Chapter 2 - Climate change and variability overview

Abstract

This chapter overviews climate change and variability for evaluating their impacts on forest structure and functions. It is indicated that: (1) global climate and Earth System models have been developed and validated to simulate atmospheric processes and interactions with other climate system components, (2) the Coupled Model Intercomparison Project has applied these models to projecting future global climate change and variability under various future greenhouse emission scenarios, which is further downscaled to regional and local scales, (3) more than half of the observed global temperature increase of about 0.85°C in the past 150 years was caused by elevated atmospheric CO2 concentrations. Future temperature is projected to increase from 1.5°C under representative concentration pathways (RCP) 2.6 to more than 4.5°C under RCP 8.5 by 2100, (4) projected warming is greater in the boreal forests than in temperate and tropical forests. Precipitation is likely to increase for the boreal and tropical forests in Africa and Asia, but decrease in tropical forests in Central America and the Caribbean, and (5) various strategies and tools are available to assist the selection of appropriate climate information and reduce the impacts of the uncertainty in climate change and variability projections.