Twenty-five years ago people could be excused for not knowing much, or doing much, about climate change. Today we have no excuse. No more can it be dismissed as science fiction; we are already feeling the effects.

This is why, no matter where you live, it is appalling that the US is debating whether to approve a massive pipeline transporting 830,000 barrels of the world's dirtiest oil from Canada to the Gulf of Mexico. Producing and transporting this quantity of oil, via the Keystone XL pipeline, could increase Canada's carbon emissions by over 30%.

If the negative impacts of the pipeline would affect only Canada and the US, we could say good luck to them. But it will affect the whole world, our shared world, the only world we have. We don't have much time.

This week in Berlin, scientists and public representatives have been weighing up radical options for curbing emissions contained in the third report of the UN's Intergovernmental Panel on Climate Change. The bottom line is that we have 15 years to take the necessary steps. The horse may not have bolted, but it's well on its way through the stable door.

To read the rest visit http://www.theguardian.com/commentisfree/2014/apr/10/divest-fossil-fuels-climate-change-keystone-xl