Much debate in the last five years over the greenhouse effect has centered on interpreting temperature numbers generated at weather stations all over the world. The data from these thermometers are averaged and plotted in attempts to determine just how fast the earth has heated up since the measurements began.
There is now no doubt the world is getting warmer. The thermometers show the world is warmer now than at any time since thermometers have been available for measurements. Perhaps the most startling revelation came early in 1989, when British weather scientists from the University of East Anglia's Climatic Research Unit announced that 1988 was the hottest year in the last century. Together with 1988, the years of 1987, 1983, 1981, 1980, and 1986 have been measured to be the warmest 6 years in the last hundred. (The order given is the ranking, with the warmest years first.)
Even before results of the 1988 year were tabulated, lead scientist James Hansen from NASA's Goddard Institute for Space Studies, told Senators in Washington he was 99% confident that the warm weather of the 80's decade was due to global warming, and not simply random events:
"The present observed global warming is close to 0.4 deg. C, relative to 'climatology,' which is defined as the 30-year (1951- 1980) mean. A warming of 0.4 deg. C is three times larger than the standard deviation of annual mean temperatures in the 30-year climatology. The standard deviation of 0.13 deg. C is a typical amount by which the global temperature fluctuates annually about its 30-year mean; the probability of a chance warming of three standard deviations is about 1%. Thus we can state with about 99% confidence that current temperatures represent a real warming trend rather that a chance fluctuation over the 30-year period."[Senate Committe on Energy & Natural Resources,6/23/88]
Scientist Hansen is telling us that the 'greenhouse warming signal' has been detected. Not all researchers yet agree with him - these people say we need more data and further studies. More research continues, but certainly many people believe the first stages of greenhouse warming are already upon us. After looking at the graphs and data in this program, what do you think?
1990 Global Temperature update: At greenhouse hearings in October, Dr. P.D. Jones, scientist from E. Anglia's Climate Research Unit, told US Senators that 1990 will probably go down as the warmest year on record. Based on careful analysis of temperatures from 3,300 stations worldwide, Dr. Jones stated that 1990 is almost certain to be the warmest, even though data from the last 4 months had not yet been collected. Dr. Jones expects the new ranking for the 4 hottest years ever to be: 1990, 1988, 1987, 1983. Official results now comfirm 1990 to be the warmest year ever! ***
