IPCC recommendations understate our current situation and underestimate our near-future risks by relying on the outdated 1979 “Charney Sensitivity” of the IPCC computer model ensemble. This sensitivity value of the surface temperature of the planet to the amount of CO2 in the atmosphere, always challenged by other models, merely seems the one most acceptable to the conservative IPCC consensus policy process.

In this case we are talking about the sensitivity value of the surface temperature of the planet to double the amount of CO2 in the atmosphere. A low value suggests that we can keep on with business as usual burning fossil fuels for awhile longer. A high value suggests that we need to stop now and indicates how much trouble we’re in already.

The differences between the sensitivity values given by the models, it seems, concerns how well the various models account for the numerous and complex feedbacks. All the models seem to miss some of the feedbacks, as to be expected since no model can totally represent the total reality. The valid proof of any computer model can only be confirmation from the observation of reality.

To understand the implications of the IPCC preferring a certain model, we can compare three of the more famous models. The observable reality against which modeled values can be checked is the change in average surface temperature of the planet between the last glacial maximum and the preindustrial benchmark.

This temperature change between the last glacial maximum and the preindustrial benchmark is assumed to be about 5°C, during which time the CO2 levels went from around 180 ppm to 280 ppm. These are the more conservative numbers produced from fossilized vegetation and early ice core samples. These numbers were later confirmed in other ways and I’ll get to that.

Then, we can compare the three models in a chart showing how they stack up to reality. The first model is named after Jule G. Charney. The second model is named after the Hadley Centre of the UK Meteorological Office. The third model is named after James Hansen, who had previously worked with Charney on the first model.

Jule G. Charney was Chairman of the Ad Hoc Study Group on Carbon Dioxide and Climate that produced the “Caron Dioxide and Climate: A Scientific Assessment”. It’s pretty easy to do a simple search and still find a copy of the “charney_report1979.pdf” online.

The New York Times published a good article about this called “Losing Earth: The Decade We Almost Stopped Climate Change” online at https://www.nytimes.com/interactive/2018/08/01/magazine/climate-change-losing-earth.html. It’s worth taking the time to read it. This article was later expanded into a book.

The Charney Sensitivity only included some of the relatively fast feedbacks in terms of water-vapor concentration, some albedo change from reduced sea ice coverage, together with estimates of changes in cloud effects. This was the best computers could do in 1979 and they knew then that they had not included all of the feedbacks.

The Charney Sensitivity indicates about 3°C warming for a doubling of CO2. As you can see from the chart, it shows we can expect about 1.5°C warming from our current level of CO2. At 440 ppm CO2 we should expect about 2°C warming from CO2 alone. We haven’t experienced all that heat yet because Earth’s thermal inertia delays Earth’s thermal equilibrium with the GHG (greenhouse gas) already in the atmosphere.

The thermal inertia of the global system is confirmed by the time-lag between cause and effect, between the human use of fossil fuels and the full manifestation of global heating and climate change. The Earth has yet to reach thermal equilibrium with the total amount of both CO2 and non-CO2 GHG already in the atmosphere.

It’s as if the Earth is a huge pot of water on a small stove and we have the heat turned very low. It will just take some time for the heat to equally warm up the Earth. And, of course, the heat is still turned on, so we know it will eventually get much hotter because we are still pumping more GHG into the atmosphere.

It’s just that there was never a time in Earth’s natural history that so much GHG has been added to the atmosphere is such a short time period. What we’ve done in a little over a couple of hundred of years it took Earth thousands of years to accomplish previous to the past extinction events.

Starting in 2000 with more powerful computers, the Hadley Centre of the UK Meteorological Office appeared to lead the field with their evolving HadGen3 programs. They were able to include the so-called carbon cycle feedbacks from things like vegetation changes.

The Hadley Sensitivity indicated about 4.5°C warming for a doubling of CO2. With this sensitivity we can expect about 2.25°C of warming from our current level of CO2. At 440 ppm CO2 we should expect about 3°C warming from CO2 alone. That would be hot enough to to end people, that is human extinction.

