Ship trails in the North Pacific cool our climate through the oldest climate pollution treatment (geoengineering) strategy humans have been practicing for 150 years. Image: NASA.
By Bruce Melton PE / The Rag Blog / May 27, 2026
Summary: Geonegineering is not as it seems to our current climate culture. Geoengineering is the bad things we have done to Mother Earth by burning fossil fuels and clearing half of the world’s forests. Geoengineering in our current climate culture should actually be called climate pollution treatment, because what we need to do to cool our climate is not a bad thing.
~ ~ ~
Most Earth systems are now degrading from the effects of human-caused warming. Tropical, high altitude, and boreal forests, permafrost, ice sheets, sea ice, ocean currents, and corals are now degrading and most of these have begun to emit millennia of stored carbon as greenhouse gases because of this degradation. The damage to these systems does not stop, ever, unless the thing that caused the degradation to begin is removed. Eliminating human-caused greenhouse gas emissions from fossil fuels, and from land use and abuse, and creating net zero climate pollution emissions (greenhouse gases) tomorrow morning — only — reduces future warming, it does nothing to remove the warming effects from current warming and past emissions that have accumulated in our sky, that have caused our Earth systems to begin to degrade. This degradation must be separated from other human-caused degradation forces. It is entirely from warming effects related to heat and drought, and very important: If the warming effects are not removed by about mid-century for most of our systems that are currently in degradation, the damages to those systems and ecologies will become so profound that even if the warming effects are removed, the system would not be able to stabilize and recover.
This is climate tipping, or climate tipping elements responses. It is now active because of three decades of failure to limit greenhouse gas emissions, and it is irreversible with existential outcomes if our climate is not restored, or cooled from today, back to within the evolutionary boundaries our Earth systems before these collapse become irreversible. This is why we have to ungineer our world from the effects of excess climate pollution emitted by humans, so that we can have the time to remove the excess greenhouse gases from our atmosphere that have cause the degradation to begin, so that we then have time to create a sustainable fossil fuel and greenhouse gas emissions culture, so we and our children can be safe.
What is this un-engineering, this ungineering? Most call it geoengineering, which it is not. This is a pretty bold statement considering the breadth of thought today, on exactly what geoengineering is:
Intergovernmental Panel on Climate Change – Geoengineering refers to a broad set of methods and technologies that aim to deliberately alter the climate system in order to alleviate the impacts of climate change.
EPA – Geoengineering encompasses a broad range of activities, including those that intentionally attempt to cool the Earth or remove certain gases from the atmosphere.
Royal Society – Geoengineering proposals aim to intervene in the climate system by deliberately modifying the Earth’s energy balance to reduce increases of temperature and eventually stabilize temperature at a lower level than would otherwise be attained.
Center for International Environmental Law – Geoengineering refers to large or planetary-scale interventions in the Earth’s atmosphere, oceans, and soils with the intention of counteracting only some of the effects of climate change.
So why the bold statement that geoengineering is not the deliberate manipulation of our climate systems to mitigate for the effects of human-caused greenhouse gas pollution? Let’s look at a few other discussions of geoengineering:
Collins – Geoengineering is the use of scientific processes to improve the environment, especially to stop the Earth becoming any hotter.
Environmental Justice – Geoengineering is the intentional, large-scale technological manipulation of the Earth’s systems.
Los Alamos Labs – tells us about the new possibilities of terraforming Mars with advances in geoengineering.
The Journal Science – An article form August 2024, Terraforming Mars could be easier than scientists thought, talks about planetary-scale engineering on Mars.
The Institute for Climate and Sustainable Growth at the University of Chicago, in an article published in The Economist – talks about injecting vast quantities of greenhouse gases into the Martian atmosphere to create a human-habitable planet.
