2023 planetary heat uptake from termination shock of inadvertent geoengineering?
nature.com
nature.com
The conclusions of this paper are being disputed. Read more about that at the page linked above.
For balance: Nature (the journal) does have a high bar for entry.. but also a high number of retractions...
1. Nature really does value getting studies correct, and thus is probably even more stringent about retractions. They will retract studies for smaller problems than other journals. So, high bar of entry, and also highly focused on vetting any challenges that would cause a retraction.
2. There are anti-climate change groups that challenge everything. So just some random link to someone challenging this, doesn't immediately make me doubt it. The trust in Nature is high enough that the challenger must be pretty good, not just saying "well this model looks too simplistic too me, thus it is false".
> The amount of radiative forcing could lead to a doubling (or more) of the warming rate in the 2020 s compared with the rate since 1980 with strong spatiotemporal heterogeneity. The warming effect is consistent with the recent observed strong warming in 2023 and expected to make the 2020 s anomalously warm. The forcing is equivalent in magnitude to 80% of the measured increase in planetary heat uptake since 2020.
Truly, all bets are off for being able to predict the climate going forward
Deliberately adding such aerosols to the upper atmosphere (where they're less harmful than ground-level pollution), which volcanic eruptions already do, is one of a few major geoengineering proposals to counteract climate change.
[1] https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6...
https://ntrs.nasa.gov/api/citations/20220015136/downloads/Yu...
The same ze of the cooling has long been uncertain though. It depends a lot on assumptions you make about the pre-industrial atmosphere,something that we don't have great observations of.
Sulfur in the atmosphere causes acid rain. We can deliberately seed clouds much less damagingly than by encouraging sulphur emissions.
The warming rate they quote (0.24K per decade) is the instantaneous warming, which decreases over time. The warming over 10 years is actually about half of this (0.12K). While still significant, it's not a doubling of the warming rate (which is around 0.19K per decade).
The forcing being equal to 80% of the heatuptake is also interesting, but we have not seen such a large step change in energy imbalance in the Earth system. This doesn't mean they are wrong about the forcing estimate, but it does not mean that 80% of the warming since 2020 has been due to ship fuel regulations either.
am i parsing this correctly?
But Sulfur might be a solution if we can loft it into the upper atmosphere and bypass where the acid rain forms. - subject of book Termination Shock proposed this.
It's honestly scary howany people think that this is reasonable; I'd be horrified if it wasn't so damn human.
Lets say a few more decades go by, we make no progress on 'non-awful' options.
Then suddenly we get a summer where a few 10k's or millions die, and suddenly politicians/public are like 'wow, guess this is real after all, lets do something. Guess we can start spreading sulfur around pretty quickly'.
Wouldn't be surprised if this happens, and then we over-compensate and create an ice age.
Go read the abstract and the introduction. Highly recommended!
What do you propose?
The potential heating effect from reducing atmospheric aerosols was predictable and was a foreseen consequence of this regulation that was considered at the time.
But it’s important to remember that this is a “one time bump” to global heating, not cumulative like GHG emissions. In the overall context of global heating it’s pretty insignificant in the longer term.
That's not entirely accurate. Short lived climate pollutants (SLCPs) that are being continuously emitted (e.g. SO4, NOx, contrail-cirrus) have cumulative effects. The heat trapped on earth is cumulative with a long equilibration time constant, and SO4 (not just from ships) has wiped out a huge fraction of the warming up to now.
(disclaimer that I manage a climate research group)
There is heat being continually trapped by the SLCP, which analogous to a one-time (large) release of CO2. The earth will warm up in response, and will keep absorbing heat from the SLCP as long as the pollutant is being emitted.
As we heat up, though, we'll radiate more heat back into space (blackbody) leading to a new equilibrium temperature (the trapped flux and outgoing flux are now both larger, but balanced).
If you think about it as heat, it's cumulative. If you think about it as temperature, it'll effectively lead to a ~fixed bump (not quite a fixed one-time bump, as the effects are not linear, but one can think of it that way).
This is one question I have regarding stratospheric sulfide injection. What goes up must come down right? What are the population wide effects of having higher concentrations of sulfide in the atmosphere?
The doubling of the rate of warming only applies for the first year or two. Based on this paper, over the period 2020-2030, the impact of ship fuel regulations is warming of about 0.12K. The long term temperature trend is around +0.19K over this 10 year period.
The problem remains in large parts of Asia, where sulfur emissions have continued rising. These emission caps are necessary. They may make climate change a more urgent problem, but that's not a valid excuse to repeal the caps.
So we could seed the upper atmosphere by shooting rockets into it (as in book Termination Shock), and thus bypass the layer where the sulfur was being added by pollution and causing acid rain.
The emissions were seeding reflective white clouds that were offsetting up to half the temperature increase that would have occurred without them. Now all that warming is happening at full strength.
Great topic, why bury it in verbosity?
Surface water slightly warmer
...
Damn humans
I acknowledge that the phrase “put it back” is doing a lot of heavy lifting here. There is no ctrl+z for the fuel manufacturing processes that were changed to accommodate the sulfur ban, but this is such a recent change that there is still an enormous amount of direct subject matter expertise available for a crash-restart. Course correction here, now provides runway for the future.
The industrial capacity of worldwide maritime shipping already exists _and_ is already internationally regulated. There is no other “safer” alternative that could be implemented as quickly, or with less risk.
But the point is the same: we only transitioned recently, so going back is a known quantity - and now we know exactly how it will impact the worldwide climate. Do any other current geoengineering projects have a directly tangible blueprint?
I believe there’s a solution where ships just spray sea water into the atmosphere.
Put the sulfur back in now so we have a few additional years to mobilize a safer replacement.
Akin to saying "You pulled the knife out of my torso, and now I'm bleeding more! Put it back!"
Putting it back will certainly cause more harm than just leaving it out.
A better analogy would be having some infection that's somehow preventing a cancer from metastasis - you treat the infection and now you see the cancer spike. Worth risking reinfection to slow down cancer ? Depends on how bad the infection/cancer is I guess.
Global warming and sulphur pollution are two separate (but realated) problems - it's possible that by making one worse you make the other better - and then it's a cost/benefit calculation.
Eg. chemotherapy is destroying a lot of your body - but it also kills cancer.
Sure. But I'd argue the case is being made for active cloud seeding. Versus random seeding with commercial vessels with sulphur.
Restoring sulphur in ship fuel would sap the mainline argument of a lot of strength. If the ships can have their sulphur back, why not every industry their [insert ask]. It won't be scientifically valid. But it would win a decade of inaction.
Leaving the knife in hurts like hell, but maybe it’ll kill you slow enough that you’ll be able to find help before you die.
Pulling out the knife seems right but just means you bleed out quickly.
I don’t know why you assume I’m failing to understand that. I’m saying it’s already happened, so here we are.
This would be incredibly idiotic for so many reasons. You’d be condemning millions of people to suffering with crippling respiratory diseases, and harming countless aquatic and coastal ecosystems. All for a relatively modest gain against global heating.
Check the last page - https://sustmob.org/PCFV/GlobalSulphurStatus_Progress2006-20...