I have several methods I plan to use to improve America's footprint on the world. I will start by using as many government resources as possible to fund research and development in environmentally friendly technologies.
I will then work to create a sin tax on pollution. Companies will either be clean or pay extra taxes that I will use to fund environmental initiatives. My intent is for the companies to invest their time and resources into running a low environmental impact operation.
Last, it is not enough for America to be clean if we support companies polluting other places on earth. I will make it a priority of the US government to push that any company that violates a basic standard of environmentalism anywhere is not able to sell their products in our borders. We can't necessarily stop others from polluting and poisoning, but we can refuse to be customers of theirs.