MOST PEOPLE HAVE NEVER HEARD of geoengineering and many of those who have don't know quite what it is. Yet geoengineering is all the rage in some scientific circles and some climate policy circles in wealthy countries. Should you be worried? Definitely.
Geoengineers propose an array of speculative techniques by which humans might try to deliberately modify the Earth's climate and weather systems to counteract global warming. Until now humans have altered the climate by accident. Now some scientists, buoyed by a faith in technological solutions and computer models, believe we know enough about climate systems to actually control them. Some are even advocating experimentation in the relatively short term, and some technologies (such as ocean fertilization) have already been tested on the open seas (unsuccessfully).
The Future Isn't Far Ahead
So what are these technologies? There are, broadly, three types of geoengineering techniques under consideration.
The first set of geoengineering proposals is known as Solar Radiation Management (SRM). These aim to reduce the amount of sunlight reaching the planet by reflecting more of it back to space, thereby reducing atmospheric warming. SRM proposals include putting sulfate or aluminum aerosols or engineered nanoparticles into the stratosphere, making clouds whiter by spraying seawater at them, covering deserts with plastic or creating a layer of foaming bubbles on the surface of the ocean.
The second type involves attempts to draw megatonnes of greenhouse gases out of the atmosphere and lock them up either biologically or mechanically. An example of this is ocean fertilization, which entails growing plankton in the hope of sequestering [CO.sub.2] in the bottom of the sea. This category also includes suggestions to change the chemistry of the ocean to improve [CO.sub.2] absorption (enhanced weathering), artificial trees, and appropriating and burning forest and crop residues into a charcoal that is subsequently buried for carbon sequestration.
A third set of geoengineering proposals entails attempts to directly control weather--acting to reduce or redirect hurricanes or seeding clouds for rainfall in drying regions. There are many instances of such interventions (150 incidents in forty countries according to one report), often connected to military objectives.
Although it sounds futuristic, this isn't the first time that policymakers have flirted with the concept of geoengineering. As early as 1965, the U.S. President's Science Advisory Committee warned Lyndon B Johnson that CO2 emissions were modifying the earth's heat balance. In a report regarded as the first high-level acknowledgment of climate change, the authors recommended--not emissions reductions, but a suite of geoengineering options. They suggested that reflective particles could be dispersed on tropical seas (at an annual cost of around $500 million), which might also inhibit hurricane formation. Thankfully Johnson ignored their proposal.
Thirty years later, two older military scientists re-ignited interest in the topic by presenting a 1997 paper favouring the sulphate pollution approach. They were weapons scientist Edward Teller, dubbed the "father of the Atom Bomb," and his protege Lowell Wood, the architect of Ronald Reagan's "Star Wars" missile defence system. Their proposals gained currency a few years later when Nobel laureate Paul Crutzen, famous for his work on ozone depletion, threw his support their way in a controversial article in the journal Nature. Geoengineering was no longer a taboo topic for respectable scientists.
A Cheap Solution Instead of Emission Commitments
New geoengineering enthusiasts emerged and have worked assiduously over the past decade to get more funding and political backing for the controversial technologies. As with nuclear testing, proponents contend that we need to test the technology first to know if it is a viable tool for later use. …