In this paper, we present the results of a Global Sensitivity Analysis (GSA) proving that Animal Agriculture is the leading cause of climate change, responsible for 87% of human-made greenhouse gas emissions. The burning of fossil fuels is currently the leading source of human-made carbon dioxide (CO2) emissions. However, climate change is caused by cumulative human-made greenhouse gas and aerosol emissions and not just current CO2 emissions alone. While humans have been burning fossil fuels for a little over 200 years, we have been burning down forests for Animal Agriculture for well over 8,000 years! For the GSA analysis, we use factual data from the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) and other peer-reviewed scientific sources. We show that we need to transition to a global plant-based economy first and that blindly eliminating fossil fuel usage first will accelerate the warming of the planet. We show that the annual methane emissions from Animal Agriculture alone causes more incremental global warming than the annual CO2 emissions from all fossil fuel sources combined. We further show that the transition to a global plant-based economy has the potential to sequester over 2000 Giga tons (Gt) of CO2 in regenerating soils and vegetation, returning atmospheric greenhouse gas levels to the “safe zone” of under 350 parts per million (ppm) of CO2 equivalent, while restoring the biodiversity of the planet and healing its climate. This paper clearly illustrates why the scientific community, government institutions, corporations and news media, who vastly underestimate the role of Animal Agriculture and focus primarily on reducing fossil fuel use, need to urgently change their priorities in order to be effective.