Originally published at http://www.commondreams.org/views/2020/10/07/60-minutes-guardian-and-game-changing-new-science
Glad I saw this. I have been telling people for a decade or more that, in Mann’s words, “There’s about as much scientific consensus about human-caused climate change as there is about gravity.” I’ve been saying it on the strength of a mere BA in Physics (and last in the class at that). I don’t know how long Mann has been putting it in those terms, but at least now I can quote somebody with clout.
Mann has said before, and he reiterated in The Guardian interview, that a second presidential term for Trump would be “game over” for the climate. That’s not Mann’s partisan judgement, he insisted. It’s straightforward math. To prevent a catastrophic rise in global temperature, humanity must cut emissions in half by 2030, Mann said, citing 2018’s landmark report by the UN’s Intergovernmental Panel on Climate Change. That will require a rate of change “unprecedented” in human history…
Ok. The obvious problem with this article’s argument is that the alternative to Trump, Biden, is nowhere near able and willing to lead a global change “unprecedented in human history.”
Aye, there’s the rub, and the reason that some number of otherwise intelligent and committed people will either once again vote Green or whatever or even decline to vote at all, as happened four years ago. We can only hope that (1) Biden somehow manages to win by a margin sufficient to overwhelm any challenges, and (2) he either changes his colors or has them changed for him with great weeping and gnashing of teeth.
But there is a third possibility: Under withering popular pressure from Sunrise, 350dotorg, Greenpeace, and other climate sanity organizations, Biden will have a road to Damascus experience and realize that he can barely serve as a figurehead. Unable to cover all the growing number of bases, he could reorganize the executive branch accordingly, acting as president but shuffling off all the heavy lifting to Harris and groups of advisors quite different from most of those with which his campaign began. Hey, in the unlikely event that he gets through the election intact almost anything is possible!
This would not be a replay of FDR’s “Brain Trust,” because FDR supplied the brain behind the brains. But with all the talent and determination of the people in those NGOs, and with a steady hand on the helm that Harris might be able to provide, it might work.
We can dream, can’t we?
What aspect of gravity? Because I’m sure there is a lot of consensus about equations like F = G * m1 * m2 / r^2 being an accurate description of the attracting force. And I’d imagine there are aspects to gravity like trying to come up with a theory to unify the 4 forces for which there is little consensus.
On the article, I’m lost. What does this mean?
Instead, if humans “stop emitting carbon right now … the oceans start to take up carbon more rapidly.” The actual lag effect between halting CO2 emissions and halting temperature rise, then, is not 25 to 30 years but, per Mann, “more like three to five years.”
How do oceans take up carbon more rapidly when we put up less carbon? Obviously the atmospheric level is reduced more rapidly if we stop putting carbon up there because there are paths from air to ocean and air to ground still going and we’ve reduced the amount going on the path from ground to air. But saying the ocean actually pulls more gigatons/yr (or whatever rate units atmospheric scientists use) from the atmosphere when there is less carbon in the atmosphere seems to violate the monotonic relationship I would have expected.
But that statement aside, the overall change in viewing how much climate change inertia there actually is by a factor of 10 (30 to 3 years) is a big change - is there any consensus on that? I can’t imagine.
@Trog, do you have time to comment?
Just my two cents: C02 is part of a cycle where the oceans don’t just absorb carbon but are also a source. Some parts of the ocean are C02 dependent.
Photosynthesis, Decomposition, Respiration and Combustion
Agreed. So are you thinking there is some form of system overload which breaks the monotonicity assumption? Say if plankton growth reacted badly to 400 ppm CO2 in the air, but when you hit 350 ppm it took off and so the net flow from air to ocean that year could be even more? I agree that this type of explanation doesn’t break physics and I wasn’t trying to imply what was said is impossible - I just want to understand the hypothesis for why some scientists think it’s true (or if it isn’t true and it was an editing mistake and only the rate of reduction of atmospheric CO2 going down faster was being commented on).
If I get some time, I’ll try to dig into to the source material and see what the claims are.
Oh goodness. I don’t really think in those terms but generally this indicates a disrupted cycle as well as C02 as a factor or possibly a monotonicity indication. I think it is important to see the complete cycle if possible.
To answer your question, I’ll refer you back to economagic as a better source.
