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A Global Climate Tipping Point? Understanding The U.N. IPCC Report

People use a ferry to evacuate from Pefki village on Evia island, about 189 kilometers (118 miles) north of Athens, Greece, Sunday, Aug. 8. (Petros Karadjias/AP Photo)
People use a ferry to evacuate from Pefki village on Evia island, about 189 kilometers (118 miles) north of Athens, Greece, Sunday, Aug. 8. (Petros Karadjias/AP Photo)

Around the world, extreme climate events everywhere —

From wildfires to severe floods and droughts.

The U.N.’s International Panel on Climate Change’s latest report points to temperature changes happening faster, and the likelihood of the world reaching a climate tipping point sooner.

“I call it the Paul Revere phase. … Scientists saying, ‘The British are coming, the British are coming.’ But then now the British are here, and what do we do?” William Moomaw says. “Things are getting worse, much more rapidly than we anticipated.”

Today, On Point: The IPCC’s latest warning on climate change. Are nations ready to act?


William Moomaw, professor emeritus of international environmental policy at Tufts University. Visiting scientist at the Woodwell Climate Research Center. (@FletcherSchool)

Alexis Papahelas, executive editor of the Greek daily newspaper Kathimerini. (@Kathimerini_gr)

Beverly Law, professor emeritus in the College of Forestry at Oregon State University.

Interview Highlights

What is it about this latest report from the IPCC that makes it a code red moment?

William Moomaw: “For the first time there is just no equivocation that human activities — and they are specified in this report — that those activities have caused the changes that we are seeing. And that we have to act very quickly to abate them. And we will have some of these with us, not just for years, but for centuries and maybe millennia.”

What is raising the greatest alarm bells for you?

William Moomaw: “My alarm bells have been ringing for some time, to be frank with you. But in this report, I think the points that are being made, that the warnings of the past have simply just not been listened to, or they’ve been listened to but not heard … and that now is the time that we have to act. We can make a huge difference in the coming decades as to what will happen.

“But there are some things, and this is new for IPCC to say, there are some things that will be with us for essentially, I don’t know, beyond anything we can imagine. Hundreds of years, maybe thousands of years. Like sea level rise. It will take, I don’t know, 10,000 years to rebuild the glaciers and the lost ice from Antarctica and Greenland. And the acidity of the ocean will be with us forever, perhaps. So we have done serious damage, but we can mitigate some of that damage for other things, like the temperature. We can manage the temperature and get things back to a livable situation.”

A hotter future is essentially guaranteed. Am I reading that right?

Beverly Law: “It looks like at least 1.5 degrees Celsius, and we’re hoping to keep it there. So one of the things that that has bothered us and that’s been hard to get a grasp of is the extreme events. And we’ve had some recent hot extremes over the past decade. And as they stated, that would have been extremely unlikely to occur without human influence on climate change.

“And so these record-shattering heat waves are occurring three times more often than they did in the 1960s. We’ve lived long enough to have experienced what this is like. And now we’re trying to figure out how to grapple with the extremes. Again, they’re pretty hard to predict over the long term. But the people who are predicting weather had a really good handle on this with their modeling.”

On extreme weather events around the world, and droughts in the West

William Moomaw: “The Earth is not heating uniformly. And the Arctic is warming vastly faster than the rest of the Earth. And that is changing the dynamics of the atmosphere, weather patterns. And so, for example, in the past, well, whatever it was a month or so ago, Professor Law in Oregon was nearby Portland, was at 116 degrees, unprecedented. Meanwhile, I, here in New England, was experiencing a summer day of 73 degrees. I mean, that’s the regional disparity that we’re seeing just within the United States.

“And so one of the aspects of this report is it uses longer term averages. So it says, OK, over the past two decades, the average temperature has risen by .9 degrees Celsius, which is roughly a couple of degrees Fahrenheit. And in fact, last year, the rise above pre-industrial levels was about 1.2 degrees. So we’re talking about 1.5 degrees. By focusing on the longer term trends, which is understandable, because there’s a lot of fluctuation going on, and not mentioning the more recent changes, people may have the sense that we have more time, we can take more time to do this.

“When, in fact, what we’re doing is those past decades are like we were driving along the fine interstate highway. And only in the last 100 yards do we see that it’s going off a cliff. But we’re not looking at the last 100 yards. And that’s what we’re facing, is the last 100 yards right now. And that’s showing that these trends are accelerating. And the IPCC has been warning about this for years, and it’s fallen on deaf ears. And we could talk about why that is the case, and the role that governments have played in doing so.”

What can we do to prevent this global climate tipping point?

William Moomaw: “The tipping points are when the system begins to change to the point that the changes accelerate more changes. So there are these reinforcing feedbacks. Just a couple of quick examples. You know, the melting of the Arctic sea ice means there’s less light reflected, sunlight reflected, and so it’s warming much faster. And that then warms the Arctic more, which then causes the permafrost to thaw and to dry out and be more forest fires in the Boreal region and so on.

“And if that cycle gets out of control in the sense that it can’t be turned around, even if we lowered the amount of carbon dioxide in the atmosphere, that would be catastrophic. But fortunately, a lot of what we’re seeing in terms of the weather changes can be changed by lowering the temperature of the Earth towards what it used to be. And that can only be done by it by reducing the amount of heat trapping gases in the atmosphere.

“And so, I mean, this all sounds like gloom and doom. But for me, the hope is knowing that there are things that we can do that will turn this around. And we can’t slow down sea-level rise. But we can slow down these weather events that these terrible weather events, including these incredible droughts, if we could lower the temperature. And so to do that, we need to obviously, as rapidly as possible, reduce our emissions.

“So run out as fast as you can, get those solar panels, get your electric vehicle, make your house better insulated. Make sure that your place of work is doing what it can to reduce its emissions. And let’s make that energy transition as rapidly as possible. But at the same time, we have to increase the rate at which carbon dioxide is removed from the atmosphere. And that can be done by a combination of letting more existing forests grow.

“Beverly Law pointed out the need for these strategic forest reserves. The same is true with our grasslands, the way they’re managed. With our agriculture, the way it’s practiced and the protection. People don’t think much of wetlands as anything but wastelands, but they have been hugely important in the amount of carbon that they store. And yet we degrade them and release that carbon dioxide almost instantly. So taking a look at what we can do in the natural world, and what we can do in terms of reducing our emissions from the way we live our lives have to go hand in hand. And all those efforts need to be accelerated immediately.”

From The Reading List

Oxford Academic: “World Scientists’ Warning of a Climate Emergency 2021” — “In 2019, Ripple and colleagues (2020) warned of untold suffering and declared a climate emergency together with more than 11,000 scientist signatories from 153 countries.”

More from WBUR

This article was originally published on WBUR.org.

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