much. the odd thing is here when a volcano explodes, there is both a negative and positive impact as well. jeff goodell recently set out to learn more about cutting edge technology and reversing the effects of climate change. he joins me as we kick off green week on msnbc. when you have this ash in the air, it blocks the sunlight. you talked to scientists who are looking at similar ways of trying to reflect back some of that sunlight. >> one of the things that scientists are looking at is putting small particles high up into the atmosphere which can then act as tiny mirrors to reflect away sunlight. only a small amount and you can actually cool down the planet. >> they're also talking about making the clouds more reflective. how would they do that? >> all you have to do is shoot up -- some of the ideas, to