As the world awoke to the news that America has elected Donald Trump as president the politics of hope felt a little further from our grasp. We must not let it slip through our fingers.
When faced with division, we must unite. When faced with hatred, we must love. And when faced with despair, we must hold onto the hope we have that we can, that we will, create a better world.
The facts are irrefutable: a dangerous racist who is openly misogynistic is now president of the most powerful country in the world. What is more, Trump has repeatedly denied climate change and his election creates a gaping uncertainty over how we now take on the greatest single threat we all face.
Last week the Paris Agreement came into force. Talks in Marrakech on how to stop temperatures rising are happening right now. The commitment from more than 100 countries is a clear demonstration of the global will to stop climate change. But this is a global will Trump has repeatedly positioned himself against.
He has not only said he will stop spending on climate action to back coal and oil, but he has also said he will pull the US out of this historic agreement. Whether we like it or not, the world looks to America for leadership. The precedent which this would set would be horrendous. This would bring devastation on the world's poorest, who are on the sharp end of climate change and will see the worst effects of warming.
But instead of giving way to fear, now is the time to organise. Just as surely as climate change is real, the action to halt it must be unstoppable. The Paris Agreement is itself the result of robust international co-operation and an example of what we can achieve when we work together. Now negotiators in Marrakech must make it bullet-proof.
But we need not only look to Paris to find evidence of the momentum and commitment to save our planet - it can also be seen in the very fact that renewables have over-taken coal as a global power source. In the auto industry it is the electric vehicle sector that is seeing growth, and more jobs are being created in clean industries than anywhere else. Trump's election has, undoubtedly, made our work harder. But these things show us that it is not in vain - they give us reason to hope. They are proof that we can bring about change.
As we come to the end of this historic, but heart-breaking week, we must renew our strength and each take responsibility for the things we care about. Where Trump threatens our environment we will protect it. Where he mocks the disabled, we will care. Where he peddles racism, we will open our homes with hospitality. Where he is misogynistic and homophobic we will continue to fight for equality. We must unite across communities, political parties and borders because the hope of what we can achieve when we stand together is too precious to give up.
Jon Bartley is the co-leader of the Green Party