Climate change is caused by humans
The chart to the right, provided by Skeptical Science, show the variations in Carbon Dioxide (CO2) over the last 400,000 years as measured in ice cores. Following the blue line shows variability from approximately 275 parts per million by volume (ppmv) to just under 200ppmv until the 1800s.
With the onset of the Industrial Revolution, carbon fuels and higher population densities, CO2 has risen far beyond the 400,000 year historical pattern.
There is a natural carbon cycle which includes significant carbon transfer to and from plants and the ocean. A mind boggling 450 gigatonnes (GT) of carbon is absorbed by plants each year which more than compensates for the 439 GT of carbon naturally released by vegetation and land during that same time. The ocean has a similar dynamic, absorbing 338 GT of carbon while releasing 332 GT.
While approximately 40% (as of 2004) of the 29 GT of human CO2 emissions are absorbed via this natural cleansing cycle, the remaining CO2 is trapped in the atmosphere with nowhere to go. The earth’s atmosphere cannot release this carbon and so each year, as humans increase their CO2 emissions, the amount of carbon trapped increases.
Next page: “Is climate change a problem?”