Thursday, December 10, 2015

Satellite vs. Thermometer Temperature Trends

Source: Forbes
Many of you have asked or commented about difference in the temperature trends from satellites or surface-based thermometers, as well as the adjustments that are made to these records.

Marshall Shepherd has an outstanding piece in Forbes today fully summarizing the issues at play.  Marshall is the Director of the Atmospheric Sciences Program at the University of Georgia, host of the Weather Channel show Weather Geeks, and a NASA scientist.  He was also the 2013 President of the American Meteorological Society.  He's an outstanding scientist and an outstanding scientific communicator.

It's clear that Marshall put a great deal of thought went into explaining the strengths and weaknesses of the two approaches.  Note that he emphasizes the importance of looking at the climate system holistically, including the use of oceanic heat content, rather than just surface temperatures.  This is something that we have discussed in previous posts (see Global Warming Hasn't Stopped).  We are seeing unequivocal warming of the climate system.  Arguments that global warming has stopped simply have no basis.

5 comments:

  1. One thing that seems to me to be somewhat lacking from the discussion as a whole is direct insight from the field of chemistry. Is there a fairly simple mathematical function that describes the absorption of outgoing radiation by concentration of a particular gas such as CO2? I know it is non-linear but it would be interesting to see what the approximate mathematical function looks like. What is the relative effect of doubling CO2 from 400 to 800ppm vs doubling from 200 to 400ppm, etc?

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  2. An entire chapter of IPCC-AR5 is dedicated to this: https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter08_FINAL.pdf.

    There are also feedbacks, however, which can amplify or weaken these forcings (in most cases, it appears the amplify positive forcings). It's snowing, so that's a discussion for the future...

    Jim

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    1. Thanks, I will have to look at that link. You probably posted something like that at one time and I forgot about it.

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  3. A good quote to remember from the article is "The key takeaway here is that multiple data streams should be considered for complex climate problems". Rather than sweeping it under the rug all climate scientists need to consider that some satellite data sets show no global warming for 17+ years now.

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    1. That is a good quote to remember, but you seem to have swept data streams that you don't like under the rug, and scientists don't need to consider that satellite data sets don't show global warming over the past 17 years because that isn't true. There has been unabated global warming for the past 17+ years because the oceans have continued warming and constitute >90% of climate warming. No data set shows no global climate warming over the past 17+ years. If you consider the lower troposphere alone, to have no satellite observed warming in the last 17+ years, you need to disingenuously start your time series in 1998 (https://www.ncdc.noaa.gov/temp-and-precip/msu/time-series/global/lt/oct/ytd), which is by no means an average year because of the massive El Nino. That is akin to starting the time series in 1992 when the Pinatubo eruption cooled global temperatures.

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