It's been nearly four years since the majority of the world’s nations met to draft what would become known as the Paris Agreement: a commitment, among other things, to limit global temperature increase to no more than 1.5°C above pre-industrial levels.
But how can the world's biggest economies meet this target? According to a 2018 report chaired by an Oxford scientist, it will require not only extensive cuts to carbon emissions but the active removal and storage of greenhouse gases from the atmosphere.
The report, commissioned by the Royal Academy of Engineering and the Royal Society, presents an ambitious plan for how the UK can lead the way in deploying greenhouse gas removal (GGR) technologies to achieve net-zero carbon emissions by 2050 – from well-known methods such as planting trees to more speculative techniques like capturing CO2 directly from the air.
The report assesses a range of GGR technologies for their real-world potential to help meet climate goals in the UK over the next 30 years.
Professor Gideon Henderson, Professor of Earth Sciences at the University of Oxford and now Chief Scientific Adviser at Defra, chaired the report working group. He says: 'If the UK acts now on greenhouse gas removal, we can reach national emissions targets and show how a major industrialised economy can play a leading role in meeting the goals of the Paris Agreement.
'In this report we’ve identified the available GGR technologies, how they might be used together for maximum effect, and how their phased development and deployment could enable the urgent action required to avoid the devastating impact of climate change.
'We must absolutely continue to prioritise rapid cuts in greenhouse gas emissions, but we will also have to use these GGR methods to achieve international climate goals and steward the planet for future generations.'
Each technology is assessed on its readiness for deployment in the timescale required, its potential for scalability, its financial, environmental and social impacts, and how much of a 'dent' it can make in removing excess carbon to meet the targets.
The report states that while the UK’s first priority must be to maintain efforts to rapidly cut greenhouse gas emissions, GGR technologies have a role to play in counteracting emissions from aviation and agriculture, where the scope to completely reduce emissions is limited. However, to meet climate targets significant action is essential – starting now. Bringing the UK to net-zero emissions in 2050 will require annual removal of an estimated 130 megatonnes of CO2, even with stringent reductions in emissions.
The report also considers the global picture and outlines a scenario in which a portfolio of GGR technologies can be implemented together to achieve carbon removal across the world by 2100 to meet the goals of the Paris Agreement. Biological solutions like planting trees will become saturated by the end of the century, and other GGR technologies will need to be developed and used in the longer term.
The UK 2050 net-zero scenario
GGR technologies suitable for the UK to use to meet net-zero emissions by 2050
- Ready-to-use GGR methods such as forestation, habitat restoration, soil carbon sequestration, and building with wood or carbonated waste could provide just over a quarter of the target to reach net-zero emissions.
- Biochar, enhanced terrestrial weathering in agricultural soils, direct air capture (DACCS), and bioenergy with carbon capture and storage (BECCS) could contribute to the rest of the 2050 target.
What we need to do to achieve net-zero emissions in the UK
- Rapidly increase forestation to 5% of UK land, restore wetlands and salt marshes, and store more carbon in farmland.
- Establish an incentive or subsidy system to encourage farmers to use their land to store carbon. This could be part of the framework that replaces the Common Agricultural Policy after the UK leaves the EU.
- Encourage changes in building practice to use wood and cement manufactured with carbonated waste.
- Develop better ways of monitoring the effectiveness of GGR technologies.
- Pursue research into the potential of longer- term GGR technologies such as enhanced weathering, biochar, BECCS and DACCS.
- Capitalise on the UK’s strengths in engineering and industry to establish the infrastructure required for the storage of CO2.
How to meet the Paris Agreement using GGR technologies
- Continue and increase global efforts to reduce emissions of greenhouse gases.
- Implement a global portfolio of GGR technologies now to meet the goals of the Paris Agreement.
- Build carbon capture and storage infrastructure, essential to meeting the scale required for achieving climate goals.
- Encourage investment in the development and piloting of GGR projects to assess their real-world potential and understand any environmental and social impacts.
- Establish incentives, for example carbon pricing, to pay for removal of CO2 and encourage business to use a wide portfolio of GGR technologies.
- Establish a framework to govern use of GGR technologies that addresses sustainability and engages the public.
- Build GGR into regulatory frameworks and carbon trading systems.
- Establish international science-based standards for monitoring the effectiveness of GGR technologies and their environmental impacts.