title: Estimation and uncertainty analysis of impacts of future heat waves on mortality in the eastern United States.
abstract: BACKGROUND
  Climate change is anticipated to influence heat-related mortality in the future. However, estimates of excess mortality attributable to future heat waves are subject to large uncertainties and have not been projected under the latest greenhouse gas emission scenarios.
  
  
  OBJECTIVE
  We estimated future heat wave mortality in the eastern United States (approximately 1,700 counties) under two Representative Concentration Pathways (RCPs) and investigated sources of uncertainty.
  
  
  METHODS
  Using dynamically downscaled hourly temperature projections for 2057-2059, we projected heat wave days that were defined using four heat wave metrics and estimated the excess mortality attributable to them. We apportioned the sources of uncertainty in excess mortality estimates using a variance-decomposition method.
  
  
  RESULTS
  Estimates suggest that excess mortality attributable to heat waves in the eastern United States would result in 200-7,807 deaths/year (mean 2,379 deaths/year) in 2057-2059. Average excess mortality projections under RCP4.5 and RCP8.5 scenarios were 1,403 and 3,556 deaths/year, respectively. Excess mortality would be relatively high in the southern states and eastern coastal areas (excluding Maine). The major sources of uncertainty were the relative risk estimates for mortality on heat wave versus non-heat wave days, the RCP scenarios, and the heat wave definitions.
  
  
  CONCLUSIONS
  Mortality risks from future heat waves may be an order of magnitude higher than the mortality risks reported in 2002-2004, with thousands of heat wave-related deaths per year in the study area projected under the RCP8.5 scenario. Substantial spatial variability in county-level heat mortality estimates suggests that effective mitigation and adaptation measures should be developed based on spatially resolved data.
authors.affiliation: Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Jianyong
authors.initials: J
authors.lastname: Wu
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.forename: Yang
authors.initials: Y
authors.lastname: Gao
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Fu
authors.forename: Brent A
authors.initials: BA
authors.lastname: Johnson
authors.forename: Cheng
authors.initials: C
authors.lastname: Huang
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kim
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
mesh_terms: D057231:Climate Change / Q000706:statistics & numerical data; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D014481:United States