“Shipping lanes (top image) and lightning strikes (bottom)
near the Port of Singapore. image: Chris Wright”
SHIPPING EMMISIONS and LIGHTNING
https://acp.copernicus.org/articles/25/2937/2025/
https://theconversation.com/world-regulated-sulfur-in-ship-fuels-and-the-lightning-stopped
The world regulated sulfur in ship fuels − and the lightning stopped
by Chris Wright / March 11, 2025
“If you look at a map of lightning near the Port of Singapore, you’ll notice an odd streak of intense lightning activity right over the busiest shipping lane in the world. As it turns out, the lightning really is responding to the ships, or rather the tiny particles they emit. Using data from a global lightning detection network, my colleagues and I have been studying how exhaust plumes from ships are associated with an increase in the frequency of lightning. For decades, ship emissions steadily rose as increasing global trade drove higher ship traffic. Then, in 2020, new international regulations cut ships’ sulfur emissions by 77%.
Our newly published research shows how lightning over shipping lanes dropped by half almost overnight after the regulations went into effect. That unplanned experiment demonstrates how thunderstorms, which can be 10 miles tall, are sensitive to the emission of particles that are smaller than a grain of sand. The responsiveness of lightning to human pollution helps us get closer to understanding a long-standing mystery: To what extent, if any, have human emissions influenced thunderstorms? Aerosol particles, also known as particulate matter, are everywhere.
Some are kicked up by wind or produced from biological sources, such as tropical and boreal forests. Others are generated by human industrial activity, such as transportation, agricultural burning and manufacturing. It’s hard to imagine, but in a single liter of air – about the size of a water bottle – there are tens of thousands of tiny suspended clusters of liquid or solid. In a polluted city, there can be millions of particles per liter, mostly invisible to the naked eye. These particles are a key ingredient in cloud formation. They serve as seeds, or nuclei, for water vapor to condense into cloud droplets.
“Water molecules condense around nuclei to form clouds. David Babb/Penn State“
The more aerosol particles, the more cloud droplets. In shallow clouds, such as the puffy-looking cumulus clouds you might see on a sunny day, having more seeds has the effect of making the cloud brighter, because the increase in droplet surface area scatters more light. In storm clouds, however, those additional droplets freeze into ice crystals, making the effects of aerosol particles on storms tricky to pin down. The freezing of cloud droplets releases latent heat and causes ice to splinter. That freezing, combined with the powerful thermodynamic instabilities that generate storms, produces a system that is very chaotic, making it difficult to isolate how any one factor is influencing them.
We can’t generate a thunderstorm in the lab. However, we can study the accidental experiment taking place in the busiest shipping corridor in the world. With engines that are often three stories tall and burn viscous fuel oil, ships traveling into and out of ports emit copious quantities of soot and sulfur particles. The shipping lanes near the Port of Singapore are the most highly trafficked in the world – roughly 20% of the world’s bunkering oil, used by ships, is purchased there. In order to limit toxicity to people near ports, the International Maritime Organization – a United Nations agency that oversees shipping rules and security – began regulating sulfur emissions in 2020. At the Port of Singapore, the sales of high-sulfur fuel plummeted, from nearly 100% of ship fuel before the regulation to 25% after, replaced by low-sulfur fuels.
But what do shipping emissions have to do with lightning? Scientists have proposed a number of hypotheses to explain the correlation between lightning and pollution, all of which revolve around the crux of electrifying a cloud: collisions between snowflake-like ice crystals and denser chunks of ice. When the charged, lightweight ice crystals are lofted as the denser ice falls, the cloud becomes a giant capacitor, building electrical energy as the ice crystals bump past each other. Eventually, that capacitor discharges, and out shoots a lightning bolt, five times hotter than the surface of the Sun.