The simile is Mann’s, although it seemed evident to me before I knew of him. My point, and presumably his, was simply that by the mid-aughts climate science and its findings w/r/t/ global warming were about as well established as Newton’s laws, though not to a similar order of magnitude for many reasons.
The comments about CO2 uptake by the ocean are also Mann’s. That is a little beyond my areas of expertise, but I think what he is quoted as saying assumes some prior knowledge of “the interaction among the Earth’s atmosphere, oceans, and other parts of the biosphere.” I don’t have much such knowledge, but I do know that the water-gas interface is a busy place. As the concentration of any of the several gases in the air increases relative to the others, more of it is taken up by the ocean as an effect of “vapor pressure.”
But the concentration of CO2 in the ocean is not static, as some processes tend to absorb or otherwise reduce it in an otherwise steady state while others tend to increase it. I think this is at least part of what Fern is trying to get at. The CO2 concentration in the ocean has been increasing for a couple of centuries due to the burning of fossil fuels, but at a decreasing rate as the ocean becomes more saturated.
But if we stop adding CO2 to the atmosphere, its concentration in the ocean begins to decline toward an earlier “equilibrium,” reversing the processes by which it was packed in, making “more room” for additional CO2 at the current (and declining) vapor pressure.
Now, don’t quote me: This is physical chemistry, which I have studied only slightly. But I think this is what Mann is saying, and that he is also saying that new research indicates that the processes that affect the concentration of CO2 in the ocean are significantly more rapid than previously thought.
Caveat: Assuming all of the above is essentially correct, it is the reason that it may still be possible to return to a path that will limit the rise of Mean Global Surface Temperature to 1.5 degree C above pre-industrial levels, which will require a reduction in atmospheric CO2 of 50% of its current level. Blow it this time (starting right now, following the Sunshine Movement, 350dotorg, Greenpeace, Extinction Rebellion, and others), and we’re boiled alive like the lobster.
It would have been a lot easier had we begun that process ten years ago, and a piece of cake had we responded when Hansen sounded the alarm in 1989. Now it is not just the politics we’re up against but the physics.
[Mann: “There’s about as much scientific consensus about human-caused climate change as there is about gravity.”]
What an unfortunate comparison. Mann should have stuck to a science area he has expertise in.
"What aspect of gravity? Because I’m sure there is a lot of consensus about equations like F = G * m1 * m2 / r^2 being an accurate description of the attracting force.
We don’t know what causes gravity or how it works. We don’t even know whether it should properly be classified as a force. Einstein thought it was not a true force but a relative or apparent force (like centrifugal “force”).
[Article: Instead, if humans “stop emitting carbon right now … the oceans start to take up carbon more rapidly.” The actual lag effect between halting CO2 emissions and halting temperature rise, then, is not 25 to 30 years but, per Mann, “more like three to five years.”]
“How do oceans take up carbon more rapidly when we put up less carbon? …saying the ocean actually pulls more gigatons/yr (or whatever rate units atmospheric scientists use) from the atmosphere when there is less carbon in the atmosphere seems to violate the monotonic relationship I would have expected.”
Yeah, there’s a lot of ambiguity in that claim. Some people look at the rate the oceans take up carbon as a percentage of our emissions, so on that basis, a steady rate by tonnage would be an increased proportional rate after emissions have halted. Some people also look at increases and decreases relative to projections (kind of like how a chained CPI would be an effective cut in Social Security benefits, even though the benefits would still increase in nominal dollars).
Be we already know that marine uptake of CO2 is not uniform (some areas do most of the absorbing, large areas do little absorbing, some areas actually release more CO2 than they absorb) and it may not even be monotonic over time. It’s definitely not monotonic on a regional scale. The annual tonnage absorption rate for the North Atlantic fell by half between 1994 and 2005, even though atmospheric CO2 levels in that region increased steadily (in terms of annual average) over the same period. This appears to have been due largely to changes in regional weather systems.
Overall, we are expecting the oceans to lose some of their capacity to absorb CO2. This is mostly due to increased surface temperatures and decreased surface salinity resulting in greater stratification of the ocean, and less exchange between deep and surface waters. The result is less organic carbon from the surface going deep, and less mineral upwelling needed for chemical sequestration at the surface. Even if we halted emissions now, 3 to 5 years is not enough time to reverse this process, but it might be enough time to detect a divergence relative to continuing with our emissions. And it might be possible to characterize that as the oceans taking up carbon more rapidly (relative to not halting emissions), even if the uptake rate is down in the sense of tons per year.
