[katieHaylor (OP)]

Christine asks:

I saw that there is something like 100 000 hectares of land in Spain covered with greenhouses and I heard that the greenhouses caused the temperature to drop by 1 degree in the area. If we, in South Africa, painted all our roofs white, would that make a difference at all to climate change in our country?

What do you think?

[Kryptid]

Painting all of the rooftops white would increase the local albedo and thus cause more light to be reflected away from the Earth's surface. It should have the net effect of cooling the area a little bit. By how much, I do not know.