Earth has been warming for thousands of years

摘要

I don't know where Col Hodgson (Mailbag, May 2015) gets the idea that "for thousands of years the Earth's energy balance has been in a state of equilibrium with global temperatures remaining relatively constant" but he is seriously mistaken. The Earth has, in fact, been warming for the last 20,000 years. Were it not so, much of Europe, Asia, and North America, together with the higher latitude areas of the southern hemisphere, would still be blanketed by ice and sea levels would now be some 90m (300 feet) lower.