is to bring the natural carbon cycle, or the natural exchange of carbon in various forms between the earth and atmosphere, back into equilibrium. Data from the EPA shows that fossil fuels burned each year in the United States account for about 98 percent of U.S. carbon dioxide emissions -- and these mounting emissions, year after year, have tipped the scales slightly. Just how much is questionable.\n"Sequestration is trying to bring it back slightly," Richards said. "Mathematically you could figure out what it takes to get back to equilibrium, but the number is changing constantly. It's like trying to manage a moving target."\nBut Richards said he believes carbon sequestration is the most viable option available. He and another IU researcher, hydrogeochemist Chen Zhu, are devoting their academic careers to sizing it up.\nRichards concentrates on forests, or as he calls them, "biological scrubbers to sequester the carbon." As an economist and analyst, he is looking at the costs of turning agricultural land into forests for storing carbon. Trees store carbon naturally by drawing carbon dioxide out of the atmosphere through photosynthesis. Planting more trees and paying farmers to convert their land into forests would simply enhance the storage of carbon that already is happening naturally.\nOn the other hand, Zhu is concentrating on analyzing the chemical reactions that occur when carbon dioxide is captured and stored -- out of sight, out of mind -- in the ground. In this approach to carbon sequestration, carbon dioxide is captured before its emission from a power plant, separated out and then injected into a natural "storage vault" like an aquifer -- a water-bearing, porous layer of rock. If all goes well, the gas will stay there for thousands of years. But some will seep back to the surface eventually. An indication of how long before this happens is exactly what Zhu is trying to determine by analyzing the reaction rates of the carbon with the minerals around it and by looking for leaks.\n"I'm trying to determine the fate of the carbon dioxide," Zhu said. "I look at the time frame of how many years it will be safe there (in a storage vault). We need to predict it with a model."\nZhu has examined data from tons of carbon dioxide placed into a geological "carbon sink" in the ground. He said he is hoping the reaction rates he has calculated out in the field -- which show a low reaction with other minerals near the carbon -- will allow him to calculate the length of time the carbon will be safely stored.\nThis "divide and conquer" tactic has received the most attention from the government's Department of Energy, which will help host the fourth annual carbon sequestration meeting this May. The meeting will focus on sequestration from an engineering standpoint, or what Richards calls the "brute force engineering approach." Sequestration is expensive, but it may give quick results. However, Zhu is quick to point out that his work is hardly the answer to the problem. He said it can only help stabilize growing levels of carbon dioxide.\n"We are trying to predict the future, and we are building models on models," he said. "There are many uncertainties. We don't even really know the weather from one week to the next."\nSo just how important is it to look at carbon sequestration as a stop-gap move for limiting global warming? "Maybe we're just generating hot air, so to speak. And lots of paperwork," Richards said. "Is it the silver bullet? No."\nOn the individual level, making changes to avoid the "frog in hot water" scenario requires lifestyle changes. Zhu pointed to hydrogen-energy fueled cars as good investments personally and for the planet. Richards said he believes paying more for gasoline at a price that reflects the "full price" of using it, including its environmental costs and the labor costs of producing it, eventually would decrease U.S. carbon dioxide levels, as people might purchase less.\nRegardless, both Richards and Zhu said they believe this problem will not go away easily.\n"We're going to have some climate change in the future -- that train's left the station already," Richards said.\n-- Contact Managing Editor Kelly Phillips at kephilli@indiana.edu.