Many years ago I found this chart on the NOAA web site. Strangely, they removed it at some point.
It shows the temperature corrections admitted to by NOAA. You can see how they warmed their data as time passed. That, all by itself, would create a warming trend in the temperature data.
In fact, The_Watcher's archives still have an archived link. Scroll down to see the graph.
Many years ago I found this chart on the NOAA web site. Strangely, they removed it at some point.
It shows the temperature corrections admitted to by NOAA. You can see how they warmed their data as time passed. That, all by itself, would create a warming trend in the temperature data.
In fact, The_Watcher's archives still have an archived link. Scroll down to see the graph.