 In February 2007 Gingrich stated that he "would strongly support" a cap and trade system for reducing carbon emissions based on the success of the Acid Rain Program enacted by Congress during his tenure.He later changed his position, saying that such a trading system "would lead to corruption, political favoritism, and would have a huge impact on the economy".In April 2007 Gingrich called for "Green conservatism" and carbon-reduction tax credits.