“What scientists know, and what cannot be denied, about global warming, carbon dioxide, the greenhouse effect.” Flam sheds light on where the politics end and science begins with this issue, and answers some questions we’ve probably all pondered, such as:
Who came up with this greenhouse gas concept and how seriously is it taken?
According to physicist and historian Spencer Weart, the idea can be traced to French mathematician Joseph Fourier. Back in the 1820s, Fourier did some calculations to show that a rock like Earth orbiting at 93 million miles from the sun should be a big snowball. He suggested our balmy temperatures could be attributed to our atmosphere, which might hold in heat – sort of like a greenhouse.
There wasn’t much experimental evidence to back this up until the 1850s, when British scientist John Tyndall started shining infrared light through various gases.
Tyndall knew the Earth absorbs solar radiation and emits infrared. If the greenhouse theory was right, gases that make up the atmosphere would absorb some of this infrared, thus raising the temperature.
At first he almost disproved the greenhouse effect by showing that infrared passes straight through oxygen and nitrogen – the main components of our atmosphere. But before he quit, Tyndall tried a few other gases, including CO2, and found it was a powerful absorber of infrared. Water vapor had the same property.
That suggested that while carbon dioxide makes up less than 0.001 percent of our atmosphere, it’s working along with water vapor to prevent infrared radiation from escaping to space. These gases also emit radiation, some of which is directed back toward the ground. “As a dam built across a river causes a local deepening of the stream, so our atmosphere . . . produces a local heightening of temperature at Earth’s surface,” Tyndall wrote.
Knowledge is power. Understanding the basic science behind these claims will sharpen your Spidey senses so it won’t be quite as easy for folks to confuse me…I mean you! Get informed then get engaged. My colleagues Professor David Guston and Dr. Richard Sclove helped shape thethis summer. The effort made it possible for thousands of people to learn about and weigh in on the topic of Global Climate Change. We know where the people stand. This week’s conference in Copenhagen will speak volumes about the mindset of the world’s political leaders. Stay tuned or check out live feeds from the conference on .