Scientists warn Earth’s climate may have already passed a number of tipping points. These tipping points happen when a series of events becomes unchangeable, such as melting Arctic sea ice, and rising sea levels. The fear is that these cycles can become self-perpetuating and unstoppable.

One serious scenario which scientists warn of involves cascading rising temperatures. As human-made greenhouse gasses emissions rise - like methane and C02, they collect in the atmosphere and trap in the heat from the sun. As the temperature rises, permafrost melts which release even more methane. That methane traps in more heat and the cycles continue. Some signs already point to an inevitable collapse of some large ice sheets, such as the West Antarctic. If these collapses, scientists say we could see a rise in sea level of many feet.

Another tipping point involves rising sea temperatures. The ocean is the largest carbon sink on Earth, meaning it collects and absorbs a massive amount of C02 from the environment. It does this through various biological and physical ways. If the sea temperature rises too much, it could kill of plankton and coral, which are both responsible for a large part of the biological carbon sink system.

But hope isn’t lost.

The authors of the article in Nature pointed out that, “This article is not meant to be a counsel of despair. If we want to avoid the worst of these bad climate tipping points, we need to activate some positive social and economic tipping points [such as renewable energy] towards what should ultimately be a happier, flourishing, sustainable future for the generations to come.”