"National Geographic" fact-checked 6 persistent scientific conspiracy theories. Regarding the persistent belief in a global warming hoax they note that the Earth is continuing to warm and the rate of warming is increasing as documented in numerous scientific studies. The rise in global temperature and its rate of increase coincides with the rise of greenhouse gases in the atmosphere due to human activity. Moreover, global warming is causing Arctic sea ice to thaw at historic rates, many species of plants are blooming earlier than expected, and the migration routes of many birds, fish, mammals, and insects are changing.