On WUWT today Anthony Watts has posted an article about the faint young sun paradox. A research team at the University of Colorado Boulder has used the Janus supercomputer to run a sophisticated three-dimensional climate model.
The model was run for 6,000 hours or, by my reckoning, more than ten thousand years of home computing time on a laptop if they had used the full capacity of Janus. (The article says the computing time was the equivalent of ten years on a home computer, which suggests the researchers weren't using all the available computing capacity - or someone got their sums wrong. My guess is the former. Either that or Eric Wolf and Brian Toon have remarkable status at U Colorado to tie up Janus for more than eight months!)
|Janus - photo source: U Colorado|
Forget 18 weeks and a year or two ago and travel back to 2.5 billion years ago. From the press release:
Wolf and Toon used a general circulation model known as the Community Atmospheric Model version 3.0 developed by the National Center for Atmospheric Research in Boulder and which contains 3-D atmosphere, ocean, land, cloud and sea ice components. The two researchers also “tuned up” the model with a sophisticated radiative transfer component that allowed for the absorption, emission and scattering of solar energy and an accurate calculation of the greenhouse effect for the unusual atmosphere of early Earth, where there was no oxygen and no ozone, but lots of CO2 and possibly methane.
The simplest solution to the faint sun paradox, which duplicates Earth’s present climate, involves maintaining roughly 20,000 parts per million of the greenhouse gas CO2 and 1,000 ppm of methane in the ancient atmosphere some 2.8 billion years ago, said Wolf. While that may seem like a lot compared to today’s 400 ppm of CO2 in the atmosphere, geological studies of ancient soil samples support the idea that CO2 likely could have been that high during that time period. Methane is considered to be at least 20 times more powerful as a greenhouse gas than CO2 and could have played a significant role in warming the early Earth as well, said the CU researchers.
There are other reasons to believe that CO2 was much higher in the Archean, said Toon, who along with Wolf is associated with CU’s Laboratory for Atmospheric and Space Physics. The continental area of Earth was smaller back then so there was less weathering of the land and a lower release of minerals to the oceans. As a result there was a smaller conversion of CO2 to limestone in the ocean. Likewise, there were no “rooted” land plants in the Archean, which could have accelerated the weathering of the soils and indirectly lowered the atmospheric abundance of CO2, Toon said.
Another solution to achieving a habitable but slightly cooler climate under the faint sun conditions is for the Archean atmosphere to have contained roughly 15,000 to 20,000 ppm of CO2 and no methane, said Wolf. “Our results indicate that a weak version of the faint young sun paradox, requiring only that some portion of the planet’s surface maintain liquid water, may be resolved with moderate greenhouse gas inventories,” the authors wrote in Astrobiology.
“Even if half of Earth’s surface was below freezing back in the Archean and half was above freezing, it still would have constituted a habitable planet since at least 50 percent of the ocean would have remained open,” said Wolf. “Most scientists have not considered that there might have been a middle ground for the climate of the Archean.
Wolf and Toon have been researching the faint young sun for some time. Here is an earlier paper of theirs published in Science in 2004, in which they postulated that earth was enshrouded by a photochemical haze back in the Archean, which acted as a UV shield.
Reaction from the WUWT illiterati
Naturally, the blog "scientists" at WUWT know better than the researchers who, in their view "don't no nuffin'". They put up their own blog science to point out what those dumb scientists forgot to take into account. Some excerpts:
Barry Cullen says:
July 9, 2013 at 8:07 pm I suspect the authors did not take into account ...(blah blah blah)
July 9, 2013 at 7:50 pm Is this computer model study a genuine attempt to explain the faint sun paradox or just another sorry attempt to promote the idea that adding radiative gases to the atmosphere will reduce the atmospheres radiative cooling ability? Sadly I suspect the latter....(blah blah blah)
July 9, 2013 at 7:46 pm We have no idea what the early atmosphere was....(blah blah blah)
July 9, 2013 at 7:19 pm Assumptions = faith
Gunga Din says:
July 9, 2013 at 7:16 pm A question. Is there anything to indicate (i.e. “evidence”) that the atmosphere really was as they say other than the assumption it was so their model would work?
July 9, 2013 at 7:05 pm I wonder how complete the modelling was. For example the Moon was a lot closer so ....(blah blah blah)
Hockey Schtick says:
July 9, 2013 at 6:58 pm “Paradox Solved” – no, hardly, as the estimates for the young Earth CO2 levels were considerably less as pointed out by a recent paper in GRL, and this paper is based upon climate models which are unable to replicate even the Holocene, RWP, MWP, LIA, 20th and 21st centuries... (blah blah blah)
July 9, 2013 at 6:46 pm Data finally confessed. It’s CO2 of course, but “more research is needed”, i.e. better models and faster computers and more money for us.
July 9, 2013 at 6:29 pm Make the atmosphere thicker due to more volcanic activity and it becomes a lot easier problem to solve. Were they trying to solve the paradox using the atmospheric thickness of today? That might not be correct. Double or triple the amount of atmosphere present and the problem gets a bit more manageable.
Eric Worrall says:
July 9, 2013 at 9:25 pm Hilarious – what do they plan to do about the normal sun paradox they’ve just created?.... (blah blah blah)
Austin compares his available 40 nodes to the "JANUS supercomputer, which is comprised of 1368 compute nodes, each containing 12 cores, for a total 16,416 available cores. JANUS can achieve 184 TFLOPS (Trillion Floating Point Operations)", and says:
July 9, 2013 at 10:53 pm Janus is not that impressive. I have ten four-node machines in one rack with that kind of power. Of course, they each have a GPU card and a Fusion IO card and 512GB of RAM and sit on a 40Gbps backbone…
Of all the comments, this recent one from Steve Garcia best sums up the attitude towards science that is fostered by Anthony Watts at WUWT:
July 9, 2013 at 8:25 pm I think Leif Svaalgard sent it over to Anthony so we could have a laugh..... (blah blah blah)
WUWT-ers don't value science
You know, I didn't see even one comment on WUWT saying "that's interesting" or "fascinating stuff" or "wow - that Janus supercomputer is amazingly powerful" or "brilliant research" or "that raises some interesting questions" or even "Thanks, Anthony - it's good to keep up with the latest science."
The scientific illiterati at WUWT aren't into science. The sole purpose of their existence is to bash away on the keyboard of their powerful home computer, sending electronic messages across cyberspace using wireless transmissions, advanced microwave technology or optical fibre or all of these, moaning that all knowledge is bad, "syintists don't no nuffin and are only init fer the money" and that "lernin' is for fools" and any money spent on adding to the world's knowledge is wasted and that it is better residing (temporarily) in their hip pocket so they can buy more fancy gizmos developed through the scientific advances they so despise.