The greenhouse effect occurs when gases like carbon dioxide and methane trap heat in the atmosphere; burning fossil fuels such as coal, oil, and gas releases carbon that took millions of years to form, faster than natural processes can absorb it, which is the primary driver of modern climate change. A carbon footprint is the total greenhouse gas emissions caused directly or indirectly by a person, product, or organization, while 'net zero' describes a state where any remaining emissions are balanced by an equivalent amount removed from the atmosphere. Businesses increasingly adopt sustainability practices for several overlapping reasons: energy efficiency cuts operating costs, regulations in many markets are tightening, and investors and consumers increasingly factor Environmental, Social, and Governance (ESG) performance into their decisions.