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Part 2: A Gathering Storm
The summer of 1988 burned a new fear into the minds of many Americans. We watched amber waves of grain in the nation's heartland turn brown and shriveled under the rainless sky, while water levels dropped along the Mississippi River and temporarily stranded thousands of barges. Wildfires in the western states blazed through millions of forested acres and shrouded majestic mountains in a veil of smoke. Across the nation, record heat and drought forced us to wonder: Is Earth's climate changing before our very eyes.
Abrupt climate change — is it decades away or did it begin decades ago?
According to the National Oceanic and Atmospheric Administration's Reports to the Nation on Our Changing Planet: The Climate System, "The Earth, for all we know, is a unique planet where a thin blanket of air, a thinner film of water and the thinnest veneer of soil combine to support a web of life of wondrous diversity and continual change. The daily needs of more than five billion people now stress the limits of this naturally regulated system.
The impacts of a changing climate on such a world can be profound."
The report's authors, Robert Dickinson, University of Arizona and Richard Monastersky, Science News pose the following question, "Are we barreling down a runaway route toward climatic catastrophe or will the future bring relatively benign changes that will not threaten society? Answers to such questions will only come through intense research into the mysteries of Earth's climate system. No need could be more pressing, no mission of greater import to future generations."
In many respects, I find that the arguments raised by many, that "the government is withholding information," or "they (whoever that may be) are not telling us the truth," or "why can't they give us the answers" hold little credence and to me, are of little merit. The fact is that there is really no way to mask climate change, no way to hide, ignore, trivialize the facts the confront us.
Do we need someone to tell us that the climate is moving to critical mass, or do we need to open our eyes a bit wider and begin connecting the dots? The time has come, for many, perhaps the very first time, for us to take responsibility for finding the facts, digesting the data, and making our own decisions as to what will be the best possible course of action for our families and ourselves. It is time, to be a bit blunt, for us to think and act like adults, to think and decide, rather than to simply wait to be told what to think and what to do.
Reaction from the climatologists has been quite positive, citing that the movie is "dead right on the mark." However, all that have been interviewed by the media have been quick to point out that the timetable portrayed in the movie is entirely too compressed that such change would take decades, if not centuries, to occur. Scientists have just begun to study the possibility of an abrupt climate change. However, they caution that when they talk about abrupt climate change, they mean climate change that occurs over decades, rather than centuries. Are they correct, do we still have time, or are they just trying to put a "happy face" on the most serious threat ever to face our species?
According to the National Research Council, "Greenhouse warming and other human alterations of the earth system may increase the possibility of large, abrupt, and unwelcome regional or global climatic events. Future abrupt changes cannot be predicted with confidence, and climate surprises are to be expected."
"Some of these things are very likely to happen," says Dan Schrag, a paleoclimatologist and professor of Earth and planetary sciences at Harvard University. "We are indeed experimenting with the Earth in a way that hasn't been done for millions of years. But you're not going to see another ice age at least not like that."
"I'm heartened that there's a movie addressing real climate issues," says Marshall Shepherd, a research meteorologist at NASA's Goddard Space Flight Center in Greenbelt, MD. "But as for the science of the movie, I'd give it a D minus or an F. And I'd be concerned if the movie was made to advance a political agenda."
Patrick Michaels, a senior fellow in environmental studies at the Cato Institute, a conservative think tank in Washington, says the film is meant to generate hysteria over the thorny global warming issue.
In addition, according to the National Research Council:
A possible shutdown of the THC [North Atlantic heat pump] would not induce a new glacial period, as press reports suggested; however, it clearly would involve massive changes both in the ocean and the atmosphere.
If the increase in atmospheric greenhouse gas concentration leads to a collapse of the Atlantic THC, the result will not be global cooling. However, there might be regional cooling over and around the North Atlantic ...
