ExxonMobil, Royal Dutch/Shell, and three oil-industry groups together spend $115 million a year on advocacy designed to “obstruct” climate change policy, according to new estimates released by Influence Map, a British nonprofit research organization.

The sheer fuzziness of corporate influence prompted the project. Nations hold companies to different standards—or none at all—for disclosures of how they are trying to influence public policy and what it costs.

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