- Richard G. Newell
Some analysts argue that GHG emissions will turn out to have peaked in 2019. However, even if the tipping point has been reached, the rate of emissions reductions is slow and the accumulated concentration of GHG in the atmosphere is already high. It is doubtful that emissions reductions alone will bring the world in line with the ambitions of the Paris Accord. The realization of this sobering fact has led to increased interest in carbon removal technologies, including nature-based solutions; carbon capture, use, and sequestration (CCUS); and direct air capture. But carbon removal faces many challenges, including scale, costs, lack of public support, and issues with measurement, reporting, and verification. How viable is carbon removal technologically? Could it ever become economic? What technology breakthroughs are required? What policy support could accelerate deployment?