There has been a rash of news about how settled the global warming debate really is. From brand new ‘neutral‘ discussions that have concluded within a matter of weeks that global warming is real to Geological Society taking a stand on the issue of global warming. All of the new things are a strong attempt to put forward the idea that the debate should be over.
I very disappointed by the statement put out by the Geological Society. They put together a very nice comprehensive history of the Earth’s climate which is pretty detailed and is very much in alignment with the history that I have put together, but they also make some assumptions that are really not supported. I think the committee that put this together really had a fight on their hands.
They are clearly not convinced that any warming that took place before 1970 was emission driven and they are clear to point out that the escalation of emissions since 1970 is significant in a historical sense. There is nothing to disagree with there. While human CO2 emissions are not as large and the natural cycle, I am not going to now or ever say that mankind is not the cause of the increasing CO2 levels. We really are producing a lot of CO2.
The problems I see in the statement by the Geographical Society are in a couple of key sections where they are much less precise. Here they are discussing if there has been sudden climate change in the past.
Yes. About 55 million years ago, at the end of the Paleocene, there was a sudden warming event in which temperatures rose by about 6ºC globally and by 10-20ºC at the poles22. Carbon isotopic data show that this warming event (called by some the Paleocene-Eocene Thermal Maximum, or PETM) was accompanied by a major release of 1500-2000 billion tonnes or more of carbon into the ocean and atmosphere. This injection of carbon may have come mainly from the breakdown of methane hydrates beneath the deep sea floor
Key items that I see are that there was an increase in CO2 levels that happened at the same time, but they forget that correlation is not the same as causation. Anything that caused the Earth to rapidly warm up by a large amount could also cause the amount of CO2 in the atmosphere to increase rapidly as well. While the Earth in that condition had less CO2 in the oceans than the Earth has currently (because the oceans are much colder now and hence have absorbed much more CO2 from the atmosphere), a rapid increase in polar ocean temperatures would still release CO2 in large amounts. Especially as the warmer polar oceans would be unable to re-absorb the CO2 from the atmosphere. Such warm oceans might break down the CO2 cycle and that would result in a period of very high CO2 levels.
That one I might have given more weight too, but when it comes to the more recent climate they really do show signs of jumping on the bandwagon and taking some scientific shortcuts.
They really missed the point here. There are two points that Antarctica gets discussed. Initially it looks good when they state that the ice sheets started to form 34 million years ago (it would be hard to mess that up). But then much later in the statement they say.
Most estimates agree that there was a significant decrease of CO2 in the atmosphere from more than1000 ppm at 50 million years ago (during the Eocene) to the range recorded in the ice cores of the past 800,000 years22. This decrease in CO2 was probably one of the main causes of the cooling that led to the formation of the great ice sheets on Antarctica29. Changes in ocean circulation around Antarctica may also have also played a role in the timing and extent of formation of those ice sheets30,31,32.
It is known that the changes in the ocean played the MAJOR role in the cooling of Antarctica that took place 34 million years ago. There is almost no scientific doubt that the formation of the Antarctic Circumpolar Current was the cause of the ice sheet formation in Antarctica. There is also no doubt that such a cooling of the oceans would greatly reduce the level of CO2 in the atmosphere. This is the truly sleazy section of the statement which just really shows that they are on the AGW bandwagon. Many a geologist is going to be irritated with that statement.
Once it was clear that the Geological Society has jumped on board global warming, it is easy to dissect the other talking points that pop up throughout the statement. The final one that I will take umbrage on is the following definition of the Greenhouse Effect.
The Greenhouse Effect arises because certain gases (the so-called greenhouse gases) in the atmosphere absorb the long wavelength infrared radiation emitted by the Earth’s surface and re-radiate it, so warming the atmosphere. This natural effect keeps our atmosphere some 30ºC warmer than it would be without those gases. Increasing the concentration of such gases will increase the effect (i.e. warm the atmosphere more)19.
This recurring definition is really the best of the frauds that has been pulled off. The Greenhouse Effect is ~30 °C, but it is not only caused by the absorption of infra-red energy. It is caused by all the energy that is transferred from the Earth’s surface to the atmosphere. Since the absorption of infra-red only accounts for ~12-14% of the total energy transferred, it is a minor player in the total GHE. Trenberth should be very proud of his highly misleading energy balance. Forget the Hockey Stick, it is the Trenberth energy picture that is the most mis-leading to scientists around the world.