Two recent announcements on the Climate Change front have the blogosphere buzzing:
Richard A. Muller announced an updated paper, in the NY Times Opinion Page, originally presented and rejected for publication in 2011, claiming that global warming is indeed occurring and "essentially all of this increase results from the human emission of greenhouse gases." Oh, and he also claimed, again, despite evidence to the contrary, that he is a "converted skeptic."
Just in the nick of time, Anthony Watts announced on Sunday the paper he and others have been working on since June 2011, consisting of a reassessment of temperature instrumentation siting across North America based on a newly certified method of classification of siting criteria. Unlike the Muller paper, Watts has made the contents and data available openly for all to view and critique.
Despite evident similarities in scientific grandstanding, neither paper offers anything to a produce a sea-change in conclusions about the reality and nature of anthropogenic climate change. Muller's paper amounts to saying, "And another thing..." a year and half after the argument is over. Watts paper, makes an important contribution to the interpretation of a a small part of available atmospheric data, and may point the way to a reassessment of surface temperature measurements throughout the world.
Luboš Motl, in his blog, The Reference Frame, asks: Have Muller or Watts transformed the AGW landscape? The answer, of course, is "No."
Science doesn't work that way. Science is not advanced by opinion pieces in the New York Times nor strategically timed blog announcements, both designed to build popular interest in otherwise esoteric studies of scientific methodology. Science advances by the slow accumulation of observations, painstaking hypothesis testing of theories to explain those observations and careful modification, or in extreme cases, rejection, of established theory. Science doesn't take place in the blogosphere or on rapidly yellowing newsprint.
The climate science hyperbole exposed this past weekend is not about science, it is about credibility.
Despite recent headlines, there are only two scientific questions about climate variation of importance to politicians, policy-makers and the general public:
Does CO2 produced by human activities contribute significantly to observed changes in global average surface temperature and, thusly, global weather patterns? The corollary question is: Will reduction of human atmospheric CO2 production significantly reduce future increases in global average surface temperatures and resulting changes in global weather patterns?
On these two questions, climate science is equivocal.
The controversy centers of the observed correlation between variation in global average surface temperature and global average atmospheric CO2 concentration.
Global average atmospheric CO2 concentration has increased at a steady rate since modern measurements began in 1957.
Global average surface temperature has increased variably since modern measurements began in 1885 (in most places), 1650 in the UK.
Those who support human origin of increased temperature point out that atmospheric CO2 warms the atmosphere, and note the (rough) correlation between these two graphs and proclaim linear causation.
Judith Curry has this to say about observation-based attribution.
Those who do not support causation point out that correlation does not equal causation, and also notice that, while global average surface temperature has fluctuated throughout the study period, global average CO2 concentrations have retained a steady, linear rate of increase.
Furthermore, ice core records reveal a 200 to 800-year global lag between prehistoric global average surface temperature fluctuations and subsequent prehistoric atmospheric CO2 concentrations, indicating that atmospheric CO2 concentration variation is driven by global average surface temperature, not the other way round.
While global average surface temperature may be a largely irrelevant mathematical computation, it is increasingly evident that atmospheric dynamics are driven, to a large extent, by natural cosmic forces, such as Milanković Cycles, solar magnetic variation and cosmic rays.
It remains to be seen whether the Muller and Watts papers are recounting the deck chairs on the Titanic, or building new acceleration couches aboard SpaceShipOne.