To do this, we need to reduce annual global emissions of carbon dioxide from the 30 gigatonnes released today to 15 gigatonnes by 2050. That is a big drop, but it can be done, according to a report from Imperial College London.

To cut our emissions, fossil fuels need to be replaced with low-carbon energy sources such as nuclear power and renewables, and fossil fuel power stations need to be fitted with carbon-capture technology.

Industry also needs to reduce its reliance on fossil fuels. Steel makers, for instance, will need to replace blast furnaces that rely on coal with electric arc furnaces. Society must also become much more energy-efficient, by better insulating buildings, for example.