2019-07-01 | Dan Tong

An international joint research team led by Professor Zhang Qiang from the Department of Earth System Science at Tsinghua University and Associate Professor Steven J. Davis at the University of California, Irvine, published a paper entitled “Committed emissions from existing energy infrastructure jeopardize 1.5 °C climate target” in Nature. The paper is the first comprehensive assessment of the “CO₂ emission commitment” effects of existing and proposed energy infrastructure.

The Intergovernmental Panel on Climate Change (IPCC) issued a special report in 2018. The Report assessed the potential impact of a 1.5°C increase of the global average surface temperature and the emission reduction pathway to achieve a 1.5°C climate target. It is pointed out that the global average surface temperature is now about 1°C higher than the pre-industrial level. Following the 1.5°C climate target, there is only 420-580 Gt of CO₂ emissions quota left. What’s more, recent studies have also shown that new anthropogenic CO₂ emissions must approach zero by mid-century (2050) in order to stabilize the global mean temperature at the level targeted by international efforts. Thus, it is important to understand the tension between dwindling carbon-emissions budgets and future CO₂ emissions that are “locked-in” or “committed” by existing and proposed energy infrastructure.

The research joint research team led by Prof. Zhang Qiang use detailed datasets of existing fossil-fuel energy infrastructure in 2018 to estimate regional and sectoral patterns of committed CO₂ emissions, the sensitivity of such emissions to assumed operating lifetimes and schedules, and the economic value of the associated infrastructure. The results suggest that the most cost-effective premature infrastructure retirements will be in the electricity and industry sectors, if non-emitting alternatives are available and affordable.

The research shows that, if operated as historically, existing infrastructure will cumulatively emit about 658 Gt of CO₂ (with a range of 226 to 1,479 Gt CO₂), higher than the carbon budget under 1.5°C climate target. If built, proposed power plants (planned, permitted or under construction) would emit roughly an extra 188 (with a range of 37–427) Gt CO₂. Therefore, committed emissions from existing and proposed energy infrastructure reach about 846 Gt CO₂, thus represent more than the entire carbon budget that remains if mean warming is to be limited to 1.5°C. Together, power and industry infrastructure represent more than 75% of total committed emissions, but less than 25% of the estimated economic value of CO₂-emitting energy infrastructure. Nevertheless, the estimates suggest that little or no new CO₂-emitting infrastructure can be commissioned, and that existing infrastructure may need to be retired early (or be retrofitted with carbon capture and storage technology) in order to meet the Paris Agreement climate goals.

This study highlights the difficulties and urgency of global response to climate change. In the future, we must strictly limit high-carbon energy investment, accelerate the development of renewable energy, shorten the service life or equipment utilization rate of active high-carbon infrastructure, and promote carbon capture technologies. Starting from power, industry, and transportation infrastructures, make the rapid, far-reaching and unprecedented changes to the low-carbon sustainable development and achieve global temperature control targets.

Article link: https://www.nature.com/articles/s41586-019-1364-3