Thursday, June 2, 2011

Is this climate forcing paper for real?

Shortwave forcing of the Earth’s climate: Modern and historical
variations in the Sun’s irradiance and the Earth’s reflectance

P.R. Goode, E. Palle´
Journal of Atmospheric and Solar-Terrestrial Physics 69 (2007) 1556–1568

ABSTRACT
Changes in the Earth’s radiation budget are driven by changes in the balance between the thermal emission from the top of the atmosphere and the net sunlight absorbed. The shortwave radiation entering the climate system depends on the Sun’s irradiance and the Earth’s reflectance. Often, studies replace the net sunlight by proxy measures of solar irradiance, which is an oversimplification used in efforts to probe the Sun’s role in past climate change. With new helioseismic data and new measures of the Earth’s reflectance, we can usefully separate and constrain the relative roles of the net sunlight’s two components, while probing the degree of their linkage. First, this is possible because helioseismic data provide the most precise measure ever of the solar cycle, which ultimately yields more profound physical limits on past irradiance variations. Since irradiance variations are apparently minimal, changes in the Earth’s climate that seem to be associated with changes in the level of solar activity—the Maunder Minimum and the Little Ice age for example—would then seem to be due to terrestrial responses to more subtle changes in the Sun’s spectrum of radiative output. This leads naturally to a linkage with terrestrial reflectance, the second component of the net sunlight, as the carrier of the terrestrial amplification of the Sun’s varying output. Much progress has also been made in determining this difficult to measure, and not-so-well-known quantity. We review our understanding of these two closely linked, fundamental drivers of climate.

The Hockey Schtick makes a big deal out of this 2007 paper. If it was so seminal and important, then why is it unknown in 2011?

Might also want to read this too:
Can Earth’s Albedo and Surface Temperatures Increase Together?

At least here's an update, sort of (I'll have to see if this was actually published):
Inter-annual variations in Earth's reflectance 1999-2007.

The conclusion is kinda fun:

"In this paper, we have demonstrated that the agreement between earthshine and CERES reflectances have shown a dramatic improvement after CERES data were re-calibrated and earthshine data were re-analyzed. In the common period, earthshine, CERES along with ISCCP-FD data show a trendless albedo. However, preceding CERES, earthshine and ISCCP-FD reflectances show a significant increase before flattening and holding the increase. This implies a reduction in the net sunlight reaching Earth. In the context of the recent climate change, it is important to point out that the physical causes behind these large decadal variations in albedo are still unknown, and that we just don't know yet whether we should expect the albedo changes observed during the modern period to persist into the future."

I agree; we just don't know. We just don't know if this is an important result or not (but considering a climate skeptical site is pushing a 4-year-old paper that doesn't seem to register on the climate research radar, I tend to expect that it's not really very important. I reserve the right to later say that I was wrong about this, though.)

The thing is: Philip R. Goode is a top-notch solar physicist. So I dug around some more and found this:

NJIT Solar Physicists Report Paradox in Eos: Less Sunlight, But Temps Rise

So let's get clear:

“Recently analyzed cloud data from the International Satellite Cloud Climatology Project (ISCCP) confirm the trend in reflectance,” said Goode. “The data also reveal that from 2000 to now the clouds have changed so that the Earth may continue warming, even with declining sunlight. These large and peculiar variabilities of the clouds, coupled with a resulting increasing albedo, presents a fundamental, unmet challenge for all scientists who wish to understand and predict the Earth’s climate.” Co-authors with Goode are post-doctoral associates Enric Palle and Pilar Montanes-Rodriguez, who work at the observatory, and Steven E. Koonin, a professor of theoretical physics at California Institute of Technology (Cal Tech).

and

“That increase in the difference signals a relative decrease in the cooling effect of clouds,” said Goode. “Thus, the rising reflectance of the Earth has not led to a reversal of global warming from the increase in sunlight being reflected back into space.” What has happened is that the low, cooling clouds have decreased during the most recent years, while high, warming clouds have increased even more. Thus, the cloud data also reveal an increase in total cloud amount during 2000-2004. That increase is consistent with the earlier earthshine result of growing reflectance throughout that period.

So if we think about this a moment; this is BAD NEWS for climate skeptics, because it a) indicates that the world is still warming, and b) that clouds aren't providing a negative feedback, even though they're increasing and reflecting more sunlight back to space -- or so it seems.

So it seems that this Hockey Schtick post is schlock.

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