What are tipping points, and why should we care?
A climate “tipping point” refers to a threshold beyond which small changes to global temperatures can have big, irreversible effects.
For example, you’ve probably heard that scientists are concerned about the melting of the huge ice sheet that covers Greenland. If the world isn’t able to rein in global warming, the melting will eventually become self-sustaining and irreversible, researchers have determined.
That’s a tipping point.
If this threshold is crossed, the melting could raise sea levels by as much as 23 feet over the course of several centuries, swamping coastal cities around the world.
The idea of climate tipping points has been around for decades, although there is debate about how many there are and at what temperatures they will be reached. The big ones, however, are generally accepted to include the melting of the ice sheets in Antarctica and Greenland; the thawing of Arctic permafrost; the collapse of a major ocean circulation system; and the shrinking of the Amazon rainforest.
Recent research suggests that some of these changes may start to occur once global warming reaches between 1.5 and 2 degrees Celsius (2.7 and 3.6 degrees Fahrenheit) above preindustrial average temperatures. And the world is already 1.2 degrees Celsius warmer than it was in the 19th century. — Henry Fountain