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Response to Heat Stress in the United States: Are More Dying or Adapting?

Paper Reviewed
Bobb, J.F., Peng, R.D., Bell, M.L. and Dominici, F. 2014. Heat-related mortality and adaptation to heat in the United States. Environmental Health Perspectives 122: 811-816.

One of the concerns expressed by the United Nations Intergovernmental Panel on Climate Change (IPCC) with respect to the potential impacts of CO2-induced global warming is an increase in the number of heat related deaths, which they predict should be rising in response to enhanced summertime temperature variability and more extreme heat waves, particularly among the elderly.

But is this really the case? A new paper published by Bobb et al. (2014) in the scientific journal Environmental Health Perspectives provides an answer.

In prefacing their work the team of four U.S. researchers writes that "increasing temperatures are anticipated to have profound health impacts," but they say that "little is known about the extent to which the population may be adapting." And, therefore, they decided to examine "the hypothesis that if adaptation is occurring, then heat-related mortality would be deceasing over time."

To accomplish this objective, Bobb et al. used "a national database of daily weather, air pollution, and age-stratified mortality rates for 105 U.S. cities (covering 106 million people) during the summers of 1987-2005," employing "time-varying coefficient regression models and Bayesian hierarchical models" to estimate "city-specific, regional, and national temporal trends in heat-related mortality and to identify factors that might explain variation across cities."

With respect to their findings, Bobb et al. state that "on average across cities, the number of deaths (per 1,000 deaths) attributable to each 10°F increase in same-day temperature decreased from 51 in 1987 to 19 in 2005" (see Figure 1). Furthermore, they report that "this decline was largest among those ≥ 75 years of age, in northern regions, and in cities with cooler climates." In addition, they write that "although central air conditioning (AC) prevalence has increased, we did not find statistically significant evidence of larger temporal declines among cities with larger increases in AC prevalence."


Figure 1. The number of excess U.S. deaths (per 1,000) attributable to each 10°F increase in the same day's summer temperature over the period 1987 to 2005. Adapted from Bobb et al. (2014).

Based on these findings, Bobb et al. conclude that the U.S. population has, "become more resilient to heat over time" - in this case from 1987 to 2005 - led by the country's astute senior citizens. This discovery, coupled with many other similar findings from all across the world (Idso et al., 2014), adds yet another nail in the coffin of failed IPCC projections of increased heat related mortality in response to the so-called unprecedented warming of the past few decades. And perhaps it is high time for all the other apocalyptic projections of the global warming movement to be removed from life support, as they are each equally failing in comparisons with real world data.

Reference
Idso, C.D, Idso, S.B., Carter, R.M. and Singer, S.F. (Eds.) 2014. Climate Change Reconsidered II: Biological Impacts. Chicago, IL: The Heartland Institute.

Posted 30 December 2014