I’ve already written a few articles on the possibility of atmospheric air pressure change causing the temperature change over the ice age: (overview, calculations), this suggests that if the air pressure increased by 30% that would be enough on its own to cause the 8C warming we see coming out of an ice age.
It also means that for an ice-age cycle of around 80,000 years, the rate of drop in pressure (if pressure alone were the cause of all temperature change), would be 300mb/80,000 or 0.375mb/century.
Today I’ve just come across evidence showing long term pressure change in an old article in WUWT
Historic global annual mean atmospheric pressure at sea level between 1916 and 2007
This shows a drop in pressure from 1008.4 to 1007.6 over 91 years or of 0.87mb/century which is sufficient to drop global temperature by the 8C that occurs over an ice-age cycle in around 40,000 years.
This is now the first concrete evidence that we are part of a long term decline in atmospheric pressure which in turn will lead to a long term decline in temperature – until that is, the earth sees the triggering of another caterpillar event – whereupon the small increase in temperature from a change in the orbital cycle will lead to yet another “runaway global warming event” that will take the planet out of the next ice age and into the next interglacial.
Whereupon, the warming is brought to a “hard stop”, so that further warming is all but impossible.
Is there any link between air pressure and the strength of the solar wind?
“The average pressure of the solar wind has dropped more than 20% since the mid-1990s,” says Dave McComas of the Southwest Research Institute in San Antonio, Texas. “This is the weakest it’s been since we began monitoring solar wind almost 50 years ago.”
http://science1.nasa.gov/science-news/science-at-nasa/2008/23sep_solarwind/
In order for a pressure change to occur – we need to see massive numbers of molecules leaving the atmosphere. Given the necessary escape velocity, it appears unlikely they are escaping to space (although it’s not totally implausible that they might not get a helping hand in some way from things like a solar wind).
But the most likely way the atmosphere is leaking would be that it is being tied up into some geological process. Which doesn’t seem to implicate the solar wind.
There might be according to this.
Solar Wind Changes Atmospheric Pressure over South Korea
Evidence is growing that interplanetary magnetic fields can have a significant influence on our weather.
http://www.technologyreview.com/s/424665/solar-wind-changes-atmospheric-pressure-over-south-korea/
The simple answer was that the two are different – but then I realised that if you accept that the Greenhouse++ determines temperature, then if solar wind affects the long term average, then it must by implication affect the greenhouse++
The likely way it affects the greenhouse effect is in the cloud layer. Changes to this layer significantly affect the average radiation height and therefore the temperature of the final molecules emitting IR into space and so the amount of IR emitted from the planet.
(Greenhouse++ is greenhouse plus flows into and from the oceans and crust – the oceans are important fore “short term” climate 1-100yrs).
Yet another wonderful and thought provoking post. This is fast becoming my favorite blog rather than just in the top 10. 🙂
It is amazing that there are so many factors to consider when trying to decide what causes the planet’s average temperature to change other than CO2. It is truly amazing how many “scientists” can only see CO2 and man-caused emissions. The state of modern science is bizarre.
As an aside, I recall dimly that there was a theory (30 years ago??) that there were objects outside of our known solar system that would pass close to the earth in a periodic way and that would greatly effect the earth — but not always in exactly the same way. I wonder if there are any people who still wonder about “outside influences”?
~ Mark
Much appreciated Mark.
In the first post I started with the attitude: “it’s a bit of a daft idea that pressure changes but it would be interesting to explore what it could do if it were happening”.
I’ve now found evidence it is indeed happening – and at close to the rate I predicted. So, far from being daft, it appears to be right.
Not only that – but it’s the key to explaining how temperature expansion of the crust could result in temperature changes through the emission of volcanic gases.
But the problem is that far from me having any incentive to make this better known, I know it will just be one up hill struggle – consuming vast amounts of time energy and money – and not being an academic, there’s zero benefit to me personally – as obviously there’s no career progression, no professorships waiting for me to fill, no massive grants I could apply for on the basis of this work.
Great! I’ve worked it out – now what?
What about this? NASA press release:
SOLAR WIND SQUEEZES SOME OF EARTH’S ATMOSPHERE INTO SPACE
‘Researchers using NASA’s Polar spacecraft have found the first direct evidence that bursts of energy from the Sun can cause oxygen and other gases to gush from Earth’s upper atmosphere into space. Scientists first saw this effect September 24-25, 1998, when a storm from the Sun smacked into the Earth. Using particle detectors on Polar, they found that the flow of “polar wind” out of Earth’s upper atmosphere increased substantially when the storm hit. In effect, pressure from the solar ejection squeezed gas out of the ionosphere.’
http://science.nasa.gov/science-news/science-at-nasa/ast08dec98_1b/
This is what makes the most sense to me. I wonder to what degree changes in air pressure correlate. We might think of the quantity of molecules in the atmosphere being in a equillibrium, adjusting to the solar wind. I also think water’s vapor pressure, which reacts both to temperature and pressure, might exert a balancing effect.
It is, however, interesting to think what would be the outcome if there was a sudden, dramatic reduction in air pressure. Might that kick off an ice age. What if, for example, a pulse of solar energy or a near miss from a comet might be the mechanism that reduces pressure (by knocking out gasses) thereof.