Over 31,000 American scientists have signed the Global Warming Petition, which states that global warming is not caused by human activities, that there are actually many benefits to having a warmer planet, and that the United States should continue to reject the Kyoto Protocol. Looking at trends in such areas as ocean temperatures, solar activity, glacier shrinkage, and severe storm events, these scientists assert that upwards trends in all of these areas have been occurring since the 1800s. They believe, therefore, that policies limiting industrial and economic development are misplaced.