Revisiting the climate evidence

Julia Gillard’s deter­mi­na­tion as Prime Min­is­ter to revis­it the debate about an Aus­tralian response to the poten­tial dan­gers of cli­mate change calls for a review of the evi­dence to ensure that any response is pro­por­tion­ate and effec­tive. In my view, the rel­e­vant data show less and less rea­son to attribute recent warm­ing to human activ­i­ties (‘anthro­pogenic warm­ing’).

Although empiri­cism prob­a­bly under­de­ter­mines the truth about climate—and as we know from Ross Garnaut’s report, under­de­ter­mines cli­mate policy—it is worth lay­ing out the rea­sons seri­ous­ly to doubt the ‘man-made cli­mate’ claims once more because Gillard says she is seek­ing a nation­al con­sen­sus. I think we should take no steps oth­er than to seek a bet­ter under­stand­ing of cli­mate; but I fear that a Labor par­ty that is fond of con­demn­ing ‘denial­ism’ won’t include such con­trary views in the ‘con­sen­sus’ dis­cov­ery process­es.

Argument

The impo­si­tion of a tax (or admin­is­tered price) on an ele­ment that is not only essen­tial to cur­rent pro­duc­tion but the very stuff of a big pro­por­tion of Australia’s nation­al prod­uct is an extra­or­di­nary mea­sure requir­ing extra­or­di­nary rea­sons. But those rea­sons are not evi­dent in the data; on the con­trary:

  1. Offi­cial and ‘peer-reviewed’ data on his­tor­i­cal climate—let alone on cur­rent trends—strongly shows there is noth­ing unusu­al about 20th cen­tu­ry cli­mate vari­a­tions and no rea­son­able prospect of a cli­mate emer­gency;
  2. The con­tin­u­ing dis­con­nect between observed atmos­pher­ic car­bon diox­ide (and methane) con­cen­tra­tions and esti­mates of glob­al tro­pos­pher­ic tem­per­a­tures gives lit­tle rea­son to believe that cli­mate trends would be affect­ed by cut­ting the emis­sion of car­bon gasses.

In the past year the demand for coop­er­a­tive action by Aus­tralia to cut emis­sions has dis­ap­peared. The UN Cli­mate Convention’s Copen­hagen con­fer­ence demon­strat­ed that any mea­sures we take will be echoed by, at most, a minor­i­ty of oth­er economies. There is lit­tle doubt that they will be futile in achiev­ing even their pri­ma­ry goal (a reduc­tion in atmos­pher­ic CO2) let alone their strate­gic goal.

We could per­haps jus­ti­fy their dire impact on our nation­al wel­fare by ref­er­ence to a nation­al psy­chol­o­gy (if such a thing exists) or a col­lec­tive dread; but this would be only to say the mea­sures could not be jus­ti­fied by ref­er­ence to any objec­tive basis for pub­lic pol­i­cy.
Evidence

To show there are insuf­fi­cient grounds for ‘extra­or­di­nary’ Aus­tralian emis­sions con­trols, I have to show only good rea­sons to doubt the ‘man-made cli­mate’ case; I don’t need a con­clu­sive demon­stra­tion of the con­trary case (if it exists). So I’ll rely on just four pic­tures to sup­port my two argu­ments.

First: that offi­cial and ‘peer-reviewed’ data on his­tor­i­cal climate—let alone on cur­rent trends—strongly shows there is noth­ing remark­able about 20th cen­tu­ry cli­mate vari­a­tions.

DomeIceCoreTempsData_tmb.png This graph­ic show­ing new, high-res­o­lu­tion, esti­mates of tem­per­a­tures (using deu­teri­um prox­ies that are not con­tro­ver­sial) at two East Antarc­tic sites over 140 thou­sand years until the present has been copied from a recent­ly pub­lished, ‘peer-reviewed’ jour­nal arti­cle (B. Sten­ni et al. / Qua­ter­nary Sci­ence Reviews 29 (2010) 146–159).

