Regarding your Nov. 29 news article “U.N. summit could bring first progress in years”: As a scientist, I like to look at all of the available data before reaching conclusions, not just an isolated subset that proves a desired point. A fuller examination of the available data indicates that temperatures have been higher on Earth, and they tend to move between highs and lows over a several-hundred-year cycle.
Recent periods of rising temperatures were from 1700 B.C. to 1000 B.C., 250 B.C. to 250 A.D., 700 A.D. to 1300 A.D., and the current cycle starting around 1600 A.D. (data from Harris-Mann Climatology).
We are on an uptrend, most likely caused by solar activity, not by human activity. An article (“Mars Melt Hints at Solar, Not Human, Cause for Warming, Scientist Says,” National Geographic, Feb. 28, 2007) pointed out that the polar icecaps on Mars have also been receding, most likely from fluctuations in the sun’s output (definitely not from human activity). The author also points out that change in the sun’s heat output can account for almost all the climate changes we see on both planets.
The climate on earth will change. We must not waste large amounts of national time and treasure tilting at windmills.