Read Joseph D’Aleo and Anthony Watts 110 page report here

Recent revelations from the Climategate emails,

originating from the Climatic Research Unit at the University of East Anglia, showed how all the data centers — most notably NOAA and NASA — conspired in the manipulation of global temperature records to suggest that temperatures in the 20th century rose faster than they actually did.

This has inspired climate researchers worldwide to take a hard look at the data proffered, by comparing it to the original data and to other data sources. An in-depth report, co-authored by myself and Anthony Watts for the Science and Public Policy Institute (SPPI), compiles some of the initial alarming findings with case studies included from scientists around the world.

We don’t dispute the fact that there has been some cyclical warming in recent decades — most notably from 1979 to 1998 — but cooling took place from the 1940s to the late 1970s, again after 1998, and especially after 2001, all while CO2 rose. This fact alone questions the primary role in climate change attributed to CO2 by the IPCC, environmental groups, and others.

However, the global surface station data is seriously compromised.

There was a major station dropout — and an increase in missing data from remaining stations — which occurred suddenly around 1990. Just about the time the global warming issue was being elevated to importance in political and environmental circles.

A clear bias was found towards removing higher elevation, higher latitude, and rural stations — the cooler stations — during this culling process, though that data was not also removed from the base periods from which “averages,” and then anomalies, were computed.”