The Environment Chronicle

Science, the academic journal of the American Association for the Advancement of Science, has obtained exclusive data from NASA that indicates that 2009 was the hottest year on record south of the Equator. Southern Hemisphere temperatures can serve as a trailing indicator of global warming, says NASA mathematician Reto Ruedy of the Goddard Institute for Space Studies in New York City, given that that part of the globe is mostly water, which warms more slowly and with less variability than land. Ruedy says 2009 temperatures in the Southern Hemisphere were 0.49°C warmer than the period between 1951 and 1980. That makes 2009 the warmest year on record in that hemisphere.

At 55 percent of air measuring stations placed in urban areas in the vicinity of traffic, annual mean levels of nitrogen dioxide concentrations (NO2) in 2009 were above the 40 micrograms/cubic metre air (µg/m3) which is set as the cap as of 1.1.2010. Exceedences of threshold values occur primarily in cities and conurbations, that is, where the majority of the population resides. The main sources of nitrogen oxides are traffic emissions as well as industrial and household combustion processes. Particulate concentrations (PM10) in 2009 also rose above the statutory caps in place since 2005- despite measures taken at the federal, Laender and municipal levels. There were PM10 concentrations of 50 µg/m3 measured at 23 of the total 408 measuring stations in the network on more than 35 days. In general, particulate pollution was somewhat higher in 2009 compared to 2008, which was the year with the lowest levels of such pollution since 2000.