Ambient air pollution is associated with numerous adverse health impacts. Previous assessments of global attributable disease burden have been limited to urban areas or by coarse spatial resolution of concentration estimates. Recent developments in remote sensing, global chemical-transport models, and improvements in coverage of surface measurements facilitate virtually complete spatially resolved global air pollutant concentration estimates.

The United Nations released what are probably the most optimistic figures on AIDS since the disease was first identified. New infections have fallen drastically, mainly through the use of drugs that can stop people passing on the virus. (Editorial)

Arctic sea ice at its lowest in 2011, says World Meteorological Organization report. The year 2011 has been the 10th warmest year on record in spite of a strong La Nina, which has a relatively cooling influence. In the event of a La Nina, the sea surface temperature is lower than usual in the tropical Pacific Ocean. Also, in 2011, the extent of the Arctic sea ice was the second lowest on record, and its volume was the lowest, revealed a provisional statement by the World Meteorological Organization (WMO).