According to U.N. Secretary-General António Guterres the world is “perilously close to tipping points that could lead to cascading and irreversible” consequences. Many experts share this belief.
The most immediate threat is the Amazon rainforest. It is so vast that it creates its own rainfall and is home to 10% of the world’s species. However rising temperatures and increasing drought are bringing it ever closer to crossing the threshold from lush rainforest to arid savannah.
Coral reefs are also threatened and are vital to the health of the oceans. Although they cover only 0.2% of the ocean floor, they are home to as many as a quarter of all marine species.
Time is also running out for the world’s largest ice sheets. Both the Greenland and Antarctic ice sheets are melting and the Antarctic is believed to be the most unstable.
If they were to melt entirely, it would cause catastrophic sea level rise around the globe. Loss of the Antarctic ice sheet could result in a 11 foot rise and loss of the Greenland sheet could be 23 feet.
The circulation of the Atlantic ocean is also at risk. What’s known as the Atlantic Meridional Overturning Circulation (AMOC) keeps warmer water from the tropics flowing north along the coast of northern Europe to the Arctic, where it cools and sinks to the ocean bottom. That cooler water is then pulled back southward along the coast of North America as part of the circulation.
This cycle keeps northern Europe a few degrees warmer than it would otherwise be and brings colder water to the North American coast.
The great boreal forests of the north face a potential future of treeless grasslands. Cold weather forests that run across the Western United States, Canada and Alaska are estimated to store more than 30% of all forest carbon on Earth. Without them, massive amounts of greenhouse gasses would be released into the atmosphere, increasing global warming.
A combination of three things are destroying it: fire, heat and bark beetles. Increasing temperatures cause droughts and make forest fires more likely. Heat also boosts the population of bark beetles destroying the forests.
https://phys.org/news/2022-04-world-perilously-irreversible-climate-scientists.html