Earth has warmed one degree in past 100 years . Majority of scientists say greenhouse gases are causing temperatures to rise . The temperatures were relatively unchanged from 1880 to 1910 , according to the U.S. Environmental Protection Agency . Some critics see planets often in periods of warming or cooling .
Earth has warmed one degree in past 100 years . Majority of scientists say greenhouse gases are causing temperatures to rise . Some critics see planets often in periods of warming or cooling .