Here is an example: the NOAA site shows compiled data in graph form that indicates the the earth is, in fact, warming. They have lots of useful information. The graphs showing warming are compiled from satellite data, thermometer readings, tree rings, and cores taken in glaciers.
On another site I found a statement that tree ring data is unreliable, citing various reasons.
Now the question is, what would the graphs look like if the tree ring data was removed? Would it show less warming or more? Does the tree ring data skew the results? Or, is tree ring data actually reliable and the critic was pushing his own agenda?
Additionally, Amelia pointed out that temperature readings are often taken at airports, which have no trees and which are surrounding by thousands and thousands of square feet of asphalt and consrete, making the temperature readings higher in both summer and winter. What if we look at the temperature data only from small towns and national forests and parks? Is the trend the same, or do the urban readings skew the data?
This is why this is so difficult to decipher. I have been cruising around the net trying to find out the truth, and there is very little information that hasn't been politicized.
Politicization of science is a very dangerous game that both sides are playiing. I disagree with it when the envirals do it, and I do not want to see conservatives do it either.
California may face a dry future
UC Santa Cruz study spells out climate shifts, mirrors EPA opinions
Sierra will be hit hard by warming, study says
Global warming issue stirs new fear
Snowpack level could fall, reduce water supply