Letter: Fate of polar ice should worry us all

From Andrew Benton, Flourtown, Pennsylvania, US

Your story “Antarctic ice is at a crisis point” should be a five-alarm wake-up call for the entire planet (7 December 2024, p 8).

The fact that Earth is warming at a worrying rate shouldn’t really be a big surprise, though: 3 million years ago, when carbon dioxide in the atmosphere was at 400 parts per million, the world was 3 to 4°C warmer than now and sea levels up to 24 metres higher. There is no practical way to pull excess CO₂ out of the atmosphere, so this is where we are taking our planet.

However, we are now beyond 400 ppm, and emissions haven’t declined despite big investments in wind and solar, so atmospheric CO₂ looks set to be far higher by the end of the century.