Every decade, the Census Bureau fulfills a constitutionally-mandated count of every person living in the United States. It is the largest peacetime mobilization undertaken by the federal government, cumulating in data vital to U.S. social, political, and economic systems. Census data also form the statistical backbone of efforts to understand the impacts of the climate crisis and environmental hazards (e.g., pollution), as well as the consequences of policy decisions on communities. Due to a long and continuing history of unequal protections and racist policies (such as redlining), people of color and low-income communities disproportionately bear the health and economic burdens caused by environmental hazards. The climate crisis also hits many of these same communities the hardest. Policymakers, civil rights advocates, and others rely on census data to develop and implement equitable policies and practices that advance climate and environmental justice.