Climatologist Dr. Judith Curry praises Congressional climate debate: ‘A growing number of scientists and advocates that support the consensus are now engaging with skeptics in the scientific and public debate; this is a good thing’

GWPF Background Paper 

Benny Peiser has written a Background Paper that outlines the key areas of agreement and disagreement between the GWPF and the ‘consensus’:

A. Matters where we agree with the dominant scientific establishment and can quantify the outcome

1. The greenhouse effect is real and CO2 is a greenhouse gas.

2. CO2 has increased in the atmosphere from approximately 0.029% to 0.039% over the past 50 years.

3. CO2’s greenhouse warming potential follows a logarithmic curve with diminishing returns to higher concentrations.

4. Absent feedbacks, and other things being equal, a doubling of carbon dioxide from pre-industrial levels would warm the atmosphere by approximately 1.1C.

5. Since 1980 global temperatures have increased at an average rate of about 0.1C per decade. This is significantly slower than forecast by the vast majority of GCMs.

B.  Matters where we agree with the scientific consensus but cannot quantify the outcome.

1. Positive feedbacks from water vapour and soot, negative feedback from clouds and aerosols, and other factors, mean that actual climate sensitivity is a matter of vigorous scientific debate.

2. Natural variability caused by ocean oscillations, amplified solar variations and other factors also act to increase or decrease temperature change. Thus overall temperature prediction is doubly uncertain.

3. Arctic summer sea ice has decreased, but Antarctic sea ice has increased; this is more consistent with regional albedo changes due to soot than with global temperature changes due to greenhouse warming.

4. There is no consensus that recent climate change has affected the variability of weather or the frequency of extreme weather events.

5. Economists generally agree that net economic damage will occur above 2C of warming, net economic benefit below that level, but this cannot be certain.

C.  Matters on which we think the evidence does not support the scientific consensus

1.  There has been no net increase in global temperatures for about 16 years, a period about the same length as the warming period that preceded it.

2.  Paleo-climate proxies agree that worldwide temperatures were higher and changed faster during other periods of climate change about 1,000, 2,000, 4,000, 8,000 and 12,000 years ago.

3.  Predictions of increasing humidity and temperature in the tropical troposphere, a key prediction of rapid greenhouse warming, have been falsified by experimental data casting doubt on whether the warming of 1980-2000 was man-made.

4. Ice core data clearly show carbon dioxide responding to temperature change,