Air pollution from coal-fired power plants has negative externalities, damaging human health.  Carbon emissions from these power plants contribute to global warming.  A recent article in The Economist discusses the recent acceleration in global warming, and suggests that the twin goals of a cleaner air and a cooler planet may be in conflict:

Evidence against different culprits comes from work published recently in Science. Helge Goessling and his colleagues at the Alfred Wegener Institute in Bremerhaven used satellite data and weather records to show that over the course of this century Earth has gradually been reflecting less sunlight back into space than it used to. 2023 was the dimmest year to date. This was apparently due to paucity of cloud cover, particularly in the northern mid latitudes.

Part of this could be down to the new IMO rules [reducing ship engine emissions], but the dimming is too strong to be explained by that alone. Bjorn Samset of CICERO, a Norwegian climate research institute, points to another possibility: the lack of sulphate emissions is not a result of cleaner ships, but of cleaner Chinese coal-fired power plants. Since 2014 China has been making progress in reducing sulphur emissions by closing particularly noxious power plants and scrubbing sulphur out of the flue gases at others. New data leads Dr Samset and colleagues to think the cleanup is having a marked effect across the North Pacific, where cleaner air and fewer clouds will mean more warming.

This graph shows the recent acceleration in warming:

Some have proposed using “geoengineering” to address global warming.  A recent article in The Guardian lists three options:

Stratospheric aerosol injection:

Airplanes release tiny aerosol particles that reflect light back into space.

Cirrus cloud thinning:

The least understood method, seeding thin cirrus clouds in the upper troposphere with ice nuclei could reduce their lifespan and increase cooling. 

Marine cloud brightening: 

Boats release aerosol particles that increase the reflectivity of low clouds.

There are substantial political challenges with any geoengineering project.  Some countries might gain while other lose, especially if rainfall patterns were affected.  Nonetheless, I suspect that geoengineering will be tried at some point in the future, as the world seems to be giving up on the objective preventing global warming by restricting the emission of greenhouse gases.

Keep in mind that we are already doing “geoengineering” in the sense of artificially changing the world’s climate.  The debate is whether we should try to do so in a constructive fashion, rather than a destructive fashion.

PS.  I’ve always been a moderate on the global warming issue, about half way between the doomsters and those who dismiss the problem as a myth.