{"id":422,"date":"2010-08-25T14:22:23","date_gmt":"2010-08-25T04:22:23","guid":{"rendered":"https:\/\/scienceillustrated.com.au\/blog\/?p=422"},"modified":"2010-11-25T14:24:12","modified_gmt":"2010-11-25T03:24:12","slug":"reengineering-earth-geoengineering-may-alleviate-the-impacts-of-climate-change","status":"publish","type":"post","link":"https:\/\/scienceillustrated.com.au\/blog\/features\/reengineering-earth-geoengineering-may-alleviate-the-impacts-of-climate-change\/","title":{"rendered":"Reengineering Earth: geoengineering may alleviate the impacts of climate change"},"content":{"rendered":"
\"Space<\/p>\n

Image: Mikkel Juul Jensen<\/p>\n<\/div>\n

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 0.76\u00cb\u0161C, and the past decade is the warmest on record.<\/strong><\/p>\n

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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.<\/p>\n

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 \u2014 manipulating the planet itself \u2014 to alleviate our climate woes. And although geoengineering schemes, which range from filtering CO2<\/sub> 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.<\/p>\n

Fighting an uphill battle<\/strong>
\nWhy 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.<\/p>\n

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.<\/p>\n

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\"The<\/p>\n

Artist's impression of the Cloud Maker. Image: J.MacNeill<\/p>\n<\/div>\n

In the meantime, geoengineering has been gaining ground. In 2006, Paul Crutzen, an atmospheric chemist at the Max Planck Institute for Chemistry in Germany and a Nobel laureate, published a scientific article in the peer-reviewed journal Climatic Change<\/em> describing how we could, in principle, cool the planet by reproducing the sunlight-reflecting atmospheric conditions caused by volcanic eruptions. Last September, scientists from the UK’s Royal Society published a report on geoengineering, describing it as “potentially useful”\u009d and “probably technically feasible,”\u009d and recommended further research. Two months later, the US House of Representatives held the first in a series of hearings to help determine if geoengineering could be a tool in the fight against climate change and how much funding should be set aside for research on the strategy should it prove useful. In just four years, the idea of engineering the Earth itself to combat climate change \u2014 long considered impractical, implausible and in some cases, downright foolish by all but a handful of supporters \u2014 has managed to grab the attention of both scientists and politicians. And it isn’t letting go. <\/strong><\/p>\n

Rebooting the Earth<\/strong>
\nThere are two main classes of geoengineering projects. The first, known as solar radiation management, focuses on deflecting the sun’s heat back out into space. Earth already reflects about 30 per cent of the sun’s heat and light, mostly with clouds, the oceans, snow and ice. Increasing that figure by as little as 1 per cent could help combat climate change. Proposed solar radiation management techniques range from the mundane, like painting roofs white and planting more-reflective crops, to the extreme, such as launching giant mirrors into space. Straddling the middle ground of the simple and the audacious are techniques that inject clouds with salt particles to make them whiter and more reflective.<\/p>\n

The second main geoengineering method captures carbon dioxide before or after it is released into the atmosphere and stores it \u2014 underground, for example, or at the bottom of the ocean \u2014 reducing atmospheric CO2<\/sub>. Artificial trees, methods to boost populations of carbon-loving plankton and smokestack filters that catch carbon before it’s released into the atmosphere are all in the works.<\/p>\n

But both solar radiation management and carbon mitigation come with risks. The former could cause significant changes in the Earth’s weather patterns \u2014 changes we can’t anticipate. Likewise, plans to capture and store carbon dioxide underground or in the ocean could cause seismic activity or could further stress already fragile marine ecosystems. Even geoengineers caution that their plans aren’t a cure-all. Carbon dioxide removal is a slow process, and would have to be implemented in conjunction with carbon-emission cutbacks in order to be meaningful. And although solar radiation management could cool the planet more quickly, it would have to continue indefinitely if it weren’t also coupled with emissions cutbacks. “Geoengineering buys you a 50- or 100-year window to continue working on the problem of emissions,”\u009d says Martin Bunzl, the director of the Initiative on Climate and Social Policy at Rutgers University in the US. “It isn’t a substitute for the aggressive need to limit carbon output.”\u009d<\/p>\n

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\"Giant<\/p>\n

Artist's impression of giant snow machines. Image: A.Naeg\/AFP\/Scanpix<\/p>\n<\/div>\n

Building the political will<\/strong>
\nUnfortunately, there’s no guarantee that geoengineering could avoid the political setbacks that have plagued the process of curbing emissions. Nations would still have to agree to bear the cost of developing and implementing any geoengineering technology, and negotiations could be further complicated if the methods threatened to alter weather patterns. Some scientists counsel that solar radiation management is too risky to attempt, and that all efforts should focus on carbon capture and emissions control.<\/p>\n

But many researchers believe that we should pursue all options in an effort to curb climate change. “Carbon capture would certainly be better in some ways than solar radiation management,”\u009d says Stephen Salter, a professor of engineering design at the University of Edinburgh in Scotland who is currently working on a salt-seeding project to increase cloud cover and reflect more of the sun’s radiation back into space. “But the atmosphere weighs five million gigatons. Even if you pass only one third of it through carbon-capture machines, you have a lot of moving to do, and it isn’t going to be quick.”\u009d According to Salter, solar radiation management is better equipped to handle immediate problems like the melting of Arctic ice and the thawing of permafrost, a process that will launch millions of tons of methane and CO2<\/sub> into an already overburdened atmosphere. Neither method should be ignored, Salter says: “We need to design and test the necessary equipment so that we can get geoengineering under way very quickly if it is needed.”\u009d<\/p>\n

Although geoengineering won’t solve all of our climate-change problems, it could become a major player in our efforts to stave off a global catastrophe. “There is a 50-50 chance that curbing emissions will be politically unsuccessful,”\u009d says Thomas Schelling, a Nobel laureate and professor of economics at the University of Maryland, and a longtime proponent of geoengineering research. “If experiments demonstrate that geoengineering is effective and safe, it will likely become irresistible at some stage.”\u009d<\/p>\n

Read more: For the full article, see Science Illustrated magazine, July\/August 2010 Australian edition.<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

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