From ice cores we know the amount of carbon dioxide in the atmosphere is the highest it has been in hundreds of thousands of years. More CO2 makes oceans acidic, leading to a disruption of the food chain and the destruction of coral. With few exceptions, land (Antarctica, Greenland, Tibetan Plateau) and sea (Arctic Ocean) ice are shrinking worldwide. Globally, the temperature and the ocean level are rising.
Replacing fossil fuels would reduce levels of mercury in the fish we eat; reduce concentrations of oxides of sulfur and nitrogen, small airborne particles and arsenic in the air we breathe; avoid spending treasure and spilling blood in protecting global oil supplies; and avoid huge transfers of wealth to foreign sources of oil.
Regarding the cap-and-trade program proposed for lowering CO2 emissions, knowledgeable economists report that such programs were successful in removing tetraethyl lead from gasoline and in reducing acidification of lakes and rivers. The European Union is now successfully using cap and trade to reduce their CO2 emissions.
We urgently need the new jobs, cleaner environment, economic opportunities, international stability and moral leadership that alternative energy will provide. We must get on with it.