We think that, somehow, the aerosol particles from the ships’ smokestacks are generating more ice crystals or more frequent collisions in the clouds. In our latest study, my colleagues and I describe how lightning over the shipping lane fell by about 50% after 2020. There were no other factors, such as El Niño influences or changes in thunderstorm frequency, that could explain the sudden drop in lightning activity. We concluded that the lightning activity had fallen because of the regulation. The reduction of sulfur in ship fuels meant fewer seeds for water droplet condensation and, as a result, fewer charging collisions between ice crystals. Ultimately, there have been fewer storms that are sufficiently electrified to produce a lightning stroke.”
OCEAN ACIDIFICATION
https://science.org/doi/10.1126/sciadv.ado3103
https://newscientist.com/ocean-acidification-is-reaching-deeper-waters/
Ocean acidification is reaching deeper waters
by James Dinneen / 27 November 2024
“Ocean acidification is sinking into marine regions as deep as 1500 metres, posing new threats to organisms like sea butterflies, sea snails and cold-water corals. The ocean is the largest natural sink of carbon dioxide, absorbing about a quarter of our annual emissions. That uptake of CO2 makes the ocean’s surface more acidic, with consequences for sensitive ecosystems like coral reefs.
But until now, researchers did not know the extent to which acidification was reaching deeper waters. Jens Daniel Müller at the Federal Institute of Technology Zurich in Switzerland and his colleagues developed a 3D reconstruction of how CO2 moves through the ocean, based on global measurements of currents and other circulation patterns. They used this model to estimate how the carbon dioxide the oceans have absorbed since 1800, around the start of the industrial revolution, has affected deep-water acidity.
They found a clear acidification signal down to 1000 metres in most of the ocean. Some areas, such as the North Atlantic – where the powerful Atlantic meridional overturning current (AMOC) carries carbon from the surface to deeper waters – saw acidification down to 1500 metres. Some pockets of deeper water that are naturally more acidic saw even more acidification than the surface. Their higher original acidity reduces their capacity to absorb any added CO2, says Müller.
This is more or less what researchers expected would happen as the ocean takes up more CO2, says Hongjie Wang at the University of Rhode Island. “But it’s a different thing to really see the data coming in to affirm this.” Notably, about half of all the acidification since 1800 occurred after 1994, as our emissions of CO2 have risen exponentially. “We see this rather rapid progression,” says Müller. The magnitude of the acidification is enough to threaten the survival of organisms in large areas of the ocean.
Pteropods like sea snails and sea butterflies are at particular risk because they build their shells out of calcium, which dissolves if the water gets too acidic. The rise in acidification has also doubled the areas where cold-water corals will have trouble surviving. And ocean acidification is set to continue as the water absorbs more CO2. “Even if we were able to stop CO2 emissions immediately, we would still – for a couple of hundred of years or so – see a process of ocean acidification in the interior,” says Müller.”
TERMINATION SHOCK
http://pubs.acs.org/doi/full/10.1021/es901944r
https://geos.ed.ac.uk/~dstevens/publications/eyring_ae09.pdf
https://technologyreview.com/reason-to-never-halt-geoengineering-project-midway-through/
https://technologyreview.com/massive-accidental-experiment-in-halting-global-warming/
We’re about to kill a massive, accidental experiment in reducing global warming
by James Temple / January 22, 2018
“Studies have found that ships have a net cooling effect on the planet, despite belching out nearly a billion tons of carbon dioxide each year. That’s almost entirely because they also emit sulfur, which can scatter sunlight in the atmosphere and form or thicken clouds that reflect it away. In effect, the shipping industry has been carrying out an unintentional experiment in climate engineering for more than a century. Global mean temperatures could be as much as 0.25 ˚C lower than they would otherwise have been, based on the mean “forcing effect” calculated by a 2009 study that pulled together other findings (see “The Growing Case for Geoengineering”). For a world struggling to keep temperatures from rising more than 2 ˚C, that’s a big helping hand. And we’re about to take it away. In 2016, the UN’s International Maritime Organization announced that by 2020, international shipping vessels will have to significantly cut sulfur pollution.
