We've heard of some fairly "creative" geo-engineering schemes in the past — to name just a few, there was the giant, orbiting reflector to reduce the amount of sunlight reaching the Earth and the football-field-sized synthetic blankets to cover the Alps — but this one really takes the cake. Some scientists have argued that emulating a volcanic eruption could help mitigate global warming by pumping sulphur particles into the planet's upper atmosphere with rockets — scattering incoming sunlight and cutting down outgoing radiation.
A new study from two scientists at the National Center for Atmospheric Research in Boulder, CO, has (not suprisingly) cast doubts on this proposal — cautioning that its use would create problems of its own, including potentially disastrous droughts. Examining precipitation and streamflow records dating back to the mid-20th century, Kevin Trenberth and Aiguo Dai found that the eruptions of two volcanoes — Mexico's El Chichón in 1982 and the Philippines' Pinatubo in 1991 — caused large-scale droughts accentuated by substantial decreases in rainfall, runoff and river discharge into oceans. The authors thus reason that a geo-engineering scheme set up to achieve the same effects could have similar dramatic consequences for the planet. Assuming we did choose to pursue this strategy, we would have no way of discontinuing it even if we found the drought predictions to be true since, as Joe Romm explains, doing so would cause global temperatures to rapidly re-escalate, resulting in other potentially catastrophic side-effects.
Given their high costs and potential for dangerous and unprecedented side-effects, it's time we shelve these ideas and focus on more feasible, cost-effective solutions.