Scientists have warned that a key weapon in the fight against climate change is nowhere near as effective as first thought and may consign generations to invest in a technology for centuries to have any tangible effect.
The new research looked at the potential impact that solar radiation management could have in the world’s fight to combat global warming. Solar radiation management is a system where higher amounts of sunlight are reflected back to space through artificially altering either the Earth’s surface or the atmosphere. It was seen as a key weapon in the world’s armoury, however the research found that if it was to be deployed to limit warming to 1.5°C without emissions cuts beyond those currently envisioned by governments, it would have to be maintained for at least a hundred years.
The study examined over 350 emission scenarios that extrapolated emissions from 2030 out to 2500 based on the UK governments’ current climate targets. Most of the scenarios see solar radiation management deployed for 150-300 years. No scenario consistent with current targets sees it deployed for less than 100 years.
The paper concluded: “Our study shows that the range of possible deployment timescales is vast even if pathways start at a similar point at the beginning of SRM deployment because the evolution of mitigation under SRM, the availability of carbon removal technologies and the effects of climate reversibility are not precisely known. Since these effects will be mostly uncertain at the time of SRM initialisation, a precedent prediction of deployment length seems unlikely, with possibilities ranging from decades to multiple centuries. This is a knowledge gap that must be considered before any SRM proposal is seriously considered.”
“Other studies have laid out additional risks from reliance on such technologies, like termination shock and governance challenges. Our paper adds a perspective on the length of deployment, showing that it would be a multi-generational commitment,” commented lead author Susanne Baur based at CERFACS in Toulouse.
“We would be forcing our children and their descendants to maintain a technological regime that if suddenly stopped, could be an existential threat for the planet,” she added.
The time frames set out in the paper are much longer than the carbon dioxide removal deployment lengths in 1.5°C pathways in the Intergovernmental Panel on Climate Change’s AR6 Working Group III report, the study’s authors explained.
“We see that it’s a far larger commitment than scaling carbon dioxide removal to the levels needed for 1.5°C,” said Dr Alexander Nauels, another author on the paper from research institute Climate Analytics.
“It should also be mentioned that solar radiation management would do little to combat other symptoms of large amounts of CO2 in the atmosphere, like ocean acidification, which has huge ramifications for both ecosystems and the livelihoods that depend on them“, he added.