Specifically, ship owners must switch to fuels with no more than 0.5 percent sulfur content, down from the current 3.5 percent, or install exhaust cleaning systems that achieve the same reduction, Shell noted in a brochure for customers. There are very good reasons to cut sulfur: it contributes to both ozone depletion and acid rain, and it can cause or exacerbate respiratory problems. But as a 2009 paper in Environmental Science & Technology noted, limiting sulfur emissions is a double-edged sword. “Given these reductions, shipping will, relative to present-day impacts, impart a ‘double warming’ effect: one from [carbon dioxide], and one from the reduction of [sulfur dioxide],” wrote the authors. “Therefore, after some decades the net climate effect of shipping will shift from cooling to warming.”
Sulfur pollution from coal burning has a similar effect. Some studies suggest that China’s surge in coal consumption over the last decade partly offset the recent global warming trend (though coal does have a strong net warming effect). It’s difficult to estimate how much the new rule could affect temperatures. We don’t know enough about cloud physics and the behavior of atmospheric particles, nor how diligently the shipping industry will comply with the new rule, says Robert Wood, a professor of atmospheric sciences at the University of Washington.
Another wrinkle is that ships emit other particles that can sometimes also stimulate cloud droplets to form, including black carbon, a major component of soot. Removing the sulfur from the fuel could alter the size and quantity of these particles, which could affect clouds as well, says Lynn Russell, a professor of atmospheric science at the Scripps Institution of Oceanography. “So we can’t really say exactly what the change will be,” says Russell, though she adds that the rule change is “likely” to produce a warming effect on balance.
The upcoming change does offer a different way of thinking about intentional efforts to cool the climate, known as geoengineering, according to some proponents of research in this area. Rather than some radical experiment, deliberate geoengineering could instead be seen as a way of continuing to do what we’ve been doing inadvertently with ships, but in a safer way. Sulfur emissions cool the planet in two ways, directly and indirectly. The direct way is that when sulfur dioxide is further oxidized in the atmosphere, it can form particles that reflect sunlight back into space. This happens in large volcanic eruptions, which can release tens of millions of tons of sulfur dioxide.
The indirect way is that sulfur particles can also act as nuclei around which cloud droplets form. Clouds, too, reflect more sunlight. You can see this in satellite images, which show lines of white clouds above the ocean along busy shipping lanes. Geoengineering researchers have explored both processes, but with less toxic particles, as potential ways to alter the climate (see “Scientists Consider Brighter Clouds to Preserve the Great Barrier Reef”).
For instance, researchers with the Marine Cloud Brightening Project, centered at the University of Washington, have spent years studying the possibility of spraying tiny salt particles into the sky along coastlines to induce cloud droplets to form. The group has spent the last few years attempting to raise several million dollars to build the sort of sprayers that would be needed, in the hopes of carrying out small-scale field experiments somewhere along the Pacific coastline.
Both Russell and Wood said the upcoming rule change could also offer a chance to conduct some basic climate science by observing the interactions between airborne particles and clouds. Those insights could make climate simulations more accurate—how clouds behave is one of the least understood parts of the system, Wood says—as well as informing the debate about whether and how to carry out geoengineering. But that all depends on whether scientists can get funding for such research, which will require more frequent satellite observations and surface sensors.
Ideally, the research should start before the new rule goes into effect to ensure an accurate picture of how things change. “We’re approaching dangerous thresholds of temperature increases, so an additional bump of 0.1 or 0.2 degrees is something that we as a civilization should be watching really, really closely,” says Kelly Wanser, principal director with the Marine Cloud Brightening Project. Whether the money will be available is less clear. Certain nations have been increasing funding levels for climate research. But it’s become far more difficult to secure such grants in the United States under the Trump administration, which specifically sought to cut NASA programs that monitor clouds and airborne particles.”
