When the current President of the United States pulled out of the Paris climate agreement recently, the scientific community, climate change activists, and millions of others could have been forgiven for thinking that humanity had finally forsaken its planet. Yet in a recent talk at the STARMUS Festival in Trondheim, I was particularly struck by American coral reef biologist Nancy Knowlton’s words on Earth Optimism, and why all may not be lost just yet.

The STARMUS Festival took place in Trondheim last week. The festival, which celebrates and aims to increase public appreciation of science, featured a huge roster of stars, from Buzz Aldrin and Brian Cox to Neil DeGrasse Tyson and Lynn Rothschild. But perhaps the most impressive name was that of Stephen Hawking. With this year’s theme being Life and the Universe, you could hardly pick a more prominent keynote speaker.

I didn’t see Hawking’s talk, but upon being asked about the future of humanity, Hawking reputedly pronounced that our future was elsewhere; this planet is now beyond repair. Like I said, I didn’t hear this. I only heard Nancy Knowlton’s refutation, at the Biodiversity and Humanity Conference organised by the NTNU University Museum.

Knowlton didn’t exactly paint a rosy picture of the world. She can’t – she’s a coral reef biologist. As an Australian who was lucky enough to visit the Great Barrier Reef in 1998, I can sympathise. Acidification, eutrophication, climate change and invasive species are ruining coral reefs worldwide, and Knowlton didn’t skirt this. She worked on the reefs in Discovery Bay, Jamaica as a student, and watched an ecosystem she’d spent years studying disappear over the course of a decade.

More highly publicised events than coral reef decline seem to have brought us to new lows, however, with the Paris climate fiasco positing itself as the final straw. But Knowlton started her barrage of optimism by pointing out the futility of bombarding students with the dire predicament our planet is in. After all, environmental scientists are to be doctors to the planet, and to paraphrase Knowlton, I would hope that it is considered poor medical practice to have doctors in training conduct nothing but autopsies. Tomorrow’s conservationists need to hear that the world is in trouble, what they don’t need to hear is that there’s nothing that can be done to fix it.

What then followed were a plethora of examples in which groups and even single individuals were able to affect real change, be it on a species, community, or entire ecosystem level. I’ve linked a few of the stories below.

• Recovery of bald eagles and osprey populations in wake of DDT bans in the 70s
• Tampa Bay seagrass recovery
• Drops in shark fin soup consumption in China over the last decade

If you want further proof that our planet is not past the point of no return, look no further than Holly Jones and Oswald Schmitz’s 2009 study on ecosystem recovery, which predicted that “most ecosystems globally can, given human will, recover from very major perturbations on timescales of decades to half centuries”.

And this is not to mention the huge swings that governments worldwide are making towards renewable energy every day. Whilst Trump’s tendency to favour coal and ignore the threat of climate change may be disheartening, it’s worth noting that in 2016 coal production dropped by a record amount, and global carbon emissions stalled for the 3^rd year in a row.

Earth optimism isn’t naïveté, it’s pragmatism. It’s what will continue to inspire generations to find new ways to save species, breathe life into fading ecosystems and ensure that our planet remains a sustainable one.

What can you do?

If you’re in science, great. Keep doing your thing and spreading the message to people that we can help the environment to recover. I’ve often heard that my parents’ generation ruined the planet and that it’s up to our generation to save it. It is, but that includes making sure we can inspire the next generation to take up the fight.

And if you’re not? Well there’s a ton of things that can be done. But before I list them, here’s a quote from Voltaire that Knowlton closed with.

“Don’t let the perfect be the enemy of the good.”

Every little bit helps, and just because you don’t build a tiny house and make it plastic-free and run on grey-water doesn’t mean that doing any of the things listed below helps any less.

Cut down on meat

Last year the Economist posted this article on why eating more veggies is good for the planet. I’m not saying go vegetarian (though I promise it’s easier than it sounds), but even replacing beef with chicken once a week makes a hell of a difference.

Reuse plastic bags

You don’t have to knit your own hessian sacks, but try to reuse any plastic bags you bring shopping. If you go shopping twice a week and use 3 bags each time, if you reuse those bags for 5 weeks you’ve already saved 30 plastic bags – the amount that was found in this whale’s stomach off the coast of Norway. And check out this video for 7 other ways to cut down on plastic use.

Don’t waste food

French consumer group QueChoisir claims that if food waste were a country, it would only be behind China and the US in terms of greenhouse gas emissions. Again, I’m not saying start a dumpster-diving union, but it’s really easy to look at the contents of your fridge, figure out what’s going to go off in a few days, and use it for something. Websites like SuperCook let you bang in whatever’s lying around in your fridge/cupboard, and tell you what you can make with it.

To stay up to date with Nancy Knowlton’s work, follow @OceanOptimism on twitter.