Insufficient Forcing Uncertainty

19 07 2009

insufficient-force-catIt seems depending on who you talk to, climate sensitivity is either underestimated or overestimated. In this case, a model suggests forcing is underestimated. One thing is clear, science does not yet know for certain what the true climate sensitivity to CO2 forcings is.

There is a new Paper from Tanaka et al (download here PDF) that describes how forcing uncertainty may be underestimated. Like the story of Sisyphus, an atmospheric system with negative feedbacks will roll heat back down the hill. With positive feedbacks, it gets easier to heatup the further uphill you go. The question is, which is it?

Insufficient Forcing Uncertainty Underestimates the Risk of High Climate Sensitivity

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ABSTRACT

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Categories : Carbon dioxide, modeling

Christy on questions about UAH seasonal signals

19 07 2009

As promised, I contacted Dr. John Christy regarding the seasonal signal that the anonymous blogger “deepclimate” says he/she has identified in the UAH data, seen below. He/she says: “I am a Canadian citizen residing in Canada. For private and professional reasons, I prefer to remain anonymous to the general public, at least for now.”

I’ve never understood the need for some people to remain anonymous while at the same time attempt to do science. Imagine the furor if scientists like Christy or Spencer created an anonymous blog and then were later discovered. I’m sure it would be immediately up there on sourcewatch with “tsk tsk” attached.

Science really should be done out in the open.  Here’s Dr. Christy’s in the open response.

Dr. Christy has made a response in the readme file at the UAH website here:

http://www.nsstc.uah.edu/data/msu/t2lt/readme.18Jul2009

Update 18 Jul 2009 ************************************
Corrected trend values (1700 CST)

It was brought to my attention by Anthony Watts that there has been some discussion about the noticeable annual cycle in the LT and MT trends when done by months. In other words, the trend for Februaries is on the order of 0.12 C/decade warmer than the trend for Mays. Other data sets don’t have such a large range in trends when calculated by months, RSS for example has a range of 0.05 C/decade. (Note, this issue doesn’t affect the overall trend.)

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Categories : climate data, measurement