Here's a good article on geoengineering from The Guardian. Government's hypothesis is that blasting Aluminum Sulfate particles (aka "aluminum mirrors") into the stratosphere will help deflect sunlight and curb global warming. At least, that is the the excuse they use to pursue these agendas.
Geo-engineering: green versus greed in the race to cool the planet
Geo-engineering: green versus greed in the race to cool the planet
The range of techno-fix ideas is growing by the month. They include absorbing plankton, growing artificial trees, firing silver iodide into clouds to produce rain, genetically engineering crops to be paler in colour to reflect sunlight back to space, fertilising the ocean with iron nanoparticles to increase phytoplankton, blasting sulphate-based aerosols into the stratosphere to deflect sunlight, covering the desert with white plastic to reflect sunlight and painting cities and roads white.