Climate change: Six tipping points ‘likely’ to be crossed

Image source, Andre Seale via Getty Images

According to a new analysis, current rates of warming will put the Earth at risk of six "dangerous" climate tipping points.

The Earth's systems would be disrupted if these thresholds were crossed.

Scientific commentators used to say that reaching such a point would be aclimatic emergency.

Evidence from 200 recent papers was analysed.

• At what temperature the tipping points would be reached
• What impacts there would be for Earth's other systems
• Over what timescales the impacts would be felt.

According to the research, the world is already at risk of triggering six dangerous climate tipping points, and risks increase with each tenth of a degree of warming.

If current global climate targets are achieved, the world will see an average warming of 1.8 C.

Two decades ago the Intergovernmental Panel on Climate Change introduced the idea of "climate tipping points."

The UN says that a change in the way the Earth's systems operate could beirreversible if crossed.

The breakdown of the system will continue even if there is no more warming.

It's like if a ball crests the top of a hill and starts rolling down, and can't stop.

If global average temperatures rose to more than 5C, the tipping points would be crossed.

There is growing evidence that the thresholds may be crossed earlier.

According to the research, six tipping points are likely to be crossed.

• Greenland Ice Sheet collapse
• West Antarctic Ice Sheet collapse
• Collapse of ocean circulation in the polar region of the North Atlantic
• Coral reef die off in the low latitudes
• Sudden thawing of permafrost in the Northern regions
• Abrupt sea ice loss in the Barents Sea.

Image source, Thor Wegner/DeFodi Images via Getty Images

In the polar regions, there are signs of destabilisation which precede a system breakdown, according to the lead author of the book.

Climate change has led to the loss of ice in the region six times quicker than 30 years ago.

Unless global temperatures rise by 3.5C, dieback in the Amazon Rainforest isn't expected to be triggered, but all of these systems are connected. The likelihood of others collapsing increases when one system fails.

"Cascading tipping points are a serious additional concern due to the fact that many tipping elements in the Earth system are interrelated."

Less of the sun's energy is reflected leading to further global warming.

The team suggested increasing the number of potential tipping points from nine to sixteen.

The team used paleoclimate data, current observations, and outputs from climate models to make new identifications.

The El Nio Southern Oscillation has been removed for lack of evidence.