Reengineering Earth: geoengineering may alleviate the impacts of climate change

Space mirrors

Image: Mikkel Juul Jensen

According to the US National Climatic Data Centre, the world is getting warmer. Since the beginning of the 20th century, the average global temperature has risen by 0.76ËšC, and the past decade is the warmest on record.

Meanwhile sea levels are rising along with the temperature, and at an ever-increasing pace: from an average of 0.15cm per year over the past 100 years to an average of 0.35cm per year for the past 17 years. But don’t take it as a signal to bust out the beachwear and celebrate a perpetual summer. Unfettered, global climate change will cause widespread disruption to billions of people, in part by destroying crucial agricultural centres, fishing grounds and sources of freshwater.

The fight against climate change has mostly focused on curbing emissions of carbon dioxide and other greenhouse gases. But more researchers are turning toward a concept called geoengineering — manipulating the planet itself — to alleviate our climate woes. And although geoengineering schemes, which range from filtering CO2 from the atmosphere to launching enormous mirrors into space, have historically been dismissed as unlikely, if not impossible, they might turn out to be our best shot at saving the planet. Then again, they might just destroy it altogether.

Fighting an uphill battle
Why should we be concerned about rising temperatures? According to climate researchers, an increase just shy of 4 degrees is the global ecosphere’s limit. If the average temperature climbs any higher than that in this century, we’ll face floods from rising sea levels, food shortages due to disruptions in agriculture, and the extinction of many plant and animal species. We’re on track to surpass the limit. In 2007, the United Nations Intergovernmental Panel on Climate Change predicted an increase of about 3 degrees before the end of the century. Last year, this estimate was supported by researchers at the Met Office, the UK’s national weather service, who stated that we will probably exceed that prediction if greenhouse-gas emissions continue unchecked. Among the possible consequences: severe droughts in Africa and Australia, flooding rains in India, and Arctic temperatures up to 15 degrees warmer than they are today, thoroughly melting the ice cap.

Even in the face of such dire predictions, political efforts to reduce greenhouse-gas emissions have been unsuccessful, largely because of disagreements over which nations should bear the majority of the cost. Most of the environmental goals of the 1992 Earth Summit remain unrealised. The US has yet to commit to the 1997 Kyoto Protocol to the UN Framework Convention on Climate Change, which set up a plan for both industrialised and developing nations to work together to reduce overall global output of greenhouse gases. And at last December’s COP-15 conference, 192 nations met to draft a plan to replace the Kyoto Protocol but failed to produce a binding agreement.

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