The fight against global warming has led to many ideas for mitigation being explored. One such method aims to reduce CO2 in the atmosphere by injecting it into deep aquifers. However, such projects have only recently started to attract serious research interest as the scope of the climate issue is realised.
A recent study has shown that carbon sequestration by pumping CO2 into underground aquifers might have an unexplored downside. Steady leakage of small amounts of carbon dioxide from such artificial underground reservoirs can have impacts on the chemistry of overlying sediments. Researchers at the Netherlands University of Science and Technology have shown that CO2 seeping into a sediment can liberate toxic heavy metals, when compared to a steady-state control. While sequestration projects will aim to avoid such leaks, it is important to understand what could go wrong when such processes are used – if a sustained leak occurred, dramatic changes could be induced in the region above the aquifer, with potentially serious consequences for living things in the area.
To me, this emphasises the importance of a strong, evidence-based approach to the mitigation of climate change, and highlights the importance of actually reducing emissions: projects which try to forcibly get rid of carbon from the atmosphere may lead to knock-on effects in our highly complex environment!