Differential and combined impacts of extreme tempe

Authors: Chad Shouquan Cheng Monica Campbell Qian Li Guilong Li Heather Auld Nancy Day David Pengelly Sarah Gingrich Joan Klaassen Don MacIver Neil Comer Yang Mao Wendy Thompson Hong Lin

Publish Date: 2009/02/18

Volume: 1, Issue: 4, Pages: 223-235

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Abstract

This paper forms the second part of an introduction to a synoptic weather typing approach to assess differential and combined impacts of extreme temperatures and air pollution on human mortality focusing on future estimates A Statistical Downscaling approach was used to downscale daily five general circulation model GCM outputs three Canadian and two US GCMs and to derive sixhourly future climate information for the selected cities Montreal Ottawa Toronto and Windsor in south–central Canada Discriminant function analysis was then used to project the future weather types based on historical analysis defined in a companion paper Part I Future air pollution concentrations were estimated using the withinweathertype historical simulation models applied to the downscaled future GCM climate data Two independent approaches based on 1 comparing future and historical frequencies of the weather groups and 2 applying withinweathergroup elevated mortality prediction models were used to assess climate change impacts on elevated mortality for two time windows 2040–2059 and 2070–2089 Averaging the five GCM scenarios across the study area heatrelated mortality is projected to be more than double by the 2050s and triple by the 2080s from the current condition Coldrelated mortality could decrease by about 45–60 and 60–70 by the 2050s and the 2080s respectively Air pollutionrelated mortality could increase about 20–30 by the 2050s and 30–45 by the 2080s due to increased air pollution levels projected with climate change The increase in air pollutionrelated mortality would be largely driven by increases in ozone effects The population acclimatization to increased heat was also assessed in this paper which could reduce future heatrelated mortality by 40 It is most likely that the estimate of future extreme temperature and air pollutionrelated mortality from this study could represent a bottomline figure since many of the factors eg population growth age structure changes and adaptation measures were not directly taken into account in the analyses

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