Is there a nexus with global climate change?

• Author: Pachauri, Rajendra K.
• Position: Extreme Weather

Several extreme weather events have taken place recently in different parts of the world which have sparked interest in the subject of climate change in general. Questions have been asked in the media and by policy makers in several countries on the extent to which these events are related to the problem of global climate change. Clearly, a categorical statement cannot be made on the linkage between the two, but even by association it appears that the extent of increase in these extreme events has something to do with the process of global climate change, which has also been highlighted in the work of the Intergovernmental Panel on Climate Change (IPCC).

The changes that have taken place in global temperatures and precipitation levels in recent years appear to indicate trends that generate some degree of concern, and have even led to alarm in many parts of the world. The World Meteorological Organization has assessed that in the last ten years the number of extreme events has actually doubled. It is also significant that the 1990s have been the hottest decade worldwide since temperature data have been recorded. The year 1998, in fact, is known to have been the hottest during this entire period of formally recorded temperatures.

The Third Assessment Report explores the influence of increasing atmospheric concentration of greenhouse gases and aerosols on climate, and arrives at projections of human-induced change in climate regionally, as well as globally. It covers issues related to the frequency and magnitude of climate fluctuations, including daily, seasonal, inter-annual and decadal variability. It also explores the duration, location, frequency and intensity of extreme events. The Assessment highlights higher maximum temperatures, more hot days and heat waves over nearly all land areas as very likely outcomes. Similarly, higher minimum temperatures, fewer cold days, frost days and cold waves are very likely over nearly all land areas.

It was also concluded in the Assessment Report that there would be more intense precipitation events over many areas, which would lead to increased floods, landslides, avalanches and mud-slide damage, as well as increased soil erosion. This problem would be particularly serious in those areas that have mountain slopes characterized by prolonged deforestation, such as parts of the Himalayan range. Economically, these would have important implications for the cost of insurance if provided by the private...