In Kohlua, in central India, with no cars and little electricity, emissions of carbon dioxide, the main heat-trapping gas linked to global warming, are near zero. But soot “” also known as black carbon “” from tens of thousands of villages like this one in developing countries is emerging as a major and previously unappreciated source of global climate change.
While carbon dioxide may be the No. 1 contributor to rising global temperatures, scientists say, black carbon has emerged as an important No. 2, with recent studies estimating that it is responsible for 18 percent of the planet’s warming, compared with 40 percent for carbon dioxide. Decreasing black carbon emissions would be a relatively cheap way to significantly rein in global warming “” especially in the short term, climate experts say. Replacing primitive cooking stoves with modern versions that emit far less soot could provide a much-needed stopgap, while nations struggle with the more difficult task of enacting programs and developing technologies to curb carbon dioxide emissions from fossil fuels.
President Obama and Mexican President Felipe Calderon said today they planned to create the U.S.-Mexico Bilateral Framework on Clean Energy and Climate Change.
Asia may see more conflicts over scarce water resources in the coming years as climate change and population growth threaten access to the most basic natural resource, a report warned on Friday.
Water problems in Asia are already severe, with one in five people, or 700 million, not having access to safe drinking water and half the region’s population lacking access to basic sanitation, according to the report produced by the Asia Society, a New York-based think tank.
Population growth, rapid urbanization and climate change are expected to worsen the situation, according to the report, “Asia’s Next Challenge: Securing the Region’s Water Future.”
The world’s forests are at risk of becoming a source of planet-warming emissions instead of soaking them up like a sponge unless greenhouse gases are controlled, scientists said.
Deforestation emits 20 percent of the world’s carbon dioxide when people cut and burn trees, but standing forests soak up 25 percent of the emissions.
If the Earth heats up 2.5 degrees Celsius (4.5 degrees F) or more, evaporation from the additional heat would lead to severe droughts and heat waves that could kill wide swaths of trees in the tropics of Africa, southern Asia and South America. And emissions from the rotting trees would make forests a source of global warming.
Severe droughts lasting centuries have happened often in West Africa’s recent history, and another one is almost inevitable, researchers say.
Analysis of sediments in a Ghanaian lake shows the last of these “megadroughts” ended 250 years ago.
Writing in the journal Science, the researchers suggest man-made climate change may make the situation worse.
Renewable-energy development, which the Obama administration has made a priority, is posing conflicts between economic interests and environmental concerns, not entirely unlike the way offshore oil and gas development pits economics against environment. But because of concerns about climate, many environmentalists and government agencies could find themselves straddling both sides, especially in Western states where the federal government is a major landowner….
As the push for renewable-energy development intensifies across the United States, scientists and activists have begun to voice concern that policymakers have underestimated the environmental impact of projects that are otherwise “green.”
“There is no free lunch when it comes to meeting our energy needs,” said Johanna Wald, a senior lawyer at the Natural Resources Defense Council. She added, however, that the renewables boom “offers a chance to do it right.”
“We want to do it differently compared to how we did oil and gas development,” she said.
Compiled by Max Luken and Sean Pool