The Economics of Marine Plastic Pollution: What are the Benefits of International Cooperation?

在最近公布的25年环境计划中，英国政府强调，塑料对世界海洋的污染是一个亟需采取行动的关键环境问题。正如该计划所指出的那样，“英国致力于领导保护海洋环境的努力。为了解决海洋污染问题，我们将采取可持续、国际化和跨境的方法[……]”(第92页)最近出现了关于塑料对世界海洋和海岸线环境影响的科学证据，证实了这一问题的严重性和全球影响。此外，最近的研究首次尝试量化有多少塑料流入海水，这些塑料来自哪里，以及它的运输和命运。环境影响包括对海洋生物(如海鸟、海龟和海洋哺乳动物)的影响；海洋塑料通过这些影响以及通过污染海岸线/海滩和通过食物链中积累的塑料对健康的影响导致人类福祉的损失。然而，流入海洋的塑料排放量似乎在随着时间的推移而上升。解决这一日益严重的问题的有效解决办法将需要各国之间的合作，因为海洋塑料具有许多全球“公共有害”的特征--任何一个国家的排放都会对其他国家的公民以及其他国家的国家水域和海岸线造成影响。由于大多数减排行动都是代价高昂的，个别国家有搭乘其他国家减少污染努力的便车的动机，导致在减少污染方面缺乏国际合作的问题。正如英国政府的25年计划(第92页)所述：“解决海洋垃圾问题需要协调的全球和区域战略。”这个跨学科的项目聚焦于这一国际合作问题。基于北大西洋国家的案例研究，该项目的主要目的是开发和测试一个框架，以确定在减少海洋塑料污染方面开展国际合作的好处。该项目有5个目标：1.审查和总结关于海洋塑料对海洋生物的生态影响的科学数据；2.量化塑料跨越北大西洋的运输方式，以显示任何一个国家的排放对国际水域和其他北大西洋国家沿海水域塑料水平的影响(以及目前对这些转移影响大小的不确定性)；3.对8个北大西洋国家海洋塑料的经济损害成本进行估计。这将利用英国和美国最初声明的偏好研究以及利益转移方法的组合来实现；4.对这些国家中的每个国家，制定减少向海洋排放塑料的(边际)成本的估计，包括与改变消费者对购买决定和塑料包装的行为有关的政策选择；以及与废物处理和处理系统改变有关的政策选择；5.使用博弈论框架，量化减少海洋塑料污染的不同行动对每个国家的净收益，并量化合作与不合作行动相比的净收益。我们预计，该项目将在海洋塑料污染的经济成本、减少海洋塑料的行动的成本以及加强国际合作的好处方面产生与英国政策制定者和其他利益攸关方直接相关的结果。此外，我们将开发的框架旨在可转移到其他海洋塑料污染的区域环境(如南中国海)和其他类似的国际污染控制问题。为承担这一项目而组建的跨学科团队包括经济学家和海洋科学家，他们都有成功合作的记录。

In its recently-announced 25 year environmental plan, the UK government highlights the pollution of the world's oceans by plastics as a key environmental problem in need of urgent action. As the plan notes, "The UK is committed to leading efforts to protect the marine environment. To tackle marine pollution, we will pursue a sustainable, international and transboundary approach [...]" (p.92). Scientific evidence on the environmental impacts of plastics in the world's oceans and coastlines has recently emerged, confirming the severity and global reach of this problem. Moreover, recent studies have made first attempts to quantify how much plastic is flowing into marine waters, where this comes from, and its transport and fate. Environmental impacts include those on marine life (such as sea birds, turtles, and marine mammals); marine plastics lead to a loss of human well-being through these effects, as well as through pollution of coastlines/beaches and through health effects from plastics accumulating in the food chain. However, emissions of plastics into the seas and oceans appear to be rising over time. Effective solutions to tackling this growing problem will require cooperation between nations, since marine plastics have many of the characteristics of a global "public bad" - emissions from any one country have impacts on citizens of other countries, and the national waters and coastlines of other countries. Since most actions to reduce emissions are costly, individual countries have an incentive to "free ride" on the pollution-reduction efforts of others, leading to problems of a lack of international cooperation on pollution reduction. As the UK government's 25 year plan states (p.92): "Tackling marine litter requires coordinated global and regional strategies."This inter-disciplinary project focusses on this international cooperation problem. Based on a case study of the North Atlantic nations, the main aim of the project is to develop and test a framework for identifying the benefits of international cooperation in reducing marine plastic pollution. The project has 5 objectives:1. To review and summarise scientific data on the ecological impacts of marine plastics on marine life;2. To quantify the way in which plastics are transported across the North Atlantic, so as to show the impacts of emissions from any one country on levels of plastic in international waters and on the coastal waters of other North Atlantic countries (along with current uncertainty over the size of these transfer effects);3. To develop estimates of the economic damage costs of marine plastics for 8 North Atlantic countries. This will be accomplished using a mix of original stated preference studies in the UK and US, along with benefits transfer methods;4. For each of these countries, to develop estimates of the (marginal) costs of reducing plastic "emissions" to the sea, including policy options related to changing consumer behaviour over purchase decisions and plastics packaging; and those related to changes in waste handling and processing systems;5. Using a game theoretical framework, to quantify the net benefits to each country of different levels of actions to reduce marine plastic pollution, and to quantify the net benefits of cooperation compared to non-cooperative actions.We anticipate that the project will produce results of direct interest to UK policymakers and other stakeholders in terms of the economic costs of marine plastic pollution, the costs of actions to reduce marine plastic, and the benefits of greater international cooperation. Moreover, the framework we will develop is designed to be transferable to other regional settings for marine plastic pollution (such as the South China Sea) and to other, comparable international pollution control problems. The inter-disciplinary team assembled to undertake this project includes economists and marine scientists with a track record of working together successfully.