Over the last decade, while the effects and projections of climate change have intensified, tremendous progress has still been achieved in global decarbonization efforts. The levelized costs of renewable energy technologies such as wind and solar have dropped precipitously. Humanity has outpaced projections in grid and transportation sector decarbonization and a politico-economic consensus on the need for emissions reduction has slowly but surely formed. However, in tackling climate change, there is an additional technological requirement for negative emission technologies (NETs), in particular direct air capture (DAC) of CO₂.

Even if humanity approaches net zero emissions, there is still an urgent need for NETs to recapture the carbon that our civilization has already emitted, to get to pre-industrial atmospheric CO₂ levels to curtail global warming. Additionally, there are many hard-to-decarbonize sectors which will produce emissions for which DAC can offset more efficiently than other forms of decarbonization. Most relevantly to the global consensus building at a United Nations level, NETs can help wealthier regions offset the emissions of industrializing nations that have later timelines on reaching net zero.

There is a three-fold challenge in developing these NETs. First, there must be substantial engineering progress in designing systems that are dramatically more efficient and cost-effective than those available today. Second, there must be a rigorous process for quantifying the efficacy and CO₂ capture potential of these technologies, given uncertainty around sequestration, storage, and conversion. Many contemporary practices for CO₂ “credits” or “offsets” rely on clever carbon-budgeting without leading to actual reductions in atmospheric levels. Third, there must be global progress towards appropriately factoring in these NETs into international agreements to reflect the ground truth on their development and use. This presentation will focus on these challenges, as well as report on proceedings from COP28—the 2023 United Nations Climate Change Conference—relevant to this topic.

Keith Peterman

York College of Pennsylvania

Appearances