Climate Change and the Lancet’s ‘Heat Death’ Deception

The study offers a frightening statistic: Rapidly rising temperatures have increased annual global heat deaths among older people by 68% in less than two decades. That stark figure has been cited all over, from the BBC and Time to the Washington Post and the Times of India, the world’s largest-selling English-language daily. U.N. Secretary-General

António Guterres

publicized the report, tweeting a link with a grave statement of his own, “The climate crisis is killing us. #COP27 must deliver a down-payment on climate solutions that match the scale of the problem.”

But while their model for heat deaths is based on solid academic research, the report commits an amateur statistical fallacy by blaming the increase in heat deaths on “rapidly increasing temperatures.”

Annual heat deaths have increased significantly among people 65 and older world-wide. The average deaths per year increased 68% from the early 2000s to the late 2010s. But that is almost entirely because there are so many more older people today than there were 20 years ago, in no small part thanks to medical innovations that keep us alive longer. Measured across the same time span the Lancet maps heat deaths, the number of people 65 and older has risen by 60%, or almost as much as heat deaths. When the increase in heat mortality is adjusted for this population growth, the actual rise that can be attributed to rising temperatures is only 5%.

It is hard not to see the Lancet study’s failure to adjust this figure as a deliberate act of deception. Any academic who works with statistics would know to adjust the deaths to account for population growth. I’ve actually raised this issue to the Lancet before. Last September the journal published a study with the same fallacious argument, and I sent the editor a detailed letter explaining the problem. The Lancet never corrected it and here it is, over a year later, committing the same error.

This year’s study also cherry-picks data by discussing only heat deaths. Around the world, far more people die each year from cold than heat. In the U.S. and Canada between 2000 and 2019, an average of 20,000 people died from heat annually and more than 170,000 from cold. This omission matters even more because cold deaths are decreasing with rising temperatures. Modeling from the Global Burden of Disease replicates the relatively small increase in heat deaths shown by the Lancet, but shows a much larger decline in cold deaths from rising temperatures. Based on today’s population size, the current temperatures cause about 17,000 more heat deaths in older people, but also result in more than half a million fewer cold deaths. Reporting one finding without the other is misleading about the true effect of climate change.

This dishonesty leads to worse policy outcomes. While activists push for extreme and expensive climate policies that threaten economic growth, those aren’t the only or even the best ways to help. Temperatures rose throughout the 20th century, but the U.S. nonetheless saw a decrease in heat deaths, largely thanks to air-conditioning. Policies that focus on lifting people out of poverty and providing affordable, reliable sources of energy would allow the rest of the world to reduce heat deaths and live more comfortable lives. They would also help stave off the much greater threat of cold deaths.

Climate change is a real problem, but academics do themselves and their readers a gross disservice when they put activism above honest scientific inquiry.

Mr. Lomborg is president of the Copenhagen Consensus and a visiting fellow at Stanford University’s Hoover Institution. His latest book is “False Alarm: How Climate Change Panic Costs Us Trillions, Hurts the Poor, and Fails to Fix the Planet.”