“Global emissions of SO2 from shipping prior to IMO regulations limiting sulphur content
of marine fuel (left) and the pattern of natural dimethyl sulphide (DMS) emissions (right)”
MARINE CLOUD BRIGHTENING
http://doi.org/10.1029/2024gl109077
http://doi.org/10.1073/pnas.2206885119
https://science.org/doi/10.1126/sciadv.abn7988
https://carbonbrief.org/how-low-sulphur-shipping-rules-are-affecting-global-warming/
https://news.mongabay.com/shipping-emissions-marine-cloud-geoengineering
Shipping emissions reduction sheds light on marine cloud geoengineering
by Claire Asher / November 13, 2024
“For many years, the North Atlantic Ocean warmed more slowly than other parts of the world. In 2023, that changed — dramatically. Over the last year and a half, North Atlantic sea surface temperatures surged, with record-breaking heat extending roughly from Greenland south to the Caribbean, bleaching corals there, while whipping up violent European storms and fueling U.S. hurricanes like Helene and Milton. The underlying cause of this regionalized heating is undoubtedly greenhouse gas emissions. But while global emissions have been increasingly steadily, the climate has shown an abrupt and dramatic acceleration of warming over the North Atlantic. Many in the scientific community were taken by surprise by the rapid uptick in temperatures there.
“With satellite data and artificial intelligence, scientists identified ship tracks
across 17 years of daytime images (2003-2020)”
After months of analysis, researchers now see several possible factors at play, including climate change and the unusually strong El Niño event that began in June 2023. Another, more controversial explanation for the unprecedented North Atlantic warming seen over the past two years is that it is being driven by a change in shipping regulations, which reduced emissions of a harmful aerosol pollutant into the atmosphere. This hypothesis hinges on the basic science of how clouds form. Water vapor in the atmosphere can’t form cloud droplets on its own — it needs a tiny particle, or aerosol, to condense around, such as a speck of dust, a grain of sea salt, or a pollutant. Sulfur dioxide emissions from commercial shipping used to create lots of sulfate aerosols, which could seed low-lying, highly reflective clouds, creating long strings of cloud known as “ship tracks” over the ocean. These low marine clouds reflected solar radiation back into space, helping cool the Earth’s climate. This cooling effect was greatest in regions with more shipping.
https://svs.gsfc.nasa.gov/3667
“Aerosol emissions from shipping can seed low-lying, highly reflective clouds, known as “ship tracks.” These low marine clouds help to cool the Earth’s climate by reflecting solar radiation back into space”
The current hypothesis: Human-manipulated marine clouds caused by aerosol pollution have helped mask approximately a third of the warming that would have otherwise been caused by greenhouse gas emissions globally. But starting several years ago, those cooling aerosols largely disappeared. As global shipping has boomed, so has its contribution to atmospheric aerosol pollution — around 13% of global sulfur dioxide emissions come from shipping. These aerosol pollutants pose a risk to human health, prompting national and international legislation to curb them. First, emissions control zones were introduced in U.S. and European coastal areas.
“Ship tracks fell significantly in 2020, due to new fuel regulations
and the COVID-19 pandemic, according to a new NASA study.”
Then, in 2020, the International Maritime Organization (IMO) established new regulations reducing the maximum allowable sulfur dioxide emissions from ship fuel by 80%. The impact of this dramatic reduction in shipping emissions on marine clouds was felt quickly. Soon after the new IMO regulations came into effect in January 2020, scientists measured a 25% decrease in the number of ship tracks planetwide. The basic science tells us that fewer marine clouds means less solar energy reflected back into space, and more planet warming. But exactly how much warming this one regulation is responsible for, and where, is still being hotly debated.
With just a few years of data available for analysis, “we are searching for the proverbial needle in a haystack,” says Graham Feingold, a research scientist at the chemical laboratory of the U.S. National Oceanic and Atmospheric Administration (NOAA). This is because “the [warming] signal is small compared to very large variability in the cloud brightness dictated largely by meteorological conditions.” Several analyses, each using slightly different methods — including computer modeling, satellite imagery, meteorological data and artificial intelligence — have converged on a global estimate of about 0.1 watts per square meter of warming caused by the 2020 IMO shipping emissions regulations. This is equivalent to roughly 3% of the total global warming effect being driven by greenhouse gases. That’s “a tiny bit of added warming,” says Earth scientist Andrew Gettelman at the Pacific Northwest National Laboratory.
