HB 866 establishes the Climate Change Impact Assessment Council to evaluate the effects of climate change on Texas residents, natural resources, public health, and the state economy. The council will study mitigation strategies for issues such as flooding, erosion, drought, and wildfires, as well as recommend legislative or regulatory actions. The council is composed of legislative and public members with expertise in relevant fields and will submit a report to the legislature by January 1, 2027. The council is dissolved on September 1, 2027, with appointments required by December 1, 2025. The Act takes effect September 1, 2025​.