New PNAS paper: Experts surveyed on the probability of climate “tipping points”

Pofarmer – you said the underground temperature near the surface is constant. So to the atmosphere it’s probably treated as just another constant. It is also obvious on a hot beach, particularly one which was snow-covered a few months earlier. that surface temperature is significantly affected by weather. Of course, it probably should have been studied – and maybe has been. Good hunting.

Pofarmer (13:50:14) :

What is the function of the internal temperature of the earth on earths temperature? I see discussion of earth as a black body, grey body, etc, etc, etc, but, nobody seems to want to think about the fact that the earth has a MOLTEN core, and an approximate constant soil temp of 56 degrees F or so. How much does this play into climate models and temperature.

When there is a geothermal event such as a volcano, then it is taken into account when modeling climate reactions. However as the internal heat of the planet is notionally constant then it is not. That’s not to say it’s effect is the same for all points on the earth, but rather they don’t alter much. Unless a new rift opened that upset the homogenized nature of the geothermal balance then at least I think it is reasonable to ignore it.

hereticfringe
you mean Bill Engvall… Here’s Your Sign…
Jeff Foxworthy does You Might Be a Redneck…
Larry the Cable Guy does Git Er Done!
Ron White just does everything funny…all he has to do is talk….

On geothermal energy: Did you know that there exist applications for heating and cooling houses with it?
http://www.geothermal-heat-pump-resource.org/index.html
Their physics is off but the application is good 🙂
So this .93 WATS per acre are just what comes out of the insulating top layer. In the ocean bottoms, at which level in the ground the temperatures are 50C, convection is taking away much more energy than estimated up to now. Of course it will be constant unless there is volcanic activity.

John Hultquist quoted:
“This estimate, corroborated by thousands of observations of heat flow in boreholes all over the world, gives a global average of 3×10−2 W/m². Thus, if the geothermal heat flow rising through an acre of granite terrain could be efficiently captured, it would light two 60 watt light bulbs.”
This leaves me completely puzzled as to how geothermal heating systems can work. If heat transfer through the ground is that low, one would think that ground loop systems would gradually cool the ambient soil and cease to work. But this doesn’t happen….

E.M.Smith (17:34:50) :Is there any other term for ‘feedback loop leading to limit cases at each end with both ends stable” other than hysteresis? I find explaining it to non-tech folks tiring.

