The latest from our crack scientists is that UHI has huge effects which extend thousands of miles, but they are too small to be adjusted for in the local temperature record.
Those who wonder why large parts of North America seem to be skipping winter have a new answer in addition to climate change: big city life.
A study, published in the journal Nature Climate Change, found that the heat thrown off by major metropolitan areas on America’s east coast caused winter warming across large areas of North America, thousands of miles away from those cities.
Winter warming was detected as far away as the Canadian prairies. In some remote areas, temperature rose by as much as 1 degree C (1.8F) under the influence of big cities, which produced changes in the jet stream and other atmospheric systems, the study found.
So the UHI effect is huge and massively alters the temperature record. At the same time, USHCN makes no correction for it – because it is unimportant.
no specific urban correction is applied in HCN version 2
USHCN only makes “corrections” which warm the present and cool the past. Corrections which go the other way are politically incorrect(ions)