TECH RECKONING: A Green Whitewash

Jim Thomas

Written for The Ecologist- December/January 2009

The extreme climate technologists behind monochrome schemes to slow global warming are one colour short of a palette 

It is hardly high-tech, but if Hashem Akbari is to be believed, a reprieve from the climate crisis might be found in a few million tonnes of white gloss emulsion. According to Akbari, climate modeller at Lawrence Berkeley National Lab in California, the world could offset a year’s worth of carbon dioxide emissions if all the roofs and roads of our 100 largest cities were painted brilliant white.

Dazzled and confused by how exterior decorating could decrease greenhouse gases? Mostly, it won’t. Akbari is part of an increasingly vocal band of extreme climate technologists, known as geo-engineers, who point out that our warming world is not just the result of too much gas in the atmosphere, but also too much sunshine trapped between those gases. If we can’t reduce the gas fast enough, they reason, how about turning down the sunshine instead? 

If we can’t reduce the gas fast enough, they reason, how about turning down the sunshine instead? 

Since nobody has yet developed an actual dimmer switch for the sun, most of these schemes amount to reflecting the sun’s rays back into space – a project known as ‘Global Albedo Enhancement’. Akbari claims that every 10 square metres of newly whitewashed rooftop has the same cooling effect as removing a tonne of CO ² from the atmosphere. Unfortunately, since no actual CO ² is removed, it’s a one-hit wonder. After that first year of delayed warming, further surfaces would need to be painted to keep the Albedo effect going. 

Underwhelmed by the availability of ready-to-paint rooftops, other geo-engineers are now mapping out alternative plans to whiten the planet. Such as growing whiter crops: agricultural crops inhabit 11 per cent of our land surface, but breeding or engineering them to display whiter leaves might come at the expense of green. Trading the chlorophyll that absorbs CO ² for increased reflectivity is not a smart move. 

Wrapping deserts in white plastic is another proposal floated by geoengineer Alvia Gaskill, who would like to wrap 67,000 square miles of desert every year until 2060 to buy enough time to reduce greenhouse emissions. He reckons that every square mile of plastic desert could offset the emissions of 7,000 SUVs. He has even floated the idea of issuing ‘thermal credits’ (akin to carbon credits) as a financial mechanism to encourage global whiteness. Once again, however, there is no actual CO² reduction involved, and Gaskill’s glib proposal to subject the Sahara, Arabian and Gobi deserts to this shrink-wrap solution fails to account for the interests of pastoralists who live there. As for the fragile desert ecologies, Gaskill notes bluntly that all covered plant and animal life will die and that regional weather and wind patterns will shift. Ultimately, it’s a ‘solution’ as fragile as the plastic it’s made of. If the shiny, white wrapping were to come undone we might see a devastating jump in global temperature. 

Then there is the iconic proposal to turn the sky itself white. In 1974, climatologist Mikhail Budyko proposed slowing global warming by releasing reflective particles at high altitudes from aeroplanes. Today, that idea has surprising heavyweight support from scientists including Paul Crutzen, the Nobel laureate who alerted the world to ozone depletion. Crutzen and others have noted that sulphur plumes from volcanoes, such as the 1991 Mount Pinatubo explosion, correlate with decreases in global temperatures. But white skies – like white deserts – would come at a heavy cost. According to scientists at the US National Center for Atmospheric Research (NCAR), extra particles in the atmosphere would massively increase ozone depletion. They would also likely change weather patterns, increase drought and may also kill off ocean plankton. 

None of these proposals changes the underlying causes of climate change, since CO² emissions would continue to rise in a whiter world. Still, for politicians and industrialists, the idea of a great, global whitewash could prove an easier sell than overhauling our energy and industrial infrastructure. Whether daubed on your roof or shot into the skies, white might look cool but really, it ain’t the new green.

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