The ice-core data makes it clear that tem­per­a­tures in Antarc­tia have var­ied a great deal in geo­log­i­cal­ly ‘recent’ his­to­ry; that tem­per­a­tures in the dis­tant past (120 thou­sand years ago) were much high­er than those of the present cen­tu­ry and were high­er even in his­tor­i­cal times (1,000 years ago in the ‘Medi­ae­val Warm Peri­od’ and in Roman times 2,000 years ago). All of this must be attrib­uted to ‘nat­ur­al caus­es’; there is no rea­son to seek a man-made expla­na­tion for vari­able tem­per­a­ture trends.

ClimateEpisodeVariationsChart_tmb.png

This vari­abil­i­ty of sur­face tem­per­a­tures and their inde­pen­dence of human influ­ence is not, of course, a secret hid­den in Antarc­tic ice: it has always been there. Many proxy series for his­tor­i­cal tem­per­a­tures tell a sim­i­lar, close­ly cor­re­lat­ed, story.The chart at left (remote link) rep­re­sents the ampli­tude of known episodes of cli­mat­ic vari­a­tion over the past sev­en thou­sand years—roughly, since the dawn of agriculture—taken from offi­cial (NOAA) data. The 0.7°C increase in esti­mat­ed glob­al tem­per­a­ture since 1880 is the small­est of the his­tor­i­cal warm­ing episodes over all that time.

Sec­ond: that the con­tin­u­ing dis­con­nect between observed atmos­pher­ic car­bon diox­ide (and methane) con­cen­tra­tions and esti­mates of glob­al tro­pos­pher­ic tem­per­a­tures gives lit­tle rea­son to believe that cli­mate trends would be affect­ed by cut­ting the emis­sion of car­bon gasses.

GlobalLandOceanTempsAndCO2_tmb.png The chart at left (remote link), drawn from ofi­cial data series (includ­ing GISS tem­per­a­tures, the Antarc­tic ‘Law Dome’ ice-core and the NOAA Mau­na Loa atmos­pher­ic CO2 series) shows the actu­al lev­els and trend increas­es for atmos­pher­ic CO2 and glob­al tem­per­a­ture esti­mates over the peri­od since 1880. Not only are the trends very dif­fer­ent but the vari­a­tions show no evi­dence of a rela­tion­ship. The chart also shows the tem­per­a­ture pro­jec­tions of the MIT atmos­pher­ic mod­el which are out of touch with any phys­i­cal real­i­ty.

MaunaLoaVsHadCrut_tmb.jpg

A sec­ond chart based on the UK’s Had­CRUT tem­per­a­ture series and the Mau­na Loa CO2 series shows the peri­od since 1960 in greater detail. Once again, the only remark­able fact is that the trends in the data are entire­ly unre­lat­ed, con­tra­dict­ing the IPCC’s ‘cer­tain­ty’ that one explains the oth­er. Over the peri­od since 1960 the trends have been neg­a­tive­ly cor­re­lat­ed up to about 1977, then pos­i­tive­ly cor­re­lat­ed up to about 2002, then neg­a­tive­ly cor­re­lat­ed again.

Conclusion

Since short­ly after the IPCC began to build its even­tu­al­ly-hyper­bol­ic case for con­cern about cli­mate change in the mid-1990s, tem­per­a­ture trends have flat­tened and—depending on the peri­od you select—have even shown a decline.

How­ev­er embar­rass­ing, a rever­sal of the trend, on its own, doesn’t point to a fault in their sci­ence. The fault would be to resist revi­sion of their theory—and espe­cial­ly of their ‘certainty’—in the fact of an accu­mu­la­tion of con­trary facts. What I’ve tried to show here is that the con­tra­dic­tions are mount­ing. The con­trary facts draw atten­tion to the lacu­nae (clouds, aerosols, indi­rect solar influ­cences) and crude con­struc­tion (100–150km grids) in the IPCC cli­mate mod­els and the increas­ing­ly doubt­ful sta­tus of their pre­dic­tions.

There are signs that, in response to the new data, the IPCC will adjust but not aban­don their under­ly­ing claim that man makes cli­mate change. Above all they will cling to their asser­tions of ‘cer­tain­ty’ in order to retain their polit­i­cal ascen­den­cy. That’s not unusu­al in pub­lic sci­ence either (see the Tomkow link in my sec­ond para.).

But in doing so, the IPCC risks allow­ing their the­o­ry to become myth. We must decide not to jeop­ar­dise our nation­al wel­fare in sup­port of a mere faith.

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