Guest post by Alec Rawls
Here is the puzzle, as noted by Nigel Calder and others: how can BEST insist that a modicum of additional evidence of late 20th century warming should put skepticism of the CO2-warming theory to rest, while at the same time admitting that they never even tried to examine the possible causes of warming?
Elizabeth Muller’s press statement in support of anti-CO2 alarmism is extreme:
Elizabeth Muller, co-founder and Executive Director of Berkeley Earth, said she hopes the Berkeley Earth findings will help “cool the debate over global warming by addressing many of the valid concerns of the skeptics in a clear and rigorous way.” This will be especially important in the run-up to the COP 17 meeting in Durban, South Africa, later this year, where participants will discuss targets for reducing Greenhouse Gas (GHG)emissions for the next commitment period as well as issues such as financing, technology transfer and cooperative action.
She is strongly implying that BEST’s findings not only support the CO2 theory of late 20th century warming, but justify radical worldwide government action to reduce carbon emissions.
Richard Muller’s statement of ignorance on the cause of the observed warming is equally absolute:
What Berkeley Earth has not done is make an independent assessment of how much of the observed warming is due to human actions.
Contradictory, yes, but also explanatory. Muller et al. must be so ignorant of this climate science subject that they are brand-new to that they are not even aware that the leading competing climate theory, where solar-magnetic activity modulates cloud formation, also predicts and explains late 20th warming. All they know is that the CO2 theory predicts warming, prompting them to see evidence of warming as evidence for that theory.
This is the only logical explanation for Muller vs. Muller, and it would also explain why BEST made such a complete hash of the only part of their data that does have any power to discriminate between CO2-warming and solar-warming.
Opposite temperature predictions for quiet-sun era
If late 20th century warming was mostly caused by the industrial release of atmospheric CO2, then warming should be continuing apace, but if 20th century warming was mostly caused by the 80 year grand maximum of solar activity that waned in the 1990’s and ended in 2005, then planetary temperature (as measured by the heat content of the oceans) should have been falling for several years now. In a less smooth way, surface temperatures would also be passing the peak of the Modern Warm period.
Nature is right now conducting an ideal experiment for determining which theory is right, but on this crucial part of the temperature record—what happened when solar activity waned and then dropped into the cellar—BEST’s presentation is remarkably confused. The sample station analysis that they released shows substantially more post-98 cooling than any of the other land records, while their full data set has recent temperatures going up compared to the other records.
Here is a zoom-in on figure 1 from BEST’s “decadal variations” paper. It shows the most recent temperatures for a sub-sample of temperature stations (“[this] Berkeley Earth data were randomly chosen from 30,964 sites that were not used by the other groups”):
Wow, this sub-sample really favors the sun as the primary driver of climate, certainly compared to the NOAA, GISS and Hadley evidence. The BEST temperatures are equal or above the other temperature records throughout the 80’s and 90’s, then drop precipitously below them over the last ten years, as the sun has gone quiet.
BEST’s full data set tells the opposite story. Here is their 12 month average surface temperature (figure 8 from their “Temperature Averaging Process” paper):
The second part of figure 8 shows the differences. NOAA and GISS both drop off a couple of tenths of a degree relative to BEST after 2000, while Hadley drops off about a half a degree!
Wow, compared to the evidence provided by the other temperature records, BEST’s full sample really favors the CO2 theory over this critical period. Thus on the only part of the temperature record that is probative, BEST displays two strongly contradictory graphs without a word of commentary. That’s a pretty good sign that they are oblivious to the discriminatory power of this part of the record, indicating again that they are not even aware of the GCR-cloud theory and its implications. No wonder they can do such incredibly biased things as calling “the late part of the 20th century,” “the anthropogenic era” (p. 30). Anthropogenic warming is their premise.
BEST evidence is not best evidence
Almost all of the heat capacity of the biosphere is in the oceans. Thus climate change over time means a change in ocean heat content. Land surface temperature is a volatile expression of this global temperature, depending on whether colder or warmer ocean currents are at the surface. That volatility makes surface temperatures an iffy way to track climate change, and today, better evidence is available.
In recent years, ARGO’s automated fleet of temperature sounding devices provides much improved direct measurement of ocean temperature. According to NOAA, data from these floats show ocean heat content for the top 700 meters as close to flat for about 10 years now:
Ocean heat content can also be measured by sea level, which is determined by the thermal expansion of the oceans, plus net land-ice melt. Here is NOAA’s sea level data, compensated for land-ice melt and variations in salinity. It shows ocean heat content as roughly flat for about the last eight years:
This best evidence indicates that global warming has stopped, which militates against the CO2 theory of late 20th century warming, but the oceans do not show the global cooling that the solar-theory predicts, so it does not clearly favor the cosmic-ray-cloud hypothesis either. The very latest sea level data, however, may finally be telling the tale:
Steve Goddard, September 2011: “The latest sea level numbers are out, and Envisat shows that the two year long decline is continuing, at a rate of 5mm per year.”
That’s actual sea level, not steric sea level. Subtract out the ongoing land-ice melt from our currently warm climate and thermosteric sea level is falling even more rapidly. If cosmic-ray-cloud effects do dominate CO2 effects, we’ll probably have full proof within the next couple of years.
Can BEST actually be unaware of the cosmic-ray-cloud theory, or are they just accepting the CO2-alarmists’ excuses for dismissing solar effects?
Unless Muller is a world-class fruitcake, he can’t have waded into the climate arena without at least being aware of Svensmark’s theory. He must also know that the sun has gone quiet, and his Nobel-physics brain would be able to figure out how this natural experiment provides a test of which theory is right. Yet he might still act as if he is unaware of solar warming theory if he has been convinced by the alarmists’ bogus excuses for why recent warming can’t have been caused by the sun.
Over and over, these folks claim that late 20th century cannot have been caused by the sun because solar activity was not rising over this period. e.g. Rasmus Benestad, 2005:
A further comparison with the monthly sunspot number, cosmic galactic rays and 10.7 cm absolute radio flux since 1950 gives no indication of a systematic trend in the level of solar activity that can explain the most recent global warming.
That reasoning obviously requires an assumption that ocean temperatures had equilibrated to the high level of 20th century solar forcing by 1950. Otherwise the continued high level of solar forcing (the hypothesis under consideration) would cause continued warming until ocean equilibrium was reached. Yet Benestad did not even acknowledge this assumption, never mind make any case for it, and this has been the pattern.
I have written several posts on the alarmists’ excuses for dismissing the solar explanation and how they utterly fail to stand up to scrutiny. But without even going into those details, the more basic point is that the various rationales for dismissing the solar warming hypothesis are theoretical. They are, in effect, part of the CO2 warming theory. Our recently quiet sun offers a test of which theory makes the right prediction. To ignore that test because one already agrees with one of the theories, as BEST seems to be doing, is to put theory over evidence, the opposite of what scientists are supposed to do.