Objective estimate of future climate analogues projected by an ensemble AGCM experiment under the SRES A1B scenario

Abstract

Climate analogues (CAs), regions whose present climates are similar to the future climate of a target place, are identified to assess the effects of climate change towards the end of the 21st century. The location of CAs and their present climates yield information that may be used to mitigate the harmful impacts of climate change. Present (1979–2003) and future (2075–2099) climates are projected in an ensemble experiment using the atmospheric general circulation model of the Meteorological Research Institute in Japan. The ensemble members consist of combinations of four distributions of sea surface temperature, three convection schemes, and two initial conditions. The emission scenario for greenhouse gases is A1B of the Special Report on Emissions Scenarios. A new method to identify the location of CAs is introduced, in which the uncertainty in the climate projection is taken into account. CAs for all land regions of the world are presented and those of four capital cities are analyzed in detail. The CAs are generally distributed equator-ward from the target places, consistent with the global warming. It is also found that ensemble experiments that encompass the uncertainty of climate projections can yield robust results for the CA and lead to reliable assessments of climate change.