Many scientists argue that the increase in global warming we are currently experiencing is due to normal climate cycles on Earth. However, the facts that support human-caused acceleration of global warming are too numerous to come to any conclusion other than we are experiencing atypical climate change induced by the activities of humans.
Patrick Abbott, author of Natural Disasters, explains that the greenhouse effect is a normal, necessary phenomenon on Earth. Without it, our planet’s average surface temperature would be about 3 degrees Fahrenheit (2009). However, the burning of fossil fuels has released unprecedented amounts of carbon dioxide into our atmosphere, heating this greenhouse to dangerously high temperatures. According to the National Oceanic and Atmospheric Administration (NOAA), pre-industrial levels of carbon dioxide were about 280 parts per million by volume (ppmv), compared to today’s levels of 380 ppmv. In addition, the Earth’s average surface temperature has increased about three quarters of a degree Centigrade since the late 1800s, and the ten warmest years in recorded history have all occurred since 1995. When you also consider that we are now experiencing significant changes in our atmospheric and oceanic circulation patterns, notable changes in length of growing seasons, increased number and intensity of tropical storms, and sea levels rising at rates unprecedented over the last several thousand years (NOAA, 2008), which are all due to a warming climate, it becomes increasingly more difficult to deny that these are atypical times.
Abbott, P.L. (2009). Natural disasters (7th ed.). New York, NY: McGraw-Hill Companies, Inc.
NOAA. (2008). Global warming. Retrieved July 5, 2009, from http://www.ncdc.noaa.gov/oa/climate/global warming.html#q5