After the Mount Pinatubo volcano erupted in 1991, the earth cooled by half a degree Celsius for the next two years.

Our audience
typically understands climate science. This section is for anyone who may not be in that category.
Unfortunately, the message to "Keep 1.5 Alive!"
is no longer a reasonable hope. Some scientists feel convinced that we are currently passing that mark. Others run the numbers differently, and feel that we are not quite there yet. But no one we know actually believes it is still possible to limit warming to 1.5 degrees. (Nature Geoscience) In fact, few we know believe we can even limit it to 2.5.
Emissions reductions and decarbonization
have proven to be hard. Energy, agriculture, buildings, and all sectors of the economy are involved. The COVID pandemic taught many of us an especially hard lesson - that even shutting down the entire world only reduced emissions by 7%.
What’s worse is that emissions reductions will not cool the planet.
It will only stop the warming from getting worse. And eliminating emissions by getting to “Net Zero” seems an elusive dream in a world in which global emissions continue to rise, year after year.
There are bright spots.
Someday, there will be breakthroughs on clean energy production, which will allow us to run enormous carbon dioxide removal systems at true scale. And today, methane scientists have two new satellites tracking one of the most dangerous greenhouse gasses (See EDF). Others are working on removing methane from the sky - efficiently and at scale (See Spark). And many more are working on mind-bogglingly creative ideas for removing carbon dioxide from the air and oceans (See Carbon to Sea) in meaningful quantities on timelines that matter.
Our community, more than most, is especially encouraging of all of these alternative solutions. And we are especially aware that solar geoengineering will never solve ocean acidification.
But, in the meantime, it seems the time has come for us to at least understand solar geoengineering.