 More recently Gingrich has expressed skepticism that mankind is significantly altering the climate and has preferred curbing carbon emissions through market-incentives instead of by taxes or cap-and-trade plans.He has opposed the Kyoto Protocol, stating that the protocols unfairly favor Europe, China and India to the disadvantage of the U.S.In 2008, Gingrich accepted an invitation from Al Gore to appear with Democratic House Speaker Nancy Pelosi in a commercial produced by one of Gore's climate advocacy organizations.