in U.S. CO 2 emissions.  Possible negative impacts on the overall U.S. economy by redirecting $Trillions of investment into more costly zero carbon energy supply projects is an additional concern.  Another possible risk is the ongoing debate and level of uncertainty as to the actual impacts of CO 2 on climate change and whether substantially reducing anthropological sources will tangibly benefit the U.S. or the world. How to Manage Carbon Reductions and Impacts -- Substantially reducing U.S. fossil fuels consumption could be achieved by a number of regulatory strategies.  Politically popular cap-n-trade and carbon credits are problematic.  Besides effectively increasing costs further for average Households (above the levels estimated in this analysis), actual reductions in CO 2 emissions by use of carbon credits are significantly uncertain.  A more effective strategy could be through maximum free market engagement (not cap-n-trade).  A more promising strategy would involve the Federal Government creating a combination of reasonably aggressive 'zero carbon power standards' and 'increased efficiency standards'.  Rather than having the Government pick winners/losers, the free markets would decide which new energy mix/efficiency technologies should be developed to meet zero carbon power/efficiency standards.  The Government's role should be limited to supporting energy R&D and helping facilitate the new power plants and transmission & distribution lines construction permitting processes.  Limited duration zero carbon power production subsidies should also be considered, but these must be managed within current-future Federal deficit spending. Another factor that should be included in the new CO 2 emission reduction regulatory strategy is