A wonderful dialogue - Climate scientist v/s Climate skeptic

There is a wonderful dialogue going on over at Anthony Watt's blog between Willis Eschenbach -- best classified as a climate skeptic but one who is more than willing to participate in a debate -- and Dr. Walter Meier from the National Snow and Ice Data Center (NSIDC). It starts here: Trust and Mistrust with Willis posing fourteen questions and two preface questions. Walt's replies are here: NSIDC�s Walt Meier responds to Willis Willis in turn posts Walt's replies and offers some commentary and debate here: My Thanks and Comments for Dr. Walt Meier

First, I would like to thank Dr. Meier of the National Snow and Ice Data Center (NSIDC) for answering the questions I had posed (and had given my own personal answers) in �Trust and Mistrust�. I found his replies to be both temperate and well-reasoned. Also, I appreciate the positive and considerate tone of most of those who commented on his reply. It is only through such a peaceful and temperate discussion that we can come to understand what the other side of the debate thinks.

Onwards to the questions, Dr. Meier�s answers, and my comments:

Question 1. Does the earth have a preferred temperature, which is actively maintained by the climate system?

Willis says that he �believes the answer is yes�. In science �belief� doesn�t have much standing beyond initial hypotheses. Scientists need to look for evidence to support or refute any such initial beliefs. So, does the earth have a preferred temperature? Well, there are certainly some self-regulating mechanisms that can keep temperatures reasonably stable at least over a certain range of climate forcings. However, this question doesn�t seem particularly relevant to the issue of climate change and anthropogenic global warming. The relevant question is: can the earth�s temperature change over a range that could significantly impact modern human society?

My comment: Since unfortunately so little attention has been given to this important question, my idea of how it works is indeed a hypothesis. Therefore, �belief� is appropriate. However, I have provided several kinds of evidence in support of the hypothesis at the post I cited in my original answer to this question, �The Thermostat Hypothesis�.

Next, Dr. Meier says that there are �some self-regulating mechanisms that can keep temperature reasonably stable at least over a certain range of climate forcings.� Unfortunately, he does not say what the mechanisms might be, at what timescale they operate, or what range of forcings they can handle.

However, he says that they can safely be ignored in favor of seeing what the small changes are, which doesn�t make sense to me. Before we start looking at what causes the small fluctuations in temperature that we are discussing (0.6�C/century), we should investigate the existence and mechanism of large-scale processes that regulate the temperature. If we are trying to understand a change in the temperature of a house, surely one of the first questions we would want answered is �does the house have a thermostat?� The same is true of the climate.

A wonderful read... Over 140 comments to look through too. It is nice to finally see this sort of measured dialog happening. All too often throughout the Anthropogenic Global Warming debate matters have degraded to poo-flinging with no real science, just opinion and political agendas. The Science is not settled. In Science there is never a consensus. In Politics yes but not in Science.