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Comment by k__ | Hacker News Reader

"Europe's rapid warming is partly the result of [...] a drop in the number of tiny polluting particles in the air. This means that less of the Sun's energy is reflected back into space, leaving more energy to heat the Earth's surface."

Hmmm...

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This is a fairly well-known phenomenon, and sometimes comes up in geoengineering discussions. It’s dangerous ground; thing about fine particulate matter is you generally don’t want to breathe it.

Ideally we would want a fine particulate that stays high in the atmosphere, and doesn't come down where we need to breathe

Fine particulates aren't a problem if you wear a gas mask though.

Yay.

This is now quite well-studied because we have had two periods in our own lifetimes (OK I guess maybe not in the lifetimes of some HN readers!), where we have cut air pollution radically almost overnight. 9/11 and the COVID pandemic transport shutdown.

In both cases, the pan evaporation rate went up; in the case of 9/11 it went up very noticeably in a short period of time.

Essentially: clean air == less "global dimming". Whether any really recent changes like the increasingly successful rollout of electric cars is yet having an effect, I don't know.

Yeah, another example is when the Internation Maritime Organization reduced the legal sulfur content limit in shipping fuel.

This reduced SO2 emissions by about 80%, which improved human health, but also caused an increase in short-term atmospheric warming.

The full quote is

> Europe's rapid warming is partly the result of the melting of bright snow and ice, and a drop in the number of tiny polluting particles in the air.

That first one is kind of important and it seems intentionally misleading to omit it

Revs the coal-rolling truck's engine. "Once and for all."

"But ..."

Revs the engine again. "ONCE AND FOR ALL!"

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