Bishop Hill Diary dates, hold on a minute edition
Sep 2, 2015 Climate: other The Geological Society is holding an event in the autumn which looks as though it is going to ask some slightly awkward questions about this whole global warming malarkey:
Environmental conditions at the Earth's surface have been continuously suitable for life for more than three billion years. Temperatures, for example, have only varied by few tens of centigrade despite large changes in solar luminosity and atmospheric composition. Since the Archean, the planet has not once been rendered sterile. However, the reasons for this long-term life-friendliness remain contentious. How has Earth’s climate avoided the runaway warming shown on Venus or the runaway cooling of Mars? Has Earth’s relative stability resulted from geochemical feedback (e.g. through silicate weathering), the stabilizing influence of a complex biosphere (i.e. the Gaia hypothesis), good luck (e.g. purely fortuitous cancellation of solar warming by decreased greenhouse gas concentrations) or is long-term life-friendliness simply the consequence of life’s extraordinary adaptability (allowing it to survive even Snowball Earth events)?
This conference will bring together proponents of these various views in an attempt to forge a consensus on how to move the debate forward. This debate will be informed by data relating to the latest understanding of silicate weathering, Neoproterozoic ice ages, and the environmental history of Earth.
This meeting would be suitable for anyone interested in the long-term habitability of the Earth, its long-term climate history, geo-biochemical cycles, the highly controversial Gaia hypothesis or the likelihood of habitable worlds beyond the solar system.
Reader Comments (16)
From Prof Tim Lenton's staff profile:
So he is convinced that tipping points will exist.
In the context of evidence from the real world, it could be an awkward night for him.
I think you're over reading this.
This event may not be immediately relevant to the the present climate debate, since it is clear that 'a few tens of degrees' would be nothing to be complacent about in relation to human comfort or - if arriving in a short space - survival, but I expect it could be very interesting in a wider sense and might, if the quality of the speakers is high, inform our general understanding of how the world works.
As a lifelong student of natural history, and an 'environmentalist' in the old sense of the term, the overriding lesson which has been impressed in me is the quite extraordinary resilience of biological systems and the breadth and depth of resource of all kinds that the earth provides for its inhabitants. 'Fragile Earth' doesn't seem to be a particularly apt description, as far as I can see, although if you took a poll of the general public, I'm sure they'd buy into the idea of fragility with relish.
I accept the Gaia hypothesis in so far it gives some idea of that resilience, but I'm not sure I'd take it to an extreme conclusion, where it begins to look a bit like 'Intelligent Design'
It's the H2O. The fact that water can exist in all of its forms at the surface of the Earth and in most areas can easily exchange between the forms, picking up heat in one place and dumping it in another. Why don't they even give it a nod in their list of factors?
The real reason for the +3 C, -3 C stability about the mean for the past few millions of years is quite simple to work out.
1. The IPCC's modelling is based on pushing 333 W/^2 extra from the surface and then cancelling all but the non-existent EGHE warming. It started off in 1976 at GISS where they invented an unphysical negative convective process. At some stage the Met Office replaced it by adapting Kirchhoff's Law of Radiation to include Down IR from clouds, so they massage cloud physics. The next part of the mystery took until 2010 to work out; the GISS models use double real low level cloud optical depth in hind-casting to purport non-existent extra ocean evaporation; 'positive feedback'.
2. The water cycle gives the extraordinary stability. The 10 K higher temperature for the hot-house planet was from higher atmosphere pressure, hence a lapse rate effect.
3. Forget Carl Sagan's 4 major mistakes, the basis of this pseudoscience and which have almost led to the end of the Scientific Enlightenment.
mothcatcher, I identify with your description of yourself as a life long student of natural history and old fashioned environmentalism.
Whether the Geological Society has been taken over by New Age Environmentalists, remains to be seen. Muslim extremist groups like to destroy archaeological evidence of the existence of civilizations pre-dating their belief system. They seem to have borrowed from the global warming alarmist technique of rewriting history to match their narrative.
I like and agree with mothcatcher's comment.
So that covers much of Life, The Universe, and Everything. They are being too modest, Doug McNeall.
Forty Two
Deep Thought - that' s what I was going to say. ( I could have saved you trillions of years of processing there).
mothcatcher - The Gaia thesis does have a lot to be said for it - in terms of balancing negative feedbacks especially - but likewise I think Intelligent Design is a step too far. Especially when we now know that Slartibartfast crafted much of the planet.
It looks like the Geological Society is sticking here to what it should stick to, the climate history of the "ancient" Earth. Only when it has explained that adequately should it dare to pontificate about Anthropogenic effects, but sadly they took the profile-raising but credibility-lowering option.
I think that Willis Eschenbach (WUWT) is right with his theory of evaporation in the tropics leading to cloud formation and cooling and the spreading of the heat from tropics to north/south to disperse the heat. Rhoda above hints at the same.
There is an inbuilt mechanism keeping Mother Earth average temperature within a relatively narrow range and prohibiting "run away warming".
Have never been able to believe in "positive feedback" in the climate system. Willis is right - we have negative feedback whatever the alarmists preach.
John Peter -
Sensible comment by you (whether or not Willis E. is right about the mechanism) and quite pertinent to my earlier comment on this thread.
Positive feedbacks seem generally unlikely (though shouldn't be dismissed out of hand - there are examples of same) but in relation to the climate system I would suggest that the circumstantial evidence for the existence of stabilising feedbacks is overwhelming. What I have never had satisfactorily answered by the climate mainstream, on any forum, is my question that stems, in fact, from their own claims:
?If the real damage to the climate derives only trivially from CO2 greenhouse, and largely from a potentiation of the H2O greenhouse through CO2 warming, how is it that the H20 greenhouse doesn't potentiate itself, bearing in mind just how much evaporable water there is on the planet? What is it, in terms I can understand.. spatial or altitude distribution of H20 being limited? Some direct effect between Co2 and H20 molecules in the atmosphere? Come on, you mainstream guys, how does it work?
"long-term climate history"
The good thing about geologists is that when they say 'long-term', they mean it.
Climatologists, OTOH, think that 30 years is significant, when the world has been habitable for 100,000,000 times that.
Stability of the Earth's climate, reasons for?
One: 2260 kJ/kg, i.e the latent heat of vaporisation of water, helped along with its co-travellers on the same molecule
334 kJ/kg (latent heat of fusion) and its heat capacity of 4.2kJ/kg/K.
No other common substance comes close. The ultimate heat buffer and heat transport vector.
Oh, and you can make beer with it.
Agus uisge beatha.