According to Florida Trend and Watts Up, some of the "global warming" we've been reading about is based on local temperature readings that have been biased by local development.
In a previous posting on this Blog I reported possible biases due to NOAA-GISS reporting stations that may have been properly located in the past but have been artifically warmed by encroaching civilization, such as asphalt roads, buildings spewing air conditioner heat, sewage treatment plants, and, in one case, a poorly located barbeque! A distance of at least 100 ft (30 meters) from artificial heat sources is recommended, with 100 meters considered ideal.
The above map shows the results of some new research here in Florida. As you all know, every summer we have a hot season with days over 80 degrees. Well, that hot season has been getting longer in some parts of Florida and shorter in others!
The blue areas on the map show where the hot season has been getting shorter since 1950. The red, yellow, and green areas show where it has been getting longer. I'm in the big blue area in the center where the number of 80 degree days per year have decreased by 18 days. The red spot just below us is Orlando where major development has increased the number of 80 degree days by 9 to 25 days! In over-developed Miami-Ft. Lauderdale near the tip of Florida, the number of over 80 degree days has increased by 33 to 45 days!
Accepted worldwide global warming data claims an average increase of about 0.6 degrees C (1.1 degrees F) since 1950. How then could large areas of Florida (and many other places) have experienced a reduction in very hot 80 degree days over the same time period? At least part of that 1.1 degree measured average global increase must be due to temperature reporting stations that have been encroached by artificial heat islands. Thus, part of reported global warming appears to be due to local biases in reporting stations due to development in those locations.
I hasten to add that the increased ice melts in polar areas are clear evidence that at least part of the reported average global warming is real. We still have to take action on increased human-caused CO2, but we can do that in a more considered way because global warming is not as dire as originally thought.