x Abu Dhabi, UAEFriday 28 July 2017

Grey skies are going to clear up?

There is a word that should be in the lexicon of anyone trying to protect the environment. Like schadenfreude, it's one of those German words that has no direct equivalent even in the vast vocabulary of the English language

According to one recent study, rapeseed biodiesel, which makes up the bulk of biofuel production in Europe, produces up to 70 per cent more warming through the release of nitrous oxide than it cancels out by reduced fossil fuel use.
According to one recent study, rapeseed biodiesel, which makes up the bulk of biofuel production in Europe, produces up to 70 per cent more warming through the release of nitrous oxide than it cancels out by reduced fossil fuel use.

There is a word that should be in the lexicon of anyone trying to protect the environment. Like schadenfreude, it's one of those German words that has no direct equivalent even in the vast vocabulary of the English language. The word is schlimmbesserung - literally a "worse bettering". And as the results of studies published over the last week show, it is all too apt a description of many attempts to "improve" our environment.

Last week a draft report from the World Bank confirmed what many have suspected for some time: that world food prices are being driven upwards largely because of the increasing use of biofuels. Such energy sources have been long been touted as environmentally friendly because, unlike traditional fossil fuels, the carbon released when they are burnt is mopped up by the crops from which they are derived.

Encouraged by their governments, farmers around the world have now switched land use to biofuel crops at the expense of food production - with consequences now being felt by consumers around the world. This is a classic example of a schlimbesserung: a change made with the best of intentions which turns out to have an unwelcome downside. In the case of biofuels, it's far from being the only one. Other research published last week has added to concern that in turning uncultivated land over biofuel crops, the decay and burning of existing vegetation will inject enough carbon into the atmosphere to cancel out any net benefit for centuries.

There are also growing suspicions that current biofuels emit far more of the potent greenhouse gas nitrous oxide than previously thought - so much, in fact, that the fuels may actually boost global warming. According to one recent study, rapeseed biodiesel, which makes up the bulk of biofuel production in Europe, produces up to 70 per cent more warming through the release of nitrous oxide than it cancels out by reduced fossil fuel use.

As if all this wasn't enough, a study by Stanford University suggests such biofuels are also a richer source of ozone, a toxic gas which may boost deaths from asthma and respiratory disease. Many environmentalists are already calling on governments to rethink their policies and focus on so-called second generation biofuels, extracted from trees and grasses. Yet it's already possible to see another unintended consequence looming. Vegetation such as trees affects the reflectivity of the Earth, and thus its ability to bounce back some of the sun's heat back into space. Covering large swathes of light ground with dark trees could thus lead to more heat being absorbed, boosting temperatures.

This effect has been studied in detail by scientists at the US-based Carnegie Institution in Washington DC, who found that only trees planted in equatorial regions are likely to produce a net benefit. Those planted further away - especially in high latitudes, where snow is common - are likely to lead to increased global warming. The upshot of all this is clear: when it comes to the environment, a little knowledge is a dangerous thing. What isn't at all clear is whether it will ever be possible to have sufficient knowledge to make big environmental policy decisions with any confidence.

The signs are not good. Past experience shows that environmentalists are clearly right about one thing: the interconnectedness of nature. But those connections are both ill-understood and exceptionally hard to capture mathematically - making attempts to predict the impact of policy decisions the devil's own job. Nowhere is this more clear than in the huge effort put into creating computer models of the world's climate. These attempt to capture the incredibly complex interaction of the oceans, land and atmosphere and thus reveal the impact of various scenarios on global temperatures.

As anyone who has ever been let down by a weather forecast knows, this is easier said than done. The blame is often put on the so-called Butterfly Effect, whereby even small errors in a computer simulation - caused by the proverbial flap of a butterfly's wings - produces dramatically different outcomes. In the case of climate models, however, this isn't the real problem. Roughly speaking, the impact of these small errors tends to average out as the models run further into the future.

The real problem with computer simulations with the climate is more familiar: "garbage in, garbage out" - or what the experts call model error. In other words, the reliability of such simulation depends crucially on what's fed into them. And in the case of climate models the principal source of such error is held to be how they deal with the effect of clouds. In an ongoing experiment at Oxford University, a climate model is being run repeatedly with different values for the effect of clouds and moisture. Worryingly, early results revealed that the impact on the simulation can be dramatic, with forecasts ranging from a staggering 11.5 deg C increase in global temperatures to a slight cooling.

Now climate modellers may have another, even more important, source of uncertainty to contend with: atmospheric pollution. Research published last week by a team led by Dr Christian Ruckstuhl of the Institute for Atmospheric and Climate Science in Switzerland found that dramatic reductions in industrial pollution achieved by European countries has served to drive temperatures up far more rapidly than by global warming alone.

In other words, the clean-up campaigns are another schlimmbesserung, with the airborne gunk actually having a powerful - and beneficial - impact on temperatures, by reflecting the sun's heat back into space. Dr Ruckstuhl and his colleagues describe the sheer size of the effect as "very surprising". But with no current climate models taking it into account, anyone using computer simulations to guide policy decisions can only hope this latest schlimmbesserung doesn't have consequences best summed up by a short Americanism: "Doh !".

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