1. What gas is responsible for approximately 95% of the "greenhouse effect" on planet Earth?
2. Is the United States a net A) Emitter, or B) Absorber of carbon dioxide?
3. Is the global climate now A) Warmer, or B) Cooler than it was approximately 1,000 to 1,100 years ago?
These questions come from a letter on Jerry Pournelles' web site. Here's the complete text.
Here are the answers from the letter:
1. Water vapor is responsible for about 95% of the Earth's greenhouse effect. Carbon dioxide is less than 2% of the total effect, with methane taking up most of the balance, and other gasses responsible for the remainder. But all we EVER hear about is CO2.
2. The U.S., with it's vast forests (more now than in pre-Columbian times) and farmlands is a net ABSORBER of CO2...as opposed to Europe and Japan, which are net emitters.
3. Let's see...they were raising crops of oats in Greenland, and the Icelandic/Viking explorers were calling what is now the chilly area of Newfoundland "Vinland" because of the grapes which grew there. It's an era referred to as the "Medieval Climate Optimum" in old climate textbooks, and was followed by the spread of Black Plague (the fleas of the rats taking advantage of the warmer climate to spread to northern Europe). That period was followed by what used to be referred to as the "Little Ice Age", in which England saw snow in areas never before seen, and the River Thames froze quite solidly on a regular basis. That period ended in the early/middle 1700's, and we've been in a warming trend ever since.