Letters to the Editor
droogoy
Published Letters: 590 Editor's Choice: 9
-
Waking up on Warming
[Read the article: Dogma days ]
[Read more letters about this article: Here]Anonymous wrote:
"I keep repeating to journalists that climate science is much like economics. Both deal with complex systems," Tulaczyk observed. "Just as a single stock going up or down cannot be interpreted as a reliable indicator of economic recovery or collapse, we have to accept the occurrence of contradictory trends in the global climate."
Fair enough, but very often complexity is used as a foil to delay arrival at a fairly well consolidated consensus. The fact is, the IPCC is a very conservative group - not a radical one- and the statements they have made in the past few monts are the result of a consensus process. By not attending amply to the IPCC consensus, way too much leverage is provided for cranks like S. Fred Singer and others employed by the prof -fossil fuel lobbies and think tanks.
I find the thrust of the global warming position of near emergency, well expressed in The American Geophysical Union's (2003) position statement (cf. Eos Transactions of the AGU, Vol. 84, No. 51, December, 2003, p. 574):
Human activities are increasingly altering the Earth's climate. These effects add to natural effects present over Earth's history. Scientific evidence strongly indicates that natural influences cannot explain the rapid increase in global near-surface temperatures observed during the second half of the 20th century.
Human impacts on the climate system include increasing concentrations of greenhouse gases, air pollution, increasing concentrations of airborne particles and land alteration. A particular concern is that atmospheric levels of carbon dioxide may be rising faster than at any time in Earth's history, except possibly following rare events like impacts from large extraterrestrial objects
In terms of the last statement, this is a reminder that we’re approaching catastrophic climate change. Since the 'rare events' referred to here were two asteroid strikes that altered the Earth's climate - the last 65 million years ago, wiping out all the dinosaurs in a literal cosmic 'heartbeat'.
The statement continues:
Atmospheric carbon dioxide concentrations have increased since the mid-1700s through fossil fuel burning and changes in land use, with more than 80% of this increase occurring since 1900. Moreover, research indicates that increased levels of carbon dioxide will remain in the atmosphere for hundreds of thousands of years.
This last is cognizant of the fact that CO2 accumulates because earlier depositions remain even as new burdens are added yearly! Thus, the CO2 warming we’re now experiencing is not the result of just one year – but 100 years’ accumulation. The process may be described something like a series with terms being added, viz: to describe the CO2 content now in the atmosphere, we must initiate the series with n= 1 (for 1907), viz.
CO2( 2007) = x_1 + x_2 + x_3 + x_4 +.............+ x_100
E.g. terminating at the last term 100 years later. Here each ‘x’ denotes the CO2 burden added for each year in succession.
Thus, the CO2 effect for a given year is not just for that year, but rather inclusive of the cumulative additions for all the years - starting up to 100 years before!
This means things can only get worse.
The AGU 2003 position statement goes on for another 12-14 lengthy paragraphs noting the complexity of the problem, but also the urgency in solving it or at least getting better predictions. It also suggests ways and means of doing this, e.g. "enhanced international research."
Re: the Antarctic data, let's bear in mind that in some places (Antarctica) – positive feedback may drive the opposite effect: accumulation of ice resulting in higher albedo and more solar radiation reflected back into space. There is no reason, in point of fact, why both processes could not be going on at the same time. Eventually, of course, this “equilibrium” will be shattered- probably after the oceans reach maximum CO2 absorption capacity and begin massive outgassing, evidence for which is already occurring in terms of higher land temperatures (‘Warm Oceans Raise Land Temperatures’ in Eos Transactions, Vol. 87., No. 19, 19 May 2006.)
And I quote verbatim (ibid., p. 189):
“During 2004, sea surface temperatures were the third warmest in the past 125 years, and land temperatures were the fourth warmest, and globally averaged temperatures likewise ranked fourth highest”
Let us be reminded, again, that early versions of the IPCC model actually predicted the Arctic would first experience global change in melting ice caps, permafrost, and it did. It predicted the warmest years of the decade would correlate to CO2 concentrations > 366 ppm, and they did. (Nine of the past 13 years were the warmest on record, all displayed CO2 concentrations > 367 ppm)
In terms of the significance of global warming, I prefer to stand with the AGU statement, and believe we need to act based on the precautionary principle - not wait forever for evidence to manifest of 99% or higher threshold (e.g. less than 1% uncertainty) by which time we will be powerless to do much of anything in terms of avoiding the tipping point, and the runaway greenhouse effect