Guest post: Dr Dave Reay on Climate Engineering

Climate Engineering and Emergency: The ‘Magic Bullet’

by Dr Dave Reay

Tackling anthropogenic climate change is all about risk management. We are already committed to additional 21st century warming of ~0.75 degrees C due to the thermal inertia of our oceans. This warming will inevitably result in some negative impacts in some regions. For those areas most affected, emergency action may already be inevitable (e.g. planning for complete population migration from some small island states). However, emergency action on a global scale is also a possibility. Either a major state is so negatively impacted that it takes unilateral emergency action of a type with global impacts (e.g. China employing sulphate aerosol injection to the stratosphere) OR the net impact of climate change globally becomes so negative as to drive emergency actions at the international/UN level.

Through the 1990s and early 21st century, GHG emissions reduction (i.e. mitigation) was the primary focus. Here, the narrative of avoiding ‘dangerous climate change’ and exceeding 2 degrees C of post-industrial warming became embedded in national and international policy. The Stern Review attempted to quantify the financial risk of inaction, providing policy makers with the kind of cost-benefit framework often employed in assessing whether a particular action was worthwhile. More recently, the ‘risk’ equation has more overtly included the possibility that the 2 degree target will be missed and that climate risk management should involve a greater degree of impact and adaptation assessment.

In 2011 global anthropogenic greenhouse gas emissions reached an all-time high. Analyses of current GHG emissions reduction commitments and voluntary targets (Copenhagen/Cancun/Durban COPs) indicate that global emissions will continue to rise and that the 2 degree target is likely to be missed. In terms of risk management this strengthens the likelihood of ‘emergency action’ by a large state or group of states centered on climate engineering approaches.

Climate engineering (also called ‘Geoengineering’) involves the use of a ‘magic bullet’ strategy to mitigate the effects of anthropogenic climate change. The strategies fall into two main types:

Solar Radiation Management (SRM), where the amount of solar energy received and absorbed by Earth is reduced. Examples include placing mirrors in space between the Earth and the Sun to reflect energy, increasing the albedo (reflectance) of the atmosphere through sulphate aerosols (stratosphere) or cloud whitening (troposphere), and increasing the albedo of the urban land surface through the use of more reflective roofing.

Carbon Dioxide Reduction (CDR), where the concentration of carbon dioxide in the atmosphere is radically reduced. Examples include ocean fertilisation, artificial trees, and biochar amendment to soils.

For a detailed view of these strategies see:

These various climate engineering approaches each have a degree of risk associated with them. The uncertainties around these risks are large but, as the balancing risk of negative climate change impacts on a nation increases, the case for their emergency use is gaining more traction.

Given the regionally-specific nature of current and projected climate change impacts, the risk of a large nation state taking emergency unilateral action via climate engineering is growing. This is dangerous. The science is nowhere near robust enough for deployment of any of the climate-engineering strategies so far suggested – this would take years of careful testing and experimentation to identify the true effectiveness and negative side-effects. What is required urgently is a strong international legal framework for climate engineering that can prevent premature use of these strategies.  This framework would also ensure that if (and it’s a big if) a convincing case is made for their use, the right regulation is in place to safeguard human populations and natural ecosystems wherever they are in the world.

(Author Dr Dave Reay)

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