“地球工程”作为减缓气候变化手段的几个关键问题

减缓气候变化可以在大的地理尺度上以工程技术手段来实施。地球工程包括所有能源生产和消费以外的、不涉及工业生产过程管理的,在较大的地球尺度或规模上,去除大气中的CO2或直接控制太阳辐射而降温的各种人为的工程技术手段,主要包括三大类:绿色生物技术手段、碳捕获与埋存技术和太阳光辐射额度控制管理技术。这一类地球工程手段有着一系列经济、技术、环境、伦理、安全和不确定性含义。本文就近年来国际上关于地球工程作为减缓气候变化可能技术选择的几个关键问题开展了分析和讨论,涉及概念界定、技术特点、可能影响、治理构架等。作者认为,对于直接作用于碳的地球工程手段,如绿色生物技术手段和碳捕获与埋存技术,风险小、可操控;太阳光辐管理技术,通过人为排放到大气的SO2和气溶胶等的降温效应,来控制地球气温的上升,尽管使用的经济成本可能不高,具有实际操作可能,但其巨大的不确定性和可能的安全含义,需要引起足够的重视。从伦理上看,当代人是否有权来开展太阳光辐管理技术这类具有巨大科学不确定性的地球工程存在争议,在科学不确定的情况下采取任何行动,就失去了伦理学基础。从法律上看,人工干预太阳辐射,即使是科学实验或研究,由于其影响超出了国界,超出了当代人,也超出了人类社会,如果有人采取行动,也存在法律依据上的质疑。人工干预太阳辐射的研究和实施,需要一个国际治理构架。为了防止其他国家单独行动,需要"相互约束"的治理构架——"自我约束"以换取他国同意"自我约束"。鉴于气候变化和光辐管理在科学上的不确定性,目前不宜实施,短期内也不会提上议事日程。太阳光辐管理技术影响的复杂性和气候变化风险的迫切性,需要我们加大科学研究力度,为科学决策提供依据。中国作为一个新兴经济体,世界第一大CO2排放国,地域空间气候条件存在巨大差异性。从减排成本的角度,从气候影响的空间差异性,开展地球工程的科学研究,有着科学、政策和国际气候外交的积极意义。但是,相关的科学研究需要国际制度构架。由于气候变化框架公约及其谈判尚未涉及,需要开展系统科学、技术、经济、法律和国家安全等方面的相关研究,提高科学认知度,为国际谈判和政策选择提供决策依据。

Key Issues Related to Geo-engineering as Approaches to Climate Change Mitigation

Climate change mitigation can be implemented through the approach of engineering technologies at a large geographic scale.Geo-engineering refers to,in the large Earth yardstick or scale,all kinds of artificial approaches of engineering technologies in temperature reduction by removing CO2 in the atmosphere or directly controlling solar radiation,instead of emission reductions related to production and consumption of energy,and to the management of industrial production process.It is mainly classified into three big categories: approach of green biological technology,carbon capture and storage,and control and management technology of solar radiation.This kind of geo-engineering approach has a series of implications in economy,technology,environment,ethics,security,and uncertainty.The present paper makes an analysis and conducts a discussion on several recent international key issues of the possible technological options for mitigation of climate change,involving definitions of concept,technological features,possible effects and governance framework,etc..The author argues that geo-engineering approach directly acting on carbon,such as biological sinks and carbon capture and storage technologies,are assessed with relatively low risk and high level of control.Through temperature reduction effects by artificially emitting SO2 into the atmosphere and aerosols,solar radiation management technology is used to control the rise of the Earth’s temperature,which,though having not a high economic cost of use but practical maneuverability,has huge uncertainty and possible implication of security,needing enough attention.Ethically,there are disputes over whether or not the contemporary people have the right to carry on geo-engineering of solar radiation management technology with such huge scientific uncertainty,and in such scientific uncertainty,to take any action will lose the ethnic basis.Legally,human intervention in solar radiation,even scientific experiment or research,will raise doubt on the legal basis,if people take action,because its effect will go beyond national boundaries,beyond the contemporary generation,and also beyond the human society.Researches on and implementation of artificial intervention in solar radiation needs an international governance framework.To prevent other countries from taking individual action needs to have a "mutual constraint" governance framework-to use "self-constraint" to trade for "self-constraint" consented by other countries.As for scientific uncertainty of climate change and solar radiation management,at present,it is not appropriate for geo-engineering to be implemented,and in the short term,will not be put on the agenda.The complexity of the effect of solar radiation management technology and the urgency of the risk of climate change require us to intensify scientific research so as to provide the basis for scientific policy-making.As an emerging economy,China is the first biggest country of CO2 emission in the world and has huge disparity in its regional spatial climate conditions.From the perspective of cost reduction and spatial disparity in climate effect,to carry on scientific research on geo-engineering is of positive significance in science,policy and international climate diplomacy.However,related scientific research needs an international system framework.Since the framework convention on climate change and its negotiations have not yet been involved,relevant researches need to be carried out in systematic science,technology,economy,law and national security,and scientific recognition be raised to provide a policy-making basis for international negotiations and policy options.