Frazier folks on IPCC

A reader friendly analysis of the IPCC's work, I came upon, is here.  It is from Canada's Frazier Institute and reviews current information and the IPCC's work.  Recall, the summary of the IPCC work was not written by scientists and half of those involved in the program agreed with the summary for policy makers. 

 I have no idea why the selection, below, is goofy or why a picture of a dog sleeping in the snow didn't load. Ayway, now and then, we have to actually read stuff, very annoying. There are good graphs in the report

7Overall conclusions 

The following concluding statement is not in the Fourth Assessment Report, but was 

agreed upon by the ISPM writers based on their review of the current evidence. 

The Earth's climate is an extremely complex system and we must not understate the 

difficulties involved in analyzing it. Despite the many data limitations and uncertainties, 

knowledge of the climate system continues to advance based on improved and expanding  data sets and improved understanding of meteorological and oceanographic mechanisms. 

The climate in most places has undergone minor changes over the past 200 years, and 

the land-based surface temperature record of the past 100 years exhibits warming trends in 

many places. Measurement problems, including uneven sampling, missing data and local 

land-use changes, make interpretation of these trends difficult. Other, more stable data sets, 

such as satellite, radiosonde and ocean temperatures yield smaller warming trends. The 

actual climate change in many locations has been relatively small and within the range of 

known natural variability. There is no compelling evidence that dangerous or unprecedented 

changes are underway. 

The available data over the past century can be interpreted within the framework of a 

variety of hypotheses as to cause and mechanisms for the measured changes. The hypo- 

thesis that greenhouse gas emissions have produced or are capable of producing a signifi- 

cant warming of the Earthís climate since the start of the industrial era is credible, and 

merits continued attention. However, the hypothesis cannot be proven by formal theoretical 

arguments, and the available data allow the hypothesis to be credibly disputed. 

Arguments for the hypothesis rely on computer simulations, which can never be decisive 

as supporting evidence. The computer models in use are not, by necessity, direct calculations 

of all basic physics but rely upon empirical approximations for many of the smaller scale 

processes of the oceans and atmosphere. They are tuned to produce a credible simulation 

of current global climate statistics, but this does not guarantee reliability in future climate 

regimes. And there are enough degrees of freedom in tunable models that simulations 

cannot serve as supporting evidence for any one tuning scheme, such as that associated 

with a strong effect from greenhouse gases. 

There is no evidence provided by the IPCC in its Fourth Assessment Report that the 

uncertainty can be formally resolved from first principles, statistical hypothesis testing or 

modeling exercises. Consequently, there will remain an unavoidable element of uncertainty 

as to the extent that humans are contributing to future climate change, and indeed whether 

or not such change is a good or bad thing.