cancel2 2022
Canceled
The Intergovernmental Panel on Climate Change, the bureaucratic agency which appropriated the role of arbiter of things climatic, has advanced a theory for the lack of warming since the turn of the century, viz:
Now, you’d think that you could just use the Stefan-Boltzmann equation to figure out how many more upwelling watts would be represented by a global surface temperature rise of 3°C. Even that number was a surprise to me … 16.8 watts per square metre.
Figure 1. Blue line shows the anomaly in total downwelling surface radiation, longwave plus shortwave, in the CERES dataset, March 2003 to September 2012. Red line shows the trend in the downwelling radiation, which is 0.01 W/m2 per decade. Gray area shows the 95% confidence interval of the trend. Black line shows the expected effect of the increase in CO2 over the period, calculated at 21 W/m2 per doubling. CO2 data are from NOAA. Trend of the expected CO2 change in total downwelling surface radiation is 1.6 W/m2 per decade. CO2 data from NOAA.
But as they say on TV, wait, there’s more. The problem is, the surface loses energy in three ways—as radiation, as sensible heat, and as the latent heat of evapotranspiration. The energy loss from the surface by radiation (per CERES) is ~ 400 watts per square metre (W/m2), and the loss by sensible and latent heat is ~ 100 W/m2, or a quarter of the radiation loss.
Now, the sensible and latent heat loss is a parasitic loss, which means a loss in a heat engine that costs efficiency. And as any engineer can testify, parasitic losses are proportional to temperature, and as the operating temperatures rise, parasitic losses rise faster and faster. In addition, the 100 W/m2 is the global average, but these losses are disproportionately centered at the hot end of the system. At that end, they are rising as some power factor of the increasing temperature.
But let’s be real generous, and ignore all that. For the purpose of this analysis, we’ll swallow the whopper that a 3° temperature rise wouldn’t drive evaporation through the roof, and we’ll assume that the parasitic sensible and latent heat losses from the surface stay at a quarter of the radiation losses.
This means, of course, that instead of the increase of 16.8 W/m2 in downwelling radiation that we calculated above, we need 25% more downwelling radiation to account for the parasitic losses from the surface. (As I said, the true percentage of parasitic losses would be more than that, likely much more, but we’ll use a quarter for purposes of conservative estimation.)
Read more: http://wattsupwiththat.com/2014/01/13/co2-and-ceres/#more-101292
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The observed reduction in warming trend over the period 1998–2012 as compared to the period 1951–2012, is due in roughly equal measure to a cooling contribution from internal variability and a reduced trend in radiative forcing (medium confidence). The reduced trend in radiative forcing is primarily due to volcanic eruptions and the downward phase of the current solar cycle. However, there is low confidence in quantifying the role of changes in radiative forcing in causing this reduced warming trend.
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So I thought I’d look at the CERES dataset, and see what it has to say. I started with the surface temperature question. CERES contains a calculated surface dataset that covers twelve years. But in the process, I got surprised by the results of a calculation that for some reason I’d never done before. You know how the IPCC says that if the CO2 doubles, the earth will warm up by 3°C? Here was the question that somehow I’d never asked myself … how many watts/m2 will the surface downwelling radiation (longwave + shortwave) have to increase by, if the surface temperature rises by 3°C? The observed reduction in warming trend over the period 1998–2012 as compared to the period 1951–2012, is due in roughly equal measure to a cooling contribution from internal variability and a reduced trend in radiative forcing (medium confidence). The reduced trend in radiative forcing is primarily due to volcanic eruptions and the downward phase of the current solar cycle. However, there is low confidence in quantifying the role of changes in radiative forcing in causing this reduced warming trend.
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Now, you’d think that you could just use the Stefan-Boltzmann equation to figure out how many more upwelling watts would be represented by a global surface temperature rise of 3°C. Even that number was a surprise to me … 16.8 watts per square metre.
Figure 1. Blue line shows the anomaly in total downwelling surface radiation, longwave plus shortwave, in the CERES dataset, March 2003 to September 2012. Red line shows the trend in the downwelling radiation, which is 0.01 W/m2 per decade. Gray area shows the 95% confidence interval of the trend. Black line shows the expected effect of the increase in CO2 over the period, calculated at 21 W/m2 per doubling. CO2 data are from NOAA. Trend of the expected CO2 change in total downwelling surface radiation is 1.6 W/m2 per decade. CO2 data from NOAA.
Now, the sensible and latent heat loss is a parasitic loss, which means a loss in a heat engine that costs efficiency. And as any engineer can testify, parasitic losses are proportional to temperature, and as the operating temperatures rise, parasitic losses rise faster and faster. In addition, the 100 W/m2 is the global average, but these losses are disproportionately centered at the hot end of the system. At that end, they are rising as some power factor of the increasing temperature.
But let’s be real generous, and ignore all that. For the purpose of this analysis, we’ll swallow the whopper that a 3° temperature rise wouldn’t drive evaporation through the roof, and we’ll assume that the parasitic sensible and latent heat losses from the surface stay at a quarter of the radiation losses.
This means, of course, that instead of the increase of 16.8 W/m2 in downwelling radiation that we calculated above, we need 25% more downwelling radiation to account for the parasitic losses from the surface. (As I said, the true percentage of parasitic losses would be more than that, likely much more, but we’ll use a quarter for purposes of conservative estimation.)
Read more: http://wattsupwiththat.com/2014/01/13/co2-and-ceres/#more-101292
