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Sucking carbon out of the atmosphere will only have ‘limited’ impact

Carbon capture and storage technologies only have a “limited realistic potential” to stymie climate change according to a new report.

The European Academies' Science Advisory Council (EASAC), formed from national science academies of EU members, has reviewed scientific evidence about several options for removing carbon dioxide (CO2) from the atmosphere with so-called negative emission technologies (NETs).

These technologies – including capturing emissions from the air and storing them underground, or planting much more of the world’s land to trees – are unlikely to significantly help hold the line on climate change, they said in the report.

Other potential measures include managing land to increase carbon stored in the soil, directly capturing carbon dioxide from the air and adding certain minerals to land or oceans to absorb the greenhouse gas.

But none of the measures can take carbon out of the atmosphere at the scale and rate of deployment required to meet targets set in the world’s first comprehensive climate treaty, the Paris Agreement, the report warned.

“Scenarios and projections that suggest that NETs’ future contribution to CO2 removal will allow Paris targets to be met appear optimistic on the basis of current knowledge and should not form the basis of developing, analysing, and comparing scenarios of longer-term energy pathways for the EU. Relying on NETs to compensate for failures to adequately mitigate emissions may have serious implications for future generations,” EASAC stated.

There is no “single silver bullet”, it said, and the focus needs to be on deep and rapid cuts to the amount of greenhouse gases being put into the atmosphere by human activities such as burning fossil fuels and deforestation.

The Paris Agreement commits countries to holding temperature rises to “well below” 2°C above pre-industrial levels, which means emissions must be cut to net zero by the second half of the century.

But with emissions from some sectors such as aviation and agriculture hard to tackle, “negative emissions technologies” would have a role to play, EASAC added.

Some 87 per cent of scenarios by the Intergovernmental Panel on Climate Change (IPCC) for meeting the 2°C target require negative emissions technologies, while all models for meeting a more stringent 1.5°C limit involve such measures.

Professor Michael Norton, EASAC environment programme director, said: “There’s no single technology that offers potential for removing carbon dioxide from the atmosphere at the scale envisaged in IPCC models, which are now Paris Agreement targets.”

He warned of “severe drawbacks” to one of the main suggested technologies, which would see renewable energy sources such as wood pellets burned in power stations and the carbon emissions captured and permanently stored.

Even if all the carbon was captured when biomass was burned, there could be significant emissions during the supply chain as a whole, including changing use of land to grow energy crops and transporting them, he said.

Last month, US researchers demonstrated a chemical process for producing useful products – including electricity – from fossil fuels such as shale gas, coal and biomass without emitting CO2

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