Tag: heat-related mortality

Global Science Report: Health Effects of Global Warming

The impact of global warming on temperature-induced human mortality has long been a concern, where it has been hypothesized that rising temperatures will lead to an increase in the number of deaths due to an increase in the frequency and intensity of heat waves. Others claim that rising temperatures will also reduce the number of deaths at the cold end of the temperature spectrum (fewer and less severe cold spells), resulting in possibly no net change or even fewer total temperature-related deaths in the future.

The largest study—by far—on temperature-related mortality was published by Gasparrini et al. in the journal Lancet in 2015. They examined over 74 million (!) deaths worldwide from 1985 to 2012 and found that the ratio of cold-related to heat-related deaths was a whopping 17 to 1. Moreover, the temperature percentile for minimum mortality was around the 60th in the tropics and “80–90th” in the temperate zones. Based upon real-world data, it is obvious that global warming is going to directly prevent a large number of deaths.

One of us (Michaels) co-authored a peer-reviewed literature article showing that as heat waves become more frequent, heat-related deaths decrease because of adaptation. Given that our cities are heating up on their own—without needing a push from greenhouse gases—under our hypothesis, heat-related mortality should be dropping, which it is.

Heat-related Death Projections Don’t Square with Observations

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”

We realize that we are 180° out of sync with the news cycle when we discuss heat-related death in the middle of Northern Hemisphere winter, but we’ve come across a recent paper that can’t wait for the heat and hype of next summer.

The paper, by Arizona State University’s David Hondula and colleagues, is a review of the recent scientific literature on “human health impacts of observed and projected increases in summer temperature.”

This topic is near and dear to our hearts, as we have ourselves contributed many papers to the scientific literature on this matter (see here).  We are especially interested in seeing how the literature has evolved over the past several years and Hondula and colleagues’ paper, which specifically looked at findings published in the 2012-2015 timeframe, fills this interest nicely.

Here’s how they summed up their analysis:

We find that studies based on projected changes in climate indicate substantial increases in heat-related mortality and morbidity in the future, while observational studies based on historical climate and health records show a decrease in negative impacts during recent warming. The discrepancy between the two groups of studies generally involves how well and how quickly humans can adapt to changes in climate via physiological, behavioral, infrastructural, and/or technological adaptation, and how such adaptation is quantified.

Did you get that? When assessing what actually happens to heat-related mortality rates in the face of rising temperatures, researchers find that “negative impacts” decline. But, when researchers attempt to project the impacts of rising temperature in the future on heat-related mortality, they predict “substantial increases.”

In other words, in the real world, people adapt to changing climate conditions (e.g., rising temperatures), but in the modeled world of the future, adaptation can’t keep up. 

Spin Cycle: Is Climate Change Already Taking Lives in New England?

The Spin Cycle is a reoccurring feature based upon just how much the latest weather or climate story, policy pronouncement, or simply poo-bah blather spins the truth. Statements are given a rating between 1-5 spin cycles, with fewer cycles meaning less spin. For a more in-depth description, visit the inaugural edition.

The headline from a CBS News story read “Study: Climate change may be costing lives in the U.S.” The tone is in perfect keeping with the White House wanting the media to focus on the (negative) health impacts from climate change to help drive home the “moral imperative” of administration’s greenhouse gas emissions regulations.

There is one key problem: the findings from the “study” do nothing to shed light on whether “climate change” is taking lives in New England (the region that the study focused on) or anywhere else in the United States. In fact, taking the literature as a whole (including the results of the new study), the more appropriate headline would have been “Studies: Climate change may be saving lives in the U.S.”

The new study in question appears in the journal Nature Climate Change written by a research team headed by Liuhua Shi from the Harvard School of Public Health. Shi and colleagues examined how temperature and temperature variability during the summer and winter seasons impacts the annual mortality of Medicare recipients (i.e., a population aged 65+) residing in New England.

In general, Shi and colleagues found that warmer summers slightly increased mortality while warmer winters slightly lowered it. They also found that more variable temperature (in either winter or summer) led to increases in overall mortality.

Aside from the very real possibility that the statistical significance of these findings was inflated by the mythological design (over inflation of the number of independent data points), the most obvious flaw is that the study didn’t look for any trends in their results. This means, of course, that they aren’t very applicable when it comes to trying to ascertain future behavior (under climate change or not).

Climate Change, Heat Waves, and Adaptation

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”


The main idea, as it is portrayed, driving the Obama administration’s pursuit of carbon dioxide regulations is that climate change is leading to all manner of bad things. Pointing to concrete example of bad things that have resulted from human greenhouse gas emissions, however, is much more challenging than just saying it is the case. In fact, for most climate/weather events and their resulting effect, the bulk of the science contradicts the administration’s contentions.

Roger Pielke Jr. makes it a habit to point out how White House proclamations concerning extreme weather events go awry. We have similar habits.

An especially egregious example concerns heat-related mortality. It is true that extreme heat can lead to excess mortality. It is also true that global warming should lead to more heat waves. However, it is NOT true that global warming will lead to more heat-related mortality—the logic forwarded by the administration. Frequent readers of this blog are well aware of this.

However, as not everyone (to his or her detriment) is a frequent reader of this blog, we presented our findings on climate change and heat-related mortality to the audience at a science policy conference held by the American Geophysical Union (AGU) this week. Our conclusions were:

A Tale of Two Studies

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”


A week ago, the White House released a report on the health consequences of global warming that was meant to supplement and reinforce the heath benefit claims made during the roll-out of new Environmental Protection Agency regulations aimed at reducing carbon dioxide emissions from existing power plants.

Those claims, which border on the bizarre, were met with a great deal of pushback—and deservingly so. 

The supplemental White House report didn’t make things better. Take for example, how they handle extreme heat events and heat-related mortality.

To say that we are disappointed with how the White House/EPA presents the data on heat-related mortality is an understatement. No matter how many times we point out—through official means, op-eds, blogs posts, etc.—that they are mishandling the data to such an extent that they present the opposite conclusion from that reached in the scientific literature, it never gets better.

In fact, it seems to be getting worse.

Below the jump, in its entirety, is the section on heat waves from the new White House report, The Health Impacts of Climate Change on Americans: