Geoengineering: The last resort to combat climate change risks?

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There is extensive evidence that the climate on earth is changing and that this is set to impact the world's population, property and businesses. While reducing CO2 emissions may be crucial to mitigate some of the consequences, the results may take too long to materialise and geoengineering, however controversial, may offer a quick fix.

Geoengineering, also called climate engineering or climate intervention, is split into two broader themes: Greenhouse gas removal and solar radiation management. While the former seeks to remove carbon dioxide from the atmosphere, the latter may offer the quickest solution with low direct implementation costs relative to greenhouse gas emissions cuts and carbon dioxide removal, according to some scientists.

The world's population is increasingly concerned about the threat posed by global warming, which has already reached 1°C above the pre-industrial level, due to past and current greenhouse gas emissions, the Intergovernmental Panel on Climate Change (IPCC) noted in a recent report.

Glaciers, snow, ice and permafrost are declining and will continue doing so, the IPCC Special Report on the Ocean and Cryosphere in a Changing Climate warned. Consequently, hazards for people will increase, for example through landslides, avalanches, rock falls and floods.

Glaciers and ice sheets in polar and mountain regions are losing mass, contributing to an increasing rate of sea level rise, together with expansion of the warmer ocean. While sea level has risen globally by around 15 cm during the 20th century, it is currently rising more than twice as fast – 3.6 mm per year – and accelerating, the report noted.

Sea level rise will increase the frequency of extreme sea level events, which occur for example during high tides and intense storms. Indications are that with any degree of additional warming, events that occurred once per century in the past will occur every year by mid-century in many regions, increasing risks for many low-lying coastal cities and small islands.

Hoesung Lee, Chair of the IPCC, warned that even if we reduce emissions sharply, consequences for people and their livelihoods would still be challenging. Moreover, Debra Roberts, Co-Chair of IPCC Working Group II, explained that we will only be able to keep global warming to well below 2°C above pre-industrial levels if we effect unprecedented transitions in all aspects of society, including energy, land and ecosystems, urban and infrastructure as well as industry.

The Paris climate agreement of 2015 set a goal to limit global average temperature increase to ‘well below 2°C above preindustrial levels', and to ‘pursue efforts' to limit it to 1.5°C. 
There are reasons to doubt that this will be achievable, not least because major countries like the US are not supporting the efforts. In 2017, President Donald Trump pulled the US from the Paris climate agreement.

Removing greenhouse gas from the atmosphere

To meet the 2°C goals of the Paris Agreement requires not only rapid and dramatic decreases in emissions, but also active removal of greenhouse gases from the atmosphere, according to The Royal Society and Royal Academy of Engineering. Greenhouse gas removal (GGR) methods involve two main steps: the removal of greenhouse gases from the atmosphere and their storage for long periods. Removal is achieved through a wide variety of approaches, involving either biology or engineered chemical processes, the organisations explained in their September 2018 report “Greenhouse gas removal”. The carbon is then stored in land-based biomass, sub-surface geological formations, the oceans, or the built environment.

There are, however, challenges linked to this process. GGR methods require resources, like land, energy or water, placing limits on the scale and location of their application, and leading to resource competition between them, and with other human activities, such as food production. Increased forestation and bioenergy with carbon capture and storage, sequestering carbon and simultaneously providing energy, are often considered as major routes to deploy GGR. One option is ocean afforestation, which involves expanding natural populations of macroalgae, which absorb carbon dioxide, and then harvesting them to produce biomethane and biocarbon.

The alternative option: Solar radiation management 

An alternative or additional option may be solar radiation management (SRM). This approach involves reducing some of the impacts of climate change by reflecting a small amount of inbound sunlight back out into space, reducing some climate risks the world is facing. If it could be made to work, SRM would be the only known method for quickly stopping the rise in global temperatures, according to NGO-driven Solar Radiation Management Governance Initiative. It could even be used to cool the planet, should that ever be deemed necessary, the group claims.

SRM methods involve brightening marine clouds by spraying seawater into the lower atmosphere, or replicating the cooling effect of volcanoes by spraying reflective sulfate particles into the upper atmosphere (the stratosphere).

When very large volcanoes erupt they blast millions of tonnes of reflective sulphate particles into the stratosphere. These particles circulate the planet on the powerful stratospheric winds, reflecting away a small amount of inbound sunlight and cooling the planet for a year or two. Stratospheric aerosol ejection would seek to replicate this effect, with aeroplanes or balloons used to inject reflective aerosol particles into the upper atmosphere.

Some scientists also believe they can take advantage of marine stratus clouds that cover large areas of the oceans. They propose that spraying tiny droplets of seawater into these clouds could make them lighter and more reflective. Whiter, brighter clouds reflect more sunlight back out into space, and could help cool the planet.

But SRM is controversial for several reasons. It is not yet known what all the side effects of SRM could be, or whether they would be very damaging. Some possible side effects are known, however. For instance, stratospheric aerosols might delay the regeneration of the ozone layer. There might also be some health effects from the additional aerosols in the atmosphere.

Other consequences that need to be considered are what would happen if a country used SRM unilaterally, and then other countries experienced extreme weather events that might have been caused by the geoengineering. Or, how the world could agree over how much SRM cooling should be done? There are also concerns that the idea of SRM could distract politicians from the task of implementing deep cuts to greenhouse gas emissions.

A hot topic for the insurance industry

Leading insurers and reinsurers have identified climate change as an emerging risk over 20 years ago, perhaps also because the industry is at the forefront of dealing with the impact climate change has on communities and infrastructure all over the world. On the one hand, an increased frequency and severity of major weather events means a higher number of more costly claims for insurers to deal with. At the same time, insurers are responsible for investing billions of pounds of assets, which need to grow to fund people's retirements and to cover future claims. There is a risk that, if there is a disorderly transition to a low-carbon economy, the value of many of the assets in which insurers invest will fall with little warning.

The UK's Prudential Regulation Authority (PRA) has just launched a stress test that will measure insurers' exposure to the risk that the world misses its carbon reduction targets. 

Insurers and reinsurers are engaging in many ways to reduce climate change and its impact. The industry is working with clients and partners, for example, to enhance resilience and advocate for solutions to prevent, or minimize, damage and harm from weather and climate-related perils for customers and communities.

The industry is also developing insurance and risk management solutions for the new technologies, business models and approaches that will be required to achieve the transition to a low-carbon economy. In addition, insurers and reinsurers are integrating assessments of both physical and transition risks into their investment strategies. As part of this approach, the industry is disengaging and divesting from activities predominantly focused CO2-heavy and non-renewable energy production.