Longer duration global warming is a signature of global warming being driven by an accumulation of greenhouse gases in the atmosphere.
Persistent warming is also shown in several 100 year temperatures plots from measurements at NOAA National Weather Service climate stations - even more evidence of greenhouse climate change rather than radiation climate change which is typically shorter duration warming and cooling.
The Northern Plains and Upper Midwest are warming faster than other regions in the contiguous United States. Higher latitude temperature amplification is further evidence of greenhouse climate change.
Northern Plains states: Montana, Wyoming, North Dakota, South Dakota.
Upper Midwest states: Minnesota, Wisconsin, Upper Peninsula of Michigan.
View global temperature plot and 100 year temperature plots at climate stations at Glendive, Montana and Jamestown, North Dakota at:
link to npat1.newsvine.com