A new study has found that exceeding 1.5 degrees C of global warming could trigger disastrous climate tipping points -- which become accelerated at certain thresholds and have serious implications for human habitability and resources. Currently, the world has warmed 1.1 degrees C, which means five of the nine critical tipping points pointed to in the study may have already surpassed their thresholds. These include the melting of Greenland’s ice cap, the collapse of the Atlantic Meridional Overturning Circulation (AMOC) -- an important Gulf Stream current, and the destabilization of the Amazon rainforest.

The idea of tipping points was introduced over 20 years ago by the IPCC, and according to 2019 article in Nature:

If current national pledges to reduce greenhouse-gas emissions are implemented -- and that’s a big ‘if’ -- they are likely to result in at least 3 degrees C of global warming … The stability and resilience of our planet is in peril. International action -- not just words -- must reflect this.

Why This Matters

A risk analysis conducted at the Potsdam Institute for Climate Impact Research (PIK) in Germany, found that climatic events on the brink of a tipping point can destabilize one another and create a domino effect that could lead to a runaway greenhouse effect. In this scenario, Earth would continue to warm even with a complete halt to human-caused carbon emissions.

As of now, excess carbon emissions and the world’s dependence on fossil fuels aren’t waning to the scale and speed necessary. As a result, the earth continues warming and creeping towards critical tipping point thresholds. The window for prevention is closing, and when it does, there will be “irreversible changes and cascades” to the planet’s complex climate system, making it harder to “maintain liveable conditions on Earth and enable stable societies”.

Tipping Points for Melting: Greenland & Antarctica

Last year, a study found that Greenland’s ice cap was on the brink of a tipping point that could result in trillions of tons of ice being dumped into the ocean. Now scientists say the melting of Greenland’s ice sheet is inevitable and will cause at least 10.6 inches of sea level rise, and if emissions aren’t curbed other ice caps too will melt, possibly resulting in meters of sea level rise.

The Twaites Glacier, an Antarctic ice shelf nicknamed the “doomsday glacier” is on the brink of collapse and is predicted to melt within the next three to five years. Currently responsible for about 4% of global sea rise, accelerated melting could spell disaster for coastal communities around the US -- especially the East Coast -- already at risk of inundation.

Circulation Change Tipping Points: Indian Monsoon Shift & AMOC

The climate crisis continues to demonstrate its ability to devastate, especially with flooding. In Pakistan, 33 million people were impacted by cataclysmic floods from the summer’s record-breaking monsoon season, nearly 1,400 people died, and around half a million people are now without homes. The current cost of damages has reached $30 billion.

“Even today, emissions are rising as people die in floods and famines. This is insanity. This is collective suicide,” stated UN Secretary-General António Guterres. “From Pakistan, I am issuing a global appeal: Stop the madness; end the war with nature; invest in renewable energy now.”

The AMOC is a current system in the North Atlantic Ocean that effectively mediates weather across Europe and sea levels along the US Atlantic coast. However, it has significantly weakened with global warming. Scientists now estimate the AMOC will slow by 34% to 45% by the end of the century as freshwater from melting glaciers pours into the ocean, leading to harsher winters in the UK and an increased frequency of heatwaves and droughts across Europe.

Biome Shift Tipping Points: Amazon Rainforest Dieback

A deadly combination of deforestation and habitat degradation has pushed the Amazon to the brink of a tipping point and threatens to turn the lush rainforest into a dry savannah, cause significant biodiversity loss, and reduce the region’s carbon storage capabilities. Other concerns include the forest becoming more prone to wildfire and drought and slower to recover. Without the Amazon, the world would lose an effective carbon sink and experience an accelerated greenhouse effect and rapid global warming.

“It’s Not Game Over”

Despite underlining concerns around tipping points in this latest study, lead author Dr. David Armstrong McKay states, “[There] are also still grounds for hope … We’re not saying that, because we’re probably going to hit some tipping points, everything is lost and it’s game over. Every fraction of a degree that we stop beyond 1.5C reduces the likelihood of hitting more tipping points.”