We’re on course to hit six climate tipping points in the 2030s

The author is Adam Vaughan.

The collapse of the West Antarctic ice sheet is one of six tipping points in Earth's climate that are now likely to be reached if global warming exceeds 1.5C.

Nine tipping points in the planet's climate system were identified in 2008 and they could be used to speed up climate change. The first major assessment of those possible shifts, and how much global warming it might take to cause them, has been completed.

There are now 16 tipping points. Changes in the Labrador Sea, part of the North Atlantic, which could cool Europe, is one of the new ones that has been added.

Since the industrial revolution, the world has warmed by 1.1C, which means there is a low chance of tipping points. The collapse of the Greenland ice sheet and the die-off of coral reefs are possible at 1.5C. The collapse of the Atlantic Ocean conveyor belt could lead to more extreme heat and cold on both sides of the ocean due to the large system of currents.

The support for rapid cutting of emissions in line with the 1.5C goal is provided by this. The closer you get to 2C the more likely some of these tipping points are. The current temperature is 2.6C, which is going to hit a lot of tipping points.

The risk of tipping points was highlighted in last year's Intergovernmental Panel on Climate change report. Experts were asked to give estimates of how much warming would be required to set off the tipping points.

Since 2008 there has been an explosion of research. Modelling ice sheets has been important. When the world was 1.5C hotter, ice sheets responded by releasing bubbles of air thousands of years old. Observations show signs of destabilisation of the ice sheet and the Atlantic conveyer belt.

In the intervening 14 years, the science of climate change has advanced greatly and the study authors now provide a revision based on the latest science. Mark Maslin was not involved in the research.

The tipping points can now be expected. The Intergovernmental Panel on Climate Change has said that it is possible for many to occur at 1.5C of warming. The McKays were feeling like they were before.

The most imminent tipping points, such as the collapse of the WestAntarctic ice sheet, won't have a huge feedback effect that leads to runaway warming. Some people will look at this and say if we hit tipping points at 1.5C, then it's over. They don't cause runaway global warming because they lock in some really unpleasant impacts.

He says it's urgent that societies act to stop tipping points being reached, to prevent impacts such as huge sea level rise, which could result from losing the glaciers. Future generations would be locked in to a different planet with sea level rise. It would change the coastlines of all the continents.

Most of the systems they assess contribute to human welfare. An abrupt thaw of the permafrost would be devastating for human society, says Maslin.

The research doesn't consider how the tipping points might interact with each other The warming effect of others could be mitigated by some.

The tipping point that concerns him the most is when the Amazon transforms into a savannah and releases more carbon dioxide. Unless warming exceeds 2C, the models don't think this will happen.

The Amazon's collapse could unfold in our lifetimes, and there are signs that the transition has already begun in some areas. He says that you would see it in real time.

The journal is called Science.