One of the most terrifying concepts in environmental science is the idea of a "tipping point." A tipping point is a critical threshold that, once crossed, leads to massive, unstoppable, and irreversible changes in the global climate system. It is the moment when global warming stops being something that humans are doing to the Earth, and starts being a self-sustaining chain reaction that the Earth is doing to itself. Politicians love to talk about climate change as if it is a slow, gradual curve that we can fix fifty years from now. But the science of tipping points tells us a completely different, much more urgent story: we are running out of time to stop the dominoes from falling.

The Methane Time Bomb

The most famous example of a climate tipping point is the melting of the permafrost in the Arctic. Permafrost is a thick subsurface layer of soil that remains frozen throughout the year. Trapped inside this frozen dirt are millions of tons of ancient, dead plant matter and methane gas. Because the Arctic is warming much faster than the rest of the planet, this permafrost is beginning to thaw. As it thaws, the dead plants rot, releasing massive amounts of methane into the atmosphere. Methane is an incredibly powerful greenhouse gas, which causes the Earth to heat up even faster. This melts more permafrost, which releases more methane, in an endless, terrifying loop. Once this cycle truly begins, no amount of solar panels or political treaties will be able to stop it.

The Collapse of the Albedo Effect

Another terrifying tipping point is the loss of the Earth's "albedo effect." The massive sheets of white ice at the North and South Poles act like giant mirrors, reflecting a massive amount of the sun's heat back into space. But as global warming melts this white ice, it exposes the dark blue ocean underneath. Dark blue ocean water absorbs heat rather than reflecting it. So, as the ice melts, the ocean absorbs more heat, which causes even more ice to melt, exposing even more dark water. It is another unstoppable feedback loop that will radically alter global weather systems.

The Political Urgency

The existence of these tipping points is why youth activists are so incredibly angry at the slow pace of political action. We do not have until the year 2050 to "gradually" transition away from fossil fuels. Every fraction of a degree of warming pushes us closer to the edge of the cliff. We need radical, immediate, structural change to the global economy today, before the Earth takes the controls out of our hands permanently.