“If we want to talk about the craziest-sounding ideas dreamt up by mad scientists with disheveled hair and demented glints in their eyes, geoengineering would admirably fit the bill. This is the stuff that pulpy science fiction is made of, when horrible accidents engineered by technology-obsessed scientists cast humanity into eternal doom. Yet, geoengineering is now seriously being considered by top scientists and policy makers. It also has a long history that is permeated by some of the most brilliant minds of the twentieth century. Science fiction it may sound like, but it’s being treated as serious science by serious people. Some have predicted that the issue of geoengineering will be catapulted in a few years into one of the most visible public debates of our times, regularly bandied about in the mainstream media. It will become a topic rich with scientific, political, social and moral dilemmas.” This passage is from The Lindau Nobel Laureate Meetings, established in 1951, where 30 to 40 Nobel Laureates meet in Lindau, Germany, with up to 600 aspiring undergrads, graduate students, and PhD candidates, so as to inspire the next generation of scientists every year.
Nobel Laureate Paul Crutzen frequented the Lindau Laureate Meetings. He was awarded the Nobel Prize in Chemistry in 1995 for discovery of the mechanisms that deplete stratospheric Ozone. In 2006 in the journal Climatic Change, Crutzen published, Albedo Enhancement by Stratospheric Sulfur Injections: A Contribution to Resolve a Policy Dilemma? https://link.springer.com/article/10.1007/s10584-006-9101-y#preview This essay was not the first on “geo-engineering,” as Crutzen wrote the term, but because of his Nobel status, it brought attention to the most dominant concept of geoengineering today of stratospheric aerosol injection. This concept is the same as happens with volcanoes and curiously, with the burning of fossil fuels. When naturally occurring sulfur in fossil fuels is burned, or released from volcanic eruptions, it produces sulfate aerosols similar to smoke, only they reflect sunlight rather than absorb it.
Sulfur emissions created “global dimming,” and literally caused China to begin regulating air pollution in a serious way because of the Beijing Olympics in 2008. Volcanic eruptions have been demonstrated to cool our atmosphere by at least a half degree C, enough to create years without summer in northern latitudes. The aerosols created from burning fossil fuels are also one of the main components of air pollution that today, account for 7 to 8 million deaths per year from respiratory disease. In the U.S. and Western Europe in the 1960s, this air pollution became so bad that laws were enacted (The Clean Air Act in the U.S.) that limited sulfur in fossil fuels. The curiosity part though, is that the reflection of sunlight by sulfate aerosols cools our climate, in direct contradiction to the global warming gases emitted by burning the same fossil fuels.
The cooling from sulfate aerosols is almost exactly half of the warming from excess carbon dioxide emitted by humans from fossil fuels and land use and abuse, and a third of total warming from all warming forcings including methane, N2O, refrigerants, water vapor, and ozone. Using sulfate aerosols to cool Earth then, is something humans have been doing since we began burning fossil fuels, or volcanoes have been doing since the beginning of time. Because of the negative side effects of sulfates, the West’s began regulating sulfur in fossil fuels generations ago, and this is now being repeated by China and India in quantities far larger than what was done in the West. We can treat a lot of warming by temporarily relaxing sulfur regulations, but Injecting sulfur into the stratosphere comes with a distinct advantage over that at near land elevations. Pound for pound, only about 2 percent of the sulfur emitted near the Earth’s surface, would create similar cooling if injected into the stratosphere, virtually eliminating side effects of respiratory disease and others like acid rain and ocean acidification. The reason is simple. Sunlight has a much shorter path reflected out of our atmosphere if reflected very high, where if reflected very low, it can be scattered by other aerosols on the way back into space, keeping it here on Earth where it can cause warming.
There is even a shovel ready sulfur aerosol injection strategy that could be implemented immediately and would cool our climate by at least 0.2 degrees C. This would be the temporary reversal of new International Maritime Organization’s new sulfur limits on ship fuels. These aerosols enhance ships’ trails, similar to condensation trails from jet aircraft only at very low altitudes just above the sea surface from ships’ stacks. These reflective aerosols create brighter clouds and enhance formation of clouds in ships trails shown in the cover image to this article. These then reflect more light harmlessly back into space, instead of allowing that light to hit the ocean where it is absorbed creating warming that can be trapped by the greenhouse effect.
