Half of the world's population lives in urban areas today, and 80% of the world's population is predicted to be city dwelling by 2030. The urban heat island effect, in which cities are several degrees warmer than their surrounding areas, is therefore likely to increase along with increasing urbanization.

Scientists at the 2010 AGU Fall Meeting last week discussed new research on urban areas and climate change. A.-L. Beaulant of Centre National de Recherches Météorologiques (CNRM), Météo-France, used modeling studies to predict characteristics of future heat waves in the Paris metropolitan area. In a scenario in which emissions continue torise, she found that there could be three heat waves per year on average between 2075 and 2099. With some emissions mitigation, there might be two heat waves per year during that time, compared with only one heat wave every 4 years on average now