Trees to offset the carbon footprint?April 10, 2007LIVERMORE, Calif. - How effective are new trees in offsetting the carbon footprint? A new study suggests that the location of the new trees is an important factor when considering such carbon offset projects. Planting and preserving forests in the tropics is more likely to slow down global warming. But the study concludes that planting new trees in certain parts of the planet may actually warm the Earth. The new study, which combines climate and carbon-cycle effects of large-scale deforestation in a fully interactive three-dimensional climate-carbon model, confirms that planting more tropical rainforests could help slow global warming worldwide. The research, led by Lawrence Livermore National Laboratory atmospheric scientist Govindasamy Bala, appears in the April 9-13 online edition of the Proceedings of the National Academy of Sciences. According to the study, new forests in mid- to high-latitude locations could actually create a net warming. Specifically, more trees in mid-latitude locations like the United States and most of Europe would only create marginal benefits from a climate perspective. But those extra trees in the boreal forests of Canada, Scandinavia and Siberia could actually be counterproductive, Bala said. Forests affect climate in three different ways: they absorb the greenhouse gas - carbon dioxide - from the atmosphere and help keep the planet cool; they evaporate water to the atmosphere and increase cloudiness, which also helps keep the planet cool; and they are dark and absorb sunlight (the albedo effect), warming the Earth. Previous climate change mitigation strategies that promote planting trees have taken only the first effect into account. "Our study shows that only tropical rainforests are strongly beneficial in helping slow down global warming," Bala said. "It is a win-win situation in the tropics because trees in the tropics, in addition to absorbing carbon dioxide, promote convective clouds that help to cool the planet. In other locations, the warming from the albedo effect either cancels or exceeds the net cooling from the other two effects." Other researchers from the Carnegie Institution, Stanford and Université Montpellier II, France also contributed to the report. The study concludes that by the year 2100, forests in mid- and high-latitudes will make some places up to 10 degrees Fahrenheit warmer than would have occurred if the forests did not exist. The authors caution that the cooling from deforestation outside the tropics should not be viewed as a strategy for mitigating climate change. "Preservation of ecosystems is a primary goal of preventing global warming, and the destruction of ecosystems to prevent global warming would be a counterproductive and perverse strategy," said Ken Caldeira, from the Carnegie Institution and a co-author of this report. "Apart from their role in altering the planet's climate, forests are valuable in many other aspects," Bala said. "Forests provide natural habitat to plants and animals, preserve the biodiversity, produce economically valuable timber and firewood, protect watersheds and indirectly prevent ocean acidification. "In planning responses to global challenges, it is important to pursue broad goals and avoid narrow criteria that may lead to environmentally harmful consequences,\\\ DOE/Lawrence Livermore National Laboratory |
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| Related Global Warming Current Events and Global Warming News Articles Is global warming unstoppable? In a provocative new study, a University of Utah scientist argues that rising carbon dioxide emissions - the major cause of global warming - cannot be stabilized unless the world's economy collapses or society builds the equivalent of one new nuclear power plant each day. Oceans' uptake of manmade carbon may be slowing The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. Research challenges for understanding landscape changes identified Nine research challenges and four research initiatives that are poised to advance the study of how Earth's landscapes change were unveiled today in a new report by the National Research Council. Study: Sea stars bulk up to beat the heat A new study finds that a species of sea star stays cool using a strategy never before seen in the animal kingdom. The sea stars soak up cold sea water into their bodies during high tide as buffer against potentially damaging temperatures brought about by direct sunlight at low tide. Drug industry, nonprofits join forces to fight world's neglected diseases Drug companies and nonprofit organizations are joining forces to develop new drugs and vaccines to target so-called "neglected" diseases that claim millions of lives in the developing world each year. Health care accounts for 8 percent of US carbon footprint The American health care sector accounts for nearly a tenth of the country's carbon dioxide emissions, according to a first-of-its-kind calculation of health care's carbon footprint. Cave Study Links Climate Change to California Droughts California experienced centuries-long droughts in the past 20,000 years that coincided with the thawing of ice caps in the Arctic. Reducing greenhouse gases may not be enough to slow climate change Because land use changes are responsible for 50 percent of warming in the US, policymakers need to address the influence of global deforestation and urbanization on climate change, in addition to greenhouse gas emissions. Past climate of the northern Antarctic Peninsular informs global warming debate The seriousness of current global warming is underlined by a reconstruction of climate at Maxwell Bay in the South Shetland Islands of the Antarctic Peninsula over approximately the last 14,000 years, which appears to show that the current warming and widespread loss of glacial ice are unprecedented. Climate variability impacts the deep sea Deep-sea ecosystems occupying 60% of the Earth's surface could be vulnerable to the effects of global warming warn scientists writing in the Proceedings of the National Academy of Sciences. More Global Warming Current Events and Global Warming News Articles |
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