Up to 90 percent of sunlight is reflected by bright-white clouds, versus up to 90 percent absorbed by the dark ocean. The difference between ships’ air pollution and that over land from autos and energy generation from fossil fuels is that at very low altitudes, the aerosols drop out of the atmosphere from gravity or rainfall in a few days, where in the stratosphere they can last a few years. This has a great advantages: the air pollution from ships is mostly gone by the time it reaches land. By shifting to low sulfur fuels 200 miles from land, the advantage is enhanced further. This type of “geoengineering” btw, is called marine cloud brightening and, is it really geoengineering?
Our current climate culture is bent on believing that geoengineering is bad, or it has a distinct possibility of being bad because of its supposedly unknown attributes. It is believed to be novel, never before tried, and full of unanticipated side effects that could cause harm. It is believed that much research is needed to identify these shortcomings and understand the side effects. Observation of this so-called geoengineering however, shows that yes, there are risks. These risks are truly unknown with many niche geoengineering strategies like space umbrellas, but risks are known with sulfur aerosols. Up to 8 million people are killed every year from respiratory disease caused by low altitude sulfur air pollution. But what are the risks of not using these strategies to cool our climate?
In the introduction to this article, it is clear that little time remains to restore our climate back to within the evolutionary boundaries of our degrading Earth systems before they become so degraded they cannot stabilize and collapse or tip irreversibly. Emissions reductions have proved impossible so far, because over the last 35 years of trying to reduce them, the concentration of carbon dioxide in our atmosphere has instead doubled, not been reduced. The warming from this failure to reduce emissions is now responsible for these climate tipping activations of Earth systems degradation, that if allowed to complete and become irreversible, risk the re-emissions stored carbon (greenhouse gases) of more than ten times all the greenhouse gases that humans have ever emitted.
Atmospheric removal of greenhouse gases accumulated in our sky is the only way to reduce the warming effects in time frames that matter to climate tipping, and there is a significant risk that this time is too long to prevent the completion of Earth systems collapses. Because greenhouse gas emissions elimination only limits further warming, there is a risk that if we do not use strategies to rapidly and temporarily cool our atmosphere, the systems our advanced human civilization relies upon for its existence could fail. We therefore have a responsibility to the future of humankind to do something to treat this heat pollution that we have created that threatens the existence of our Earth systems and their dependent subsystems like humanity. So, what then are we afraid of?
“Geoengineering” is a compound word derived from the Greek prefix geo- (from gē or gaia), meaning “Earth,“ and engineering, from the American Council of Engineering Companies, “Engineering is the art of the possible. It’s applying skill and creative thinking to solving the world’s biggest challenges. It’s seeing what isn’t so and finding ways to make it so.”
Geoengineering, as defined by many, is the manipulation of our bio- and geosphere that is widely believed to be bad. If bad is defined by risk, geoengineering then, is obviously the burning of fossil fuels and release of greenhouse gases and the destruction of half of Earth’s forests, that has created the bad outcome of global warming that now threatens humanity because of the imminent failure of many of Earth’s systems.
What if we looked at our climate problem as one of a pollution problem? After all, global warming gases are emitted just like any other air pollution, and the sulfur pollution emitted right alongside of carbon dioxide from burning fossil fuels has been widely regulated since the 1970s. What if this was (and is) actually a pollution problem? Our culture has been treating pollution for thousands of years. What if we could simply treat the global warming pollution? Of course we can, and the treatment is the same concept as the oldest pollution treatment known to humans. This strategy is dispersion, or more commonly, dilution. Remember, “the solution to pollution is dilution?” This is dispersion. Atmospheric dispersion is a very important process in regulating air quality. Tall stacks releasing pollutants high above the ground were the predominant form dispersion or dilution “treatment” until the late 1970s. Fenceline monitoring receptors allow pollution emissions from processes today, if they are diluted enough at the fenceline to meet regulatory requirements.
Dilution of human wastewater is almost certainly the oldest pollution treatment strategy known, perfected by Romans, by diluting their human sewage in streams that pass through Roman cities. Today we call this, “Combined sewers.” Over 700 combined sewer discharges, where human waste and stormwater runoff are mixed to dilute the sewage, are still in use in the U.S. today.
