Why do we need to drill offshore?

Why do we need to drill offshore when 31 of the 50 states already produce oil? Our National Seashore is under protection for a reason. I thought the idea of becoming more GREEN is to look for more alternative fuel and energy sources. I do not want to hear someone tell me again that the technology is too new and un-researched because that would be a LIE. Research into solar, steam, water, wind, air, and bio-fuels has been ongoing for over a hundred years for some and others for more than twenty years. If you truly looked at the polution to the waters where offshore drilling occurs, such as the Gulf of Mexico, you would know that we would be headed for disaster. Not only would our migratory birds, turtles, and crabs be effected, but our fish, oyster, clam, and mussels would also take a blow from our digging offshore. Polution is a very real problem. Even Alaska, Lousiana, and other offshore drilling sites report some form of damage to the natural environment, but they think it is minimal enough to not cause major concern. I have a problem with that. As the levels of Mercury are rising in our fish and more and more shellfish are becoming contaminated, it will only be a matter of time, no matter how distant in the future, before our food supply is so tainted with polutants that we will have a serious problem on our hands. I am very passionate about using alternatives to oil and I know that if we can start weaning ourselves off of oil as a major source of energy and start using more GREEN alternatives that the U.S. will make a major impression upon the world that if we can change, so can any other country. I believe it is worth it to our children both now and in the future to start changing over to more GREENER methods of energy and, in turn, help to slow down the current damage already unfolding in our atmosphere, our waters, our land, and our world. If all you can think about is the here and now, then I feel sorry for you and your children and your children's children, for it is their future that we are destroying.