An article in the Daily Mail today piqued my interest. It trumpets empirical results which they say empirically confirm the theoretical CO2 greenhouse effect for the first time:
A new study in the journal Nature demonstrates in real-time field measurements what scientists already knew from basic physics, lab tests, numerous simulations, temperature records and dozens of other climatic indicators.
They say it confirms the science of climate change and the amount of heat-trapping previously blamed on carbon dioxide.”
“These instruments, located at ARM research sites in Oklahoma and Alaska, measure thermal infrared energy that travels down through the atmosphere to the surface.
They can detect the unique spectral signature of infrared energy from CO2.
Other instruments at the two locations detect the unique signatures of phenomena that can also emit infrared energy, such as clouds and water vapor.
The result is two time-series from two very different locations. Each series spans from 2000 to the end of 2010, and includes 3300 measurements from Alaska and 8300 measurements from Oklahoma obtained on a near-daily basis.”
“Both series showed the same trend: atmospheric CO2 emitted an increasing amount of infrared energy, to the tune of 0.2 Watts per square meter per decade. This increase is about ten percent of the trend from all sources of infrared energy such as clouds and water vapor.”
Wow!. So so the amplification theory which says increasing CO2 will cause an increase in water vapour and raise temperatures must be true then, since that’s the only way greenhouse theorists can get increasing CO2 to do anything exciting. Lets take a look at state-wide temperature in Alaska, including the 2000-2011 period to empirically confirm this.
Oh. The temperature fell by around 4 degrees Centigrade during the 2000-2011 period! So maybe the trend from clouds and water vapour was a downward trend not an upward one? But if there was less longwave downward cloud radiative forcing, that would be because there was less cloud, which would mean there were more sunshine hours. That would have raised temperatures. On the other hand, if the reduced cloud were during winter, when the Sun is weak or absent, that would allow more outgoing longwave radiation to escape, causing surface cooling.
Either way, what the study shows, is that increasing CO2 has had very little effect on water vapour levels or near surface air temperature in Alaska, and is easily overcome by natural variability.
But then, CO2 is a ‘well mixed gas’ which spreads worldwide, and has been rising at a fairly steady rate for decades. So decadal periods when temperature went up or down can be cherry picked to support either argument. But what that reveals is that the whole ‘CO2 driven global warming’ period from 1975-2005 just happened to coincide with the positive phase of the ~60 year oceanic cycle. Until that oscillation is subtracted out from the longterm temperature trend, we shouldn’t trust any estimate of climate sensitivity.
Since there is an even longer term ~1000 yr oscillation evident in the proxy temperature record, running through the Minoan warm period, Halstatt disaster, Roman warm period, dark ages, Medieval warm period, little ice age and right up to the modern warm period, we should probably be wary of ascribing any upward temperature trend underlying the ~60 year oscillations to increases in trace gases in the atmosphere too.
Our simple solar system harmonic resonance model (yellow curve), which provides a potential explanation for these longer term oscillations, well reproduces changes in solar activity as reconstructed from the deposition of the 10Be solar proxy (blue curve), which itself seems to match this history of millennial up and downs in climatic conditions.
The CO2 driven climate theorists are completely unable to hindcast climatic change back thousands of years like this, so the challenge for them is to justify their certainty. MET Office scientist Richard Betts told me on twitter yesterday that they are only claiming that CO2 took over as the dominant climate forcing in recent decades. That sounds like special pleading for a failed theory to me.