Atmospheric cooling, or treatment of heat pollution, uses the oldest pollution treatment strategy in the world of dilution. It is the same concept that electrical generation facilities and industry use to treat their excess heat pollution in cooling towers, reservoirs, lakes, and oceans.
Now the concepts are reversed. Geoengineering is obviously the bad thing we have done to Mother Earth via the burning of fossil fuels, agriculture and land abuses. This geoengineering has not only caused global warming that has now created irreversibly existential outcomes unless we restore our climate rapidly, but it has vastly reduced the fertility of Earth’s soils and oceans, making artificial fertilizers mandatory for the continuance of the human civilization. Hundreds of thousands of species have been driven to extinction because of humans, and a million, or half that remain, are at risk of extinction. These things have been caused by humans geoengineering our planet. It has been caused by the pollution that we have created, or the forests we have cut, or the land we have raped, or the oceans we have fouled and overfished. This is geoengineering.
Pollution treatment is what must be done to forestall the inevitable Earth systems collapses so that we have time to remove the excess climate pollution from our atmosphere, and so that we have time to create a truly sustainable fossil fuels culture. Pollution treatment is what humans do to achieve the goals we have, to create the things we need; then we understand that we must treat that pollution do we can be safe because, we need those things, or we need to achieve those goals. Pollution treatment is what has allowed our culture to take advantage of fossil fuels to grow from 1 billion to 8 billion souls.
Aerosol cooling is pollution treatment. It is dilution, pure and simple. Aerosols reflect light back into space before it can create heat. It is the dilution of heat pollution, like the oldest pollution treatment strategy known to humans.
We know exactly how many people sulfur aerosols kill every year, and we know how to reduce the effects of sulfur aerosols pollution. We also know that our Earth systems will collapse by mid-century, and we know that without the Earth systems that our advanced human culture evolved with, the human race itself is at risk, just like any other systems whose evolutionary boundary conditions have been exceeded.
We need to rethink the way we think about pollution treatment and geoengineering. Pollution treatment is good; geoengineering is the nasty things we have done to this planet that now require we treat the climate pollution we have been emitting for over 200 years.
~ ~ ~
Nobel Laureate Paul Crutzen frequented the Lindau Laureate Meetings. He was awarded the Nobel Prize in Chemistry in 1995 for discovery of the mechanisms that deplete stratospheric Ozone. In 2006 in the journal Climatic Change, Crutzen published, Albedo Enhancement by Stratospheric Sulfur Injections: A Contribution to Resolve a Policy Dilemma? https://link.springer.com/article/10.1007/s10584-006-9101-y#preview This essay was not the first on “geo-engineering,” as Crutzen wrote the term, but because of his Nobel status, it brought attention to the most dominant concept of geoengineering today of stratospheric aerosol injection. This concept is the same as happens with volcanoes and curiously, with the burning of fossil fuels. When naturally occurring sulfur in fossil fuels is burned, or released from volcanic eruptions, it produces sulfate aerosols similar to smoke, only they reflect sunlight rather than absorb it.
Sulfur emissions created “global dimming,” and literally caused China to begin regulating air pollution in a serious way because of the Beijing Olympics in 2008. Volcanic eruptions have been demonstrated to cool our atmosphere by at least a half degree C, enough to create years without summer in northern latitudes. The aerosols created from burning fossil fuels are also one of the main components of air pollution that today, account for 7 to 8 million deaths per year from respiratory disease. In the U.S. and Western Europe in the 1960s, this air pollution became so bad that laws were enacted (The Clean Air Act in the U.S.) that limited sulfur in fossil fuels. The curiosity part though, is that the reflection of sunlight by sulfate aerosols cools our climate, in direct contradiction to the global warming gases emitted by burning the same fossil fuels.