There you have it. Can we all breathe a collective sigh of relief, knowing that while climate change may be of grave importance, it is still many decades from even coming close to reaching critical mass? The short answer is NO, because, while their assertion is correct that massive climate change does take decades and decades to reach this point of going over the brink, the truth is that we may well be nearer the brink then they are willing to admit. The process of critical change began decades ago and what we have begun to witness now is the gaining momentum on its downhill slide to abrupt change.
Climate is an ill tempered beast, and we are poking it with sticks
In their groundbreaking paper, Sudden Climate Transitions During the Quaternary, Jonathan Adams Environmental Sciences Division, Oak Ridge National Laboratory, Mark Maslin, Environmental Change Research Centre, Department of Geography, University College London, and Ellen Thomas Environmental Change Research Centre, Department of Geography, University College London, in New Haven, Connecticut and Department of Earth and Environmental Sciences, Wesleyan University, and a later revised and updated piece (Sudden Climate Change Through Human History) by Adams and science writer Randy Foote present evidence to indicate that rapid climate is not only possible, but that there is evidence to suggest that it has happened before.
The tendency of climate to change very suddenly (often in just a few decades) and then reverse has been one of the most surprising lessons of recent study of the last 130,000 years, and its implications for biogeography and for the evolution of human cultures and biology have barely begun to be considered. Judging by what we see from the past, conditions might gradually be building up to a 'break point' at which a sudden dramatic change in the climate system will occur over just a decade or two.
They maintain that the new accumulation data suggests "... the climate system tends to undergo most of its changes in sudden jumps. "
They conclude that:
Whilst these are only preliminary models, and thus subject to revision as more work is done, they do seem to point in the same direction as the ancient climate record in suggesting that sudden shutdowns or intensification of the Gulf Stream circulation might occur under full interglacial conditions, and be brought on by the disturbance caused by rising greenhouse gas levels.
They rather grimly state,
Gradualist arguments have assumed that Man could adapt to the effects of slow global warming, with the associated rising of sea levels and changes in agricultural growing patterns. It is likely, though, that earth's climate does not change in such gentle rhythms. A better model than the gradualist one might be plate tectonics, where stress generally surfaces in the form of earthquakes, rather than gradual motion and shifting. In sum, what has been called the gloom and doom warnings of the long term effects of global warming may actually turn out to have been optimistic. The future could well be far more catastrophic than is generally projected.
They point to two periods in particular that hold great similarities to our present climate environment.
...However, a major sudden cold event did probably occur under global climate conditions similar to those of the present, during the Eemian interglacial, around 122,000 years ago. Less intensive, but significant rapid climate changes also occurred during the present (Holocene) interglacial, with cold and dry phases occurring on a 1500 year cycle, and with climate transitions on a decade to century timescale.
In the past few centuries, smaller transitions (such as the ending of the Little Ice Age at about 1650 AD) probably occurred over only a few decades at most.
An accidental discovery — a possible key to our climatic future
In there 1997 paper, Sultry Last Interglacial Gets a Sudden Chill, Mark Maslin, Environmental Change Research Centre, Department of Geography, University College, London; and Chronis Tzedakis, Godwin Institute of Quaternary Research, Department of Geography, University of Cambridge, United Kingdom write that "Over 100,000 years ago, during an interglacial period known as the Eemian, a climate event lasting only several hundred years was chronicled in climate records from the deep sea sediments of the Atlantic Ocean and from lake sediments of Northern Europe." The researchers go on to say that this event, which may provide a clue to future climate change, would not have been discovered had it not been for the "Eemian controversy" stirred by the Greenland ice core records.
They say that these records confirmed a sudden chill:
Peak interglacial climatic conditions allow certain plant species to proliferate: the `yew phase' north of the Alps, which coincided with an `olive phase' and maximum expansion of Mediterranean vegetation in southern Europe. The olive phase can be traced in marine pollen records from the eastern Mediterranean, and it coincides with the deposition of sapropel S5, which is associated with increased monsoonal activity during maximum Northern Hemisphere insolation (125–126 ka). (author's note ka = dielectric constants)
They go on to say that following this period, temperate conditions persisted for about 3500 years as shown by the expansion of the hornbeam deciduous tree (Carpinus betula) across Europe. "Only after this period do pollen sequences suggest climate instability." They also indicate that the evidence suggests that the cold events recorded in various pollen sequences occurred much later than the disputed GRIP events, and they appear to have persisted for only hundreds of years rather than thousands.
"The timing (about 122 ka) and duration of the cold oscillation recorded after the hornbeam expansion observed in lake sediments from Northern Europe appears to correlate more convincingly with the intra Eemian cold event seen in the marine record from the Ocean Drilling Program."
Further support for the Eemian cold event comes indirectly from coral reef records.
It is possible to determine the age of a piece of coral by analyzing the amount of radioactive uranium it contains. This is because radioactive uranium breaks down or "decays" over time. These dated corals indicate that the last interglacial period lasted at least between 130 and 117 ka. Moreover, evidence suggests that globally, the main episode of coral reef building was confined to a narrow range of dates between 127–122 ka.
Interestingly, Maslin and Tzedakis report that the period of reef building seems to end at the same time the Eemian cold event begins, that is, at about 122 ka.
Finally, both indicate that there are similarities to today:
Today, a similar freshening of the North Atlantic Drift and the Norwegian Current would reduce deep water formation in the Nordic seas. This would slow the great global deep water conveyor belt and would lead to colder conditions in Europe. We suggest that a similar chain of events may have occurred in the mid Eemian. Based on the absence of ice, rafted debris, and other evidence of melting icebergs during the Eemian, the observed freshening of the surface waters and the corresponding reduction of deep water formation cannot be ascribed to an ice surge event but rather to overlapping processes: the increased incursion of "fresh" North Pacific water via the Bering Strait during times of raised sea level, and enhanced precipitation over the North Atlantic and Nordic Seas following the Northern Hemisphere insolation maximum.
Adams, Maslin, Thomas, Tzedakis and Foote were not the first to sound the alarm that there was a strange wind blowing.
In 1975, Wallace Broecker, a geochemist at Columbia's Lamont Doherty Earth Observatory, published a paper entitled: "Climate Change: Are We on the Brink of a Pronounced Global Warming?" The opening sentence of the abstract reads "If man made dust is unimportant as a major cause of climate change, then a strong case can be made that the present cooling trend will, within a decade or so, give way to a pronounced warming induced by carbon dioxide." However, even Broecker was not the first to draw this conclusion; Svante Arsenics predicted in the late 1890s that a doubling of atmospheric carbon dioxide concentration ([CO2]) from its pre industrial level would produce a 5 degree C world wide increase in temperature. However, Broecker was the first to analyze real data. His conclusion was based upon an astute assemblage of information from three sources. The first was an 800-year record of natural global temperature cycles deduced from oxygen isotope ratios in the ice core taken at Camp Century, Greenland. The second was the direct measurements, which began in 1958, of [CO2] made at Mauna Loa Observatory, Hawaii. The third was the running average of global surface temperature assembled from world wide meteorological data back to 1880.
Prior to the direct measurements, Broecker estimated past atmospheric [CO2] from fuel consumption data for 1900 through 1950. He projected future atmospheric [CO2] three decades beyond 1975 based upon the growth rate in the Mauna Loa data. Then he calculated the global temperature contribution expected from the past, present and future [CO2]. The results were added to the natural temperature, Camp Century cycles (CCC). This, in turn, he compared to the meteorological data on 1880 to 1975 mean global surface air temperature (MGST).
The latter data were a compelling match. Because of Broecker's paper, both scientific and popular debate ensued on the likelihood that future global warming was real and furthermore, how much there might be and whether significant warming was unavoidable. While the controversy continued, the evidence has rapidly mounted that large, abrupt climate changes are taking place throughout the globe.
According to Broecker, "I can only see one element of the climate system capable of generating these fast, global changes, that is, changes in the tropical atmosphere leading to changes in the inventory of the earth's most powerful greenhouse gas, water vapor, The quest must then be to discover the link between global ocean circulation and convective activity in the tropical atmosphere."