INTERVIEW | SHAUN FITZGERALD Reversing history If carbon-reduction targets are to be met by nations attending COP26, greenhouse gas removal technologies must be on the agenda, says Dr Shaun Fitzgerald FCIBSE, of the Centre for Climate Repair at Cambridge University. Alex Smith I n August, the Intergovernmental Panel on Climate Change (IPCC) offered a stark warning: to limit global warming to 1.5C above pre-industrial levels, greenhouse gas emissions would need to be cut in half over the next decade, and net zero carbon would have to be achieved by 2050. Shaun Fitzgerald believes more has to be done than merely reducing emissions at source for global warming to be limited to 1.5C. He is the director of the Centre for Climate Repair at Cambridge University (CCRC), which states that greenhouse gases must be removed from the atmosphere if catastrophic climate change is to be avoided. The IPCCs sixth assessment report made it really clear that, even under the most ambitious emissions-reduction scenario, we will have 1.5C of warming. Climate change is just going to continue as populations grow, the middle classes swell, and people want increased standards of living. Weve got to do something about it, says Fitzgerald. Founded by former government chief scientific adviser Sir David King, CCRC has three objectives: deep and rapid greenhouse gas emissions reduction; the removal of greenhouse gases from the atmosphere; and restoration of parts of the climate system that already pose risks to humanity. King, who is the CCRC chair, is also focused on working with policy-makers in the UK and abroad to build alliances dedicated to carbon sequestration solutions and technologies. Technologies being considered including direct air carbon capture and storage (DACCS), and solar radiation management solutions such as marine cloud brightening, which involves spraying tiny droplets of seawater into clouds to make them whiter and lighter, leading to more sunlight being reflected back out to space. Some have argued that, by using science to repair the climate, there will be little incentive for governments to cut emissions, with individuals feeling they have a licence to pollute. Fitzgerald says the IPCC report makes it clear that more has to be done than just reducing emissions to hit climatechange targets. We should definitely be tackling emissions at source, or not emitting them in the first place, but the IPCC report has laid it on our doorsteps that emissions reduction is not enough. Its necessary, but we must also do negative emissions, he adds. Without reducing emissions, the task of removing greenhouse gases from the atmosphere would be enormous. Fitzgerald would rather not be doing this research, but says he has had to because this is the position society is Climate change is just going to continue as populations grow, the middle classes swell, and people want increased standards of living in. Why would you tackle CO2 or methane in the ambient atmosphere if you didnt have to? he says. One area of research that CCRC has been looking at is a method of removing methane which represents 25% of global warming gasses from the atmosphere. When there is a concentrated stream of methane, it can be oxidised and converted to water vapour and CO2. For example, if you have a landfill site with leaky methane, it would be sensible to gather up the methane and produce electricity in a gas turbine, says Fitzgerald. However, methane in the atmosphere is too dilute to generate electricity through a gas turbine. Fitzgerald says it can be captured using photocatalytic oxidation, whereby methane is passed over a metal oxide such as titanium dioxide or zinc oxide in the presence of UV light. CCRC is looking at research on using zinc oxide decorated with silver, which is particularly good at 18 November 2021 www.cibsejournal.com CIBSE Nov21 pp18-19 Shaun Fitzgerald.indd 18 22/10/2021 18:21