In electronics you have circuits that show hysteresis and “latch up” to the high supply voltage or ground potential, which would be a rough analog to the square wave oscillator that our climate appears to be, flopping from the low limit (ice age) to the high limit (warming peak).
For the sake of discussion you might try explaining it like a logistic curve that approaches a limit. For example the percentage of a population that are infected with a disease.
At the starting point you have no one infected (ice age), then a single person gets a communicable disease. He spreads it at some rate into the uninfected population, which starts an exponential growth cycle. This is where the tipping point and the simple limited logistic curve differ. The tipping point concept assumes an irreversible over shoot like a mass death event, that wipes out the population. If on the other hand, the curve is limited by some natural means like a low mortality infectious disease is, at some point the infection rate drops as you reach a point where almost everyone who can be infected is infected. At that point the new infection rate drops toward zero, and the total number of infected people reaches a maximum plateau at some value dependent on how many people are naturally immune to the disease, or due to living habits are not likely to contact an infected person and contract the disease.
That sort of logistic curve approaches an upper limit and then the total number of infected persons drops back to zero according to the natural recovery rate of the population.
The trick is figuring out what is the mechanism that establishes the apparent upper and lower limits to the climate and global temperature.
The natural historical cycle implies that some effect stops the cooling at some minimum temperature (maximum ice cover), and some effect limits maximum temperature when some mechanism of cooling begins to dominate heat input.
To use a very crude analogy. You hold your home at some temperature that you find comfortable with a thermostat. When you have a party, as new guests arrive the heat load in the house increases by about 300 watts for each additional warm body that shows up at the house. The temperature in the rooms rises slowly until some one notices it is hot and stuffy, and people start opening windows or leaving doors open or moving out on the patio where it is more comfortable. The human comfort zone establishes a natural upper limit to the temperature the crowd of people will tolerate.
We know that at sea surface temperatures near 84 deg F (29 deg C), some basic weather processes change. For example the Indian Monsoon turns on when SST get near that upper limit, and rainfall during the monsoon tracks well with SST temperatures during the period just prior to the Monsoon season. Cyclones also become stronger and larger (with larger cloud shields) as sea surface temperatures increase.
http://www.nature.com/nature/journal/v306/n5943/abs/306576a0.html
That “trigger temperature” for strong convective storms is not far from that long term global average upper limit of 22 deg C. Local humidity conditions also play into this over land, where humidities may not be high enough for strong convection to develop due to instability, as warm moist air is unlikely to be lifted above its condensation level to trigger thunder storm development in low humidity conditions. In the oceans available humidity is not likely to ever be an issue at these temps.
That I think, would be a reasonable explanation of that observed “implied” upper limit. When large areas of the ocean reach these critical SST numbers the heat transported to high altitudes by convection and the dramatic albedo changes produced by these large convective storms over whelms stored heat in the ocean and solar heating and cools every thing down. I see thunder storm development like a pressure safety valve. As temperatures and humidities rise, thunderstorms move enormous amounts of energy to high altitudes in very short time periods, and also cut off radiant heating by the sun to the lower atmosphere and ground while they are active. Once that excess heat is radiated to space falling rain and hail rapidly cool down the ground and lower atmosphere to temperatures below that critical temperature humidity combination that is inherently unstable (high CAPE “convective available potential energy”). When CAPE is high it takes very small triggers to kick of massive thunderstorm developments. At low CAPE numbers it is almost impossible to trigger a thunderstorm even at high temperatures. Here in the high plains temperatures over about 84 deg F and humidities over 50% RH almost guarantee an active thunderstorm day.
The only thing left is to figure out a counter balancing effect that would put a low limit on the earths surface temperatures. For example as the earth cools at some point, no place on the earth would be warm enough and moist enough to trigger convective storm development. That would completely shut off that “heat pump” that pushes warm moist air to high altitudes and creates large areas of very white clouds during the summer peak heating.
Then you have dry cold conditions and stable weather during the local summer where the oceans slowly store up heat until that water vapor heat pump begins to turn on again. Once temperatures and humidities get high enough, in the summer months as warm moist air moves over the ice fields, it would lots of warm rain on the coastal ice fields and snow cover. Rainfall on snow can lead to very rapid melting of snow, which changes albedo as more and more land is melting off each summer the ice cover slowly melts back and the climate warms back up until it switches into a rapid warming mode (interglacial).
If this cycle works as I imagine it, I would expect at the end of the interglacial cycle you would see much higher precipitation (pumping massive amounts of heat to high altitudes), and higher snow depths during the early fall, late spring that would shift the earths albedo toward a higher heat loss due to higher reflection (snow blitz concept). This in turn would cause less time for the snow fields to melt off in the spring and summer, so less total heating due to the higher albedo.
If the climate hovers at a central point in that oscillation very small changes in TSI could make it “flop” to either warming or cooling trend, until these limits kick in stopping it and conditions gradually creep back toward that median value. Throw in the additional effect of seasonal heating cycles the Milankovitch cycles,and volcanic dust inputs, and they could move that whole upper limit lower limit higher and lower.
Suppose the lower limit during an interglacial cycle was about what we saw during the little ice age, and the upper limit is that 22 deg C limit implied by historical records during warm cycles?
To drop back to the infectious disease analogy, suppose that you substitute convective storms for infected people. If during the summer you have lots of convective storms covering most of the warm ocean with high cloud layers you effectively “cut off heating” in the afternoon every day when the storms build. When you get to the point that all the warm ocean water is covered by storm clouds every afternoon, you have created that upper limit barrier. The oceans cannot heat up any more because they are screened from the sun during the afternoon heating period, and heat losses to space go through the roof while the storms are active pumping warm moist air to 50-65k ft altitudes. When the storms collapse in the evening, the sky clears and night time radiant cooling is easy in the now clear skies.
This is the pattern we see during the summer thunderstorm season as the thunderstorms build during the peak of the heating day, grow vigorously until shortly after sunset then the skies clear into the night. Each part of the country has a natural time of the day when this process kicks off. Farther east the peak time for thunderstorm development is later in the evening and would have less impact on day time heating but would still pump large amounts of heat energy to high altitudes.
It seems to be a logical cycle to me, but I do not have the information to verify or falsify the concept.
This is sort of an off the top of my head post so I hope that makes sense as a possible pair of boundary conditions that naturally limit climate shifts to a relatively narrow band depending on the prevailing heat input due to TSI and its modifiers like volcanic ash and planetary motions.
Larry

OT: Mount Redoubt in Alaska alert level raised to orange.
http://www.msnbc.msn.com/id/29719558/

Anthony: AGW doctrine based on CO2-greenhouse effect eliminated?:
From: http://algorelied.com/?p=899
New peer-reviewed study: In summary, there is no atmospheric greenhouse effect, in particular CO2-greenhouse effect, in theoretical physics and engineering thermodynamics. Thus it is illegitimate to deduce predictions which provide a consulting solution for economics and intergovernmental policy.
That sucking sound you hear is all of the air and energy being sucked out of Al Gore’s global warming climate change climate crisis machine.
Source: Falsification of The Atmospheric CO2 Greenhouse Effects Within The Frame of Physics published in The International Journal of Modern Physics. Authors: Gerhard Gerlich, Ralf D. Tscheuschner

CMOC hikes to MGIS while NINO hooks to the sideline and DAIS runs a post. MGIS can hit DAIS long if he’s open, but otherwise can throw to NINO who laterals to AMAZ coming out of the backfield.
This is exactly the play the Cardinals ran in the Super Bowl and look where that got them.

LA NINA
Speaking of tipping, looks like we may be tipping into yet another La Nina. There’s some awfully cold water pooling out there.
http://www.osdpd.noaa.gov/PSB/EPS/SST/climo&hot.html