The cooling from sulfate aerosols is almost exactly half of the warming from excess carbon dioxide emitted by humans from fossil fuels and land use and abuse, and a third of total warming from all warming forcings including methane, N2O, refrigerants, water vapor, and ozone. Using sulfate aerosols to cool Earth then, is something humans have been doing since we began burning fossil fuels, or volcanoes have been doing since the beginning of time. Because of the negative side effects of sulfates, the West’s began regulating sulfur in fossil fuels generations ago, and this is now being repeated by China and India in quantities far larger than what was done in the West. We can treat a lot of warming by temporarily relaxing sulfur regulations, but Injecting sulfur into the stratosphere comes with a distinct advantage over that at near land elevations. Pound for pound, only about 2 percent of the sulfur emitted near the Earth’s surface, would create similar cooling if injected into the stratosphere, virtually eliminating side effects of respiratory disease and others like acid rain and ocean acidification. The reason is simple. Sunlight has a much shorter path reflected out of our atmosphere if reflected very high, where if reflected very low, it can be scattered by other aerosols on the way back into space, keeping it here on Earth where it can cause warming.
There is even a shovel ready sulfur aerosol injection strategy that could be implemented immediately and would cool our climate by at least 0.2 degrees C. This would be the temporary reversal of new International Maritime Organization’s new sulfur limits on ship fuels. These aerosols enhance ships’ trails, similar to condensation trails from jet aircraft only at very low altitudes just above the sea surface from ships’ stacks. These reflective aerosols create brighter clouds and enhance formation of clouds in ships trails shown in the cover image to this article. These then reflect more light harmlessly back into space, instead of allowing that light to hit the ocean where it is absorbed creating warming that can be trapped by the greenhouse effect.
Up to 90 percent of sunlight is reflected by bright-white clouds, versus up to 90 percent absorbed by the dark ocean. The difference between ships’ air pollution and that over land from autos and energy generation from fossil fuels is that at very low altitudes, the aerosols drop out of the atmosphere from gravity or rainfall in a few days, where in the stratosphere they can last a few years. This has a great advantages: the air pollution from ships is mostly gone by the time it reaches land. By shifting to low sulfur fuels 200 miles from land, the advantage is enhanced further. This type of “geoengineering” btw, is called marine cloud brightening and, is it really geoengineering?
Our current climate culture is bent on believing that geoengineering is bad, or it has a distinct possibility of being bad because of its supposedly unknown attributes. It is believed to be novel, never before tried, and full of unanticipated side effects that could cause harm. It is believed that much research is needed to identify these shortcomings and understand the side effects. Observation of this so-called geoengineering however, shows that yes, there are risks. These risks are truly unknown with many niche geoengineering strategies like space umbrellas, but risks are known with sulfur aerosols. Up to 8 million people are killed every year from respiratory disease caused by low altitude sulfur air pollution. But what are the risks of not using these strategies to cool our climate?
In the introduction to this article, it is clear that little time remains to restore our climate back to within the evolutionary boundaries of our degrading Earth systems before they become so degraded they cannot stabilize and collapse or tip irreversibly. Emissions reductions have proved impossible so far, because over the last 35 years of trying to reduce them, the concentration of carbon dioxide in our atmosphere has instead doubled, not been reduced. The warming from this failure to reduce emissions is now responsible for these climate tipping activations of Earth systems degradation, that if allowed to complete and become irreversible, risk the re-emissions stored carbon (greenhouse gases,) of more than ten times all the greenhouse gases that humans have ever emitted.
Atmospheric removal of greenhouse gases accumulated in our sky is the only way to reduce the warming effects in time frames that matter to climate tipping, and there is a significant risk that this time is too long to prevent the completion of Earth systems collapses. Because greenhouse gas emissions elimination only limits further warming, there is a risk that if we do not use strategies to rapidly and temporarily cool our atmosphere, the systems our advanced human civilization relies upon for its existence could fail. We therefore have a responsibility to the future of humankind to do something to treat this heat pollution that we have created that threatens the existence of our Earth systems and their dependent subsystems like humanity. So, what then are we afraid of?
