When rocks fall, so can the temperature. But it’s no quick fix

Climate change hit the headlines again last week during the Paris climate summit. The speed at which we have burned fossil fuels and increased the proportion of greenhouse gases in Earth's atmosphere is staggering. But we are far from the first to wreak climate havoc on our planet.

A mind boggling 2800 million years ago photosynthesising bacteria began to flourish, using sunlight to convert carbon dioxide and water into food, and producing oxygen as waste. Their success rebalanced Earth's atmosphere, increasing oxygen and reducing greenhouse gases. The result was one of Earth's most severe ice ages - the Huronian glaciation - which lasted 300 million years.