Atmospheric CO2 is currently well above 400 ppm (horizontal dotted line; right scale). This chart, going back to the Cambrian Period, shows how unusual the current situation is. The last time CO2 was greater than 400 ppm was when the Indian subcontinent slammed into Asia from the south (note the rise and fall in CO2 around 50 million years ago). What we're doing to the atmosphere in two years took tens of million years last time. The dark red path on the far right, labeled "RCP8.5," is the path we're on today, thanks to billionaire control of our political system. (Chart from "Past and Future CO2" at Skeptical Science.)by Gaius PubliusThis is the second in a short series on the new IPCC report, "Global Warming of 1.5°C." I want to reiterate a single point here, one that's been made before in this space, but one that's easily missed.That point: We're already far closer to global warming of +1.5°C "above the pre-industrial baseline" than most are acknowledging. The reason is simple; most people, including the scientists at the IPCC, set the pre-industrial baseline too high, which obscures how much global warming humans have already caused. Of course, in the world we are experiencing quite a lot of global warming and its effects, regardless of what the numbers say, but it's the numbers that drive conversations in the halls of power, not the world outside, where people without power reside. Positioning those numbers lower allows the current generation of policymakers to take their time — and continue to take fossil fuel money from the donor class as they do it. (More on that below.)1.5°C Global Warming Is Almost Upon UsTo see how close we are to 1.5°C global warming, let's look at this interview at the Real News Network with Dr. Michael Mann, one of the most prominent voices in the climate science community. Dr. Mann had argued in 2015 that pre-industrial global warming can be observed to start around 1800 (thanks to the Watt steam engine of 1781), far earlier than the baseline year, roughly 1870, assigned to it by the IPCC. In Dr. Mann's words, "It is evident that ... roughly 0.2C warming [had already taken place] by 1870," the implied IPCC baseline.Dr. Mann concludes from this, "We exceeded 1C warming more than a decade ago." Here are a few selections from the RNN interview. First, a reaffirmation of how close we already are to global warming of +1.5°C (emphasis mine throughout):
DHARNA NOOR: You mentioned that you thought that these IPCC scientists might have been too conservative in their estimates. And in coverage of this report of this IPCC report several outlets — the New York Times, Business Insider — are saying that we’re on track to reach 1.5 degrees by 2040, not 2030. So we’re seeing even more conservative estimates from the coverage of the report than is in the report itself. Can you talk about this a little bit?MICHAEL MANN: Yeah. I think it’s sort of a bad game of telephone where, you know, parts of the report have been translated for the purpose of the summary for policymakers [he's being polite; more on that here]. And then there are press releases that have been sent out. And there’s been a lot of nuance that has been lost in translation, as it were. I also pointed out that the IPCC made a number of extremely conservative- I would argue overly conservative- decisions in how they measure the warming that has already happened. And by doing that they underestimate how close we are to these 1.5 degree Celsius and 2 degrees Celsius thresholds. And they overestimate how much carbon we have left to burn.If you look, for example, at the Northern Hemisphere, which is where most of us live, and you ask the question when do we cross the 2 degree warming — 2 degree Celsius warming — threshold for the Northern Hemisphere if we continue with business as usual burning of fossil fuels? I showed in an article several years ago in Scientific American [here] we cross that threshold before 2040, in the late 2030s. So we are on the way, on our way to blowing past the 1.5 degree Celsius mark and crossing the 2 degrees Celsius threshold in a matter of, you know, depending on how you define it, it really doesn’t matter. Is it two decades, is it three decades, it hardly matters.
He thinks we'll "blow past" warming of +2 degrees in the 2030s, which means that warming of +1.5 degrees is ... very close indeed. About the Paris agreement and the various national emissions targets:
MICHAEL MANN: ... [T]he Paris agreement alone doesn’t stabilise warming below those dangerous levels of warming, below 2 degrees Celsius. There are credible estimates that have been done that if you tally up all of the commitments under the Paris accord- and keep in mind that many countries, including Europe and the U.S., are not quite meeting their targets at this point- but assuming every country meets its target, that only gets us halfway from where we would be headed, which would be towards 4 to 5 degrees Celsius warming of the planet; a catastrophic warming of the planet by the end of the century. The Paris agreement only gets us halfway down to the 2 degrees Celsius mark, and nowhere near that 1.5 degrees Celsius mark.
And finally, Dr. Mann's prescription for success in this fight:
The reality is that there is still time to reduce our emissions by the amount necessary to avert the worst impacts of climate change, but not if we continue to vote in climate change deniers and fuel lobbyists like we have in the form of the current administration and the congressional Republicans who are enabling their agenda.
From this he pivots to the current elections and the need to vote out Republicans.What Form Should Political Action Take? This leads to a second point: Dr. Mann is right that there's time to reduce emissions "by the amount necessary to avert the worst impacts" of global warming. Note: he said "the worst impacts," not all impacts.But even by conservative IPCC estimates, the rate of reduction must be greater than the rate at which we've been proceeding under both political parties. As Dharna Noor puts it, according to the IPCC report "we must reduce global emissions by 45 per cent from 2010 levels by 2030, and altogether by 2050." Which means — and I think this is more than obvious, though rarely said — we'll have to remove from power any political leader dedicated to keeping the current financial-energy system in place if there's to be any hope of even Dr. Mann's modest goal of averting "the worst impacts." Otherwise, we won't avert any impacts at all.This does, in fact, require a kind of revolution — in its mildest form, the kind of revolution that a WWII-style demand-directed economy represents. Achieving that degree of change is not an impossible job, by the way, just an improbable one. The key to an orderly revolution of this type will be the 2020 presidential primary in the Democratic Party. To understand why, ask yourself this: What would the U.S. be doing about climate change today if Bernie Sanders, no fan of rule by "the billionaires," were in the White House?Sanders was sincere about the threat of global warming. Had he governed like he spoke, the result would have been revolutionary. GP