Air Date: Week of July 30, 2021

Early climate models may have underestimated the timing of the emergence of extreme weather events like heat waves and floods. This summer’s severe flooding events in parts of Europe, China, and the United States are a wake-up call as policy makers, scientists, and citizens consider the urgent need for climate adaptation and mitigation. (Photo: Ryan Johnson, Flickr, CC BY-SA 2.0)

As a slew of extreme weather events hits the headlines, the evidence of climate disruption is undeniable. Michael Mann, professor of atmospheric science at Penn State University and author of The New Climate War warns we are headed for dangerous thresholds of climate disruptions beyond the reach of adaptation to cope. He joins host Steve Curwood to talk about the links between extreme weather and human-forced climate change, why sea level rise could be counted in the dozens of feet by 2100, and how an unchecked climate emergency imperils human civilization.

Transcript

CURWOOD: It’s Living on Earth, I’m Steve Curwood.

Extreme, record breaking, weather is happening around the world. Thousand-year floods are drowning Europe and Asia. And exceptional drought and unprecedented heat has been broiling western North America, sparking wildfires and degrading air quality for thousands of miles. Climate disruption is making such events much more likely. That according to new research published in Nature Climate Change that calculates heat waves that shatter temperature records by 10 degrees Fahrenheit are up to seven times more likely over the next three decades, and even more likely in the years beyond. That’s under a scenario in which too little is done to curb emissions. And as the world prepares for the UN climate summit in Glasgow Scotland in November, the Intergovernmental Panel on Climate Change, or IPCC, is finishing up its latest report on climate science, impacts, and ways to respond. Michael Mann is an atmospheric science professor at Penn State University who has worked on similar studies and has contributed to IPCC reports. Welcome back to Living on Earth, Michael!

MANN: Thanks, Steve, it's great to be with you.

CURWOOD: Now, you and others have recently published studies saying that we are in for some record-shattering heat becoming far more frequent, why and how?

MANN: Well, you know, at some level, it's pretty basic: you warm up the planet, you're going to get more frequent and intense heat waves. And that's what we've seen. Now, this latest study uses climate models to try to estimate just how frequent these sort of record-breaking heat extremes, like we've seen recently, how frequent they're likely to become. And one of the things that they show is that when you have a period of rapid warming, then you're more likely to see records broken by very large amounts. Again, it's perhaps somewhat intuitive, but they have nonetheless demonstrated this rigorously using climate model simulations.

CURWOOD: Well, yeah, so tell me, I mean, about this extreme weather we're seeing right now. I mean, we have of course, the record heat in the Northwest. Oh, but maybe it is raging drought in the West? Or is it raging fires in the West? Or is it thousand-year floods in, in Europe and China? In essence, what's going on? Why suddenly, does Mother Nature seem to be really focusing on this climate disruption thing?

MANN: Yeah, well, you know, what's happening -- you know, it feels like it's all accelerating. But in fact, what's really happening here is that the signal now is becoming large enough that we can see it play out in real time. You know, a decade ago or more, we sort of had to tease out of the data, the impacts of climate change, you sort of really had to squint to see them in the data; today, you no longer have to do that. The impacts have become, again, so profound, that we can see that these weather events, these extreme weather events that are playing out right now across the Northern Hemisphere this summer, have no precedent as far back as we have records. Now, this study, this recent study that, you know, argues that we're likely to see even more and more record shattering weather extremes. Ironically, that study makes use of climate models that don't completely capture some of the dynamics in the real world that are responsible for some of the events that we are seeing. This Pacific Northwest heat dome, for example; part of what was going on is that the jet stream has slowed down, something that's predicted to happen as we warm the planet. And weather systems tend to get stuck in place, and they grow in amplitude, and they grow in magnitude. And this is actually an effect that my co authors and I have been studying over the past few years. And it has to do with one of the subtle impacts about climate change and how it changes the behavior of the jet stream. And this particular impact is not well captured in current generation climate models. It involves processes that aren't very well captured by the models. So the models, if anything, are actually underestimating the impact that climate change is already having on these extreme weather events. And the reason that we see, you know, huge floods in one place, wildfires and heat waves in another, is because the entire jet stream that circles the entire hemisphere has been impacted by climate change, in a way that leads to more intense and more persistent extreme weather events on both sides of the spectrum.

CURWOOD: Michael, sometimes people point out that nature tends to move in quantum leaps. You know, one day you have a caterpillar, another you have a moth; if you're talking physics, you know, an electron's on a p level, another day, it's on an s. So how much does this affect what's going on, what we're seeing in terms of climate disruption, because, as humans, we think of things, you know, gradually changing rather than having quantum leaps. Which are we headed for, do you think?