“Global SO2 emissions from international shipping from the global aerosol dataset (CEDS) (1970-2019). Estimates thereafter by Leon Simons based on projected effects of low-sulphur fuel regulations introduced in 2020. Chart by Zeke Hausfather for Carbon Brief, using Highcharts“
But crucially, that 3% effect was not uniformly distributed across the Earth’s surface. Most of the world’s major shipping corridors are in the Global North, so the warming effect from reduced emissions of ship-based sulfur dioxide has been felt most acutely there. “The effect is small globally, but it’s concentrated over the Northern Hemisphere,” says Gettelman. He led a recent study that estimated the global and regional effect of sulfur dioxide emissions reductions by comparing the results of computer models that simulated the change in emissions with climate and cloud distribution data from 2022 and 2023. They found that the unprecedented marine heat waves in those years occurred in regions with major shipping routes — where emissions reductions due to cleaner ship fuel would have had the greatest impact. Although there was very little change in cloud cover over the Southern Hemisphere, the team did detect a change in that half of the world along one major shipping route, just off the coast of West Africa. “There’s no reason that should have happened, except if shipping emissions were a cause of the cloud changes,” Gettelman explains. However, shipping emissions remain only one part of a complex story: The aerosol reductions explain about 10-20% of the warming experienced in the Northern Hemisphere in recent years, scientists told Mongabay. The rest is due to a combination of greenhouse gas emissions, El Niño, and natural variability.
“Sea surface temperatures over the North Atlantic have soared over the past two years, driven by a combination of greenhouse gases in the atmosphere, reduced shipping sulfur dioxide emissions, El Niño, and natural variability in the climate”
Although the effect of reduced sulfur dioxide emissions on marine clouds was noticeable almost immediately, the impact on global climate lagged behind. Gettelman estimates that by the end of 2023, Earth had experienced roughly half of the total unmasked warming that we can expect as a result of the 2020 regulatory change. This lagged effect occurs because “it takes time for the ocean to warm in response to suddenly putting more sunlight on it, because it has a lot of thermal inertia,” he explains. This “unmasking” is likely to level off in about 10 years, says aerosol and climate scientist Michael Diamond, from Florida State University. After that, “it’s just permanent at that level. Which is very different from something like CO2 emissions, [which are] rising year over year,” he says. Experts expect unmasked warming due to reductions in shipping sulfur dioxide emissions to add somewhere between 0.05 and 0.1° Celsius (0.09-0.18° Fahrenheit) to the average global temperature by 2030, with more of that warming being felt in the Northern Hemisphere.
“The world’s major shipping corridors are concentrated in the Global North, so the warming effect from shipping sulfur dioxide emissions reductions has been greatest there. A recent analysis estimated that the Northern Hemisphere has 30 times the warming effect as a result of the 2020 IMO regulation change, compared to the Southern Hemisphere.” Image by B.S. Halpern (T. Hengl; D. Groll)
The recent abrupt reduction in shipping sulfur dioxide emissions offers the clearest test to date of a controversial geoengineering approach known as marine cloud brightening (MCB), which seeks to cool the planet by spraying aerosols like sea salt into the lower atmosphere to seed the kind of low marine clouds that humans have been inadvertently seeding with sulfur dioxide emissions since the dawn of globalization. “The first thing that has to happen for marine cloud brightening to be viable as a cooling technology is you have to get the cloud property changes that you would expect,” Diamond says. The abrupt change to marine clouds detected after 2020, “is really clear evidence that we have some leverage on the system.” However, global-scale warming resulting from the IMO regulatory change has proven hard to detect, suggesting that any attempts at MCB would need to be implemented at a much larger scale to make a noticeable contribution to much-needed global warming mitigation.
