Steve —
Fresh out of meetings at the Heartland Institute (earlier involved in tobacco promotion) supported by the American Enterprise Institute, which received $1,625,000 from Exxon-Mobil between and 1998 and 2005, and an initial meeting with Penny Wong and our chief scientist, you’ve told the ABC, “So far I don’t think there’s been a real debate about the science” and “Let’s actually explore that.”
Unfortunately the climate is not waiting for your “exploration.”
So I’ve prepared some notes for you for your additional meeting with Penny and co.
According to a new paper titled “Is the climate warming or cooling by Easterling and Wehner (Geophysical Research Letters, 2009) global warming trend is tracking toward 3 or 4 degrees Celsius through the 21st century, likely including pauses, namely multi-year to a decade-long or two decades-long periods of cooling inherent in the ENSO (El-Nino La Nina) cycle to date.
Peaks in the trend represent El-Nino events (warming and droughts in some regions), whereas troughs represent La-Nina events (cooling and heavy rainfall in some regions). Such projected irregularities would continue trends observed during 1975-2009.
The paper states:
Numerous websites, blogs and articles in the media have claimed that the climate is no longer warming, and is now cooling. Here we show that periods of no trend or even cooling of the globally averaged surface air temperature are found in the last 34 years of the observed record, and in climate model simulations of the 20th and 21st century forced with increasing greenhouse gases. We show that the climate over the 21st century can and likely will produce periods of a decade or two where the globally averaged surface air temperature shows no trend or even slight cooling in the presence of longer-term warming.
And:
Society may be lulled into a false sense of security by smooth projections of global change. Our synthesis of present knowledge suggests that a variety of tipping elements could reach their critical point within this century under anthropogenic climate change. The greatest threats are tipping the Arctic sea-ice and the Greenland ice sheet.
“Good news” for climate skeptics, who will be able to continue to confuse people no-end based on La-Nina pauses … Not so “good news” for future generations!
It is not clear from these projections whether, or at what point, tipping points which may overprint the oscillating warm/cool ENSO pattern. Tipping points refer to the critical threshold at which a minor perturbation of the climate system can qualitatively alter the state or development of a system. In principle, early warning systems could be established to detect the proximity of some tipping elements.
Major consequences of the trend include warming in the north Atlantic and sea level rise. Other potential tipping elements include:
- Melting of the West Antarctica ice sheet.
- Collapse of the Atlantic thermohaline circulation, regional cooling and southward.
- Shift of the inter-tropical convergence zone.
- Intensification and rise in frequency of the El-Nino Southern Oscillation, with consequent droughts in SE Asia and elsewhere.
- Retardation of the Indian summer monsoon and consequent droughts.
- Extension of the Sahara/Sahel and West African monsoon one positive outcome of global warming.
- Reduction of the Amazon rainforest and biodiversity loss.
- Reduction of the Boreal forest.
- Reduction of circum-Antarctic ocean vertical circulation (bottom water formation) associated with ocean warming, reducing ocean CO2 storage.
- Increase in Tundra tree cover.
- Reduction in permafrost and in marine methane hydrates, threatening methane and CO2 release.
- Oceanic anoxia and marine life extinction.
- Reduction in Arctic ozone and increase in UV radiation at the surface.
Should the Atlantic Thermohaline Circulation (Gulf Stream) fail, deeper cooling would occur in western Europe and northeast America, associated with advanced melt of Greenland glaciers, similar to events 11,700 years ago and 8200 years-ago. Similar cooling of unspecified length, followed by further warming, may occur in connection with the melting of Antarctic ice sheet.
Of critical importance is the ability to predict the time table of tipping elements in advance, to help mitigate or retard the process. Such potential advanced warning may be provided by activity lulls associated with an approach to critical tipping points.
According to a recent paper by Dakos and others (2008, Proceedings of the National Academy of Science) abrupt tipping points may be preceded by slowing down of the fluctuations starting well before the actual shift, as shown by analyses of eight ancient abrupt climate shifts, potentially allowing an early warning signal for upcoming catastrophic change. We should be so lucky…
And, according to Eby et al. 2008 (“Lifetime of Anthropogenic Climate Change: Millennial Time Scales of Potential CO2 and Surface Temperature Perturbations“, while it will take centuries for anthropogenic CO2 to be naturally sequestered from the atmosphere, the consequent warming “will persist for many millennia.”
