Geoengineering is a leap from the fire into the frying pan

By Martin Leggett - 23 Apr 2011 8:47:0 GMT
Geoengineering is a leap from the fire into the frying pan

The 'Plan B' for finding a way out of the global warming fix - geoengineering - has been in the news again of late. A couple of weeks ago there was a meeting of the 'great and good' in the UK, at the Chicheley Hall conference. That meeting saw scientists, lawyers and policy experts from across the globe, invited to thrash out the complex issues surrounding geoengineering. And in Vienna, the European Geophysical Union has just had a week-long conference on the same topic.

But are the ideas, that these scientists are discussing, able to move beyond the floating of wild flights of fancy? And given that we are planted firmly in the global warming fire, right now, is geoengineering a carefully aimed bucket of cold water - or a mistaken leap into a sizzling frying pan?

In a sense we are in the middle of a great global geoengineering project already. The pumping of billions of tonnes of greenhouse gases, from our tailpipes and smokestacks is - in effect - a giant experiment in climate change. Which should give some pause for thought about the wisdom of heading down the path of 'counter-balancing' geoengineering projects.

However, with climate change talks for reducing emissions seemingly stuck, in rounds of international meetings that look more like ever-decreasing circles, it's not surprising many are seeking to put Plan A to one side. The effects of global warming are already upon us, and likely to magnify over the coming decades. So it would probably be short-sighted to not at least discuss the ideas behind Plan B.

The ideas that were coming out of the Chicheley Hall and EGU meetings focused on two main approaches to counteracting a warming planet. The first is to try and create reflective clouds, using seawater - sucked and sprayed out into the atmosphere. The salt in the sea-water drops helps to seed the water vapor and clouds - and also reflects incoming sunlight. The other idea on the table is 'global dimming'; an artificial recreation of the cooling that comes from volcanic eruptions.

These shoot vast plumes of sulfur aerosols high into the atmosphere, and major volcanic eruptions are often blamed for years where global temperatures fall. The idea would be to mimic this natural mechanism, effectively reintroducing pollution of the upper atmosphere. Both of these ideas have specific worries attached to them.

Seawater clouds could easily produce more warming, not less, if the vapor drops were the wrong size. And the high-level sulfur from global dimming attempts may attack the protective ozone layer, or alter rainfall patterns, threatening India's monsoons. But beyond worrying side-effects, and the other 'unknown unknowns' out there, is a greater problem.

By relying on a balancing act to hold back the warming floodgates, we are setting ourselves up for a long game. Warming from CO2 will persist for centuries after all CO2 emissions stop - it will take a long time for the planets temperature to stabilize after the kick that accumulated CO2 has already given it. That means we would need to carry on pumping sulfur aerosols, or seawater clouds, for centuries too.

And if those activities stopped, because of natural disaster, wars - or just because the money ran out - the pent-up warming would reassert itself; and do so fast. That would produce a warming shock far worse than our current gradual ascent towards gathering climate chaos.

These risks are recognized by sensible scientists involved in the various geoengineering discussions. And as long as politicians listen to the saner voices, and take heed, all is not lost. Perhaps our glimpse into the sizzling frying pan will convince us that putting out the fire of global warming ourselves - by slashing emissions - is our only realistic option.