In 2005, Ferdinand Engelbeen published results of a regression analysis of the correlated values of CO2 concentration and temperature based on the gas analysis of bubbles trapped deep in the Antarctic ice cap at Vostok. This work confirmed the earlier number of about 5°C temperature rise when the CO2 levels went from around 180 ppm to 280 ppm. I told you this was coming.

In 2008 James Hansen and associates attempted to close the gap between computer modeling and the empirical measurement from Vostok. Now this model also included the slow feedbacks from things like ice sheet loss.

The Hansen Sensitivity indicated about 6°C warming for a doubling of CO2. With this sensitivity we can expect, eventually, about 3°C of warming from our current level of CO2. With this added accuracy we see that people are already functionally extinct. At 440 ppm CO2 we should expect almost 4°C warming from CO2 alone.

Then scientists working in the field came up with more confirmation of the earlier numbers derived from real world evidence. Towards the end of 2009, Mark Pagani and associates published a paper on “High Earth-system climate sensitivity determined from Piocene carbon dioxide concentration”. Their analysis was based on proxy derivation of temperature and CO2 concentration using ocean-floor sediment cores reaching back some 60 to 100 million years.

In 2011, Jeffrey Kiehl surveyed current peer-reviewed academic papers reporting on the reconstruction of values of atmospheric CO2 concentration reaching back to the Eocene period. The authors also derived values for earth system climate sensitivity across this period. Kiehl’s work confirmed Pagani’s, Engelbeen’s and the previous paleo-vegetation estimates.

We now have excellent numbers for a total Earth System Sensitivity derived from actual measurements, not just computer models. The Earth System Sensitivity indicates almost 8°C warming for a doubling of CO2. With this sensitivity we can expect about 4°C of warming from our current level of CO2. At 440 ppm CO2 we should expect about 5°C warming from CO2 alone. That is warm enough to end all life on Earth.

Today we have more than just CO2 in the atmosphere. We also have a lot of methane in the atmosphere, which is a lot more warming than CO2. The question of how much more warming depends upon what time period you look at because methane breaks down to CO2 over time.

The carbon majors like using the number for methane’s warming ability of 34 times that of CO2 over a hundred years time. Over a shorter period of time, say 20 years, methane’s warming ability is about 86 times that of CO2. Methane is also measured in ppb, 1/1000 the ppm concentration that’s used for measuring CO2, so there is a bit of math involved to determine its CO2 equivalence.

As the planet heats up another powerful GHG, water vapor, levels also go up because of increased evaporation. The evidence of this increased level of evaporation shows up in extreme weather events including more flooding from heavier rainfall and greater droughts.

Methane in the atmosphere also increases the level of ozone in the atmosphere, another powerful GHG. Then we have nitrous oxide levels to account for, which is another powerful GHG. Altogether, to say that we now have about about 700 parts per million CO2e in the atmosphere is a totally reasonable estimate.

At 700 parts per million CO2e in the atmosphere we already have more than a 10°C temperature rise in the pipeline. Even if we just stop all trains, planes and automobiles plus stop all fossil fuel electricity generation and petrol-chemical production, we’d still have to stop all the leaks from our natural gas wells and pipelines.

Don’t forget the methane bubbling up from the East Siberian Arctic Shelf and the East Siberian Sea and the GHG from the thawing permafrost tundra. Now those GHG emissions are on their own being run by natural reactions to an already too warm planet. If we can’t do something about that, then we are in run-a-way global heating

We don’t have any carbon budget left. With immediate carbon drawdown and sequestration to 280 ppm to refreeze the Arctic, we can save life on Earth.

Best overview on ClimateCrisis is Harsh Realities by David Wasdell. PDF:

http://apollo-gaia.org/Harsh%20Realities.pdf

Also hear his Harsh Realities podcast on Radio EcoShock:

https://www.ecoshock.org/2017/12/the-harsh-realities-of-now-replay.html

Most downloaded interview on Radio EcoShock