Three satellites showed that on July 8, about 40 per cent of the ice sheet had undergone thawing at or near the surface and by July 12 an estimated 97 per cent of the ice sheet had begun melting. (NASA/Associated Press)
Nearly all of Greenland’s massive ice sheet suddenly started melting a bit this month, a freak event that surprised scientists.
Even Greenland’s coldest and highest place, Summit station, showed melting. Ice core records show that last happened in 1889 and occurs about once every 150 years.
Three satellites show what NASA calls unprecedented melting of the ice sheet that blankets the island, starting on July 8 and lasting four days. Most of the thick ice remains. While some ice usually melts during the summer, what was unusual was that the melting happened in a flash and over a widespread area.
“You literally had this wave of warm air wash over the Greenland ice sheet and melt it,” NASA ice scientist Tom Wagner said Tuesday.
The ice melt area went from 40 per cent of the ice sheet to 97 per cent in four days, according to NASA. Until now, the most extensive melt seen by satellites in the past three decades was about 55 per cent.
Wagner said researchers don’t know how much of Greenland’s ice melted, but it seems to be freezing again.
“When we see melt in places that we haven’t seen before, at least in a long period of time, it makes you sit up and ask what’s happening?” NASA chief scientist Waleed Abdalati said. It’s a big signal, the meaning of which we’re going to sort out for years to come.”
Scientists are starting to consider planet-scale engineering projects to slow the pace of climate change–anything from causing massive plankton growth in the ocean to putting a giant mirror in space above Greenland to stop ice from melting.
These ideas to alter the earth’s environment at large scale, called “geoengineering,” are increasingly being articulated and seriously evaluated even though they are likely to be controversial.
Earlier this month, climate scientists held a conference in Cambridge, Mass., to discuss the importance of geoengineering projects. The overall consensus was that geoengineering deserves further study, according to one of the organizers and news reports.
Beyond that general agreement, though, there was a wide diversity of views on the potential effectiveness of these proposals and the impact they could have on how people address climate change, according to a report in Science magazine. Some feared that geoengineering could dampen efforts to address global warming in other ways, such as using less energy and investing in renewable energies.
One of the summit organizers is Harvard University Professor Daniel Schrag, a geochemist who studies climate changes over the Earth’s history. Last Wednesday in Cambridge, he gave a brief outline of some of the techniques being considered and his feelings on the subject during an MIT Enterprise Forum on energy.
Most of all, Schrag is scared of the risks that undertaking these projects pose.
“We don’t understand the climate system very well and so trying to engineer a system that is probably unknowable and almost certainly uncontrollable is a very frightening thing,” Schrag said.
Large-scale geoengineering concepts go back decades but they appear to be gaining more currency as concerns about global warming heighten. During a presentation, Schrag noted that greenhouse gas emissions over the last two years have been higher than the “business as usual” scenario created by the Intergovernmental Panel on Climate Change.
“This may be a terrible idea but it might be better than the alternative, which is to let greenhouse-gas forming run away,” he said.
Tiny Mirrors in Space
In order to deflect enough sunlight to bring the Earth’s climate back to its pre-industrial level, geoengineers could go another route: launch a mirror the size of Greenland and strategically position it between the planet and the sun. Because launching any Greenland-size object into space may seem impractical, University of Arizona researcher and optics expert Roger Angel offers another solution: launch trillions of tiny mirrors.
Of all the grand, sweeping plans to fight global warming, Angel’s scheme, proposed in 2006, may be the most majestic–and impractical. The trillion or so mirrors, 2 ft in diameter but only one-five-thousandth of an inch thick, would form a cloud twice the diameter of Earth. In order to stay perfectly positioned between the Earth and the sun and consequently filter out about 2 percent of sunlight, the mirrors would have to orbit at L1, a balancing point between the Earth’s and the sun’s gravitational fields.
A trillion mirrors, even whisper-thin ones, would amount to 20 million tons of material. A space shuttle can only carry 25 tons, so to avoid making 800,000 shuttle flights, researchers would have to find a new way to launch the mirrors–perhaps electromagnetic power. Though we now use it for trains it is only theoretical for space launches.
And then there’s the expense: Angel anticipates he can bring the cost down from an exorbitant $10,000 per pound to only $20 per pound. But even at the low end, the solar sunshade would still cost $800 billion. If Angel’s plan did cost $10,000 per pound, it would total about $400 trillion. For perspective, the national debt currently stands at $10 trillion.
A recent study released by a team of scientists from Germany, Norway, France and the United Kingdom which warned that large-scale geoengineering projects could negatively impact the environment is being supported by another geoengineering study out of Germany.
The Max Planck Institute for Meteorology ran through a series of different computer simulation climate models, each using CO2 levels four times that of pre-industrial revolution times. The team then reduced the amount of sunlight hitting our planet to mimic what effect using “space mirrors” to deflect sunlight from the earth to reduce global warming could have.
The results, while showing that the mirrors could indeed help reduce global warming, could also mean substantially less rainfall for North and South America along with northern Europe. The models showed that those parts of the world could receive 10 to 20 percent less rainfall than they currently do, which could spell disaster for areas currently stricken with drought conditions.
The idea that we will be able to completely geoengineer our way out of the climate crisis without having to change our behavior is a dangerous one, as we really don’t have any idea what these types of projects could do to the planet in the long run. And while some aspects are certainly worth discussing and possibly even implementing, we need to combine them with real-life solutions such as reducing carbon emissions and our dependence on fossil fuels. Space mirrors sound cool and futuristic, but there’s a lot we can do today that we are avoiding doing because we believe technology will save us.
The following article was published by The Daily Telegraph on 29 Nov 2010.
UN scientists are to consider moves such as putting mirrors in space and sprinkling iron in the sea in an attempt to cut global warming, the head of the IPCC said.
Speaking at the climate change conference in Cancun, Dr Rajendra Pachauri said the next report on global warming by the Intergovernmental Panel on Climate Change (IPCC) will not only look at the threat of rising temperatures but so-called “geo-engineering” options that could actually reverse warming.
Options include putting mirrors in space to reflect sunlight or covering Greenland in a massive blanket so it does not melt.
Sprinkling iron filings in the ocean “fertilises” algae so that it sucks up CO2 and “seeding clouds” means that less sunlight can get in.
Other options include artificial “trees” that suck carbon dioxide out of the air, painting roofs white to reflect sunlight and man-made volcanoes that spray sulphate particles high in the atmosphere to scatter the sun’s rays back into space.