Michael Mann: Climate Change Still in Human Hands

February 23, 2022

Michael Mann has been underlining this on twitter for a few days. I don’t know if that’s what sparked this Washington Post editorial, but this has to be emphasized at every opportunity.

Mark Hertsgaard, Saleemul Huq, Michael Mann in Washington Post:

One of the biggest obstacles to avoiding global climate breakdown is that so many people think there’s nothing we can do about it.

They point out that record-breaking heat waves, fires and storms are already devastating communities and economies throughout the world. And they’ve long been told that temperatures will keep rising for decades to come, no matter how many solar panels replace oil derricks or how many meat-eaters go vegetarian. No wonder they think we’re doomed.

But climate science actually doesn’t say this. To the contrary, the best climate science you’ve probably never heard of suggests that humanity can still limit the damage to a fraction of the worst projections if — and, we admit, this is a big if — governments, businesses, and all of us take strong action starting now.

For many years, the scientific rule of thumb was that a sizable amount of temperature rise was locked into the Earth’s climate system. Scientists believed — and told policymakers and journalists, who in turn told the public — that even if humanity hypothetically halted all heat trapping emissions overnight, carbon dioxide’s long lifetime in the atmosphere, combined with the sluggish thermal properties of the oceans, would nevertheless keep global temperatures rising for 30 to 40 more years. Since shifting to a zero-carbon global economy would take at least a decade or two, temperatures were bound to keep rising for at least another half-century.

But guided by subsequent research, scientists dramatically revised that lag time estimate down to as little as three to five years. That is an enormous difference that carries paradigm-shifting and broadly hopeful implications for how people, especially young people, think and feel about the climate emergency and how societies can respond to it.

This revised science means that if humanity slashes emissions to zero, global temperatures will stop rising almost immediately. To be clear, this is not a get-out-of-jail free card. Global temperatures also will not fall if emissions go to zero, so the planet’s ice will keep melting and sea levels keep rising. But global temperatures will stop their relentless climb, buying humanity time to devise ways to deal with such unavoidable impacts. In short, we are not irrevocably doomed — or at least we don’t have to be, if we take bold, rapid action.

The science we’re referencing was included — but buried — in the U.N. Intergovernmental Panel on Climate Change’s most recent report, issued last August. Indeed, it was first featured in the IPCC’s landmark 2018 report, “Global Warming of 1.5 C. The 2018 report’s key finding — that global emissions must fall by 45 percent by 2030 to avoid catastrophic climate disruption — generated headlines about “12 Years To Save the Planet.” That 12-year timeline, and the related concept of a “carbon budget” — the amount of carbon that can be burned while still limiting temperature rise to 1.5 degrees C above preindustrial levels — were both rooted in this revised science. Meanwhile, the public and policy worlds have largely neglected the revised science that enabled these very estimates.

Nonscientists can reasonably ask: What made scientists change their minds? Why should we believe their new estimate of a 3 to 5 years lag time if their previous estimate of 30 to 40 years is now known to be incorrect? And does this mean that the world still must cut emissions in half by 2030 to avoid climate catastrophe?

The short answer to the last question is yes. Remember, temperatures only stop rising once global emissions fall to zero. Currently, emissions are not falling. Instead, humanity continues to pump approximately 36 billion tons of carbon dioxide a year into the atmosphere. The longer it takes to cut those 36 billion tons to zero, the more temperature rise humanity eventually will face. And as the IPCC’s 2018 report made hauntingly clear, pushing temperatures above 1.5 degrees C would cause unspeakable amounts of human suffering, economic loss and social breakdown — and perhaps trigger genuinely irreversible impacts.

Scientists changed their minds about how much warming is locked because additional research gave them a much better understanding of how the climate system works. Their initial 30- to 40-year estimates were based on relatively simple computer models that treated the concentration of carbon dioxide in the atmosphere as a “control knob” that determines temperature levels. The long lag in the warming impact is due to the oceans, which continue to warm long after the control knob is turned up. More recent climate models account for the more dynamic nature of carbon emissions. Yes, CO2 pushes temperatures higher, but carbon “sinks” including forests, and in particular the oceans, absorb almost half of the CO2 that is emitted, causing atmospheric CO2 levels to drop, offsetting the delayed warming effect.

Knowing that 30 more years of rising temperatures are not necessarily locked in can be a game changer for how people, governments and businesses respond to the climate crisis. Understanding that we can still save our civilization if we take strong, fast action can banish the psychological despair that paralyzes people and instead motivate them to get involved. Lifestyle changes can help, but that involvement must include political engagement. Slashing emissions in half by 2030 demands the fastest possible transition away from today’s fossil fueled economies in favor of wind, solar and other non-carbon alternatives. That can only happen if governments enact dramatically different policies. If citizens understand that things in fact aren’t hopeless, they can better push elected officials to make such changes.

3 Responses to “Michael Mann: Climate Change Still in Human Hands”

  1. indy222 Says:

    What is never said, by Mann or other happy talk people, is – “emissions” means both direct human emissions and the in-direct human-caused “natural” emissions from the rising wildfires, methane emissions from tropical and Arctic wetlands, soil warming, and the rest. Renewables are just another card in the energy deck, and Energy is Everything when it comes to the eternal never-questioned goal of policy and economics people…. GROWTH. So FF’s are going to decline only slowly at best, if they ever stop rising, that is. If demand drops from competition, so will prices and this will raise demand back upwards. We’ll continue always and forever to do what is most profitable and most short-term growth advantaged. But let’s assume somehow that we really do end all direct human emissions here (US is only 13% of annual global CO2 emissions), but across the whole world, how will we stop the indirect emissions caused already by existing temperatures, and the temperatures in the pipeline? A recent poll found that most climate scientists expect that global temperatures will rise +3C to +4C or more. That question did not ask if the scientists were to assume RCP 8.5, it merely asked what do you expect the world will actually deliver.

    That’s not extinction, but it could and likely will, tip society to a much more chaotic regime than anything we’ve seen before. Stanford studies show that +4C will cause the tropical countries (every country inside the tropics) to drop their annual GDP by about 70-85%, which sounds like collapse to me.

    • rhymeswithgoalie Says:

      I now see Mann’s interviews as a strategy to manage moods, but he still speaks in terms of whether it’s theoretically possible in the physical sense to stop the warming. Even without the ongoing positive feedbacks (lower Arctic albedo, increased wildfires from heat-stressed, emissions from thawing permafrost, etc.), he lives in a country where one of the major political parties is anti-science and pro-fossil fuels. They’re still digging.

  2. rhymeswithgoalie Says:

    Amy W. uses “doomerism” to mean “specific belief that all is lost and thus it’s time to stop trying to avert or lessen climate crisis and instead enjoy the last remaining years before chaos is upon us.” Who’s advocating to stop trying to lessen the climate crisis because it’s too late?

    My own version of “doomerism” (for want of a better term), is realizing that not only will a large number of people not inconvenience themselves to lessen their tiny contribution to the problem, but that powerful people that have made their money off of the fossil fuel industries will cut off the source of their wealth.

    That said, I’m a big fan of killing off the fossil fuel industry for a lot of reasons unrelated to the GHG properties of emissions: Extracting, refining, shipping and combusting fossil fuels is a nasty, nasty business. Even the portion that isn’t combusted and goes to making plastics has major downsides.

    I really like my EV. Getting rid of my gas appliances means I don’t need special vents through my roof to prevent toxic buildup of CO2 or CO, and my last gas bill had all sorts of safety warning about what to do if I smell gas. Less stinky SOx on city streets will be a breath of fresh air, too.

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