Greenpeace members gather while the Intergovernmental Panel on Climate Change, IPCC, hold a press conference in Incheon, South Korea, on 8 October.

In response to Monday’s release of the IPCC report on the climate crisis – which warned that “unprecedented” changes were needed if global warming increases 1.5C beyond the pre-industrial period – a standup comic I know posted this plaintive request on her Facebook: “Damn this latest report about climate change is just terrifying. People that know a lot about this stuff, is there anything to be potentially optimistic about? I think this week I feel even worse than Nov 2016 and I’m really trying to find some hope here.”

A bunch of her friends posted variations on “we’re doomed” and “it’s hopeless,” which perhaps made them feel that they were in charge of one thing in this overwhelming situation, the facts. They weren’t, of course. They were letting understandable grief at the news morph into an assumption that they know just how the future is going to turn out. They don’t.

The future hasn’t already been decided. That is, climate change is an inescapable present and future reality, but the point of the IPCC report is that there is still a chance to seize the best-case scenario rather than surrender to the worst. Natan Sharansky, who spent nine years in a gulag for his work with Soviet dissident Andrei Sarkovsky, recalls his mentor saying, “They want us to believe there’s no chance of success. But whether or not there’s hope for change is not the question. If you want to be a free person, you don’t stand up for human rights because it will work, but because it is right. We must continue living as decent people.” Right now living as decent people means every one of us with resources taking serious climate action, or stepping up what we’re already doing.

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Climate action is human rights, because climate change affects the most vulnerable first and hardest – it already has, with droughts, fires, floods, crop failures. It affects the myriad species and habitats that make this earth such an intricately beautiful place, from the coral reefs to the caribou herds. What we’re deciding now is what life will be like for the kids born this year who will be 82 in 2100, and their grandchildren, and their grandchildren’s grandchildren. They will curse the era that devastated the planet, and perhaps they’ll bless the memory of those who tried to limit this destruction. The report says we need to drop fossil fuel consumption by 45% by 2030, when these kids will be 12. That’s a difficult but not impossible proposition.

Taking action is the best way to live in conditions of crisis and violation, for your spirit and your conscience as well as for society. It’s entirely compatible with grief and horror; you can work to elect climate heroes while being sad. There are no guarantees – but just as Sakharov and Sharansky probably didn’t imagine that the Soviet Union would dissolve itself in the early 1990s, so we can anticipate that we don’t exactly know what will happen and how our actions will help shape the future.

The histories of change that have made me hopeful are often about small groups that seem at the outset unrealistic in their ambition. Whether they were taking on slavery in antebellum USA or human rights in the Soviet bloc, these movements grew exponentially and changed consciousness and then toppled institutions or regimes. We also don’t know what technological breakthroughs, large-scale social changes, or catastrophic ecological feedback loops will shape the next 20 years. Knowing that we don’t know isn’t grounds for confidence, but it is fuel against despair, which is a form of certainty. This future is as uncertain as it’s ever been.

There have been countless encouraging developments in the global climate movement. The movement was small, fragmented, mild a dozen years ago, and the climate recommendations then were mostly polite, with too much change-your-lightbulbs focus on personal virtue. But personal virtue only matters if it scales up (and even individual acts depend on collective decisions – I have, for example, 100% renewable electricity at home because other citizens pushed our amoral power company to evolve, and it’s more feasible for me to ride a bike because there are now bike…