Ken's comments are great for bringing some real science into the frequently speculative discussions around the decadal temperature trends.
It is unfortunate that Lovelock also got caught up in this misunderstanding of the climate system, given his prominent public role. Two recent papers which I found very helpful in making the science behind this clear (admittedly this is not my central expertise, so recently I was looking around for useful studies clarifying this), which some of you might not yet be aware of, are: ==> Santer, B. D., et al. (2011), Separating signal and noise in atmospheric temperature changes: The importance of timescale, J. Geophys. Res., 116, D22105, doi:10.1029/2011JD016263. http://www.agu.org/pubs/crossref/2011/2011JD016263.shtml "Executive Summary": * A multi-model ensemble run with contemporary human forcing oftens produce 10-year periods with little or no warming * S/N (signal-to-noise) ratios for tropospheric temperature are about 1 for 10-yr trends (i.e., no signal is detectable above the noise), but increase to 4 for 32-yr trends * Trends >17 yrs are required for identifying human effects on tropospheric temperature ==> Foster and Rahmstorf, Global temperature evolution 1979-2010, Environ. Res. Lett., 6, 044022, 2011. http://iopscience.iop.org/1748-9326/6/4/044022 This one nicely shows how taking into account ENSO and other major factors of natural variability, applied to FIVE different datasets, results in a quite stable background decadal temperature increase in all the datasets. The whole abstract is worth quoting: We analyze five prominent time series of global temperature (over land and ocean) for their common time interval since 1979: three surface temperature records (from NASA/GISS, NOAA/NCDC and HadCRU) and two lower-troposphere (LT) temperature records based on satellite microwave sensors (from RSS and UAH). All five series show consistent global warming trends ranging from 0.014 to 0.018 K yr-1. When the data are adjusted to remove the estimated impact of known factors on short-term temperature variations (El Niño/southern oscillation, volcanic aerosols and solar variability), the global warming signal becomes even more evident as noise is reduced. Lower-troposphere temperature responds more strongly to El Niño/southern oscillation and to volcanic forcing than surface temperature data. The adjusted data show warming at very similar rates to the unadjusted data, with smaller probable errors, and the warming rate is steady over the whole time interval. In all adjusted series, the two hottest years are 2009 and 2010. There are also earlier analyses by Ramanathan and others that essentially made the same basic points, but more generally, not applied so specifically to the recent decadal trend (or apparant lack thereof). Question: is Lovelock a part of this discussion group, i.e., has he gotten to read these posts? If not, would anyone who knows him personally think it's a good idea to send him some of the climate science background in these posts? --mark lawrence -- PD Dr. Mark G. Lawrence Scientific Director Cluster SIWA - Sustainable Interactions With the Atmosphere IASS - Institute for Advanced Sustainability Studies e. V. Berliner Str. 130 D-14467 Potsdam Germany On 30 Apr., 22:18, Ken Caldeira <[email protected]> wrote: > More evidence that Lovelock is making too much of decadal scale trends in > atmospheric temperature. Look at ocean temperature. Oceans represent most > of the heat capacity in the climate system, > > http://www.agu.org/pubs/crossref/pip/2012GL051106.shtmlhttp://news.sciencemag.org/sciencenow/2012/04/scienceshot-no-letup-in... > > On Fri, Apr 27, 2012 at 8:15 PM, Joshua Horton > <[email protected]>wrote: > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
