Food systems— encompassing activities in food production, land-use change, supply chains and waste management— contribute significantly to climate change. Recent estimates suggest that food systems produce over 30% of annual anthropogenic greenhouse gas (GHG) emissions (about 20% of CO2, 50% of CH4, and 75% of N2O), with the Intergovernmental Panel on Climate Change (IPCC) estimating a notably broad range of 23-42% of global GHG emissions. This perspective synthesizes current research on the contributions of food systems to climate change, highlighting challenges in quantifying their impact and the need for a harmonized accounting framework for more effective climate action. We recommend that an expert committee aligned with the Intergovernmental Panel on Climate Change (IPCC) develop good practice guidance for food systems emissions accounting in four key areas, including: (1) clearly defining system boundaries and nomenclature; (2) developing protocols to allocate sectoral emissions to food systems; (3) prioritizing critical areas to enhance food systems activity data and emissions factors; and (4) developing a balanced framework for estimating and monitoring the impact of mitigation interventions in light of other food systems imperatives. Such a committee should be integrated into two key international policy processes— the United Nations Framework Convention on Climate Change (UNFCCC) and the United Nations Food Systems Summit (UNFSS)— to support coordinated action towards global net-zero goals. Guidance from the committee could significantly improve the ability of governments, companies, and researchers to estimate, report, monitor and ultimately reduce the climate impacts of food systems.