dr. kimberly prathser at, atmospheric chemist. leads a team of researchers who are investigating how particles like dust and sea patterns? >> air solis can impact some of the extreme we think patterns we are starting to see? >> the way you can explain some cases of drought is, let's say, for example, you are in a polluted urban region. things like soot and smoke can reduce the amount of rainfall that comes out of that cloud. understanding how these particles play a roll in whether a cloud will produce rain or through. >> the scientists trying to understand the science as fast as we can but the choices that humans make are going to be the thing that determines how fast we can fix this problem. coming up techknow, standing up to tropical force winds we want to hear what you think about these stories. join the conversation by following us on twitter and at aljazeera.com/techknow. >> welcome back to techknow. we are talking extreme weather events. over this last year, we have seen some big ones. >> the scientific community is tackling