The Economics of Climate Change Vulnerability, Adaptation and Mitigation in Tanzania

1.1 Background to the study and statement of the problem The term climate change here is defined as variation in the mean state of climate or its continuing, long term variability (IPCC, 2003). Climate variability consists of the statistics of temperature, rainfall, wind, humidity, atmospheric pressure, and other meteorological elemental measurements in a given region over long periods. This is unlike weather variability, which is the present condition of these elements and their variation over shorter periods. Climates can be classified according to the average and the typical ranges of different variables, most commonly precipitation and temperature (Trenberth et al., 2000). In this study, we use the term climate change to refer to any long term (i.e. 20 years)1 variation in climate regardless of cause as put forward by IPCC (2003). Climate variability refers to;(i) change in rainfall seasons, that is, earlier or later rainfall seasons than usual; (ii) an increase or decrease in rainfall beyond what is expected; and (iii) an increase or decrease in temperature beyond what is expected (Huber and Gulledge, 2011). Environmental scholars in their Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC, 2007) reached a tentative consensus that climates are changing. Stern (2007) points out that these changes in climate will be more unreliable in the future. That is, it has been observed in recent years, that climate change is currently the greatest environmental, social and economic threat to the planet. In the last few years, scientific research and knowledge on climate change has progressed substantially, confirming that the current warming of the planet's climate is very likely due to human activities. For instance, regular burning of fossil fuels2 , deforestation and other changes in land-use result in an increase in emissions of greenhouse gases in the environment (Stern, 2007:4; Van Aalst, 2006).