“Global daily sea surface temperature (SST) between 60S and 60N from NOAA’s OISST dataset for each year since 1981. The current year is shown in black
But it’s not clear that the cooling effect inadvertently produced via shipping emissions could be scaled up to make MCB a workable strategy. “There’s only certain regions where clouds are susceptible” to cloud-brightening efforts, Gettelman explains. Unlike carbon dioxide, aerosols have a very short lifespan in the atmosphere — they remain there only for a few days before they are brought back to Earth by rain. This means that decreases in aerosol emissions can have a much more rapid climate impact than decreases in carbon emissions. It also means that for an MCB project to work, aerosols would need to be released almost continuously and sustained over the long term to avoid dangerous termination shocks — sudden temperature surges bringing on disruptive climate effects.
Even if MCB could be implemented effectively, critics have highlighted numerous potential issues. Not least of which is the lack of a clear regulatory framework or system of international governance for a technology that would have global effects. The highly regional impact of marine clouds also underscores another major geoengineering concern: Because oceans are not evenly distributed across the planet, the cooling effect of MCB deployment would also be unevenly distributed. One recent study estimated that the Northern Hemisphere has experienced 0.32 watts per square meter of warming as a result of the 2020 IMO shipping emissions regulation, compared to just 0.1 watts per square meter in the Southern Hemisphere.
“Global emissions of SO2 from shipping prior to IMO regulations limiting sulphur content of marine fuel (left) and the pattern of natural dimethyl sulphide (DMS) emissions (right)”
Experts warn that creating or exacerbating temperature disparities between the northern and southern hemispheres could have serious effects on regional rainfall patterns. For example, seeding clouds in the southeast Atlantic Ocean could lead to hotter drier conditions in the Amazon Rainforest — which could in turn push the already hotter, drier Amazon past a tipping point, causing rainforest die-off and massive CO2 releases. “Focusing seeding efforts in specific areas … may generate changes in regional circulation patterns, with unintended consequences,” warns Feingold, who adds: “the potential for ‘winners’ and ‘losers’ is of great concern.” Early in 2024, African nations proposed a solar geoengineering non-use agreement precisely because of the risk of such Global North vs. Global South inequities.
“Global mean temperature change from the FaIR model simulating the effects of a reduction in SO2 emissions equivalent to 8.5MtSO2 per year after 2020, relative to the SSP2-4.5 scenario across 66 different CMIP6 models. The solid line shows the average of all model runs, while the shaded area shows the 5th to 95th percentile range. Chart by Zeke Hausfather for Carbon Brief.”
Perhaps the clearest lesson from recent shipping emissions reductions is that, if we initiate marine cloud brightening at a scale large enough to make a real dent in climate warming, then we would probably be locked in to that strategy for years or decades. Any sudden unexpected end during this hypothetical future MCB project — caused by war, civil unrest, natural disaster, political turnover, or economic downturn, for example — could trigger a termination shock that causes more harm than the climate warming the geoengineering averted. “The disruptiveness of that termination shock is going to be totally dependent on how much cooling you’re doing,” Diamond says. If humanity was offsetting a great deal of warming caused by carbon emissions through deliberate marine cloud brightening, then suddenly stopped, the effects would be much more immediate and noticeable. However, if you reduced MCB gradually “in a planned way, you wouldn’t necessarily have a termination shock” but more of a “glide path back to where you would have been before” without MCB mitigation, explains Diamond.
Aerosol emissions reductions are already built in to climate models, including the Shared Socioeconomic Pathway (SSP) scenarios used by the Intergovernmental Panel on Climate Change (IPCC) to project future climate change. However, most climate models anticipate a more gradual decrease in aerosol emissions than those just accomplished by the IMO regulations. The dramatic shipping emissions reductions since 2020 are part of a larger-scale gradual trend of cutting aerosol emissions, which began more than 30 years ago. What makes recent events different is the speed of the change, which appear to have accelerated global warming in the Northern Hemisphere.
