Summary: The pause in temperatures since roughly 2000 has become the hot topic in both climate science and climate politics. While scientists study its causes and estimate its duration, activists on both sides use it to work their tribes. On the Left they deny its existence, ignoring or misrepresenting the many papers about it. On the Right they use the pause to discredit climate models and even climate science. In this long and somewhat technical post an eminent climate scientist walks us though the debate. (1st of 2 posts today.)
Donald C. Morton, posted at Climate Etc, 15 December 2014
Reposted under their Creative Commons License
- Time Scales
- Natural Versus Anthropogenic Contributions
- Parameterization in Place of Physics
- Uncertainty in the Climate Sensitivity
- Applying Statistics to Biased Samples
- Nonlinearity and Chaos in Climate
- The Validation of Climate Models
- What Should We Do Now?
- About the Author
- For More Information
The coincidence of the current plateau in global surface temperatures with the continuing rise in the atmospheric concentration of carbon dioxide has raised many questions about the climate models and their forecasts of serious anthropogenic global warming.
This article presents multiple reasons why any future increase in temperature should not be regarded as a vindication of the current models and their predictions. Indefinite time scales, natural contributions, many adjustable parameters, uncertain response to CO2, averaging of model outputs, non linearity, chaos and the absence of successful predictions are all reasons to continue to challenge the present models. This essay concludes with some suggestions for useful immediate actions during this time of uncertainty.
What if the global climate began to warm again? Would all the criticisms of the climate models be nullified and the dire predictions based on them be confirmed? No one knows when the present plateau in the mean surface air temperature will end nor whether the change will be warmer or cooler. This essay will argue that the climate models and their predictions should not be trusted regardless of the direction of future temperatures.