What I worry about most is that "they" will actually find a way to cool off the Earth in any significant fashion. We have records of what happens when the avg temp gets about 1 to 2 degrees colder than now. The cooling period beginning in about 538 AD is believed to have been caused by the volcano Krakatoa, and civilizations fell (particularly Rome). Millions starved to death. In the same way, in 1815 Tambora erupted, and in 1816 there was no summer, and famine set in in both the US and Europe (and probably in other areas as well.) Some heating may bring some annoyances, but cooling kills millions without fail.