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Can geoengineering ever be low risk?

13 Jun 2018 Alison Cobb 
Photo of sun and clouds
Courtesy: iStock/Elyrae

Are any geoengineering options low risk? That was the topic under debate at the European Union General Assembly in Vienna in April. Oksana Tarasova of the World Meteorological Organization proposed that to meet the Paris agreement on global warming, we should look seriously at the artificial manipulation of the climate through geoengineering.

But is the term geoengineering even appropriate? Alan Robock of Rutgers University, US, explained that although it’s been in use for several years, the name geoengineering could conjure up the idea that a solution was calculated precisely and has known outcomes. Climate intervention is an alternative; this wording allows for the fact that we can’t predict exactly what will happen following any action, or what amount or combination of actions are best. This is a relatively new science with unknown unknowns, making it difficult to calculate global outcomes and to communicate the related risks to society.

Geo-engineering strategies fall into two groups: carbon dioxide removal (CDR) and solar radiation management (SRM). Afforestation and land management are soft approaches to CDR; Chris Juhlin of Uppsala University, Sweden, suggested that such techniques are low-risk. They don’t permanently store carbon, however, and aren’t enough to solve the problem on their own. At present, we are losing forest, so the first step is to stop cutting down trees. Ocean fertilisation could increase biological activity and uptake of carbon dioxide, but this is higher risk. An alternative is carbon capture and storage (CCS). This needs large-scale infrastructure and big investment, and would provide a more permanent removal of emissions. But how prepared are we to build such installations?

After presenting the current SRM technologies, Robock concluded that there are currently no low-risk technologies, and further research is needed to quantify risks. And what about the behavioural impact if we employed one or a combination of these “solutions” to climate change? Is there a risk of moral hazard, where we neglect mitigation strategies since technology is working against the natural system to prevent warming of the planet? Or perhaps making these technologies visible would have the opposite effect and lead society to increased mitigation effort.

According to Juhlin, without CCS we will breach the 2 °C warming threshold. Robock concluded that current emitting is a risk itself, so it is a risk-risk decision. Geo-engineering strategies that act to cool the planet and mitigate against global warming exist, but the question remains, how should the approach be implemented, if at all? There are over 7 billion people on Earth. What temperature should the Earth’s climate be set to? And who has the right to dictate what temperature this should be? Robock, along with Frank Schilling of Karlsruhe Institute of Technology, Germany, agreed that there would be winners and losers as both climate change and any geoengineering would vary by region. Understanding the risks is crucial and, as yet, there are no low risk solutions that could tackle this issue permanently and in full.

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