But in absolute tonnage per year, I can’t think of any effect that would necessarily increase the marine uptake of CO2 in only 3 to 5 years even if we did something as drastic as halt emissions immediately. For that to work, at a bare minimum, we should be seeing a monotonic decrease in the annual tonnage absorbed by the oceans corresponding to the monotonic rise in annual average CO2 levels in the atmosphere, and it isn’t at all clear that is what we are seeing.
If I understand you correctly, that means the oceans have a way to process CO2 and remove some of it from the point where it is being absorbed from the air. I suppose one mechanism like that is the formation of limestone where shells with CO2 sink to the ocean floor and get locked away from the surface. I don’t know if that is feasible at the time scales discussed to be significant, but at least I can think of a process now. Thanks. If I find any more detail on what hypotheses are being considered, I’ll let you know.
I believe you and @Trog and I are all in agreement that it would have been better to have started attacking this much earlier - I remember hearing about it I think in1988 or 89 from people at NCAR in Boulder. That point would have been nice to have serious discussions on a net neutral CO2 economy in 30 years (which would be now). And to the extent that many other environmental problems were understood in decades prior, I wish more action had been taken on those problems too. But here we are now and in this case (and not in Obama’s argument on GWB and torture or other war crimes where a deterrent is needed), I do prefer to look forward and not backward.
The surface waters have become more saturated. Anthropogenic CO2 has increased the overall marine supply of CO2 by slightly more than 1% (adding roughly 500 gigatonnes carbon to the 39,000 GtC already there). If we could redistribute the CO2 in the oceans, they could easily absorb all of the carbon we have released with only a minor shift in overall chemistry.
I have a long day ahead and will get back to you and Trog this evening. Remember, I am merely quoting Mann and trying to interpret what he is saying, to answer the questions you raise. I am not a scientist, much less a climate scientist (BA Physics, probably last in my class). Mann IS a climate scientist, one of our most accomplished, also with an A.B. in Physics (and applied math) plus four other degrees in various aspects of Physics. I am quoting him second-hand from a brief article on a website for J. Q. Public written by a journalist who specializes in climate change! For the actual science one would have to read his paper.
“I believe you and @Trog and I are all in agreement that it would have been better to have started attacking this much earlier - I remember hearing about it I think in1988 or 89 from people at NCAR in Boulder.”
I believe you are one hundred percent correct!
Well, sort of. The “process” (actually processes) by which CO2 is removed from the ocean are complex, but a simple example is that plants do indeed remove CO2 from the air, storing it ultimately in the soil. Once the pressure of atmospheric CO2 on the ocean surface stops increasing, it begins decreasing as plants (et al.) continue to take up that gas from the atmosphere. As the pressure of CO2 in the air decreases, the pressure in the ocean must do the same. Some probably escapes into the air (one of the many factors I don’t know), and some is probably taken up by marine flora, and other factors which had been under increasing pressure also release some. There is a very complex and ever-changing equilibrium between the CO2 in the air and that in the ocean. I avoid the term “pressure” because what little I once knew about vapor pressure and partial pressures is gone. But the end result is that the level of that equilibrium decreases with time as long as new CO2 is not added to the system.
Unlike most of the previously unaccounted-for processes that the scientists have included into their models as they became understood, this one SLOWS the temperature rise, giving us at least a little “breathing room” (pun intended), BUT ONLY IF WE REDUCE THE ADDITION OF CO2 TO THE ATMOSPHERE ASAP.
So we are left with the same two basic challenges, but with maybe a little more time: Persuading the policymakers (politicians mostly) to shut down fossil fuels ASAP, and simultaneously to ramp up non-carbon energy sources and make them available more equitably.
But we knew that.
To whatever degree his claim might have had merit in some proportional or relativistic sense, everything I’ve seen indicates it is wrong in terms of tonnage absorbed per year. This quote from an article in Oceanographic magazine seems relevant:
“The authors of the study have predicted that, as a result of the lessening global fuel consumption due to the COVID-19 pandemic, the ocean will not continue its recent historic pattern of absorbing more carbon dioxide each year than the year before. They note that it could even take up less in 2020 than in 2019.”