Could biofuels do more damage to the climate than the fossil fuels they replace?

As the energy industry hungrily eyes methane hydrates, scientists ponder the fuel's impact on climate.

Climate change authorities long ago tagged carbon dioxide public enemy number one. Now, there may be a new number two: tiny particles of black carbon, or soot. According to a new analysis reported online in Nature Geoscience, climate scientists are concluding that reports such as last November's assessment by the Intergovernmental Panel on Climate Change (IPCC) may seriously underestimate black carbon's role in global warming.

A federal study released documents the significant impact that climate change is expected to have on the U.S. transportation system. Its conclusion, says Henry Schwartz, the former head of one of the country's largest highway engineering firms, is "a pretty damning tale of what could happen."

To improve the understanding of consequences of climate change for annual plant communities, the author used a detailed, grid-based model that simulates the effect of daily rainfall variability on individual plants in five climatic regions on a gradient from 100 to 800 mm mean annual precipitation (MAP). The model explicitly considers moisture storage in the soil. The researcher manipulated daily rainfall variability by changing the daily mean rain (DMR, rain volume on rainy days averaged across years for each day of the year) by