Alongside overall warming trends, the maps show how some states are lagging in warming trends compared to others. Tthe reporter quotes UGA professor and director of the Atmospheric Sciences program, Marshall Shepherd, president-elect of the American Metoerological Society, on the phenomena of 'warming holes' to explain these variations:
The particulate pollution in the air reflects sunlight back into space before it has a chance to warm the atmosphere.
Another theory is that Southeastern tree-planting efforts (afforestation) in the mid-1900s may have slowed warming there by absorbing carbon dioxide, Dr. Shepherd said. Whatever once kept those states cooler, though, has apparently quit working, and “the Southeast is now warming with the rest of the world,” he said.
The interactive map is very compelling and recommended. It permits a deeper level of thinking about how warming occurs locally and within national borders, the variation emphasized by state borders in the U.S.
You might also notice that several Southwestern, Great Lakes and Northeastern states have warmed much more quickly than the rest of the country, both over the century-long time range and over the last 40 years. Dr. Shepherd said this might be due to shifts in atmospheric circulation patterns caused by the warming itself. Weather that usually sits over the Southwest was pushed further north, causing less precipitation and cloud cover in that region and more heat, said Dr. Shepherd.
Great stuff, all the more reason to have more people working to understand the complex array of factors that effect our climate.