A team of researchers, led by Cambridge University, has now formulated a method to assess whether carbon removal portfolios can help limit global warming over centuries.
Research on a ‘portfolio approach’ to carbon removal enables firms to mix expensive tech-based solutions that inject carbon deep underground with lower-cost and currently more available nature-based options, such as forests and biochar. The study paves the way for nature-based carbon removal projects – such as planting new forests or restoring existing ones – to become effective climate change solutions when balanced with a portfolio of other removal techniques, according to researchers.
For the latest study, the research team have developed a new “risk management framework” to accurately calculate the additional CO₂ removal needed to keep temperatures stable over centuries for various storage portfolios.
Their analysis shows that in some cases, such as a high-risk portfolio dominated by forestry projects, the extra amount of CO₂ removal needed to make up for this risk doesn’t change much – whether the timescale is 300 or even 1,000 years.
By 2050, the UK aims to achieve net zero, with geological storage expected to play a major role in storing any ongoing CO₂ emissions. Incoming UK and EU guidance states that projects must be subject to a minimum 200-year permanence requirement.