The sulfur dioxide pollution reductions resulting from the 2020 IMO regulations “have provided us with a very interesting ‘natural experiment’ to explore the unmasking of greenhouse gas warming,” says Feingold. The basic science of how aerosols, clouds and climate interact at small scales are well understood, but the complex dynamics of how these interactions might play out over longer time periods and across large expanses of atmosphere is still an active area of research. “Translating what we have learned at these smaller scales up to the scales that are relevant to [global] climate projections remains significantly more challenging,” says Feingold “An enormous challenge is … to develop climate projections based on models and observations at the full range of atmospheric scales.”
Sulfur dioxide emissions globally are currently masking between 20 and 40% of human-caused warming, Gettelman says. That’s 0.3-0.6°C (0.5-0.1.1°F) of masked warming. So the more sulfur dioxide emissions we cut, the more aerosol cooling we lose, and the more rapidly the planet will warm. But the uncertainty created by that large 20-40% range matters a great deal. If the actual masking effect is at the higher end of this estimate, “it means the termination shock [will be] larger” if big sulfate reductions are accomplished. Natural experiments, like the one resulting from the IMO shipping sulfur dioxide cuts, can help scientists improve their models of aerosol-cloud interactions and refine estimates of the amount of warming we can expect to be unmasked as aerosol emissions drop. By looking “at these unintended experiments … we can try to validate our models against the large scale,” says Gettelman.
“Inadvertent natural experiments like the 2020 IMO shipping sulfur dioxide regulations can help scientists improve their models of aerosol-cloud interactions and refine their estimates of how much warming we can expect to be unmasked as aerosol emissions drop, or if marine cloud brightening geoengineering is deployed and then abruptly terminated in the future.”
Some argue that making deep aerosol cuts — which will unmask some of the warming caused by greenhouse gas emissions, unleashing more intense and numerous extreme weather events — is a good reason to abandon attempts to cut health-harming air pollution. But Diamond says this is the wrong way to look at the situation: Rather than viewing air pollution and climate change emissions cuts as two opposing priorities, humanity should understand them as mutually dependent co-benefits. Put simply, to avoid the danger of increased atmospheric instability, we must act decisively to lower CO2 emissions, methane emissions and aerosol emissions in unison. “If we want to avoid more of this kind of ‘termination shock’ as we reduce air pollution, that means coupling it with decarbonization,” Diamond says.
Citations:
Watson-Parris, D., Christensen, M. W., Laurenson, A., Clewley, D., Gryspeerdt, E., & Stier, P. (2022). Shipping regulations lead to large reduction in cloud perturbations. Proceedings of the National Academy of Sciences, 119(41). doi:10.1073/pnas.2206885119
Zhang, J., Chen, Y., Gryspeerdt, E., Yamaguchi, T., & Feingold, G. (2024). Large radiative forcing from the 2020 shipping fuel regulation is hard to detect. doi:10.21203/rs.3.rs-4552523/v1
Gettelman, A., Christensen, M. W., Diamond, M. S., Gryspeerdt, E., Manshausen, P., Stier, P., … Yuan, T. (2024). Has reducing ship emissions brought forward global warming? Geophysical Research Letters, 51(15). doi:10.1029/2024gl109077
Yuan, T., Song, H., Oreopoulos, L., Wood, R., Bian, H., Breen, K., … Platnick, S. (2024). Abrupt reduction in shipping emission as an inadvertent geoengineering termination shock produces substantial radiative warming. Communications Earth & Environment, 5(1). doi:10.1038/s43247-024-01442-3
PREVIOUSLY
LIGHTNING CONTROL
https://spectrevision.net/2023/02/14/lightning-control/
CLIMATE INTERVENTIONS
https://spectrevision.net/2022/12/29/climate-interventions/
UNNATURAL SELECTION
https://spectrevision.net/2013/05/24/unnatural-selection/