Ecology, Environment and Conservation Paper

ANALYSING THE UNCERTAINTY IN CLIMATE PROJECTED BY RCP 4.5 OVER COIMBATORE, INDIA

A.P. Ramaraj and V. Geethalakshmi

Abstract

The climate system is comprised of numerous complex processes, interactions and no model can ever be expected to perfectly simulate this. While many processes are represented in models by fundamental physics equations, parameterizations are also employed to approximate certain processes. The scientific knowledge on which such parameterizations comes from studying the current climate and proxy studies of past climate and, as such, their ability to simulate the climate under different forcing conditions may potentially be limited. Such limitations necessitate a greater understanding and awareness of the uncertainty surrounding climate model output. If such projections are to provide an effective basis for policy-making, then as much uncertainty as possible must be accounted for. Comparing a number of climate models may derive a better understanding of the range of possible future change. The results can be best used to enable stakeholders and managers to make informed, robust decisions on adaptation and mitigation strategies in the face of many uncertainties about the future. In the present study, it is certain that the maximum temperature for Coimbatore is likely to increase in the range of 0.2 to 2.2°C at the end of 21st century under RCP 4.5. Increase in minimum temperature may vary from 0.6 to 2.7°C, which is higher in magnitude than that of maximum temperature. Projected uncertainty in rainfall ranges from a reduction of (-) 9.6 % from base period to an increase of 30% at the end of 21st century.