Earth continues to break global heat records

It makes you wonder: How hot can the Earth get? Is there a theoretically higher average global temperature? Well, in wondered that.

And so Scientific news has launched a project to regularly observe Earth’s climate extremes – and answer your questions about how to navigate our changing planet.

First, the extreme heat.

Theoretically, you can get one LOT hotter. Shortly after Earth formed nearly 4.6 billion years ago, the planet was still molten rock, with surface temperatures of perhaps 1,900 °C.

Earth’s temperature during the Neoproterozoic era, between about 800 million and 600 million years ago, alternated between freezing and boiling, with the average planetary temperature possibly as low as 32 °C. There have been similar episodes as hot or nearly as hot in Earth History: 250 million years ago, when Earth had a massive continent called Pangaea; about 92 million years ago, during the Cretaceous Hothouse; about 55 million years ago, during the Paleocene-Eocene Thermal Maximum (SN: 1/11/17; SN: 10/4/06; SN: 5/7/15).

All those times were largely ice-free on Earth, with high sea levels and forested polar regions. Not exactly ideal for humans.

Since pre-industrial times – before around 1850 – the Earth’s average surface temperature has risen by about 1.1 degrees C. The planet, on average, is now as warm as it was 125,000 years ago, at the height of the last interglacial period, they say researchers, based on data collected from ice and sediment cores. At that time, the sea level was also much higher – at least seven meters higher than today.

As for the future, much depends on continued greenhouse gas emissions, of course. Under high-emissions scenarios, some climate simulations pushed back to 2500 suggest that the world’s average temperature could be 5 degrees C higher than at present – but in some places, including the Arctic, those temperatures could be as much as 8 degrees C higher than today (SN: 19.11.21).

OK, your turn. Bring it on. What are some of your burning questions about Earth’s extreme heat? We will do our best to answer. Send us your questions here and we’ll see you next week.