date: Mon Mar 15 13:33:13 2004 from: Phil Jones subject: Re: FW: Climate: Change could come like lightning to: "Burgess Julie Ms (CRU) f083" Julie, Circulate this to all of CRU. I'm going to email a few people about the Pentagon report and to find out who Carrie Morrill is. Also some might want to go to the appalling film mentioned at the end. Cheers Phil At 12:26 15/03/2004 +0000, you wrote: Phil, This has come through unsolicited. Should it be circulated? Julie -----Original Message----- From: Jack Saporito [[1]mailto:jack@areco.org] Sent: Monday, March 15, 2004 3:22 AM To: 1-AviationWatch Subject: Climate: Change could come like lightning Climate: Change could come like lightning By Dan Whipple United Press International 3/9/04 A weekly series by UPI on the possible human impact on global climate change. -- BOULDER, Colo., March 8 (UPI) -- Those who think global climate change requires many years to unfold might want to take note of other worldwide temperature alterations in the past 15,000 years, which occurred, in geological terms, quick as a flash. "Climate has changed abruptly in the past," said Carrie Morrill, a postdoctoral fellow at the National Center for Atmospheric Research who has just completed a paper on the subject. For example, Morrill explained, there was a 14 degree Fahrenheit rise at the end of a period called the Younger Dryas -- a climate period that occurred nearly 12,000 years ago, just after the last ice age ended. While scientists are worried about the potential impact of a 2 degree or 3 degree F. global increase over the next century, the 14 degree rise occurred "in a period of decades," she said. "Future climate change probably won't be gradual." Concerns about a possible lightning-like climate shift are beginning to emerge from a number of quarters, including some surprising sources. For example, a new Pentagon report speaks of temperature rises overwhelming the world's infrastructure over the next 20 years, causing flooding, energy shortages, drought, famine and rioting. Nations might mass troops on their borders, threaten neighbors, and even wage nuclear war as they attempted to deal with the severe upheavals in their environments and economies, the report states. The report, "An Abrupt Climate Change Scenario And Its Implications For United States National Security," characterizes these possibilities as remote but "plausible." The idea of such a rapid shift in climate -- from moderate to glacial or the reverse in only a decade or two -- seems counterintuitive. But there is little doubt it has happened in the past. Two events have been particularly well studied. They occurred at the beginning and end of the Younger Dryas. About 11,600 years ago, there was a rapid drop in temperature, followed about 1,000 years later by an equally rapid increase. Then about 8,200 years ago, there was a another rapid change -- another temperature decline. This occurrence, called the 8ka event, has been especially well documented. Average temperatures, as computed from data derived from Greenland ice cores, fell nearly 11 degrees F. in a few decades. Moreover, this dramatic temperature change was not restricted to the Arctic, or even to the northern hemisphere. Paleoclimate records for Venezuela show a virtually identical pattern for both time and temperature, as do global proxy records. All indications are that the the 8ka event was global, steep and rapid. Morrill examined 105 different proxy records that can be used to track climate conditions covering about the last 15,000 years. These records include data collected from ice cores, marine sediments, lake sediments and fossils such as ostracods that demonstrate the impact of climate over time. Because of the wide range of records, she was able to narrow the time focus of the data to 150 year increments or better. Her analysis shows two new periods of abrupt climate change -- one occurring 5,500 years to 5,800 years ago, and the other from 4,000 years to 4,800 years ago. During both periods, the climate in the tropics became drier; in the Mediterranean, colder and drier; in the high latitudes, colder, and in the mid-latitudes, colder and wetter. "Technically, an abrupt climate change occurs when the climate system is forced to cross some threshold, triggering a transition to a new state at a rate determined by the climate system itself and faster than the cause," according to a definition developed by the National Research Council. Abrupt change needs a trigger, an amplifier -- some mechanism to have the trigger affect a large area -- and a source of persistence. It turns out lots of triggers have been identified, for example, an accumulation of carbon dioxide in the atmosphere, as is occurring now. A paper in Science in March 2003 by Penn State glaciologist Richard Alley and others, noted: "... the drying of the Sahara during the latter part of the Holocene, and the ice age ... oscillations, are linked in time and mechanistically to orbital forcing. The Sahara dried as the African monsoon weakened in response to reductions in summertime incoming solar radiation ... Triggers may be fast (e.g., outburst floods from glacier-dammed lakes), slow (continental drift, orbital forcing) or somewhere between (human-produced greenhouse gases) and may even be chaotic; multiple triggers also may contribute." Although potential triggers for abrupt climate change have been fairly well identified, mechanisms that can spread the impacts globally are less obvious. "Global circulation models, forced by hypothesized causes of abrupt climate changes, often simulate some regional changes rather well, underestimate others, and fail to generate sufficiently widespread anomaly patterns," according to the paper by Alley et al. In her research, Morrill looked at the possibility the El Niņo-Southern Oscillation phenomenon could serve as a globalizer for temperature changes in the tropics. El Niņos, which are triggered by changes in tropical Pacific Ocean sea surface temperatures, are known to affect climate across North and South America, and perhaps even parts of Europe. The results seem inconclusive, however, at least as they relate to the rapid climate changes Morrill identified during the Holocene. She found the El Niņo was stronger at the last glacial maximum -- about 21,000 years ago -- weaker during the mid-Holocene, and stronger now. Whatever the scientific uncertainties, rapid climate change is about to hit popular culture. The film "The Day After Tomorrow" is scheduled to be released in May. It depicts rapid climate change -- from the trailers, apparently in the matter of days, not decades -- that causes tidal waves to sweep over Manhattan and turns all that sea water into glaciers. "Most ecological and economic systems have the ability to adapt to a changing environment," the Science paper said. "Slower changes allow response with less disruption in both ecosystems and economies. Abrupt changes are particularly harmful where the individual entities have long lifetimes or are relatively immobile; damages also increase with the abruptness and unpredictability of the climate change and are likely to be larger if the system is unmanaged." Long-lived and relatively immobile unmanaged ecosystems such as mature forests and coral reefs thus are likely to be especially sensitive to climate change, the paper continued. "Specific attention to vulnerable sectors such as these is warranted," its authors wrote. =========== ** NOTICE: In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes. ** Prof. Phil Jones Climatic Research Unit Telephone +44 (0) 1603 592090 School of Environmental Sciences Fax +44 (0) 1603 507784 University of East Anglia Norwich Email p.jones@uea.ac.uk NR4 7TJ UK ----------------------------------------------------------------------------