Tuesday, February 25, 2014
Climate Change Quick Fixes - The Cure Can Be Deadlier Than The Disease
There's a growing body of opinion supporting geoengineering as humanity's last-resort salvation from catastrophic climate change. To many it's not a matter of it but when we go the geoengineering route and which of several options we'll choose. Given the near total shift in focus from mitigation - large scale greenhouse gas emissions reductions - to adaptation strategies, geoengineering would seem a logical path.
Except that like many untested notions, geoengineering is premised on the assumption it can work. What if it not only won't work but could in fact make the problem immeasurably worse?
Researchers from the Helmholtz Centre for Ocean Research in Kiel, Germany have explored the five recognized geoengineering options and contend that, at best they won't make much of a dent in global warming and, at worst, they may trigger runaway side effects that we will be unable to control.
The potential side effects would be potentially disastrous, say the scientists, writing in Nature Communications. Ocean upwelling, or the bringing up of deep cold waters, would cool surface water temperatures and reduce sea ice melting, but would unbalance the global heat budget, while adding iron filings or lime would affect the oxygen levels in the oceans. Reflecting the sun's rays into space would alter rainfall patterns and reforesting the deserts could change wind patterns and could even reduce tree growth in other regions.
In addition, say the scientists, two of the five methods considered could not be safely stopped. "We find that, if solar radiation management or ocean upwelling is discontinued then rapid warming occurs. If the other methods are discontinued, less dramatic changes occur. Essentially all of the CO2 that was taken up remains in the ocean."
Even the foresting of deserts on a massive scale could prove disastrous if the irrigation needed to grow the trees were stopped, they say. "The desert regions would eventually return to desert and the carbon that was stored in the plant biomass and soil would slowly be returned to the atmosphere through decay and respiration," says the paper.
The researchers conclude that some geoengineering technologies could help as an aid to mitigation but none offers any silver bullet solution.
"The paper sounds a timely warning about the abject stupidity of relying upon climate engineering solutions when reducing our reliance on carbon-based energy systems is the only sensible option," said Dr Matt Watson, a lecturer in geophysical natural hazards at Bristol University.