Meteorological models have been increasing in accuracy since they were introduced in the 1940s. Yet it is well know that there are many limitations imposed on the meteorological models so that they are not accurate beyond a few days to two weeks. Theoretical studies using the “Chaos Theory” indicate that accurate modeling beyond two weeks is problematical.   The AGW modelers believe AGW to be a boundary value problem which would remove the limitations.

One primary complaint is the IPCC and most government funding research have gone to complex climate models that are tuned to estimate many conditions across the globe caused by the emissions of carbon dioxide to detect a small temperature change. Small errors can propagate into unknown large ones. There are over 100 of these models written by different teams and their results differ by a range to 3 to 1. And nearly all overestimate warming compared to observed data. What is causing the errors in the climate models that cause them to overestimate global warming? How will any proposed change in CO2 emissions be tested without waiting about 10 to 30 years? The results should give some indication to the accuracy of the models on their 10 to 20 year forecasts and whether their 100 years forecasts will be scientifically defensible.

Problem 1. Failure to match 20^th century changes. There is no statistical difference between the rate of warming over the 30 years from 1910-1940 and the 25 years from 1975/1976 to 2000. Climate models fail to simulate the “natural” observed warming between 1910 and 1940. Dr. Judith Curry said “Not being able to address the attribution of change in the early 20th century to my mind precludes any highly confident attribution of change in the late 20th century.”

Problem 2. Divergence of model results in 21th century. Statistically significant global warming of the surface stopped 17 years ago and in the troposphere global warming stopped 20 years ago. The models failed to predict any period of 10 years in which the temperature would not rise with increasing carbon dioxide. Overall, the climate models at the turn of the century have forecast temperatures that were higher than the observations for the last 15 years. Over 40 reasons presented for the 17 year “pause” in surface warming indicate that natural climate variability is far greater than climate models simulate, and is capable of overwhelming any climate influence of CO2. Recently, NOAA reanalyzed sea surface temperatures and concluded there is no pause in warming, in conflict with other agencies that compute the global temperature.

Problem 3. Cloud coverage changes. The simulation of clouds in climate models remains challenging. There is very high confidence that uncertainties in cloud processes explain much of the spread in modelled climate sensitivity. However, the simulation of clouds in climate models has recently shown modest improvement relative to earlier models and this has been aided by new evaluation techniques and new observations for clouds. Nevertheless, biases in cloud simulation lead to regional errors on cloud radiative effect of several tens of watts per square meter.   Recent suggestions indicated cosmic rays, may play a part in cloud formation. The IPCC has downplayed these alternatives because they are mainly looking for carbon dioxide as the sole cause of the observed warming.

Problem 4.   Omission of long term oceanic cycles. There are many problems with the climate models and their assumptions. Scientists have shown various long term cycles such as ENSO, North Atlantic Oscillation, (NAO), and Pacific Decadal Oscillation (PDO) influence the global average temperatures, but are not generally a predicted element in the global models.

While the modelers always think their models are representative, they always need to be verified using independent data. Looking at the 10-20 year projections, all the models are much warmer than the current temperatures. All the models assume that clouds will magnify the effects of rising temperatures. (So if we have a cloudy summer, the fall will be warmer!!) The climate projection models presume that as CO₂ and the other non-water greenhouse substances increase there will be an increase in temperature. The models do not verify in any way as a good model and fails to be verified according to the Scientific Method.