Perhaps 30 years ago climate change could have been stopped or kept under control by a series of taxes and trading schemes. However, world governments have squandered that opportunity.

If climate change continues unfettered, millions of people living on coastlines will be displaced and agriculture will become difficult in many regions. This is likely to lead to political chaos and instability.

I think climate change should be the most important issue on in any election. We still have time to keep warming manageable, but it will mean halving the amount of greenhouse gas we produce. This is going to require fighting climate change on multiple fronts, including changes to almost every industry - energy, housing, transportation, commerce - and possibly even geoengineering as a last resort. But it can be done. The Green New Deal is the only family of solutions that can plausibly halt climate change. Anything less is incompatible with the science.