Extreme, record-breaking weather is happening around the world. Thousand-year floods are drowning Europe and Asia, and unprecedented heat and drought have afflicted western North America, leading to historically low reservoirs and sparking wildfires that are destroying towns and degrading air quality for thousands of miles.
Climate disruption is making these events worse, and new research published in Nature Climate Change calculates that heat waves shattering temperature records by 10 degrees Fahrenheit are up to seven times more likely to occur over the next three decades, and even more likely in the years beyond.
“It feels like [the effects of climate change are] 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,” said Michael Mann, Distinguished Professor of Atmospheric Sciences at Penn State University. Mann's latest book is called "The New Climate War: The Fight to Take Back Our Planet."
“A decade ago or more, we sort of had to tease out of the data the impacts of climate change, you sort of…had to squint to see them in the data,” Mann said. “Today, you no longer have to do that. The impacts have become so profound, that we can see that 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."
What’s more, the newest computer models are likely underestimating the impact climate change is already having on these extreme weather events, Mann added. So humanity is facing some unwelcome surprises, especially if we don’t act soon enough and aggressively enough to decarbonize our world.
“[S]ome of the scientists who have been studying this stuff for years say, ‘I never actually thought I would see anything like this. 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.'"
“[S]ome of the scientists who have been studying this stuff for years say, ‘I never actually thought I would see anything like this. 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,’” Mann noted. “There is no question that we are dealing with a whole new level of threat.”
Climate models are always imperfect, Mann noted, and scientists are often reluctant to get too far ahead of what they can confidently measure. But now, they are seeing events play out in the real world — in the realm of melting ice sheets, for example — that the models could not account for: cracks forming at the surface of the ice sheets that allow meltwater to penetrate to the bottom of the ice and lubricate it, so it slides more quickly into the ocean; ice shelves disintegrating and causing that inland ice to flow even faster toward the sea.
“These are very dynamic processes that we've only really started to really understand and appreciate,” Mann explained. “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 the models are leading scientists to reach some worrisome judgments: “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. That puts us now in the domain not just of feet or meters, but tens of meters [of sea level rise]: 10 meters, possibly, by the end of this century.”
At that point, Mann said, we can no longer talk about adaptation — about building more levees or dams. Instead, we will be talking about a managed retreat — moving huge population centers away from the coastline because they are becoming inundated. Across the globe, major cities will have to retreat inland, while increased temperatures will make larger and larger areas of the tropics unlivable.
“That's a prescription for all sorts of conflict and national security concerns,” Mann warns. “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.”
"If we allow the warming to proceed, then we will exceed our adaptive capacity as a civilization."
Mann believes the impacts of climate change will “test our capacity as a civilization to continue to operate. If we allow the warming to proceed, then we will exceed our adaptive capacity as a civilization,” he said. “So that is a potential future.”
Societal collapse may be a potential future, but it is not yet our guaranteed future, because there is still time to ensure that that isn’t, Mann insisted. “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.”
"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."
Already, a certain amount of climate change is “baked in,” Mann cautioned. "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. … 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 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.”
“Again, in a worst-case scenario, we're looking at the potential collapse of civilization as we know it,” he said. “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.”