IMPACD: Integrated macroeconomic model of pandemics, climate change, & deforestation

该项目将把大流行风险和气候风险纳入具有气候和森林生态系统的综合全球宏观经济增长模型。我们将首次深入了解大流行风险对毁林社会成本的影响，并计算减少毁林的社会价值，不仅在气候变化的背景下，而且作为减轻全球大流行风险的一种选择。我们目前的经济体制给自然环境带来了巨大的压力，尤其是世界气候和热带雨林。几个全球经济综合评估模型已经研究了全球森林对地球气候和生物多样性的关键作用。鉴于森林作为天然碳汇的作用，毁林造成的社会成本超出了生物多样性的直接损失。然而，越来越多的证据表明，森林具有额外的生态系统服务功能：它们也是疾病的宿主。例如，几个世纪以来，雨林构成了“文明”地区与野生动物之间的天然屏障，限制了人类与新的人畜共患疾病的接触。森林砍伐不仅重新安置或破坏了这一屏障；它还导致生物多样性的丧失，而生物多样性在过去也限制了新疾病的传播。在过去的二十年中，大量的实证研究已经将森林砍伐措施（作为对自然生态系统的人为侵犯的一部分）与传染病的出现联系起来。然而，到目前为止，这种联系只存在于区域范围内。最近的研究表明，在这些新出现的疾病中，有些甚至有可能在全球范围内造成健康和经济影响，最近爆发的COVID-19大流行就证明了这一点。将森林砍伐与新出现的传染病之间的联系与破坏性全球影响的风险结合起来，将改变对森林砍伐对社会造成的总成本的评估。这个项目是基于这样一种想法，即森林砍伐的潜在影响应该结合在一个单一的、综合的经济框架中。该框架必须纳入毁林的经济激励、生物多样性的永久丧失、全球变暖的损害和风险以及新出现的传染病带来的日益增加的风险之间的反馈效应。此外，该项目将明确考虑森林砍伐与新出现的传染病发生之间的随机相互作用的影响，不仅考虑到森林砍伐的经济效益，而且考虑到其对气候、生态系统和大流行病爆发的预期长期负面后果。确定新出现疾病的来源并将这些因素直接纳入综合宏观经济增长模型，可以提高我们对人类对环境影响的长期后果的理解，并有助于确定毁林和生物多样性减少的“真正”社会成本。

This project will incorporate pandemic risk and climatic risk in an integrated global macroeconomic growth model with climate and forest ecosystems. We will provide first insights into the impact of pandemic risk on the social cost of deforestation and compute the societal value of deforestation reduction not only in the context of climate change, but also as an option to mitigate the risk of global pandemics.Our current economic system has put great pressure on the natural environment, especially the world’s climate and rain forests. The crucial role of forests globally for Earth’s climate and biodiversity has already been studied in several global economic integrated assessment models. Given the forests’ role as natural carbon sinks, deforestation creates social costs that go beyond the direct loss of biodiversity. There is, however, rising evidence that forests have an additional ecosystem service: they also host diseases. Rain forests, for example, have constituted a natural barrier between “civilized” regions and wild fauna for centuries, limiting human contact with new zoonotic diseases. Deforestation not only relocates or destroys this barrier; it also leads to a loss of the very biodiversity that has in the past also limited the spread of new diseases. Over the past two decades a rich body of empirical research has linked deforestation measure as part of anthropogenic encroachment on natural ecosystems to the emergence of infectious diseases. That link, however, has so far been only present on a regional scale.Recent studies show that among these emerging diseases, some even have the potential to cause health and economic impacts on a global scale, as demonstrated recently by the outbreak of the COVID-19 pandemic. Incorporating the link between deforestation and emerging infectious diseases with the risk of devastating global impacts will change the assessment of the total cost of deforestation to society.This project is based on the idea that the potential impacts of deforestation should be combined in a single, integrated economic framework. That framework must incorporate the feedback effects between the economic incentives of deforestation, the permanent loss of biodiversity, the damages and risks from global warming, and the increasing risks posed by emerging infectious diseases. Moreover, this project will explicitly consider the effects of stochastic interactions between deforestation and the occurrences of emerging infectious diseases, taking into account not only the economic benefits of deforestation but also its expected negative long-term consequences with regard to the climate, ecosystem, and pandemic outbreaks. Identifying the source of emerging diseases and directly including these factors in an integrated macroeconomic growth model can raise our understanding of the long-term consequences of human impact on the environment and help in identifying the “true” social costs of deforestation and diminishing biodiversity.