There’s little doubt that our climate is changing, but there’s uncertainty about the direction of change and disagreement about the causal factors.
One result of the absence of consensus is a proliferation of schemes to halt or ameliorate global warming – schemes that seem to belong in the world of science fiction.
One proposal is to scatter iron filings over the oceans. This would stimulate growth of marine algae, which would absorb carbon dioxide from the atmosphere and, on their deaths, sink to the ocean floor and sequester the carbon there.
A space-based idea is to suspend a huge umbrella between the Earth and the sun where the pull of gravity and centripetal forces are in balance (the so-called Lagrange Point), so that the sunshade would remain stationary and require no energy input.
More detailed examination of the idea indicated a sunshade about four million square kilometres would offset half of the expected global warming, and no one could conjecture how to put it in place.
What seems even more outlandish is a suggestion to manipulate the trajectories of asteroids or comets to shift the earth’s orbit into a cooler part of the solar system.
A more Earth-bound project suggests scattering sulphate aerosols into the atmosphere to reflect incoming solar radiation. This would copy the recorded effects of volcanic eruptions, which in 1991 cooled earth by 0.5 C for more than a year. However, the logistics of spreading the requisite volume of aerosols are more than a little daunting.
Yet more bizarre is an idea to use sunlight to levitate huge numbers of nano-scale metallic discs into the atmosphere above the ozone layer, where they would reflect incoming radiation. Manufacturing the discs to exacting standards and deploying them would present real challenges.
All of these imaginative steps beg the question of what is really happening to climate and why.
Certainly climate was changing long before the Industrial Revolution. Technologies spawned by that revolution are responsible for consumption of finite resources and for pollution – which can be controlled if the will is there – but there is no convincing evidence proving a causal link between industrial activities and climate change; correlation and cause are not the same.
Reducing consumption and improving efficiencies are much more immediately practical measures – though less glamorous and exciting.
Rather than dreaming up fantastical schemes to halt climate change, we should think of flexibility. How can we adapt and respond to change?
(I’m indebted to Marq de Villiers’ 2011 book, Our Way Out, for background material.)
Dr. Roy Strang writes monthly on the environment for the Peace Arch News. rmstrang@shaw.ca