A Tale of Competing Tipping Points

We occupy a peculiar moment in history. On the one hand, the climate teeters on the edge of catastrophic destabilization. It’s become clear that we’re not on track to stay under 1.5 degrees Celsius, the point at which scientists consider runaway climate change to become highly likely, and even 2 degrees might be slipping out of our reach.

Other worrisome trends abound. There is increasing evidence that the West Antarctic ice sheets are heading towards irreversible melting. The Gulf Stream is slowing down noticeably, in part due to the melting of the Greenland ice sheet, a development that will have a profound impact on the weather systems and sea levels on both sides of the Atlantic. As a result of hotter and drier weather and deforestation in the Amazon, one of the planet’s most important carbon sinks is disappearing as the rain forest transitions into a savannah.

President Biden kicks off the Virtual Leaders Summit on Climate on April 22, 2021.
President Biden kicks off the Virtual Leaders Summit on Climate on April 22, 2021. White House photo by Adam Schultz/Public Domain.

These are only three of the seven climate tipping points that scientists have identified as posing the greatest threats. They constitute key elements of an earth system in which reinforcing loops, known as positive feedbacks, could send the world into an entirely different state. Seemingly small planetary changes, we’re beginning to grasp, can rapidly snowball into very big ones.

These climate tipping points have occurred before. There is compelling evidence of such abrupt shifts in the paleoclimate record. For example, sudden warming episodes during the last glacial period caused temperature changes of several degrees Celsius over short time spans in large parts of the North Atlantic Ocean.

Faced with the gravity of the current climate situation, it’s difficult not to be overcome by a growing sense of despair and even resignation. All around us signs of a dangerous, unfamiliar world are emerging: megadroughts, wildfires, rising sea levels, extreme weather events unprecedented in their scale and frequency. As Alex Steffens observes, “To look at this moment clearly is to see that the planetary crisis isn’t an issue, it’s an era.” It’s no longer a question, in other words, of saving the earth for our grandchildren; the alarming, alien world set in motion by global warming has already showed up on our doorstep.

The question is, what are we going to do about it? Both climate denialism and climate doomism are morally unacceptable options. There is another pathway. Juxtaposed against the array of runaway climate tipping points is what Gabbi Mocatta and Rebecca Harris call “a tipping point for climate action.” It’s the extraordinary tension between the tipping points for climate destabilization and collective action that makes the present moment so fraught. The probability of catastrophe versus the possibility of hope: which will win out in the end? Will the tipping point for broad-based climate action take place before the climate tipping points? The stakes have never been higher.

The case for hope rests, oddly enough, on the fact that we know more about the science of climate change than ever before. As Mocatta and Harris put it, “Although much of [this science] is devastating, it’s also resoundingly clear.” The incontrovertible nature of the climate data means that policy makers have a stronger obligation than ever before to act on its findings. The reentry of the U.S. into the Paris Agreement and the announcement at the recent White House virtual summit that the nation is committed to reducing its greenhouse gas emissions by 50%-52% below its 2005 emissions levels by 2030 are just two indications that policy makers understand the need to respond to the latest research.

At the same time, public support for action has grown dramatically. The largest global opinion survey on climate change ever conducted, The People’s Climate Vote, found that even in the midst of the 2020 pandemic 64% of people considered climate change to be “a global emergency.” Of the people who viewed climate change in this light, 59% said that “the world should do everything necessary and urgently in response.”

The sense of peril reflected in this survey is perhaps the best news of all. It suggests that we may be ready to abandon the “business as usual” approach and move beyond the gradualism that has characterized much of climate policy action up to now. It raises the possibility that we can finally engage in the debate that truly matters: how do we transform our way of life for the benefit of all to meet the existential challenge before us? “Urgency and agency,” as Michael Mann reminds us, “make a winning combination in our fight against climate change.”

Greenland and the Climate Emergency

One of the signature features of our times is the dramatic disconnect between the speed with which the climate emergency is unfurling, on the one hand, and our ability to integrate this reality into our day-to-day life, on the other. In an article earlier this summer, David Wallace-Wells, the author of The Uninhabitable Earth: Life After Warming (2019), reflected on what he called the “phenomenon of cascading climate impacts.”

An iceberg off the Greenland coast this summer. Photo by Harry and Rowena Kennedy licensed under CC BY-NC-ND 2.0.

“How many natural disasters does it take to qualify as biblical, or apocalyptic, or at least to make us understand that we are living not through a bad week, or a bad year, but an unraveling climate system in which so much of what we take for granted as permanent features of the built environment may be turned into flotsam and jetsam by unprecedented weather?” he asked.

His haunting question came to mind this month as I read one report after another about the record ice melt in Greenland. Scientists estimate that by the end of the summer something like 440 billion tons of ice will have melted or calved off Greenland’s giant ice sheet.

In just five days from July 31 to August 3, more than 58 billion tons melted from the surface of the world’s largest island, 40 billion tons more than average for this time of year. That’s not taking into account the huge ice chunks breaking off into the ocean or warm water attacking the glaciers from below.

Just since the 1990s, Greenland’s rate of ice loss has increased from 41 gigatons per year to 286 gigatons per year during the period from 2010 to 2018. A recent study found that, if greenhouse gas emissions are not cut significantly in the next decade or two, Greenland could contribute up to two feet of global sea level rise by 2100.

How does one even begin to comprehend the enormity of this catastrophe?

Wallace-Wells suggests that our capacity for denial and compartmentalization may be such that we actually never come to grips with what we are doing and the threat that it poses to our very existence. Instead, we simply incorporate each new horrifying event into a “new normal” and move on. Even more disconcerting, Wallace-Wells thinks we may begin to find ourselves normalizing ” clear and terrifying patterns,” not just single instances of extreme weather events and climate disasters such as the India heat wave in June or the vast, ongoing fires in the Amazon.

At that point, obviously, our doom will be sealed. We must do everything possible, then, to keep reminding ourselves that nothing about what is happening to our climate and its impacts is normal. We must keep talking with each other and finding ways to act collectively that push back against any of this from becoming normal.

As Greta Thunberg, the 16-year-old activist who has called for a global climate strike on September 20, reminds us, ” Yes, we are failing, but there is still time to turn everything around. We can still fix this.”