“Geoengineering” is a compound word derived from the Greek prefix geo- (from gē or gaia), meaning “Earth,“ and engineering, from the American Council of Engineering Companies, “Engineering is the art of the possible. It’s applying skill and creative thinking to solving the world’s biggest challenges. It’s seeing what isn’t so and finding ways to make it so.”
Geoengineering, as defined by many, is the manipulation of our bio- and geosphere that is widely believed to be bad. If bad is defined by risk, geoengineering then, is obviously the burning of fossil fuels and release of greenhouse gases and the destruction of half of Earth’s forests, that has created the bad outcome of global warming that now threatens humanity because of the imminent failure of many of Earth’s systems.
What if we looked at our climate problem as one of a pollution problem? After all, global warming gases are emitted just like any other air pollution, and the sulfur pollution emitted right alongside of carbon dioxide from burning fossil fuels has been widely regulated since the 1970s. What if this was (and is) actually a pollution problem? Our culture has been treating pollution for thousands of years. What if we could simply treat the global warming pollution? Of course we can, and the treatment is the same concept as the oldest pollution treatment known to humans. This strategy is dispersion, or more commonly, dilution. Remember, “the solution to pollution is dilution”? This is dispersion. Atmospheric dispersion is a very important process in regulating air quality. Tall stacks releasing pollutants high above the ground were the predominant form dispersion or dilution “treatment” until the late 1970s. Fenceline monitoring receptors allow pollution emissions from processes today, if they are diluted enough at the fenceline to meet regulatory requirements.
Dilution of human wastewater is almost certainly the oldest pollution treatment strategy known, perfected by Romans, by diluting their human sewage in streams that pass through Roman cities. Today we call this, “Combined sewers.” Over 700 combined sewer discharges, where human waste and stormwater runoff are mixed to dilute the sewage, are still in use in the U.S. today.
Atmospheric cooling, or treatment of heat pollution, uses the oldest pollution treatment strategy in the world of dilution. It is the same concept that electrical generation facilities and industry use to treat their excess heat pollution in cooling towers, reservoirs, lakes, and oceans.
Now the concepts are reversed. Geoengineering is obviously the bad thing we have done to Mother Earth via the burning of fossil fuels, agriculture and land abuses. This geoengineering has not only caused global warming that has now created irreversibly existential outcomes unless we restore our climate rapidly, but it has vastly reduced the fertility of Earth’s soils and oceans, making artificial fertilizers mandatory for the continuance of the human civilization. Hundreds of thousands of species have been driven to extinction because of humans, and a million, or half that remain, are at risk of extinction. These things have been caused by humans geoengineering our planet. It has been caused by the pollution that we have created, or the forests we have cut, or the land we have raped, or the oceans we have fouled and overfished. This is geoengineering.
Pollution treatment is what must be done to forestall the inevitable Earth systems collapses so that we have time to remove the excess climate pollution from our atmosphere, and so that we have time to create a truly sustainable fossil fuels culture. Pollution treatment is what humans do to achieve the goals we have, to create the things we need; then we understand that we must treat that pollution do we can be safe because, we need those things, or we need to achieve those goals. Pollution treatment is what has allowed our culture to take advantage of fossil fuels to grow from 1 billion to 8 billion souls.
Aerosol cooling is pollution treatment. It is dilution, pure and simple. Aerosols reflect light back into space before it can create heat. It is the dilution of heat pollution, like the oldest pollution treatment strategy known to humans.
We know exactly how many people sulfur aerosols kill every year, and we know how to reduce the effects of sulfur aerosols pollution. We also know that our Earth systems will collapse by mid-century, and we know that without the Earth systems that our advanced human culture evolved with, the human race itself is at risk, just like any other systems whose evolutionary boundary conditions have been exceeded.
We need to rethink the way we think about pollution treatment and geoengineering. Pollution treatment is good; geoengineering is the nasty things we have done to this planet that now require we treat the climate pollution we have been emitting for over 200 years.
Bruce Melton PE
Climate Change Now Initiative, 501C3
ClimateDiscovery.org
ClimateChangePhoto.org
HealthyPlanetAction.org