MANN: Yeah, well, it's, you know, an interesting choice of words to bring quantum mechanics into the conversation. And of course, my background originally was in theoretical physics, and I once studied quantum mechanics. But ironically, this behavior that I'm describing about the jet stream where it gets locked into place, and these wiggles become larger, and so the high and low pressure centers that are associated with these extreme weather events become deeper. It turns out that, to actually solve the physics of that problem, you end up using the same mathematics that was developed in the early 20th century to solve certain problems in quantum mechanics. So it turns out, the mathematics of waves that describes the behavior of matter at the smallest scale, is relevant to extreme weather events that are happening at the planetary scale. But you know, you've underscored something else which is very important here, which is our perception. Our perception does have thresholds, and impacts have thresholds. You know, at a certain point a flood is so bad that it breaks the dams, it rises over the levees. And so there are these thresholds, where when an event becomes extreme enough, it becomes so hot, for example, that human beings simply can't be outside without suffering severe health impacts. As these events become more extreme, we start to exceed some of these sort of societal and sort of behavioral thresholds. And so all of a sudden, we're talking not just about an extreme heat wave, but a deadly heat wave. All of a sudden, we're not just talking about a terrible flooding event, but the worst flooding event that China has ever seen. And it feels like we've gone through some sort of threshold in the way climate change is proceeding. But it turns out, even if climate change proceeds smoothly, the impacts and the responses to it can go through these abrupt thresholds. And that's one of the things that we fear, because there are potential climate tipping points that we worry about, like when the ice sheets give way, and the collapse of the Greenland or West Antarctic ice sheet becomes unstoppable. That's a threshold, and then, you know, we are subject to meters of sea level rise, and there's nothing we can do about it anymore. There are these potential tipping points that we are nearing. But there are also tipping points in our ability to adapt to the changes that we're witnessing, in our adaptive capacity and in our resilience, and that's something that we really have to worry about.

CURWOOD: Folks sometimes like to point out that the human impact on the climate and understanding it is an experiment that's never been done before, and we're gathering the data in real time. So we are facing surprises, surely, right, Michael?

MANN: Yeah, and unfortunately, they're not going to be welcome surprises. The surprises that are in store are some of the extreme weather events we've seen this summer, where some of the scientists who have been studying this stuff for years, say, "I never actually thought I would see anything like this, you know, I studied this on paper, I studied this in climate model simulations." But all of a sudden, we are witnessing the profound impacts of the warming of the planet. There is, you know, no question that we are dealing with a whole new level of threat. And you know, it's, it's right when people call the climate change problem a crisis or an emergency; well, it's reached that level. And it's reached that level, in part, because what we've never seen before, is, you know, a population of nearly 8 billion people on the face of the planet, competing for this diminishing food and water and space. And so the impacts of climate change really test our capacity as a civilization to continue to operate, when the conditions upon which our societal infrastructure have been built, and are based on suddenly no longer apply. If we allow the warming to proceed, then we will exceed our adaptive capacity as a civilization. So that is a potential future, societal collapse is a potential future. But it is not yet guaranteed as our future, there is still time to make sure that that isn't our future. But we have to decarbonize our economy now, rapidly. We've got to bring global carbon emissions down by 50% within the decade, if we are to have any chance of averting that one and a half degrees Celsius, nearly three degree Fahrenheit danger level.

CURWOOD: You outline what we should consider in terms of mitigation, that is reducing emissions. But what's to be done, what can be done in terms of adaptation? What do we already need to do?

MANN; Yeah, so we need to be careful that adaptation isn't used as a crutch for, you know, downplaying the importance of mitigation, of reducing carbon emissions. And there are some politicians who love to talk about resilience and adaptation, and hate to talk about mitigation. Because the fossil fuel industry doesn't want to hear about mitigation. They don't want to hear about decarbonization. They would rather say, look, we just have to adapt to the changes that are coming. And look, there is a certain amount of climate change that's already baked in. We're seeing it. We're already there. Dangerous climate change has now arrived. In the very best scenario, we're dealing with a new normal, where we have to fundamentally adapt our infrastructure to deal with these heightened threats. And we're seeing that right now. And especially those, you know, who have the least resources, the poor, folks in low income communities have the least resilience, the least resources, they're the ones who are seeing the greatest impacts. And so when we put it all onto adaptation, we're putting it on the poorest and those with the least resources. So yes, we need to provide resources, especially to those frontline communities, so that they can deal with the impacts that we are already dealing with. And likely things will get somewhat worse, but we can prevent the worst impacts from playing out. And that means there has to really be an emphasis on mitigation, because no amount of adaptation is going to allow us to flourish as a civilization in the face of an additional half a degree, one degree Celsius warming of the planet. Dangerous climate change has arrived. If we continue down this road, it will become not just dangerous, but truly catastrophic and disastrous to human civilization. That's one future; that's, that doesn't have to be our future. That's why we need to be so focused on action right now going into this major climate conference later this year, where there's a real opportunity now to act before it's too late.

CURWOOD: Over the years, the Intergovernmental Panel on Climate Change, the science panel, has been criticized because it's tended to underestimate, its projections have not been borne out by the data, that generally we've, we're moving faster in the direction of disrupting the climate. So why has that happened so many times with the IPCC process, in your view? And what do you think will happen with this one?

