2011-10-19 14:09:23Fingerprint Comparison
Daniel Bailey
Daniel Bailey

This is the blog discussion post for Stephen Luntz's first blog post.  Stephen's Author page intro is here.



Fingerprint Comparison

Posted on 19 October 2011 by Sluntz

The planet is warming. Over the last forty years the average temperature of the world has increased by 0.7%.


Most scientists and international scientific agencies say that this is caused by the increase of gases such as carbon dioxide in the atmosphere; a result of the burning of fossil fuels, felling of forests and other human activities. However, some scientists and politicians say that these changes are natural; the temperature has always varied as a result of changes in the sun, the Earth’s orbit, ocean cycles and other natural factors and that one or more of these are to blame.


So how can we tell which is right? Actually, you don’t need a degree in climatology to know. Different forms of warming have different signatures. For example, if the sun puts out more energy then most warming occurs during the day time. There is some hangover at night, but not as much. On the other hand, an increase of greenhouse gasses would catch the heat during the night, keeping it trapped closer to the surface of the Earth, so we’d get more warming then, with a smaller hangover during the day because the temperatures start from a higher point in the morning.


I’ve created a table of a number of tests, based on differing effects we would get from different causes that have been proposed. Correct predictions are in green. Wrong predictions in red. Check out the results below.


Increase in carbon dioxide, methane etc

Increased solar radiation

Solar winds blocking cosmic rays

Oceanic cycles such as El Nino, PDO

Daytime versus night time warming

More at night[1]

More during the day



Seasonal warming

More in winter

More in summer



Arctic versus tropics

Arctic warms faster

Tropics warm faster


Depends on exact cycle

Antarctic versus tropics

Antarctic warms faster[2]

Tropics warm faster


Depends on exact cycle

Stratospheric temperatures




Largely unchanged

Ionispheric temperatures






Tropospheric border





Radiation to space

Decrease at certain wavelengths[3]




As you can see what we observe fits closely with our expectations if the rise is driven by an increase in Greenhouse gasses. On the other hand, it is complely in contradiction to what we would expect if the sun was putting out more heat and light. It also doesn\\'t fit well with alternative theories, such as that we\\'re just seeing some cyclical change in ocean current. 

[1] http://www.knmi.nl/publications/showAbstract.php?id=706

[2] The Antarctic Peninsular is one of the fastest warming parts of the Earth. However, the majority of the Antarctic has been warming more slowly than the average of the globe. This appears to be a result of the effects of ozone depletion outweighing global warming at a local level.

[3] http://www.eumetsat.int/Home/index.htm

2011-10-19 14:34:29


I like the idea but I have some concerns. The entries in the tables need to be referenced to either data or better still published papers. Necessarily these are model comparisons. I asked Gavin Schmidt about this some time ago and it seems that things are not so clear cut. He pointed me to http://data.giss.nasa.gov/efficacy/ and Hansen 2005 http://pubs.giss.nasa.gov/cgi-bin/abstract.cgi?id=ha01110v

"Ocean cycles" is interesting but I think ENSO should be removed (as clearly implausible as cause of trend). Perhaps you could add OHC change to the effects?

2011-10-19 14:50:47There is great potential in this idea, it just needs finessing
John Cook


I think if we collectively work on this post, it will be a very useful and effective communication resource. But it does require a bit of work in collecting all the information and references. Stephen, I've made some tweaks to your blog post - started to add colours to the various table cells to add some definition. Note - you can add colours yourself in Author Admin when you're editing the blog post by clicking the relevant part of the table, clicking the "Table cell properties" (3rd icon in the third row) then for the Class field, select "value" in the drop down then enter either green or red.

Much of the references for this can be found in the Guide to Skepticism http://sks.to/guide for whoever wants to do the legwork.

Another comment - seems redundant having Arctic vs tropics AND Antarctic vs tropics - wouldn't it be more efficient to have "poles versus tropics"?

2011-10-20 01:24:08


Radiation to Space - Increased solar radiation, ocean cycles: Increase uniformly over entire spectra with temperature, with the emissivity spectra of the planet will only changing due to feedbacks (like clouds, long term vegetation). This is due to these two being changes to input energy, not output energy. Cosmic rays/Clouds should be close to the GHG fingerprint on outgoing radiation (albeit at different wavelengths, just H2O, not CO2), as an output change.

2011-10-24 13:34:03
Sarah Green
It doesn't make sense to say temperatures have increased by X%. That won't work on different T scales.