The motivation for this special issue on circular economy, and national and global policy, originated during the international stakeholder meeting (Ochoa 2019) for our SUNRISE flagship project (Abbott 2019; Kupferschmidt 2019) in Bruxelles in June 2019. At the same day, one mile away from our meeting, Deutsche Energie Agentur (DENA) held a panel round table meeting on regulation for renewable fuels (Powerfuels 2019), at which the author could participate. The SUNRISE flagship is a European initiative for the sustainable production of solar fuels and base chemicals. The yet to be developed technology is based on the chemical reduction of carbon dioxide (CO₂) from concentrated sources and from the atmosphere, and solar water splitting for hydrogen production. Hydrogen and carbon dioxide will be synthesized to hydrocarbons for industrial use. When the synthetic hydrocarbons are consumed, carbon dioxide will be generated and fed back in a circular process, powered by renewable energy. In this extended carbon cycle (Calvin 1961), CO₂ is a valuable asset and remains part of the global biogeochemical cycle and becomes part of the circular economy. CO₂ concentration in the atmosphere will be reduced to an acceptable, climate neutral value once the cycle is in operation (Faber et al. 2020).

关于循环经济以及国家和全球政策的这一特殊问题的动机源自于2019年6月在布鲁塞尔举行的SUNRISE旗舰项目（Abbott 2019; Kupferschmidt 2019）的国际利益相关者会议（Ochoa 2019）上。距离我们的会议一英里远的地方，德意志能源代理公司（DENA）举行了关于可再生燃料法规的小组圆桌会议（Powerfuels 2019），作者可以参加。SUNRISE旗舰产品是欧洲一项旨在可持续生产太阳能和基础化学品的倡议。尚未开发的技术基于化学还原二氧化碳（CO ₂）从集中的来源和大气中分离出来，然后将太阳能分解成氢。氢和二氧化碳将合成为碳氢化合物，用于工业用途。消耗合成烃时，将产生二氧化碳并以可再生能源为动力，以循环方式反馈。在这个延长的碳循环中（Calvin 1961），CO ₂是一种宝贵的资产，仍然是全球生物地球化学循环的一部分，并成为循环经济的一部分。一旦循环开始运行，大气中的CO ₂浓度将降低至可接受的气候中性值（Faber等人，2020）。