The Polluters Pay Climate Fund Act of 2025 aims to impose a significant assessment on fossil fuel companies to fund climate change mitigation and adaptation efforts. It establishes a new tax under the Internal Revenue Code, requiring certain assessable persons to pay a share of a $1,000,000,000,000 (one trillion dollar) total assessment. This tax applies to U.S. persons or those engaged in trade within the U.S. who were involved in extracting fossil fuels or refining crude oil between 2000 and 2023, and are responsible for over 1 billion metric tons of covered carbon dioxide emissions. The amount each company pays is proportional to its share of covered carbon dioxide emissions, defined as the total CO2 released from their operations and products during the specified period. Companies can elect to pay this tax as a lump sum by September 30, 2026, or in nine annual installments, with 20% due initially and 10% in each subsequent year. The bill clarifies that this tax is not deductible for income tax purposes. The legislation establishes the Polluters Pay Climate Fund in the U.S. Treasury, into which all collected tax revenues will be deposited. Funds from this account are to be used for a comprehensive and equitable federal response to climate change impacts, including investments in climate resilience, adaptation, disaster response, and environmental justice. Specific uses include climate-related disaster recovery and mitigation support, climate-resilient infrastructure, and initiatives for energy, food, transportation, and ecosystem resilience. The bill mandates specific allocations from the fund, including not less than $15,000,000,000 to the Federal Emergency Management Agency for climate-related disaster programs, with at least $3,000,000,000 for the Building Resilient Infrastructure and Communities (BRIC) program. Additionally, not less than $6,000,000,000 is designated for grants and technical assistance under the Clean Air Act. Crucially, 40 percent of the amounts appropriated from the Fund each fiscal year must benefit environmental justice communities , defined as those with significant representation of communities of color, low-income, or Tribal and Indigenous populations disproportionately affected by environmental issues. Finally, the Act explicitly states that it does not relieve any person from liability under common law or any State or Federal law, nor does it preempt or restrict any existing rights or remedies related to climate change claims. It also clarifies that the fund's existence or use cannot be used as evidence in such actions or to offset any awarded damages.