Post Carbon Institute (PCI) is a think tank which provides information and analysis on climate change, energy scarcity, and other issues related to sustainability and long term community resilience.

Its Fellows specialize in various fields related to the organization's mission, such as fossil fuels, renewable energy, food, water, and population.

It broadened its topical focus to include natural resource depletion, climate change, the limits to economic growth, human overpopulation, food, and other issues - partly in response to the changed U.S. political landscape following the 2008 oil crisis, the financial crisis of 2007–2008, and the election of President Barack Obama (see Post Carbon Institute Manifesto).

Its roster of Fellows was significantly expanded to include notable figures such as Bill McKibben, Wes Jackson, David Orr, and Majora Carter.

Resilience.org is a resource platform for communities building local self-reliance, emphasizing community-based responses to the rapidly emerging fallout from the end of cheap fossil fuels.