Oregonian: Has humanity's history of burning fossil fuels changed the atmosphere so much that it is causing the earth to warm? We can't be absolutely certain that the core conclusions drawn by the vast majority of the world's climate scientists are correct - that increased atmospheric carbon dioxide is making the atmosphere a better insulator, thus increasing the earth's temperature, which, in turn, changes global climate. But neither can we know with absolute certainty that they are wrong. Nevertheless, there...