The scientific consensus that human-generated carbon dioxide is changing the climate began to form in the 1980s.
For a long time, the changes to the climate were simply denied. After a while, as those changes became increasingly hard to ignore, the argument shifted to the changes being real but not caused by anything people are doing. The multi-trillion-dollar fossil fuel industry was strongly motivated to focus attention away from the association between carbon dioxide and climate change.
The greenhouse gas effect has been known since the 19th century. It isn’t just real; it is essential to life on earth. Without sufficient levels of carbon dioxide in the atmosphere to trap some of the sun’s heat, the earth would be an ice planet incapable of supporting much in the way of life. But there can be too much of a good thing.
Naysayers continue to grasp at alternative explanations for the warming planet rather than the inconvenient truth. Some people try to claim that it is the release of heat from all our energy-generating activities -power plants, heaters and air conditioners, vehicles, and so on – that is warming the planet.
That issue has been studied in detail. Human activity does generate a lot of heat and, technically speaking, that heat does help warm the planet. However, the sun dumps 10,000 times more heat on the earth than all of human energy production added together. Just the normal fluctuations in solar energy are 10 times larger than everything we do put together.
What is increasingly warming the planet is not the continuing energy striking the earth; it is primarily the fact that growing levels of greenhouse gases in the atmosphere are trapping more and more of that heat and preventing it from escaping into space.
Integrating anthropogenic heat flux with global climate models
Photo, posted August 25, 2009, courtesy of Gerald Simmons via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio