While many critics say the movie is scientifically suspect, that didn't deter Memorial Day weekend theater audiences from spending more than $86 million to check out Hollywoods walk-in message about global warming.
While theres both a scientific and political whirlwind of debate surrounding global warming, climate experts and technologists have been looking into "what if" scenarios that might curb abrupt climate change.
Ecosystems versus "egosystems"
As countries, political camps, and action groups debate the seriousness of global warning threats, there have been a steady-stream of scientific studies calling attention to the issue.
As example, a recent report from the National Academies' National Research Council (NRC) says greenhouse warming and other human alterations of the climate system may increase the possibility of large, rapid, and unwelcome regional or global climatic events.
A special NRC committee on abrupt climate change looked into the implications for science and public policy. Last year, they issued their report: Abrupt Climate Change: Inevitable Surprises.
"Abrupt climate changes in the last few thousand years generally have been less severe and affected smaller areas than some of the changes further back in the past. Nonetheless, evidence shows that rapid climate changes have affected societies and ecosystems substantially, especially when the changes that brought persistent droughts occurred in regions with human settlements," the NRC study reported. "There is no reason to believe that abrupt climate changes will not occur again."
The NRC report also underscored the importance of not being too fatalistic about the threats posed by abrupt climate change. "Societies have faced both gradual and abrupt climate changes for millennia and have learned to adapt through various mechanisms, such as moving indoors, developing irrigation for crops, and migrating away from inhospitable regions."
However, the study group added: "Nevertheless, because climate change is likely to continue and may even accelerate in the coming decades, denying the likelihood or downplaying the relevance of past abrupt changes could be costly. Societies can take steps to face the potential for abrupt climate change."
Taking steps
To paraphrase an adage: Everybody talks about global warming, but is anybody doing anything about it?
A step in that direction has been labeled "geoengineering" -- options that involve large-scale engineering of Earths environment to combat or counteract the effects of changes in atmospheric chemistry.
In reality, Earth is being terraformed -- that is, our ecosystem is being modified -- although some consider it "terror-forming". The trick now, argue some scientists, is to manipulate the environment in a healing way.
A National Academy of Sciences (NAS) study team looked into this prospect in 1992. Their final report was titled: Policy Implications of Greenhouse Warming: Mitigation, Adaptation, and the Science Base. The review was conducted under the auspices of the Committee on Science, Engineering, and Public Policy, a unit of the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
This heady assessment of greenhouse warming involved nearly 50 experts, including scientists as well as individuals with experience in government, private industry, and public interest organizations.
The 944-page report identified what should be done now to counter potential greenhouse warming or deal with its likely consequences. Within the report, a "Mitigation Panel" considered options for reducing or reversing the onset of prospective global warming.
Rifles, rockets and space mirrors
One proposal is a massive reforestation campaign used as a possible method of slowing the buildup of carbon dioxide in the atmosphere. So too was fertilizing vast areas of the ocean with iron to stimulate the growth of carbon dioxide-absorbing phytoplankton.
Another option for mitigating global warming would be to try to control our planets radiation balance by limiting the amount of incoming radiation from the Sun. This could be done by increasing the reflectivity of the Earth -- its albedo. Calculations show that an increase in planetary albedo of just 0.5 percent is adequate to halve the effect of a carbon dioxide doubling.
Several schemes suggested involved tossing additional dust -- or possibly soot -- into the stratosphere or very low stratosphere to screen out sunlight. Such dust might be delivered to the stratosphere by various means, including being fired with large rifles or rockets.
Another scheme envisioned placing thousands of large mirrors in Earth orbit to reflect incoming sunlight. Alternatively, billions of aluminized, hydrogen-filled balloons would be lofted into the stratosphere to provide a reflective screen.
Also, the NAS study team thought that vast arrays of pulsed lasers at mountain altitudes could be used to focus intense infrared beams into the atmosphere. The laser beams are on a mission to selectively destroy chlorofluorocarbon molecules in the atmosphere through the process of multiphoton dissociation.
Unintended effects
In summing up their ideas, the group of experts noted that Earths current "inadvertent" project in geoengineering -- human-induced greenhouse warming -- involves great uncertainty and great risk.
"Engineered countermeasures need to be evaluated but should not be implemented without broad understanding of the direct effects and the potential side effects, the ethical issues, and the risks. Some do have the merit of being within the range of current short-term experience, and others could be turned off if unintended effects occur," the NAS panel members stated.
Several of the geoengineering possibilities assessed -- including atmospheric CFC removal, space mirrors, and the multiple balloon stratospheric screen -- appear, with current technology or that expected to be available soon, "to be either impractical, too cumbersome to manage, or too expensive," the study concluded.
On the other hand, the 1992 report added that, while the ideas dont appear to have merit today, they should be kept in mind. Technological changes may make them more attractive in the future.
All the difference in the world
Given the numbers of advanced remote sensing spacecraft now orbiting -- and more on the way -- taking an accurate pulse of Earths biospheric condition is becoming more matter-of-fact science.
And that might make all the difference in the world, literally.
"The greatest value in Earth observations from space will be in understanding the early warning signs of abrupt climate change, planning how to respond, and to monitor the changes as they happen," said Ray Williamson, a research professor at George Washington Universitys Space Policy Institute at The Elliott School of International Affairs in Washington, D.C.
Satellite communications and position, navigation, and timing and other geospatial technologies will have a major role as well in all three aspects, Williamson told SPACE.com. "Essentially, these reflect the same aspects that are useful for meeting the challenge of large natural disasters such as hurricanes, earthquakes and the like."
Williamson said that the scale of concern, of course, would be much greater than we see from "normal" forms of natural disasters and likely require a nearly world-wide effort to adapt.
"There isn't much one could do to avert the changes once they had occurred, but perhaps very early warning would provide sufficient signals to cause countries to change habits that might lead to such a widespread disaster to mitigate some of its affects," Williamson concluded.
advertisement
