Source: US Air Force

Climate change and national security

Christian Hernandez
4 min readSep 6, 2021


Like many of you, I read the Sixth IPCC report with growing alarm. It used strong language like “unprecedented” and “irreversible.” And yet the IPCC report is written through a long and convoluted consensus process between scientists, governments and inter-government agencies. The final product we all consumed had gone through many, many edits to arrive in final form, which might have muted its sense or urgency.

There are, however, a number of other publicly available documents which need to be much more direct in their assessment, as its audience depends on them to define national strategies for leading global actors. These focus on national security risks, and climate change is most certainly a national security risk.

In the UK and US government’s own words:

“…there is a clear and present danger that afflicts all of us, every region of the world, every part of society. That is the threat posed by climate change.”

UK Ministry of Defence “Climate Change and Sustainability Strategic Approach

“Ecological degradation and a changing climate will continue to fuel disease outbreaks, threaten food and water security, and exacerbate political instability and humanitarian crises.”

US’s Office of the Director of National Intelligence “Annual Threat Assessment of the US Intelligence Community” 2021

“Climate change is not only a challenge of the future. We are already observing changes in the UK climate, with average temperatures having risen by around 1ºC over the last century.”

HM Government “UK Climate Change Risk Assessment 2017

“The effects of a changing climate are a national security issue with potential impacts to Department of Defense (DoD or the Department) missions, operational plans, and installations.”

US Department of Defense “Report on Effects of a Changing Climate to the Department of Defense” January 2019

“Climate change may exacerbate water scarcity and lead to sharp increases in food costs. The pressures caused by climate change will influence resource competition while placing additional burdens on economies, societies, and governance institutions around the world. These effects are threat multipliers that will aggravate stressors abroad such as poverty, environmental degradation, political instability, and social tensions — conditions that can enable terrorist activity and other forms of violence.”

United States Government’s “Quadrennial Defense Review 2014

The risk identified by cross-government analysis and national intelligence specialists centers not only of the risk of climate change to the US and UK (rising water levels, flooding, fires), but also to their operational military footprint (air force bases under water, forward deployment bases at risk, soldiers in extreme heat) and most critically to an increase in geopolitical risk from drought, famine, political instability and climate-caused refugee migration. It is both a national risk and a global risk.

The US and UK Defence department reports not only outline needs to integrate climate change into their operations and assessments of global risks, they are also keenly aware of the role they themselves play in the national and global crisis. A research paper published in June 2019 analysed the environmental impact of the US military and concluded that “If the US military were a country, its fuel usage alone would make it the 47th largest emitter of greenhouse gases in the world, sitting between Peru and Portugal.”


The UK Ministry of Defence directly admits that “Defence accounts for 50% of the UK central Government’s emissions”. Both sets of reports outline actions the UK and US military are already taking — from investment into research for energy sources for its equipment, to adaptation technologies deployed in bases, to lowering the carbon footprint of their vast amount of real estate assets.

Examples of UK Defence innovation on climate change

The US and UK military (I will purposely leave China and other NATO allies out of this post), with their broad purchasing power, action-focused chain of command, and understanding of the risks posed by climate change, could very clearly become a funder and early adopter of mitigation and adaptation technologies. Not as a “nice to have” but as a “must have” to succeed in their mission of defending their homelands.

On a panel on the role of climate tech and the UK Government’s Net Zero policy I recently quipped:

To that, we should clearly add that Climate is a National Security Policy!



Christian Hernandez

Partner at @2150-vc backing technologies that make our world more resilient and sustainable. Salvadoran-born Londoner. YGL of the @wef Father ^3

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