MANN: I think there are a couple different things going on at the same time. And sometimes we conflate them, but they're distinct. One of them is what my friend and colleague Naomi Orekes of Harvard University describes as "the path of least drama." Scientists just intrinsically, don't want to be out ahead of the data, when they are targets by climate change deniers, and conservative politicians, and right wing media outlets that will go after scientists who make audacious and bold claims, and alert the public to the dangers of continued fossil fuel burning. That's very inconvenient to the fossil fuel interests. And so, you know, as I found out myself when we published the hockey stick more than two decades ago, if you do work and you communicate findings that are a threat to the fossil fuel industry, there's a target on your back. In addition to that is the simple fact that our models are imperfect. Our ice sheet models, we've learned over the last decade or so that there's some important processes that we see playing out in Mother Nature: cracks forming at the surface of the ice sheets, allowing water, meltwater to penetrate to the bottom of the ice and lubricate it so it can slide more quickly into the ocean. Or, the ice shelves disintegrate, and when they do, that inland ice now starts to flow faster. So these are very dynamic processes that we've only really started to really understand and appreciate. And so they weren't in the models a decade or so ago. And now when we put them into the models, lo and behold, we find that the ice sheets can collapse faster, that sea level can rise faster. I think we're seeing something similar with extreme weather events as we start to put more realism into our atmospheric models. And so this isn't in any way sort of a conscious effort on the part of scientists to downplay the impacts. The very act of scientific consensus itself is a conservative process, because you're looking for sort of the lowest common denominator of what a very large number of scientists can all agree upon. And I think we see all of that playing out here. And we should be cognizant of that, because it impacts our ability to assess the risk from what we're hearing.

CURWOOD: Speaking of sea level, by the way, from what you understand from the models that are out there, and maybe some projections of how they might be tweaked. What are we looking at in terms of sea level, say, by 2050 and by 2100, with what we know today?

MANN: Yeah, so let's talk about 2100: three IPCC reports, we were talking about feet, a foot, maybe two feet. Two IPCC reports, we were talking about a meter, three feet. One IPCC report, we're talking about two meters, six to eight feet. Those numbers are trending up, and they're trending up in a disturbing way. And so increasingly, we are coming to the conclusion that large parts of the West Antarctic ice sheet and the Greenland ice sheet could become unstable, given even modest additional warming. And that puts us now in the domain not just of feet or meters, but tens of meters: 10 meters, possibly, by the end of this century.

CURWOOD: You're talking about a 30 foot rise in sea level by 2100, possible?

MANN: Yeah, you're talking about not just New York City having to worry about storm surges with storms like Superstorm Sandy, you're starting to worry about permanent immersion of New York City. You're no longer talking about adaptation, about levees, about dams. You're talking about managed retreat. Moving huge population centers of millions and millions of people away from the coastline, where we're now competing for less and less space, because our coastlines are becoming inundated, major cities have to retreat inward, and larger and larger parts of the tropics are becoming unlivably hot. That's a prescription for all sorts of conflict and national security concerns. It's why some of our leading national security experts have said that climate change constitutes the greatest security threat we face in the years ahead, because all of a sudden now a rising global population is competing for less food and space and water. And so this is a very real concern. And again, in a worst case scenario, we're looking at the potential collapse of civilization as we know it. In the best case scenario, we're looking at a livable planet, for us and for future generations. So let's focus on that scenario, because it's one that's still within our grasp. But it demands that we act now, and that we hold our politicians accountable for acting now, because we can't wait.

CURWOOD: Okay, and so that as much as 10 meter rise in sea level is baked into the system now, or we have a shot by slowing, getting rid of carbon and related type emissions, of never getting to that 10 meter, that 30 foot rise in sea level?

MANN: So, we don't know, with confidence, just how much sea level rise we're committed to at this point, just how much of the Greenland and West Antarctic ice sheet are likely to go at this point. What is certainly true is if we ramp down our carbon emissions, surface temperatures stabilize pretty quickly, and so we begin the healing. But we may not be able to stop the collapse of large parts of the ice sheets, we may be able to slow that down. And if we can slow that down, even by decades, it gives us far more time to adapt our infrastructure, move our population centers, but we can't rule out 20 or more feet of sea level rise already being baked in at this point. The hope is that if it is baked in, it unfolds over timescales of a century or two, and most of the models indicate that scenario. But as I've said, increasingly, as we put more realism into the models, we find that these things can happen faster than we thought.

CURWOOD: Michael Mann is a Distinguished Professor of Atmospheric Sciences at Penn State University. His new book is called The New Climate War. Thanks so much for taking the time with us today.

MANN: Thanks, Steve, always great to be talking with you.

 

Links

Check out Michael Mann’s book, The New Climate War

The Guardian | ‘Record-shattering’ heat becoming much more likely, says climate study

The Guardian | How many years until we must act on climate? Zero, say these climate thinkers

NPR | How Climate Change Is Responsible For More Extreme Weather Events Worldwide

Living on Earth's interview with Michael Mann about The New Climate War