As efforts to reduce planet-warming emissions falter, holding the line against climate change will require large-scale programs to absorb carbon dioxide from the atmosphere in the 2030s, scientists say.
Many new technologies aimed at capturing and storing carbon emissions, thereby providing „negative emissions”, are expensive, controversial and in the early stages of testing.
But “if you really care about coral reefs, biodiversity [and] „We need to scale up food production, negative emissions technology in the worst-hit areas,” said Bill Hare of climate analytics, a science and policy institute.
„I don’t think we believe anything else can do it,” the Berlin-based chief executive told a London climate change conference.
World leaders agreed in 2015 to limit global warming to 1.5C above pre-industrial levels. Scientists believe this is important for protecting small island nations from rising seas, increasing food production and preventing extreme weather.
Carbon sequestration technologies may be needed to keep the planet below two degrees of warming, say scientists at British think tank Chatham House.
The world has already seen an average of one degree of warming, they said.
„It’s something you don’t want to talk about too much, but it’s an incalculable fact: we’re going to need geoengineering by the mid-2030s. [1.5C] goal,” Hare said, referring to efforts to cool the planet through engineering.
The ideas include planting large areas of carbon-absorbing forests, then harvesting the wood for energy and sequestering the emissions produced underground – which will feature in next year’s Intergovernmental Panel on Climate Change.
Machines can be built to capture carbon dioxide directly from the air, pump it underground, or neutralize it.
But efforts to store captured carbon underground „show no progress … sometimes even steps backwards,” said Corinne Le Guerre, director of the Tyndall Center for Climate Change Research at the University of East Anglia.
Underground carbon storage has been promoted as part of the drive by the United States and other countries to develop „clean coal” technology.
Similarly, planting more forests — a technology known as Beccs, or bioenergy with carbon capture and storage — raises questions about food security and land rights, the scientists said.
Le Quéré said Beccs „could be essential to get us to zero emissions” although „it’s very difficult to imagine that we can use land at the required scale in the models”.
He called on experts to focus on proven approaches such as improving energy efficiency, promoting cleaner transportation, eating less meat and increasing renewable energy.
Many experts fear that the introduction of expensive „negative emissions” technologies will reduce pressure to act quickly to reduce emissions now.