Over the last one hundred years global temperature has increased between 0.6 and 1.1 degrees Fahrenheit, glaciers over the world have decreased in size and worldwide sea level has risen 10 to 20 centimeters. (Global Warming Opposing Viewpoints) Are these changes due to human behavior or natural causes? Is global warming a threat to the world environment? Global warming is a complex issue where scientists on both sides of the subject have a valid point of view. The green …showed first 75 words of 1375 total…

…showed last 75 words of 1375 total…