Updated: Aug 16, 2021

YES climate change is real. Yes human activity is a contributing factor. Yes there is a scientific consensus that this is true. NO there is not a scientific consensus that the appropriate action is to delegate new authority to the government to seize control over industry to attempt to fix the problem. As we have seen in almost every other issue, delegating huge new authorities to the government almost always makes the problem was worse.

Ignore the Fear Mongering, Here's What Climate Change Models Actually Say

An Earth scientist’s recent article making the rounds on social media highlights a terrifying conversation he had with “a very senior member” of the IPCC, which is the UN’s body devoted to studying climate science. The upshot of their conversation was that millions of people will die from climate change, a conclusion that leads the author to lament that humans have created a consumption-driven civilization that is “hell bent on destroying itself.”

As with most such alarmist rhetoric, there is little to document these sweeping claims—even if we restrict ourselves to “official” sources of information, including the IPCC reports themselves. The historical record does not justify panic, but instead should lead us to expect continued progress for humanity, so long as the normal operation of voluntary market interactions continues without significant political interference to sabotage it.

The Conversation

Here is the opening hook from James Dyke’s article, in which he grabs the reader with an apocalyptic conversation:

It was the spring of 2011, and I had managed to corner a very senior member of the Intergovernmental Panel on Climate Change (IPCC) during a coffee break at a workshop… The IPCC reviews the vast amounts of science being generated around climate change and produces assessment reports every four years. Given the impact the IPPC’s findings can have on policy and industry, great care is made to carefully present and communicate its scientific findings. So I wasn’t expecting much when I straight out asked him how much warming he thought we were going to achieve before we manage to make the required cuts to greenhouse gas emissions. “Oh, I think we’re heading towards 3°C at least,” he said. “But what about the many millions of people directly threatened,” I went on. “Those living in low-lying nations, the farmers affected by abrupt changes in weather, kids exposed to new diseases?” He gave a sigh, paused for a few seconds, and a sad, resigned smile crept over his face. He then simply said: “They will die.”

Putting aside the creepiness of someone smiling as he predicts millions of deaths—sort of like a James Bond villain—we must inquire: How plausible are these warnings? Does the climate change literature actually support such bold projections?

As it turns out, the answer is “no.” It is certainly true that there are many particular dangers regarding climate change, which could have deleterious consequences on human welfare (broadly defined). But in order to conclude that millions—or even billions, as the author of the article states in his concluding remarks—of deaths hang in the balance, we have to grossly exaggerate all of the various mechanisms and scenarios, and we have to assume that humans do nothing to adapt to the changing circumstances over the course of decades.

In reality, it is much more likely that humans will adapt to whatever changes the climate brings them in the coming decades, and that various measures of human well-being—including not just GDP but also life expectancy and declining mortality rates from various ailments—will continue to improve. The voluntary market economy is an excellent general purpose solution to the challenges facing humanity, including the handling of whatever curve balls climate change might throw.

IPCC’s Summary of Climate Change Damages

Unfortunately, it is difficult to come up with a statistic such as, “How many excess deaths does the IPCC predict from climate change by the year 2100, if governments don’t take further action?” If you consult the AR5, which is the latest IPCC report, and look at chapter 11 (Working Group II) on the impacts of climate change on human health, you will see various trouble areas and figures concerning at-risk populations, but nothing so crisp as to allow us to evaluate the casual claims of millions of deaths.

However, the IPCC chapter does tell us upfront:

The Fourth Assessment Report (AR4) pointed to dramatic improvement in life expectancy in most parts of the world in the 20th century, and this trend has continued through the first decade of the 21st century (Wang et al., 2012). Rapid progress in a few countries (especially China) has dominated global averages, but most countries have benefited from substantial reductions in mortality.
There remain sizable and avoidable inequalities in life expectancy within and between nations in terms of education, income, and ethnicity (Beaglehole and Bonita, 2008) and in some countries, official statistics are so patchy in quality and coverage that it is difficult to draw firm conclusions about health trends (Byass, 2010).
Years lived with disability have tended to increase in most countries (Salomon et al., 2012). If economic development continues as forecast, it is expected that mortality rates will continue to fall in most countries; the World Health Organization (WHO) estimates the global burden of disease (measured in disability-adjusted life years per capita) will decrease by 30% by 2030, compared with 2004 (WHO, 2008a).
The underlying causes of global poor health are expected to change substantially, with much greater prominence of chronic diseases and injury; nevertheless, the major infectious diseases of adults and children will remain important in some regions, particularly sub-Saharan Africa and South Asia (Hughes et al., 2011). [IPCC Fifth Assessment Report, Working Group II, Chapter 11, bold added.]

What about the Catastrophic Scenarios?

Now it’s true, nobody can guarantee that there won’t be a climate change catastrophe. But we must realize that at least several of the featured studies warning of huge negative impacts are based on obviously flawed assumptions.

Oren Cass provides us with some examples. One study looked at the increase in mortality in a cold, northern US city during a particularly brutal summer, and then extrapolated to show a staggering number of excess heat deaths decades down the road, when such “bad summers” were more common. Yet in the projections, the northern cities were no hotter than southern US cities are right now, and yes these southern cities don’t have nearly the same heat death rate as is projected for the northern cities decades down the road.

What is happening here should be obvious after a moment’s reflection: A northern city like Philadelphia is not adapted to hot summer the way Houston or Las Vegas is. But if climate change did indeed make such temperatures the norm—over the course of several decades­—then the residents of the northern cities would adapt. They would install more air conditioning, and the people born in the year (say) 2080 would be much better able physically to cope with higher temperatures in 2100 than the people alive today.