Another way to reduce worldwide temperatures is to release pyroclastic dust (fine glass dust particles) into the atmosphere to reduce heat from the sun

Though this is also feasible there are drawbacks to doing this.

For example, the pyroclastic dust from Iceland volcanoes helped create the French Revolution and the Guillotine when the common people who were French started starving to death because of reduced farm yields caused by the pyroclastic dust from erupting Iceland Volcanoes crossing France on prevailing winds at that time.

However, it is one way to reduce heat from the sun but as you can see it also can reduce farm yields as well.

Also, another problem would be that you would have to have United Nations agreements between nations for doing this because pyroclastic clouds of dust would circle the whole planet (sort of like smoke and ash does from fires and volcanic eruptions now).

I can remember when the Mt. St. Helens eruption took place around 1980 I was building my A-Frame home in Mt. Shasta area then for my family and it reduced the temperatures about 10 degrees year around which led to very high snow loads on people's roofs in the winters for at least 2 years time which is one reason why I built an A-Frame because it sheds snow automatically because of the steepness of the pitch of the roof.

However, if you are JUST interested in reducing temperatures without worrying about farm production worldwide this would be an easy answer.

One more problem: The pyroclastic dust might shut down some Jet engines in passenger planes when they got into too much of it at 30,000 to 40,000 feet in altitude.

So, though pyroclastic dust spread worldwide on the winds at high altitude would work it also would create more problems as well in regard to growing food and jet engines at high altitude.