Coral And Antarctic Sea Ice Climate Change Tipping Points Underway?

Coral bleached out from exposure to too-hot water
If this goes on for too long, the coral dies. 
Coral reefs worldwide are now suffering
from big bleaching events. 

Scientist are eyeing coral reefs and Antarctic ice more than ever lately as the two wildly different parts of nature seem to be headed toward what is known as climate tipping points. 

Climate tipping points are defined as critical thresholds that, when exceeded, can create huge, irreversible changes in ecosystems. 

Recent studies have found that we are at, or about to reach two big climate tipping points. One in the tropics, one in the icy environment around Antarctica. 

All this is part of the second Global Tipping Points report from the University of Exeter's Global Systems Institute in England. The report examines some of the fundamental processes that support life on the planet and how close they are to suffering permanent damage. 

CORAL REEFS

In recent years, we've heard about coral bleaching, in which these organisms lose their colorful appearance and turn ghostly white and die, due to the water temperatures being too hot to support them. 

As climate change warms the oceans, these bleaching or diebacks are becoming more common. 

Now, according to CBS News:

"Scientists have determined that the 'tipping point' for coral reefs begins the global warming reaches 1.2 degrees Celsius, with somewhere between 70 and 90 percent of coral dying when that number climbs to 1.5 degrees. 

About 84 percent of the world's coral reefs had bleaching this year in the most intense event of its kind in history, according to the International Coral Reef Initiative."

Sure, coral reefs are pretty, but most of us won't get to see them. So if they die back, is it really a big deal? 

The answer is a loud yes. Coral reefs provide habitat for about 25 percent of all  underwater species. They also support the livelihoods of about a billion people. 

The past two years have been the warmest recorded on Earth. Though 2025 will be a tiny bit cooler than the previous two years, it won't be by much. With such intense warmth, coral reefs have reached their breaking point. 

ANTARCTIC ICE 

This chart shows pretty stable levels of ice
around Antarctica until around 2000. Then
it began to increase. But starting a
decade ago, the amount of ice began to
drop sharply. 

A paper in the journal Nature describes previously unnoted details of interrelated effects of abruptly melting ice. 

The study in the journal Nature stated: 

"A regime shift has reduced Antarctic sea ice extent far below its natural variability of past centuries, and in some respects its more abrupt, non-linear and potentially irreversable than Arctic sea ice loss." It also said.

 Evidence is emerging for rapid, interacting and sometimes self-perpetuating changes in the Antarctic environment. "

According to Reuters, the study gathered data from observations, ice cores, and ship logbooks to charge long-term changes in the area of sea ice, putting into context a rapid decline in recent years. 

That decline means a smaller ice sheet at the bottom of the world. Ice reflects the sun's heat back, to space, So less ice in and around Antarctica means more warmth is sucked in by the planet, making climate change that much worse. 

Reduced Antarctic ice  can shift ocean currents, which changes the distribution of krill, phytoplankton and other sources of nutrition for larger animals in the region, like emperor penguins. 

The amount of Antarctic ice remained pretty stable for at least the century ending around 2000, making life relatively predictable for the region's ecosystem.

Then. as the new century began,  the level of Antarctic ice began to increase, contrary to what you'd expect from climate change. Scientists suspect increased snowfall due to a warming world's ability to produce excess precipitation, in this case, snow, was partly responsible.

After that, suddenly, around a decade ago, the amount of Antarctic ice began to plummet rapidly. The amount of ice is now well below where it was during most of the 20th century. The decline so far shows no real sign of stopping or slowing down. 

The loss of coral reefs and the Antarctic ice situation are two examples of how one effect of climate change can have a snowball effect, making other aspects of a warming world worse, and also accelerate the rate of warming. 

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