HIV has advanced from high-risk groups such as intravenous drug users to some in the general population, according to comprehensive new data from the south of China. What needs to be done to halt its spread?
The concentration of atmospheric carbon dioxide decreased between
45 million and 25 million years ago, a trend accompanied by glaciation at the poles. Modelling results suggest when and where the ice closed in.
Carbon dioxide emissions from fossil fuels and cement manufacturing are rising faster than the worst-case scenario drawn up by the Intergovernmental Panel on Climate Change (IPCC). According to the latest worldwide carbon budget, released by the Global Carbon Project, CO2 levels rose by 3.5% a year between 2000 and 2007, compared with 2.7% as calculated by the IPCC.
Preliminary data from two Arctic cruises suggest that rising temperatures are already causing substantial amounts of methane to be released from beneath the ocean floor. But catastrophic gas leaks, like those believed to have occurred 55 million years ago, are unlikely, scientists say.
The turmoil in the financial markets could lead to severe cost-cutting by governments, but US politicians would do well to note the benefits of continued support for clean energy and climate policies. (Editorial)
