FALSE: THE EARTH WASN’T 2°C HOTTER 55,000 YEARS AGO THAN IT IS NOW
Written by Odhiambo Shem on November 28, 2022
A twitter post claiming that the earth was 2°C hotter 55,000 years ago than it is now is false.
“B.S. Climate is geological and cyclical. 55,000 years ago the Earth was 2°C hotter than it is now. Guess what? The planet survived and so did humans!” states the claim.
Teams of scientists do drill ice cores in Antarctica, drill ice cores in Antarctica, including at the British Antarctic Survey and the National Science Foundation Ice Core Facility. As snow falls, it compresses, and in the Antarctic’s cold, it doesn’t thaw, even over hundreds of thousands of years. Scientists collect and study ice cores to discern information about temperatures as far back as 800,000 years ago. Tiny air bubbles trapped in the ice provide information about what the environment was like at the time, including carbon dioxide concentrations.
The temperature in one studied region of Antarctica was -35.6°C 55,000 years ago, according to data published in 2016 in the journal Proceedings of the National Academy of Sciences. It said that in 2006, the average temperature in that area of Antarctica was -28.7°C — that was about 6.9°C warmer than the temperature in that region 55,000 years ago.
There is also data about the Northern Hemisphere going back 120,000 years that shows it was colder 55,000 years ago in Greenland, too.
To visualize Earth’s climate 55,000 years ago, note that this was the time of wooly mammoths. This would have been during a period of slight warming compared with the rest of that glacial period, but it was not warmer than today, Davies says.
There are periods in Earth’s history in which the planet was much warmer than today, or even too hot for humans to live.
For instance, 600 million to 800 million years ago, long before the dinosaurs, the global average temperature was 90° Fahrenheit (32°C) as opposed to the 20th-century global average, which was about 57° F (14°C) according to modern measurements by the National Oceanic and Atmospheric Administration. The global average of 2021 was 1.51°F (0.84° Celsius) warmer than that, according to NOAA’s 2021 report on average land and sea temperature.
The past 650,000 years of Earth’s history was characterized by large climate swings as Earth moved naturally in and out of “ice ages” triggered by changes in its orbit relative to the Sun.
Initial cooling, brought on by slow changes to the shape of the Earth’s orbit and wobble of the Earth’s axis, was amplified by natural effects, including the growing ice sheets and the drawing down of carbon dioxide into the deep oceans. Over tens of thousands of years these amplifying feedbacks caused Earth’s climate to descend into an ice age.
At the peak of the last ice age (around 20,000 years ago), Earth’s global average temperature is estimated by scientists to have been about 5-6℃ cooler than it was during the pre-industrial interval.
So, yes, it is fair to describe the ice ages as much, much colder than now. But were the warm periods of the last 650,000 years “much, much hotter”?
No. The warm climates of the so-called “interglacials” – meaning the period between ice ages – were similar to today. A few of these periods were a little bit hotter; some were a little bit cooler. None had a global average temperature that was 2℃ warmer than either today or pre-industrial times.
We looked into this claim stating that the earth was 2°C hotter 55,000 years ago than it is now and found it to be false.
This fact-check was produced by Sky 106.1 FM with support from Code for Africa’s PesaCheck, International Fact-Checking Network, and African Fact Checking Alliance network.