ABSTRACT
Climate change is already happening. The Fourth Assessment Report of the Intergovernmental Pannel on Climate Change (IPCC, 2007) clearly shows that the climatic variations over recent decades have had noticeable direct consequences in natural ecosystems, glaciers and agricultural systems in many regions. Many areas of the world are already struggling today with the adverse impacts of an increase in global average temperature. The scientific literature also suggests that observed changes in climate have affected the frequency and intensity of extremes (drought, floods and heatwaves). The alarming number of extreme weather events that have occurred during the last five years may be the consequence of climate change and suggest that climate change is resulting in the increase in natural climate disasters, at least in some regions. The IPCC defines climate change as a statistically significant variation in the state variables that define the climate of a region (such as temperature or precipitation) or in its variability persistent over an extended period of time (typically decades or longer periods).
