The last decades have seen a remarkable expansion in the number of International Organizations (IOs) that have mainstreamed environmental issues into their policy scope—in many cases due to the pressure of civil society. We hypothesize that International Non-Governmental Organizations (INGOs), whose headquarters are in proximity to the headquarters of IOs, are more likely to affect IOs' expansion into the environmental domain. We test this explanation by utilizing a novel dataset on the strength of environmental global civil society in proximity to the headquarters of 76 IOs between 1950 and 2017. Three findings stand out. First, the more environmental INGOs have their secretariat in proximity to the headquarter of an IO, the more likely the IO mainstreams environmental policy. Second, proximate INGOs’ contribution increases when they can rely on domestically focused NGOs in member states. Third, a pathway case reveals that proximate INGOs played an essential role in inside lobbying, outside lobbying and information provision during the campaign to mainstream environmental issues at the World Bank. However, their efforts relied to a substantial extent on the work of local NGOs on the ground.

在过去的几十年中，将环境问题纳入其政策范围的国际组织 (IO) 的数量显着增加——在许多情况下是由于民间社会的压力。我们假设总部靠近 IO 总部的国际非政府组织 (INGO) 更有可能影响 IO 向环境领域的扩张。我们利用 1950 年至 2017 年间在 76 个 IO 总部附近的环境全球公民社会力量的新数据集来测试这一解释。三个发现脱颖而出。首先，环境 INGO 的秘书处越靠近 IO 的总部，IO 就越有可能将环境政策纳入主流。第二，当能够依赖成员国内专注于国内的非政府组织时，邻近的国际非政府组织的贡献就会增加。第三，一个路径案例表明，在世界银行将环境问题纳入主流的运动中，邻近的国际非政府组织在内部游说、外部游说和信息提供方面发挥了重要作用。然而，他们的努力在很大程度上依赖于当地非政府组织的工作。