Carbon, Power, and Sustainability in ATLAS Computing

The ATLAS collaboration operates a large, distributed computing infrastructure: almost 1M cores of computing resources and over one exabyte of data are distributed across 100 computing sites worldwide. These resources contribute significantly to the total carbon footprint of the experiment, and they are expected to grow by a large factor as a part of the experimental upgrades for the High-Luminosity LHC at the end of the decade. This contribution describes the efforts underway to understand and monitor the true carbon footprint of ATLAS computing beyond power consumption, identify opportunities for savings, and establish recommendations for the sites to reduce their carbon footprint.