The Intergovernmental Panel on Climate Change defines a tipping point as a critical threshold in a complex system that when exceeded can lead to change that is irreversible.
We know that all our planetary tipping points are related to rising temperatures. The challenging factor is that we do not fully understand the complexity of the planetary systems we have interfered with. We are reconfiguring the earth’s climate every day by making it hotter and hotter. We also know that carbon emissions may be pushing us to a planetary collapse. That means that if this continues, our planetary system may no longer be able to balance itself.
“Tipping points in the earth’s system pose threats of a magnitude never faced by humanity,” said Tim Lenton of the University of Exeter’s Global Systems Institute. “They can trigger devastating domino effects, including the loss of whole ecosystems and the capacity to grow stable crops with societal impacts including mass displacement, political instability and financial collapse.”
Here is a quick summary of some critical tipping points. If you want more detail, see the tipping point explainer on earth.org.
Scientists expect at least 70% to 90% of today’s coral reefs to die in the coming decades. We know coral reefs are vibrant ecosystems. They hold more than one-quarter of all marine life on earth, and their collapse would dramatically alter the ecosystem.
Our glaciers are melting fast, at double the speed of that of the last two decades. As the glaciers disappear there will be less water available. Melting glacial meltwater is critical to sustaining regions during dry seasons with low rainfall.
As Greenland warms the melt is faster and, if this melting becomes irreversible, it will affect ocean currents and rainfall throughout the planet. As the sun causes more ice melt, the exposed blue ocean and land absorb the sun’s energy faster, resulting in even more warming, also causing global sea rise. In addition, as the climate warms and the permafrost thaws, carbon dioxide and methane are released in the atmosphere in massive numbers, adding significantly to global warming.
Antarctica is also threatened by warm water. As water warms these ice shelves melt and weaken, they begin to lose their stability.
“If you think about the future of the world’s coastlines, 50% of the story is going to be the melt of Antarctica,” says David Holland, a New York University scientist who studies polar regions. Many scientists believe our projections of sea level rise might be significantly underestimated.
The extreme heat we are already experiencing today is causing a huge increase in ocean temperatures. Scientists believe it is leading to a shift in ocean currents. According to a University of Exeter report, the Atlantic Meridional Overturning Circulation is being disrupted because surface waters of the North Atlantic are becoming less dense. That current is critical to maintaining the climates of western and northern Europe. The AMOC is a giant conveyor belt that redistributes heat throughout the planetary system, bringing it from the tropics all the way to Greenland and carrying cold water back south. Its disruption would have consequences around the world, affecting rainfall, crop production, summer monsoons and sea level rise.
Another tipping point are monsoons themselves. Global warming affects the strength, timing and intensity of monsoons. If we cannot contain global warming, scientists estimate that production of staple crops like rice, wheat, and corn will be dramatically affected.
As the effects of climate change intensifies, drought in the Amazon is limiting ability of the Amazon to influence rain patterns. In addition, rapid deforestation has led to massive die back and is also shifting the Amazon from being a carbon sink to a source of greenhouse gases.
The tipping points are all interrelated and caused by our interventions in a planetary system we don’t fully comprehend. We do know that to avoid the worst of these tipping points we need to move quickly to cut emissions.
That is why one of the most important tipping points is the one we face right now. There are elections throughout the world this year, including in the United States. The election in our country will likely determine if we can avoid the worst of these catastrophic planetary tipping points. This most critical tipping point is in our control and one we cannot afford to ignore.
As the Scientific American recently stated, “this election is a choice between rationality and respect for all, and dark fantasies.” Truth, science, and even our planetary survival is on the ballot.
Published on October 6, 2024, in the Albuquerque Journal.
© Judith Polich. All Rights Reserved. May be republished with author’s written consent and proper attribution.