Fact Check: Is This the Hottest Summer on Earth

Claim: “This summer is on track to be the hottest recorded on Earth.”

An article in Barron’s about rising food prices made the claim on Wednesday morning.

CNN’s headline proclaimed: “The world has just experienced the hottest summer on record – by a significant margin.”

You can find similarly alarming headlines from CBS News, the Guardian, and the Associated Press.

Verdict: Misleading. Compared with most of the earth’s history, this summer is unusually cold. The “record” referred to is kept by the United Nations World Meteorological Organization and European climate service Copernicus. It goes back only to 1940.

Researchers for the Smithsonian Institution surveyed the earth’s temperatures over the last 500 million years. As you can see from the chart below, the earth has been much hotter for most of the past 500 million years.

This study was not undertaken by climate change deniers. In fact, the researchers who undertook it wanted to prove how devastating climate change can be to life on earth.

“The two researchers also thought a temperature curve could counter climate contrarians’ claim that global warming is no concern because Earth was much hotter millions of years ago. Wing and Huber wanted to show the reality of ancient temperature extremes—and how rapid shifts between them have led to mass extinctions. Abrupt climate changes, Wing says, ‘have catastrophic side effects that are really hard to adapt to,'” the Smithsonian wrote in 2019.

Even earlier on, the earth was much, much hotter. When our planet was young and still being bullied by wayward miniplanets smashing through the solar system, the heat of these collisions would have kept Earth molten, with temperatures upward of 3,600° Fahrenheit, according to this piece on climate.gov.

That website—climate.gov—is the official climate information site of the National Oceanic and Atmospheric Administration, a scientific and regulatory agency within the United States Department of Commerce.

Even if we zoom in on the time scale, as climate.gov did in their article, we can see that the Earth is far from the warmest it has ever been.

Let’s quote climate.gov again:

Modern human civilization, with its permanent agriculture and settlements, has developed over just the past 10,000 years or so. The period has generally been one of low temperatures and relative global (if not regional) climate stability. Compared to most of Earth’s history, today is unusually cold; we now live in what geologists call an interglacial—a period between glaciations of an ice age.

So what is going on with all these media organizations claiming this is the hottest recorded summer on earth? A lot of misleading work is being done by the phrase “on record” or the word “recorded” in the news stories. The “record” referred to is kept by the United Nations World Meteorological Organization and European climate service Copernicus. It goes back only to 1940.

Apparently, the headline writers thought “Hottest Summer Since 1940” was just not alarming enough.

The records of fossilized corals, leaf shapes, ancient glaciations, and hothouse periods show that global temperatures are nowhere near as warm as they have been in the past. It may be hot out there this summer—perhaps even the hottest in decades—but we are nowhere near the hottest temperatures the earth has experienced.