From conflict to climate crisis: How wars shape the future environment

Military activity is a current blind spot in global climate policy. This systematic review synthesises evidence from 263 studies and 36 reports published between 2014 and 2025. Following PRISMA framework, the review assesses the environmental impacts across pre-conflict, active conflict, and post-conflict, with a focus on four interconnected domains namely greenhouse gas (GHG) emissions, water systems, agricultural land and food security, and natural ecosystems. This study finds that military operations contribute an estimated 5.5% of total global greenhouse gas emissions, a carbon footprint that would make the world's militaries collectively the fourth-largest emitter if counted as a nation. Yet, current reporting to the United Nations Framework Convention on Climate Change covers less than one-tenth of actual emissions due to current policies and voluntary disclosure. The review identifies extensive hidden emissions from pre-conflict mobilisation and weapons manufacturing to active combat, supply chains, refugee displacement, and post-conflict reconstruction. These processes generate cumulative and cascading effects that exacerbate climate change, degrade water and soil systems, disrupt ecosystems, and undermine food security. These underreported emissions intensify climate change as well as undermines global efforts towards the Paris Agreement targets. By integrating fragmented evidence across environmental domains and conflict phases, this review advances understanding of the conflict-climate nexus and identifies structural gaps in existing climate accounting and governance frameworks. The study findings highlight an urgent need for mandatory, transparent, and standardised military emission reporting and evaluation frameworks. Incorporating military accountability into global climate policy is both feasible and essential to safeguard the planets future. Without it, any vision for a sustainable and peaceful climate future remains incomplete.