Rural Heat Islands

We have become fascinated with the range of opinion about the world's temperature. Clearly, not all such opinion can be right. Our six decades of memories reveal no particular trends in what seems to us to be New England's customarily chaotic weather. For example, now in mid-May, the forecast for last night and tonight was and is for frost. Almost everyone who has grown up in this southwest corner of Massachusetts knows that Memorial Day, or the leaves of the ash tree, whichever comes first, is the only trustworthy signpost of frost-free nights and the safe time to plant tomatoes, corn, and other sensitive plants.
One of the confounding problems for persons trying to sort sense from nonsense about global warming has been the large shift in populations from rural to urban settings. Some 50 years ago here in the US almost 50 percent of the population farmed. Today, perhaps two percent still farm, and the rest of us live in cities or towns where blacktopped roads, concrete, and buildings provide for warmer surroundings than open country farms. The effect on temperature of increased populations in larger cities is called the urban heat island effect, one that also registers on old memories as warming over time.
Even here in Sheffield, a town of 3,500, a significant UHI can be demonstrated. For example, as the above photo shows, the time and temperature sign on the local bank, its white modern sensor visible against the brick wall, read 64F at noon. However, one mile away at our cottage, both of our outdoor thermometers read 55F.
So what? Well, the popular notion that the world has a runaway fever is based in part upon an arcane calculation of the world's recording weather stations data yielding a temperature increase of about one degree Fahrenheit over the past century. Just one degree in 100 years. However, those stations were not designed to be accurate enough for use as a global thermometer, and very many have been moved or upgraded or neglected or abandoned (or all of the above), making for large shifts over time in recorded temperatures even without climate change.
Here in the US, many of the rural stations have been abandoned, so that the temperature record now reflects more urban stations, which have large UHI effects that have not been accurately measured and removed from the calculated average. When that non-climate effect becomes better known and the record adjusted, perhaps the US temperature will even show a cooling, and cool overheated claims about climate disasters. For those who want to know more about how not to measure temperature trends, see: http://wattsupwiththat.com and here: http://www.surfacestations.org, both treasure troves of information about hot air.