Guess I'll really have to look at JGR (or the Hungarian "peer-reviewed scientific journal"); but....
...oh, yea....
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, D24S05, doi:10.1029/2007JD008746,
Heat capacity, time constant, and sensitivity of Earth's climate system. Stephen E. Schwartz, Atmospheric Science Division,
Brookhaven National Laboratory, Upton, New York, USA
Abstract:
(btw, "a" translates as yr. in this JGR article)The equilibrium sensitivity of Earth's climate is determined as the quotient of the relaxation time constant of the system and the pertinent global heat capacity. The heat capacity of the global ocean, obtained from regression of ocean heat content versus global mean surface temperature, GMST, is 14 ± 6 W a m−2 K−1, equivalent to 110 m of ocean water; other sinks raise the effective planetary heat capacity to 17 ± 7 W a m−2 K−1 (all uncertainties are 1-sigma estimates). The time constant pertinent to changes in GMST is determined from autocorrelation of that quantity over 1880–2004 to be 5 ± 1 a. The resultant equilibrium climate sensitivity, 0.30 ± 0.14 K/(W m−2), corresponds to an equilibrium temperature increase for doubled CO2 of 1.1 ± 0.5 K. The short time constant implies that GMST is in near equilibrium with applied forcings and hence that net climate forcing over the twentieth century can be obtained from the observed temperature increase over this period, 0.57 ± 0.08 K, as 1.9 ± 0.9 W m−2. For this forcing considered the sum of radiative forcing by incremental greenhouse gases, 2.2 ± 0.3 W m−2, and other forcings, other forcing agents, mainly incremental tropospheric aerosols, are inferred to have exerted only a slight forcing over the twentieth century of −0.3 ± 1.0 W m−2.
....
Okay, I finally got thru that JGR paper. Interesting.
Ummm... Two points struck me before I got through the abstract; the reliance on a main assumption (and linkage to GMST), and the method for pulling out the equilibration (climate sensitivity) time constant.
Admittedly, Schwartz states,
"Here an
initial attempt is made to determine climate sensitivity through energy balance considerations that are based on the time dependence of GMST and ocean heat content over the period for which instrumental measurements are available."
I just wish he'd included some possible factors to be considered in
further attempts (or even possible confounding or currently omitted factors).
This paper is heavily based on Levitus' work on Oceanic Heat Content (more later).
I'm impressed that Schwartz comes within an order of magnitude of the IPCC estimates. One could easily imagine that this analysis has been attempted before, but the data was too sparse and unresolved. Finally we have enough data and resolution that we can more successfully attempt to look at a global energy budget.
While the math is daunting, it does lead to a figure half as much as the IPCC suggests. However, Schwartz provides ample "wiggle room" by using values with a 50% uncertainty, using new unproven assumptions, using unproven data, and by then discussing these problems.
"The findings of the present study may be considered surprising in several respects:"
"This value is well below current best estimates of this quantity, summarized in the Fourth Assessment Report of the IPCC [2007]...."
"This situation invites a scrutiny of the each of these findings for possible sources of error of interpretation in the present study."
"Perhaps a more fundamental question has to do with the representativeness of the data that comprise the Levitus et al. [2005] compilation."
"...suggest the necessity of evaluating the effective heat capacity based on a long-term record."
"Is the relaxation time constant ...the pertinent time constant of the climate system? Of the several assumptions on which the present analysis rests, this would seem to invite the greatest scrutiny."
...and finally....
"The rather large uncertainty range could be consistent with either substantial cooling forcing ...or substantial warming forcing...."
So don't bet the farm on these results yet, I guess.
Schwartz's conclusion is fair:
"Ultimately of course the climate models are essential to provide much more refined projections of climate change than would be available from the global mean quantities that result from an analysis of the present sort. Still it would seem that empirical examination of these global mean quantities, effective heat capacity, time constant, and sensitivity, can usefully constrain climate models and thereby help to identify means for improving the confidence in these models."
...can't argue with that....
Anyway, as mentioned, Levitus et al. [2005] informs a large part of Schwartz's paper.
Levitus is worth looking at; it has some neat charts and graphs.
