Unfortunately - reducing our impact in the way many advocate has serious consequences on the poor and impoverished. In fact the best way to lower humanity's impact on the environment is to reduce third world poverty and thus reduce population growth. Many scientists advocate a mixed approach - where we work on improving crops so that they'll grow in warmer climates, improve water processing, and in general improve humanity's ability to handle climate change all the while allowing developing countries to use fossil fuels to improve their standard of living. As technology advances they'll move to other means of energy.