Independent (UK): Cosmologist and astrophysicist, president of the Royal Society, Astronomer Royal, Master of Trinity College, Cambridge There are two key facts relating to our future climate — neither controversial. First, the measured CO2 concentration is rising: it’s already higher than it’s been for millions of years, and “business as usual” will lift it to twice the pre-industrial level by 2050. Second, it’s also uncontroversial that carbon dioxide is a greenhouse gas — this was recognised by …