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Defra - Climate Change at Sea - We just don't know

Climate Change: Charting Progress - Defra

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Figure 6.2 Temperature changes relative to the corresponding average for 1901-1950 (°C) from decade to decade from 1906 to 2005 over the Earth’s continents, as well as the entire globe, global land area and the global ocean (lower graphs). The black line indicates observed temperature change, while the coloured bands show the combined range covered by 90% of recent model simulations. Red indicates simulations that include natural and human factors, while blue indicates simulations that include only natural factors. Dashed black lines indicate decades and continental regions for which there are substantially fewer observations.
Reproduced from IPCC AR4 WG1 Chp 9 FAQ 9.2 Figure 1, page 703

Nice to see an old friend make a reappearance in today's report from Defra about the state of the Oceans. I just can't get past the bottom left graph which shows that the historic global temperature in the 1940s is well above what the models say it should be. Either the record is wrong or the models are. And if the models can't get it right for the past what use are they?

As they say:

While many of the changes we observe are consistent with increasing levels of atmospheric carbon dioxide (CO2) and a warming climate, for example rising sea temperature and increasing acidification, we still do not understand many of the causative links to climate change. In particular we struggle with the rate and magnitude of future change for factors such as sea-level rise, Atlantic circulation, sea-ice extent, acidification and stratification. In other cases, for example the extent to which the oceans will continue to take up CO2, or changes in storminess or salinity, we are not even sure which direction the change in marine climate will take.
Furthermore, there are often insufficient data to draw robust links between climate change and impacts on marine ecosystems, and in some cases we do not sufficiently understand the underlying effects of climate change on the physical environment.

That confession of ignorance can also be read as a cry for more research funding....


I have a problem with DEFRA's plots of ocean temperature change (bottom right in the picture) and some basic calculations on the energy budget. This is actually rather important, as I estimate that the claim of 0.6C average temperature increase in the oceans is noticeably over twice what I think it can be, on the basis of reported data from the CAWG (Catastrophic Anthropogenic Global Warming) crowd, including the IPCC.

I would much appreciate it if others would check my (physics) theory, data sources and arithmetic.

To start, back on 17th November 2009, I posted on Tim Worstall's blog at http://timworstall.com/2009/11/17/good-grief-14/#comment-37320 This started me on the train of thought that has led to my current doubts.

IPCC view of total radiative forcing for the year 2005, being very close to 1.6W per square metre; see http://en.wikipedia.org/wiki/Radiative_forcing#IPCC_usage and particularly the figure in http://en.wikipedia.org/wiki/File:Radiative-forcings.svg

Now, the surface over which the IPCC claim 1.6W of anthropogenic forcing is the tropopause, at an average of 14km above the Earth's surface (11 to 17 km), as given in http://en.wikipedia.org/wiki/Tropopause The Earth's mean (surface) radius is 6371km, from http://en.wikipedia.org/wiki/Earth%27s_radius Thus, from a sphere's surface area being 4*pi*r*r, we have a tropopause surface area of 5.12309x10^14 square metres, with r=6371+14km.

From the IPCCs forcing figure of 1.6W/m2, this gives total power, over the area of the troposphere, of 8.1969x10^14 Watts. Over a whole year, this is 2.5868x10^22 Joules.

We now need to look at the specific heat capacity of the oceans. The mass of hydrosphere (97% salt water, mostly of the oceans/seas): 1.4×10^21 kilogrammes, from http://en.wikipedia.org/wiki/Ocean#Physical_properties The specific heat capacity of sea water at 36F is 3.93 kJ/kg (compared to 4.19 kJ/kg for fresh water), from http://www.engineeringtoolbox.com/specific-heat-fluids-d_151.html And I've used figures for 100% of the water and that it is all salt.

From this, I calculate that one year of 1.6W/m2 forcing, for every sq metre of the troposphere, would raise the average temperature of the oceans by: 4.7016x10^-3 Kelvin (and so Celsius).

So, 50 years of this, again assuming all this energy is directed at warming the oceans, would warm them by 0.235C. This is well under half the warming claimed in the DEFRA document in the years from 1950 to 2000, of 0.6C.

In addition, my calculations have made no allowance for warming of the atmosphere and the earth's solid surface; they have made no allowance for the latent heat of fusion, from melting of polar and other icecaps and glaciers; they have made no allowance for the latent heat of fusion, caused by water evaporation given the higher temperatures of atmosphere and of ocean surfaces. In addition, the forcing power assumed in my calculation was the IPCC figure for 2005, whereas the actual period of forcing (for the 0.5C) was 1950 to 2000 for the approx 0.6C reported rise in temperature over those 50 years. Forcing for those years must surely have been with a lower total power, because of lower CO2 densities in the atmosphere.

Thus I do not see, if the IPCC figures for anthropogenic solar forcing are correct, how the average temperature of the oceans can have risen by more that 0.235C, whereas DEFRA claim the actual temperature has risen by over 2.5 times more.

Furthermore, DEFRA claim that their referenced computer climate models (including ocean effects) correctly model this historical temperature change in the oceans.

There must be something wrong, either with my theory and calculations, or with DEFRA's reported actual ocean temperature record, or with the IPCC's claimed level of anthropogenic forcing (including some inconsistency between DEFRA's reported computer models and the IPCC's claimed anthropogenic forcing).

I repeat my plea for someone to check my (relatively simple) theory, calculations, assumed physical values. Also that my simplifications and approximations made cannot account - anywhere near - for the difference.

Best regards

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