Or cut trees down in Canada and dump them in the profusion of lakes they have there. They will sink and the cold water and sediment will trap the carbon for many hundreds of years. (Provided temperature rises don't get silly.) Or cut trees down anywhere and dump them in rivers so they get deposited in aluvial fans on continental shelves. Hay will do too. Or burn wood or hay for electrical energy and a few percent of the carbon will be trapped as ash which can be piled up into artifical hills or whatever you like and serve as another means of trapping carbon. (This would probably be more cost effective than just dumping wood or hay in water.)