“Climate change is the biggest global health threat of the 21st century” — UCL-Lancet Commission, 2009. This lecture discusses the scientific evidence of human-caused anthropogenic climate change and why veterinarians should care. The resultant impacts on planetary health, human health, and our patients' health will be broadly described. This lecture will then pivot to the environmental impact of providing human healthcare and veterinary care, noting that it extends beyond carbon emissions to include unsustainable resource extraction, waste disposal, pollution, water use, land use change, and other factors. The importance of carbon literacy to account for the problem will be introduced. The solutions to this global problem lie with every single one of us, and as a combined collective force we will have a substantial impact. Veterinarians can become part of the solution to the climate crisis by practicing veterinary medicine sustainably. Importantly, we can become the voice of many and lead the way to a cleaner, more affordable, healthier, more equitable, everlasting sustainable system.