As the United States and nations around the world struggle to blunt the effects of rising temperatures and extreme weather, sweeping assessments released Thursday by the White House, the U.S. intelligence community and the Pentagon conclude that climate change will exacerbate long-standing threats to global security.

Together, the reports show a deepening concern within the U.S. security establishment that the shifts unleashed by climate change can reshape U.S. strategic interests, offer new opportunities to rivals such as China, and increase instability in nuclear states such as North Korea and Pakistan.

The reports emerge as world leaders prepare to gather in Glasgow, Scotland, next month for crucial U.N. climate talks. And the assessments suggest that the Biden administration is preparing to take on the national security consequences of global warming after four years of inaction under President Donald Trump. During his presidency, climate-related security assessments were routinely suppressed because they did not match his administration’s skeptical stance toward climate science.

Psychological research shows that climate change can alter an individual's mental health both directly and indirectly, impacting how we respond to this crisis. (John Farrell/The Washington Post)

Shortly after President Biden came into office, he ordered that climate change play a far more prominent role in U.S. security strategy.

The Pentagon report in particular marks a shift in how the U.S. military establishment is incorporating climate issues into its security strategy, analysts said. Until now, when the Defense Department has considered climate change, it has tended to focus on how floods and extreme heat can affect military readiness rather than the broader geopolitical consequences of a warming world. Now it is worried that climate change could lead to state failure.

“Climate change is altering the strategic landscape and shaping the security environment, posing complex threats to the United States and nations around the world,” Defense Secretary Lloyd Austin said in a statement that accompanied the Pentagon report. “To deter war and protect our country, the [Defense] Department must understand the ways climate change affects missions, plans, and capabilities.”

The shift in Washington comes as militaries and security agencies around the world are accounting for global warming in their planning. At NATO, Secretary General Jens Stoltenberg earlier this year made climate change a major focus of the defense alliance as it overhauls its strategic plans. The British military this spring unveiled a sustainability report that counsels a top-to-bottom overhaul of military operations to prepare for far more climate-related deployments in the coming decades.

The release of the U.S. assessments “sends a warning message ahead of next month’s U.N. summit of the grave risks that we’re facing and why it’s so critical. These reports are overdue,” said Erin Sikorsky, director of the Center for Climate and Security and a former senior U.S. intelligence official focused on climate issues.

The new National Intelligence Estimate (NIE) on climate, a first-of-its kind document by the Office of the Director of National Intelligence, builds on other grim warnings from national security officials about how a changing climate could upend societies and topple governments.

“We assess that climate change will increasingly exacerbate risks to U.S. national security interests as the physical impacts increase and geopolitical tensions mount about how to respond to the challenge,” the document states. It also concludes that while momentum to reduce global emissions of greenhouse gases is growing, “current policies and pledges are insufficient” to meet the goals that countries laid out in the landmark Paris climate accord.

A former senior intelligence official lauded the document’s contribution to understanding the security implications of climate change.

“This NIE represents a valuable iteration on findings from past intelligence assessments,” said Rod Schoonover, who was director of environment and natural resources at the National Intelligence Council in the Obama and Trump administrations.

“However, the report lacks a singular top-line statement that adequately conveys the seriousness and immediacy of the multifactorial risks associated with ongoing climate-linked stresses, and humanity’s tendency to increase its own vulnerability to these stresses,” Schoonover said in an email.

The NIE offers a dim assessment of the prospects for unified international action.

“Countries are arguing about who should act sooner and competing to control the growing clean energy transition,” it states, concluding that “most countries will face difficult economic choices and probably will count on technological breakthroughs to rapidly reduce their net emissions later.”

As developing and vulnerable nations cope with the effects, they may turn to Washington for help, “creating additional demands on U.S. diplomatic, economic, humanitarian, and military resources,” the report says.

The Pentagon warns that disruption to fisheries could spark conflict over food security. Unpredictable rainfall might increase tensions over access to rivers that cross national boundaries, such as the Nile and the Mekong. Even efforts to combat climate change could lead to unintended consequences, such as conflicts over access to the rare minerals that are needed to build circuitry and wind turbines.

The report says the Defense Department should ready itself to provide humanitarian assistance in climate crises, incorporate climate-related issues into its war-games — and also work on “countering malign actors who seek to exploit climate change to gain influence.” Some of the most specific analyses remained classified.

The White House report on migration, which examines the way climate change is driving human movement around the world, notes that drought and other extreme weather can spark conflicts and force population displacements — and that countries such as China and Russia are poised to take advantage.

“Absent a robust strategy from the United States and Europe to address climate-related migration, the People’s Republic of China (PRC), Russia, and other states could seek to gain influence by providing direct support to impacted countries grappling with political unrest related to migration,” the White House report says.

It advocates expanding asylum and refugee programs to better take into account climate-driven migration. And it says that U.S. policymakers need to be ready to direct funding and resources toward regions that are facing influxes of migrants driven to move by extreme weather, droughts and climate-related conflicts. It cites one report that estimates that by 2050, up to 143 million people in Latin America, sub-Saharan Africa and South Asia could move for climate-driven reasons.

“We’re leaving climate-displaced people with valid asylum claims behind,” said Ama Francis, an analyst at the International Refugee Assistance Project.

To a significant degree, China will influence how quickly and how much global temperatures rise. The NIE notes that it accounts for about 30 percent of emissions globally, the largest single source.

But “modest reduction targets” in China’s long-term plans raise doubts about whether it will meet its reduction goals, the NIE finds.

“China has not publicly articulated detailed plans for meeting its 2060 net-zero emissions target; to do so, we assess that Beijing would need to follow through on President Xi Jinping’s pledge at the U.S. Climate Summit in April to phase out coal consumption,” the NIE said.

And that will be hard to do. China, along with India — the world's fourth-largest emitter — are incorporating more renewable and low-carbon sources of energy, the NIE says, “but several factors will limit their displacement of coal.”

The NIE concludes that geopolitical tensions are likely to rise in the coming decades as countries struggle to deal with the physical effects of climate change — which scientists say already is producing more devastating floods, fires and storms — as well as the political ones. Mitigating climate-related disasters may call for solutions that some countries cannot afford and political will that some leaders cannot muster.

The physical effects are likely to be most keenly felt in parts of the world already being reshaped — such as the Arctic — and in regions and countries that are particularly vulnerable because they experience extreme climate events, such as hurricanes or droughts, and because their governments are ill-equipped to manage the fallout.

The NIE identifies 11 countries in that category of acute risk: Afghanistan, Colombia, Guatemala, Haiti, Honduras, India, Iraq, Myanmar, North Korea, Nicaragua and Pakistan.

An NIE is a unique document in that it reflects the consensus view of all the U.S. intelligence agencies. Traditionally, producing the documents can take months, and they present the most comprehensive analysis of significant national security concerns. The NIE released publicly is unclassified, but a classified version will be provided to policymakers, officials said.

The report’s warnings build on years of intelligence analysis that also painted a bleak picture. Just six months ago, in its quadrennial “Global Trends” report, the Office of the Director of National Intelligence forecast that climate change could spawn social upheaval and political instability.

In one scenario, the authors imagined fisheries devastated by rising ocean temperatures and acidity, grain harvests depressed by changes in precipitation and rising food prices conspiring to trigger “widespread hoarding” that leads to a global famine — all by the early 2030s.

A wave of protest over “governments’ inability to meet basic human needs” could bring down leaders and governments, the report warned.

In 2014, the National Intelligence Strategy warned that climate change could spark new wars over water and other vital resources that are likely to become scarce.

The CIA also recently established a center to address what it describes as transnational security threats, including climate change.