Positive feedback cycles can be found all over the planet.
Take the Arctic, for example. When there’s less sea ice, there’s more water, and water absorbs a lot more heat and stores it for long periods of time. This means that more ice melts, and so on and so forth. This amplification effect is one of the main reasons the Arctic is warming twice as fast as the rest of the world.
The Arctic’s permafrost stores of methane are set to trigger another positive feedback cycle. This potent greenhouse gas – shorter lived that carbon dioxide, but magnitudes more effective at trapping heat – is kept frozen for now, but if enough escapes during thawing, it will rapidly warm the planet. This will then unleash more frozen reserves of methane, and the new cycle begins.
The problem with positive feedback cycles is that they are incredibly difficult to stop. A lack of water, accumulating carbon dioxide and a runaway greenhouse effect is the reason that Venus is now an incredible hot world. Once it began in earnest, it was inexorable.
Thanks to our oceans absorbing an unfathomable amount of greenhouse gases, Earth has not, and will not, turn into Venus. However, warmer waters hold less carbon dioxide than colder waters, and the oceans are definitely getting warmer.
Another positive feedback cycle is beginning. Another can of fuel on the bonfire.
The Arctic contains a lot of locked-up carbon. Gregory A. Pozhvanov/Shutterstock