melanie fitzpatrick is a climate scientist who studied the impacts of climate change. >> we have to beeful that disease. >> we can seed clouds and put particles to reflect sunlight. the problem is that you have to keep going with it all the time. if we continue to emit carbon at the same time. we have not gone to the root cause of the problem. >> evan fitzpatrick believes we know what needs to be done. it takes the political will to do it. >> we know how to moderate climate, adopt energy efficiency, deploy renewables and remove the subsidies from fossil fuels. >> in an age of innovation, the idea we can reverse climate change is attractive. the truth is that we can barely understand what geoengineering must do to the planets and skies that all of us must share >>> jacob ward bringing us a breath of fresh air. that's "america tonight", tell us what you think. talk to us on twitter and facebook. come back, we'll have more of "america tonight" tomorrow. . >> ahead of u.n. brokered talks to and the country's political chaos. >> you're watching al jazeera live. also ahead tunisia orders tro