December 10, 2009
Radical Theories Offered On How To Slow Climate Change
Climate experts say geo-engineers are exploring radical new ways to combat Earth's climate crisis, including fertilizing the seas with iron, scattering particles in the stratosphere to reflect sunlight or building a sunshade in space, AFP reported.
However, many of these ideas are contested as risky for the environment and laden with unknowns about cost, practicality and legality. But mainstream scientists who once dismissed these projects are now starting to consider their possibilities.
Climate experts are attempting to hash out a plan to slow global warming at the December 7-18 UN talks in Copenhagen, where 194 nations are called to craft a post-2012 treaty to slash greenhouse-gas emissions.
Yet interlinked issues, national interests and economic stakes are but a few of the hurdles that await any attempt at reaching a unified agreement.
Meanwhile, a 12-member panel at Britain's Royal Society found that some geo-engineering techniques could have "serious unintended and detrimental effects on many people and ecosystems."
But some schemes were deemed technically feasible and could be a useful fallback tool to help the switch to a low-carbon economy.
In its landmark Fourth Assessment Report in 2007, the UN's Intergovernmental Panel on Climate Change (IPCC) warned against geo-engineering schemes, charging them with potential risk and unquantified cost.
It now intends to do its own evaluation of several radical theories.
The Royal Society said geo-engineering fell into two main categories: The first involves removal of carbon dioxide, such as by planting forests and building towers that would capture CO2 from the air.
The report said some of those projects could be harnessed alongside conventional methods to reduce emissions once they are demonstrated to be "safe, effective, sustainable and affordable".
The other category is called solar radiation management, which instead of tackling CO2 would act like a thermostat, turning down the heat that reaches Earth from the Sun.
Such concepts include deflecting the Sun's heat away from the Earth through space mirrors, scattering light-colored particles in the high atmosphere to reflect the solar rays and using ships to spray water that would create reflective low-altitude clouds.
The report said it would quickly lower temperatures and could be a possibility if global warming suddenly increased.
However, these techniques would not curb CO2 emissions that cause dangerous ocean acidification and their costs are unclear but possibly astronomical.
Additionally, such experiments could even end up generating disasters of their own.
Ken Caldeira, a professor of climate modeling at Stanford University, California, who took part in the Royal Society report, said such theories still should not be dismissed out of hand, given their potential in an emergency.
He believes these radical theories should be considered, pending an emergency such as Greenland rapidly sliding into the sea, causing rapid sea-level rise, or if methane started to de-gas rapidly from the Siberian permafrost, or if rainfall patterns were to shift in such a way to induce wide-spread famines.
"We would be remiss if we did not do what we could do to understand the potential of these options as well as their uncertainties and risks ahead of time," said Caldeira.
On the Net: