A deal to sell tar sands oil in Europe would outweigh any good the UK might do with all its other climate change measures

Here's the essential fact to bear in mind. The tar sands of northern Alberta are the second-largest pool of carbon on earth, second only to Saudi Arabia. It's burning Saudi Arabia, more than any other single thing, that has raised the temperature of the planet by a degree so far. But when oil was discovered in the Middle East, we knew nothing about climate change –