Citation: Levitus, S., J. Antonov, and T. Boyer (2005),
Warming of the world ocean, 1955–2003, Geophys. Res. Lett., 32, L02604, doi:10.1029/2004GL021592.
Looking at Schwartz's paper, I kept thinking that Levitus must have not taken enough measurement to get a good picture and/or that he'd not accounted for the Arctic melting. Silly me. This is a great paper, but I'm sure future endeavors will provide a more complete and accurate picture.
Levitus does at least talk about indications of great variability between the major oceans; as well as between basins, depths and latitudes.
"Two other regions of cooling include the North Pacific around 40_N and the North Atlantic centered at 60_N. ....Dickson et al. [2002] documented the cooling and freshening of the deep waters of the Labrador Sea since the early-1970s which has resulted in the cooling of the deep waters of the entire subarctic gyre of the North Atlantic [Levitus and Antonov, 1995]. ....In addition to our earlier work, Southern Ocean warming between the 1950s and 1980s has been documented by Gille [2002] based on in situ observations including PALACE float data. ....For the Atlantic, Pacific, and Indian Oceans the increases of heat content (linear trends) are respectively 7.7, 3.3, and 3.5 × 10^22 J. As with our previous work, it is the Atlantic Ocean that contributes most to the increase in heat content."
This is all based on over 1.5 Million measurements!
(That's one point that was better than I expected.)
(...and they account for Arctic melting.) (see the charts).
That's another point I thought maybe they'd missed, but noooo.
But Schwartz cautions us about the Levitus information.
Levitus, similarly, cautions us about the certainty and completeness of his conclusions.
"....we may be underestimating ocean warming. This is possible since we do not have complete data coverage for the world ocean."
"...we believe that the long-term trend as seen in these records is due to the increase of greenhouse gases...."
& finally,
"Our discussion here has not been to minimize the impacts of warming of the lower atmosphere due to increasing greenhouse gases, we are simply placing Earth's heat balance in perspective. The response of the Earth's climate system to changes in radiative forcing is often cast as the response of the Earth's surface temperature to these forcings. This is understandable because we live at the Earth's surface and there has been a lack of subsurface ocean data with which to conduct Earth system heat balance studies. Improved scientific understanding requires that we study the response of all components of the Earth's heat balance, of which the world ocean is the dominant term."
Maybe I'll try to find the Hungarian paper to see how certain its conclusion sounds; but this [Levitus] paper's conclusion seems to be fairly equivocal:
"...suggests that internal variability of the Earth system significantly affects Earth's heat balance...."...
There was one curious similarity; for both [Levitus & the Hungarian referenced] papers, the "result included a new term," which made the equations more accurate.
The "new terms" are completely different, so maybe that's not the "conclusions ...supported by research published in the Journal of Geophysical Research last year from Steven Schwartz" connection (I know, it's the 1.1 degree thing
-but the "1.1 degrees" comes from completely different reasoning!!!)....but that aside....
Schwartz (via Levitus) introduces "an additional term in the Earth's heat balance ...[which] is the variability of the heat content of Earth's lithosphere."
WOW! I spent a couple of hours with that one too.
"Beltrami et al. [2002] used temperature profile data from boreholes to make this estimate. They estimate that Earth's continents warmed by 0.9 × 10^22 J during the past 50 years. This value is of the same order as the warming of the Earth's atmosphere during this period...."Anyway, there is another Schwartz paper, which is not restricted/pay access.
http://www.ecd.bnl.gov/steve/pubs/HeatCapacity.pdfIt's virtually the same, but the math is harder (not refined yet?).
Schwartz et al., sure is a well-referenced paper. Beyond Levitus, Schwartz cites
Jim Hansen, Trenberth and the IPCC (as well as Einstein's 1905, seminal paper on Brownian Motion!).
...but how about that lithospheric revelation?Beltrami, H., J. E. Smerdon, H. N. Pollack, and S. Huang (2002),
Continental heat gain in the global climate system, Geophys. Res. Lett., 29(8), 1167, doi:10.1029/2001GL014310.
"These fluxes indicate that 30% of the heat gained by the ground in the last five centuries was deposited during the last fifty years, and over half of the five-century heat gain occurred during the 20th century."Feel free to ask questions; I'm fairly familiar (groan) with these papers now.
