Climatologist Maximiliano Herrera found that over 400 weather stations around the world exceeded their highest temperature records in 2021. The past six years have been the hottest on record, indicating that the world is getting warmer and warmer. Ten countries broke or tied their highest national record, while 107 beat their highest monthly record.

Why this Matters

Extreme heat is one of the most deadly consequences of climate change. Heat has made droughts more aggressive, provoked fires, and caused hundreds of deaths just this year in the US alone. The effects of extreme heat can also be cyclical -- for example, droughts can make heat waves worse because dry soil heats up much more easily.

Underwater Heat Waves?

It's not just getting hotter on land -- ocean temperatures are also skyrocketing. An extreme marine heatwave has hit the waters off Sydney, making ocean temperatures the highest on record for January. Satellite data also shows the ocean surface to be three degrees Celsius higher than average.

Rob Harcourt, a marine ecologist at Macquarie University in Sydney, told the Guardian: "A lot of animals will do poorly. A lot of animals that live in cooler waters, like seals and sharks, have a habitat that's shrinking fast and the implications are hard to measure, but its likely to be dramatic."