I’m not in general a fan of Senator Fielding, but on this occasion I think he is entitled to query whether we should impose real costs on industries & people on the basis of a succession of scientific hypotheticals such as these:
– “global warming trend *is tracking toward* 3 or 4 degrees Celsius through the 21st century, *likely* including pauses” (translation – temperatures are not currently rising, but they *might* at some point in the future)
– “tipping points refer to the critical threshold at which a minor perturbation of the climate system *can* qualitatively alter the state or development of a system”
– list of 13 *potential* tipping points
– “*should* the Atlantic Thermohaline Circulation (Gulf Stream) fail”
– “similar cooling of unspecified length, followed by further warming, *may* occur in connection with the melting of Antarctic ice sheet
– “advanced warning *may* be provided by activity lulls.
OK, some of this may be commendable scientific caution, but I’m not sure I would want to vote for such a camel of a tax scheme on the basis of what *may* happen, as projected by computer modelling on the basis of debatable assumptions.
@Andrew: The North Atlantic thermohaline circulation is not the same thing as the Gulf Stream — the gulf stream is a wind-driven surface current running northeast from the Caribbean to the coasts of France, Britain and Ireland, quite narrow, quite shallow and quite fast. The greater thermohaline circulation is deep and slow, driven partly by the Gulf Stream and other tropical upwellings but also by Greenland meltwater dilution and involving vast volumes (basically the entire ocean) but taking centuries to circulate.
@MichaelT: Yes, all the scary stuff is made from maybes, not certainties. Total catastrophe with long odds, shorter odds on numerous minor disasters. Any action to reduce emissions and/or adapt to changing circumstances a matter of insurance, not a sure remedy. Are you feeling lucky?
1. Every one knows the Gulf Stream and the North Atlantic Thermohaline Circulation are connected.
2. To appreciate the serious nature of climate change one needs to read the detailed IPCC reports plus recent Copenhagen update and related papers. From observations to date climate change projections by the IPCC since 2001 proved to be conservative, while CO2, temeprature and sea level are tracking at the top of these trajectories.
3. Once people read the recent literature, in so far as they have meaningful reservations from the science, they ought to formulate their points and submit to the peer-reviewed scientific journals.
4. This is, unless they regard climate research organizations (Hadley-Met, Tyndall, NASA, Potsdam, CSIRO, NSIDC), the IPCC, Science Journal editors, reviewers and climate scientists in general in terms of a “conspiracy theory”
It is interesting that (unless where vested interests encourage it), people don’t generally feel competent, for example, to question nuclear physicists, or aeronautic engineers, or brain surgeons, However, in the case of climate science there are those who appear to purport to know better than scientists who have dedicated more than 20 years experience in studies of the disciplines.
I suggest those who have questions read the IPCC AR4 2007 report, then return with quesitons.
Andrew Glikson
16-6-09
Wow Andrew,
You must be the smartest guy ever, the way you can control the future climate.
I think those nuclear physicists, or aeronautic engineers, or brain surgeons that you heroicly compare yourself to are unlucky they can’t just model their operations but rather have to achieve success to progress in their careers.
Good luck to you anyway.
It must be an awesome burden – saving the world , but so far so good eh!
1. In fact all these sciences both model their inputs/outputs as well as monitor the results – it is when the computer models match observations, both in nature and the alboratory, that the degree of confidence rises.
2. Climate scientists do not “control” the future climate, but compute the consequences of carbon emissions, sulphur emissions, CFC emissions and a range of other forcings on the atmosphere.
3. One example is the consequences of an extra emission of 1000 billion tons of carbon, calculated to elevate atmospheric CO2 levels above the upper limit of ice age conditions (about 500 ppm, commenced about 34 million yesrs ago, when the Antarctic began to form), with mean global temprature rise of about 4 degrees C. Look at Easterling and Wehner (Geophysical Research Letters, 2009) link given in the article.