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 is one of the reasons the Arctic is warming twice as fast as the rest of the world.
The Arctic’s permafrost could also trigger another positive feedback cycle. This potent greenhouse gas – shorter lived in our atmosphere than carbon dioxide, but magnitudes more effective at trapping heat – appears when microbes, under low-oxygen conditions, break down organic matter and release it as a biproduct.
If this escapes into the sky in vast enough quantities, this could induce a sudden warming. This will then potentially unleash more methane, and the new positive feedback cycle could possibly begin. Again, it's good to be clear, however, that a lot of uncertainty exists as to how plausible this particular scenario actually is too.
In any case, the problem with positive feedback cycles is that, by their nature, they are incredibly difficult to stop. Just to give a rather extreme example of this, 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 could be about to begin. Another can of fuel on the bonfire.
The Arctic contains a lot of locked-up carbon. Gregory A. Pozhvanov/Shutterstock