Climate data misleading

The letter writer’s (NASA’s data is not the whole picture,” Readers Write, Sept. 20) attempt to deny man-made global warming — in part based on the theory that urban heat islands have distorted the surface temperature data — is misleading.

Some of the largest increases in surface temperatures over the last two decades have occurred in the Arctic, Siberia and the Amazon, where there is no urbanization and consequently no heat island effect. Also, 1998 had an abnormally high El Nino event, causing a large spike in global temperature, so comparing subsequent years to it and not looking at the long-term trend is questionable science. Further, satellite data is not inherently more accurate than surface-based measurement. Satellites drift, their orbits decay, and they do not measure actual temperature, as do surface-based stations. KEN TIMKO, MARIETTA