The United States produces more greenhouse gas emissions through its defence operations alone than European countries such as Portugal or Sweden, a new study found.
The Pentagon’s greenhouse gas emissions totalled over 59 million metric tons of carbon dioxide in 2017, noted the study published by Brown University.
"If it were a country, it would’ve been the world’s 55th largest CO2 emitter — with emissions larger than Portugal, Sweden, or Denmark," said the study’s author and political scientist at Boston University Neta Crawford.
“This makes the Pentagon the US government’s largest fossil fuel consumer as it accounts for between 77% and 80% of all federal government energy consumption since 2001,” she said in an article.
Transporting troops and using weapons accounted for about 70% of the energy consumption, mostly due to the burning of jet and diesel fuel, said Crawford.
China is the world's largest greenhouse gas emitter, followed by the United States. But "in any one year, the Pentagon’s emissions are greater than many smaller countries total greenhouse gas emissions," noted the study.
Global temperatures are on course for a 3-5 degrees Celsius rise this century, far overshooting a global target of limiting the increase to 2C or less, the U.N. World Meteorological Organization said in November.
Back in January, the Pentagon branded climate change "a national security issue" in a report to Congress and has launched multiple initiatives to prepare for its impact.
Crawford noted the Pentagon has reduced its fuel consumption significantly since 2009 by making its vehicles more efficient and using cleaner sources of energy in its bases.
Though the researcher said they could reduce them further by cutting fuel-heavy missions to the Persian Gulf to protect access to oil, which is no longer a top priority as renewable energy was becoming more relevant.
"Many missions could actually be re-thought, and it would make the world safer," she said.