he claim that increase of human-induced “greenhouse” gases in the atmosphere would cause “global warming” ran into serious trouble right from the start.
It happens that there is no current technology that is capable of measuring the average surface temperature of the earth. There is no way that temperature sensors could be situated randomly over the whole surface of the earth, including the 71% that is ocean and 10% that is desert, and measure it all instantaneously for sufficient time to find if it is rising.
It is not even possible to measure the temperature reliably in one place. James Hansen of the Goddard Institute of Space Studies, who has made a reputation for promoting “global warming”, has an item on his website as follows:
Q. What exactly do you mean by SAT?
A. I doubt that there is a general agreement how to answer this question. Even at the same location, the temperature near the ground may be very different from the temperature 5 ft above the ground and different again from 10ft or 50ft above the ground. Particularly in the presence of vegetation (say in a rain forest) the temperature above the vegetation may be very different from the temperature below the top of the vegetation. A reasonable suggestion might be to use the average temperature of the first 50ft of air either above ground or on top of the vegetation. To measure SAT we have to agree on what it is and, as far as I know, no such standard has been adopted. I cannot imagine that a weather station would build a 50ft stack of thermometers to be able to find the true SAT at its location.
Q. What do we mean by daily SAT?
A. Again, there is no universally accepted correct answer. Should we note the temperature every 6 hours and report the mean, should we do it every two hours, hourly, have a machine record it every second, or simply take the average of the highest and lowest temperature of the day? On some days the various methods may lead to drastically different results.
Q. What SAT do the local media report?
A. The media report the reading of one particular thermometer of a nearby weather station. This temperature may be very different from the true SAT even at that location and has certainly nothing to do with the true regional SAT. To measure the true regional SAT we would have to use many 50ft stacks of thermometers distributed evenly over the whole region, an obvious practical impossibility.”
