Climate change has triggered ideas for
large scale engineering of global systems. Large-scale ‘technological fixes’
fall into two categories. Carbon dioxide removal (CDR) techniques are designed
to extract CO2 from the atmosphere. Solar radiation management (SRM) techniques
are intended to reflect a portion of the sun’s light back into space. CDR is
based on biological, chemical or geological carbon sequestration. SRM is based
on natural effects observed in the atmosphere following volcanic eruptions. A
proposal for ‘sunshade’ geo-engineering consists of the installation of
space-based sun shields, or reflective mirrors, to deflect a proportion of
incoming solar radiation before it reaches the atmosphere. Sunlight deflectors
would be placed in near-Earth orbits or near the Lagrange point, about 1.5
million kilometers above the planet, where the gravitational pull of Earth and
the sun are equal. An array of sunshades in this position would pose less
threat to orbiting satellites than would near-Earth objects (UNEP 2010b, the
Economist 2010b). If anything, these proposals underline the severity of the
situation as well as how little we really know. They also give new perspectives
on power. As Andre Matthews, an anthropologist at the University of California
puts it, it is not just a matter of constructing a switch, it is a matter of
constructing a hand you trust to flip it (the Economist 2010b). We should also
realise how little we understand and realise that the risks of such global
large scale engineering are huge and totally unpredictable.
It is
already a fact that we change many of the planet's systems enormously, but in
the same way as most of these changes are a result of many small things (the
car you drive, the meat you eat etc), also the solutions are to be found there
rather than in macro engineering.
UNEP 2010b, UNEP Year Book 2010
The Economist 2010b, We all want to change
the world, 3 April 2010
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