Does global warming exist? Yes. Did global warming exist before the industrial age? Yes. Is global warming a natural occurrence? Yes. Do humans have an effect on global warming? Absolutely. Though global warming is a natural phenomenon, its present rate of increase is not.
“The natural patterns of climate change have been altered,” said the Union of Concerned Scientists, a science-based nonprofit organization.
A study by the European Project for Ice Coring in Antarctica found that greenhouse gases today are higher than at any time in the past 650,000 years. That translates to eight ice ages. Additionally, the Environmental Protection Agency reports the eight warmest years on record have been recorded since 1998, the warmest being 2005.
“Although local temperatures fluctuate naturally, over the past 50 years the average global temperature has increased at the fastest rate in recorded history,” said the Natural Resources Defense Council, an environmental action group.
It isn’t just the atmosphere that’s heating up. In the past 50 years oceans have absorbed 20 times as much heat as the atmosphere, even to a depth of 1,500 feet below the surface, according to the UCS Web site.
“The measured increases in water temperature lie well outside the bounds of natural climate variation,” said the UCS.
What about global cooling periods? Aerosols, a subset of air pollution, cause global cooling. Unlike greenhouse gases, aerosols leave the atmosphere within a few days, weeks or years, according to the UCS. However, greenhouse gases stay in the atmosphere for decades or centuries.
“Even accounting for the occasional short-lived cooling . . . heat-trapping emissions far outweigh any other current climate driver. Once again, our scientific fingerprinting identifies human activities as the main driver of our warming climate,” said the UCS.