Climate change is not a subject of fashionable scientific or pseudo-scientific discourse. It is now a life and death question of the human race. That the Arctic ice may melt is no more a remote possibility. The polar bear is already an endangered species, because it is gradually losing its natural habitat with the polar region shedding its ice cover. The perennial environment of the people living there is also undergoing rapid changes. And the elemental force that has been behind these changes is the Green House Gas (GHG) called CO2 that we generate constantly by burning fuel. And the kinds of fuel that have been disgorging CO2 at an alarming rate into the atmosphere are the fossil-based ones. The upshot of this CO2 emission into air over the years has proved to be catastrophic. The problem with this kind of gas is that it traps part of the heat that should have normally been radiated from the Earth's surface. But over the last three centuries, especially after the Industrial Revolution, the quantity of CO2 being burnt has increased manifold. As a result, more of this GHG has been deposited in the atmosphere than any time in the past. At present the proportion of CO2 in the atmosphere is 430 parts per million (ppm) and it is rising at the rate of 2.3 annually. At this rate the level will peak at 450 ppm within the next 10 years.
But the CO2 emission must be curtailed if not stopped. For failure means catastrophe. A further rise of the atmospheric temperature by another 2 degrees centigrade will cause the Antarctic ice as well as the ice sheet of Greenland to melt. The forecast that the low-lying countries will be submerged will come true. Some 200 million people would then be driven out of their homes.
But is there a way to arrest this irreversible trend of global warming through human intervention? Are humans at all up to, and even if they are, should they be, tinkering with such a huge and complex system as the atmosphere? The way humans can cause artificial rain, or change course of rivers? Can the intervention be made in a yet grander way to reduce the temperature of the atmosphere?
Even scientists believe that this is an option and worth trying. Danny Bradbury of The Guardian describes below what prospects the geo-engineers hold out for humanity.
It sounds like something from B-movie lore. Scientists working to avert global catastrophe invent a terrible technical instrument that could affect the fundamental way that the planet operates. The question is not whether they should use it, but whether they have a choice. In both academic and privately funded laboratories, such techniques are being considered, mostly in response to global warming. Geoengineering, or "ecohacking" - using science to change the environment on a vast scale - could become a reality faster than you think.
There are roughly 385 parts per million (ppm) of carbon in the atmosphere today, and that's making scientists already concerned about global warming unhappy. "I think it's a good goal to not go over 450ppm," says Alan Robock, a professor in the department of environmental sciences at Rutgers University. Many in his field consider that figure to be a tipping point, when global warming could run out of control. "The solution is mitigation," he warns.
But how to mitigate? Paul Crutzen doesn't think we're moving fast enough with reductions in carbon emissions. The professor emeritus at Utrecht University's Institute for Marine and Atmospheric Sciences became one of the most famous geoengineering advocates for his idea of copying the Pinatubo volcano.
Its 1991 eruption sent 10m tonnes of sulphur (which became sulphur dioxide) into the atmosphere, reducing the global temperature by 0.5C the next year. Crutzen suggested a project to produce a similar effect, using balloons or artillery shells to put 1.9m tonnes of sulphur into the atmosphere to cool the Earth.
He wasn't the first would-be ecohacker. As far back as the 1970s, Russian climatologist Mikhail Budyko suggested putting reflective aerosols in the atmosphere. "And the first time that a US president was informed that there might be a global warming problem from carbon dioxide was in 1965," says Ken Caldeira, a scientist at the Carnegie Institution's department of global ecology. "President Johnson's advisors gave him a report that suggested we might put reflective materials across the surface of the ocean." The idea was that these would reflect large amounts of sunlight back into space and mitigate the effects of global warming.
When leading US meteorologist Harry Wexler predicted ecohacking in a 1962 lecture, the first weather satellite had been up for three years. "He pointed out that any intervention with the Earth's heat budget could cause a change in the downstream flow and the climactic systems and weather patterns," says Fleming. "He gave serious lectures about the possible inadvertent damage we might do."
As climate change becomes an increasing concern, geoengineering is making a comeback. Scientists are looking at the atmosphere, the ocean, the land and even space to create a variety of effects, including helping to reduce the effect of sunlight on the Earth and sequestering carbon.
Seeding the ocean: US firm Climos plans to seed the ocean with iron particles. This will encourage the development of phytoplankton, it says, which carry large amounts of carbon to the ocean floor when they die. The company hopes to turn a profit by selling carbon credits.
Others are hoping to achieve a similar effect by bringing things up from underneath the ocean, rather than dropping things in from the surface. Atmocean plans to put large tubes in the ocean which will move vertically with the waves, pumping cool water to the surface from 200 metres down, says chief executive Phil Kithil. This will bring more nutrients with it, encouraging the phytoplankton to grow, he hopes.
Kithil adds that there's another benefit: "You're also reducing hurricane intensity by cooling the upper ocean." He argues that deploying these pumps over a roughly 60 x 60km area at one every 500 metres would bring enough cool water to the surface to reduce the intensity of a hurricane or perhaps even divert it, but ultimately he thinks the tubes could cover 80% of the ocean's surface for CO2 sequestration purposes.
Peter Flynn has oceanographic ideas of his own. The professor of mechanical engineering at Canada's University of Alberta cites worries about the Gulf Stream, which cycles warm water from the south Atlantic to the north, and sends cooler water back again. Salty water in the north sinks to the ocean floor and keeps the cycle moving. Should melting fresh water from the Arctic north shut down the pump, the results could be catastrophic, and Europe could be plunged into an ice age. Flynn proposed re-icing the Arctic using 8,000 giant floating platforms that would draw salty water from the ocean and spray it on to winter ice, dramatically increasing its thickness. It would continue to do this in the summer, which would then melt the ice and send tonnes of salty water plunging into the Gulf Stream.
Looking to the stars: Roger Angel, director of the Centre for Astronomical Adaptive Optics at the University of Arizona, is looking to the stars rather than the sea. He wants to put a mesh of tiny light refractors into space to sit between the Earth and the sun. The material would bend some of the sun's rays away from the planet.
"It's probably the most expensive and the cleanest," says Angel, who would need 16 trillion gossamer-light spacecraft, each sitting about a kilometre apart. Roughly 5m tonnes of material would be shot into space by a large magnetic railgun seated at the top of a mountain near the equator. Other than the $1tn (
Reversing the trend of global warming
Syed Fattahul Alim | Published: May 31, 2008 00:00:00 | Updated: February 01, 2018 00:00:00
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