Global climate change, widening health inequalities, and epidemiology.

The most recent report from the United Nations’ Intergovernmental Panel on Climate Change (IPCC) provided compelling evidence on the effect of human release of greenhouse gases from fossil fuels and deforestation on the global climate change. 1 The IPCC estimate that since the mid-19th century there has been an increase in average temperature of 0.6 C, most of this increase occurring at the end of 20th century. In addition, it provides evidence of changes in the patterns of precipitation, aridification, and humidity. Events occurring since the publication of the IPCC report in 2001 have added substantial new evidence. The average concentration of carbon dioxide has reached 375 p.p.m. (almost 100 p.p.m. above the interglacial levels) (Figure 1); polar and alpine ice is melting at faster rates than expected 2 and mean sea level has been observed to rise by ~30 cm during the 20th century. 3