The rapid increase in cybersecurity threats since the 2020 pandemic has underscored the need for a better and deeper understanding of their broader impact. While the financial and operational consequences of cyberattacks like ransomware are well known, their environmental footprint remains largely unexplored. This paper introduces a novel approach, the CyberAttack Carbon Footprint (CACF) to estimate the carbon footprint of cyberattacks, specifically ransomware, by calculating the embodied, operational, and transfer emissions. Our analysis reveals that in 2023, the carbon emissions from ransomware attacks were 430 MtCO \(_2\) eq and surpassed those of three G7 countries and even exceeded the carbon footprint of cryptocurrency mining, two widely recognized contributors to environmental degradation. These findings highlight a critical and often overlooked dimension of cybercrime, suggesting that ransomware poses a security threat and a significant environmental challenge. This study highlights cybersecurity’s growing role in ecological sustainability.