Yesterday I watched the Dr. Richard Lindzen lecture at EIKE in Germany on Models vs. Measurements in April 2014. The folks at Watts Up With That had posted the lecture link at their site. The lecture, https://www.youtube.com/watch?v=7jOD4CK8MSM, primarily addresses these questions.

1. What is the sensitivity of global mean temperature to increases in greenhouse gases?
2. What, if any, connection is there between weather events and global mean temperature anomaly?
3. Is our understanding of the greenhouse effect adequate?
4. How relevant is the simplistic notion of global mean radiative imbalance driving global mean temperature to actual climate change?

His first point is that he does not quibble with the question that global warming exists but he does take exception with the quantitative estimates of global warming changes. He goes on to show that the change in temperature due to doubling of CO₂ in the models is very dependent on your assumptions for aerosols.

His second point is that when we look at the radiative forcing effects due to anthropogenic emissions and volcanoes we see a climate system that responds to these events in a manner that is less sensitive manner than what is being used in the climate models. The volcano data implies effects due to doubling of CO₂ is closer to 0.75~1.0 C.

He next goes on to discuss the natural variability of introduced by the oscillations in the Pacific and Atlantic oceans and argues that their effects are at least comparable in magnitude to AGW.

He finishes up his lecture with a short discussion that despite what the press says the IPCC reports do not attribute extreme weather to global warming. He reminds everyone that extreme weather depends on the temperature difference between the tropics and the high latitudes. In a warmer world, this difference is expected to decrease not increase.