Managing the Risks of Extreme Events and Disasters

Abstract

The Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), which was completed in 2007 stated that: “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.” It also stated that observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly in increases in temperature. Significantly, the AR4 found that since the mid-twentieth century most of the observed increase in global average temperatures is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. When the term “very likely” is used in this context, it denotes a probability level of 90 per cent or higher.