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A changing climate has far-reaching implications for U.S. national security interests well into the future, Susan Rice told a Stanford audience on Monday.

Rice, ’86, President Barack Obama’s national security adviser and former U.S. ambassador to the United Nations, addressed climate change and national security at an event sponsored by the Freeman Spogli Institute for International Studies.

Global climate action is an imperative, she told an audience of a few hundred people at the Bechtel Conference Center. Extreme weather is an urgent and growing threat to America’s security, contributing to warfare, refugee flows and conflicts over basic resources like food and water. It is especially challenging for less developed countries where resources are already scarce, she said.

“Today, we face no greater long-term challenge than climate change,” said Rice, adding that it is not a distant problem that humanity can avoid tackling any longer. “The science is not up for debate.”

Scientists have been warning about the changing weather since at least 1985, she said. But the United States and the world have  “failed repeatedly” to treat this ominous trend with the seriousness it deserves, due to divisive politics, both at home and abroad. The use of fossil fuels and carbon emissions need to be reduced.

While other threats certainly preoccupy American leadership – the Islamic State, al-Qaida, the Iranian nuclear issue and conflicts in Syria, the Sudan, Yemen and Ukraine – climate change is an especially global issue that touches all human beings, Rice said.

She noted that 2014 was the hottest year on record, and most of the past 15 years were among the hottest as well. In fact, the U.S. military had to cancel training exercises last year because the temperatures were too high. A discernible “wear and tear” impact exists for troops in the field, she said, and the risks are clear to bases near changing sea levels or places of scorching weather.

“Extreme precipitation events are becoming more frequent,” she said, noting the forecast for more storms like Sandy to hit the Atlantic region. “These are real threats to our homeland.”

In her address at Stanford, Susan Rice encouraged the students in the audience to use their brainpower to imagine solutions to environmental problems. (Image credit: L.A. Cicero)

Research shows that a rise in temperature is linked to an increase in war-like conflict, Rice said. A drought in Syria preceded that country’s current civil war, for example. Also, she acknowledged the role of Stanford research in better understanding the connection between worsening weather and armed conflict.

Climate change, she said, may create the spread of more insect-borne diseases, longer droughts, more severe storms, armed conflicts, more refugees and forced migration. These ripple effects explain why climate change is a “threat multiplier.”

Finally, if the Greenland ice sheets melt, oceans may rise by up to 20 feet, she said, posing devastating outcomes for a large part of the world’s population that lives near shorelines.

Then, Rice said, “I’m actually not here to preach doom and gloom.”

She acknowledged that a worldwide consensus is building for a low-carbon future in which the world uses more renewable energy sources. American leadership is addressing the issue on several fronts, Rice said, with the upcoming United Nations Conference on Climate Change conference in Paris a high priority: “Paris must deliver a long-term framework.”

Rice noted that the Obama administration has made “historic investments” in supporting green technology such as solar and wind. And it has partnered with a surprisingly eager China to chart a framework on energy and the environment. It is possible, she said, to reduce emissions and grow the economy at the same time.

“We have to act now to reduce carbon emissions,” she said. “It’s the only way to avert disaster.”

Stanford President John Hennessy introduced Rice, describing her as a “great inspiration to many” with a “long history of contribution to public service.”

Rice attended Stanford, where she received a Truman Scholarship and graduated Phi Beta Kappa with a bachelor’s degree in history in 1986.

She encouraged the many Stanford students in the audience to use their brainpower in creating innovative and imaginative solutions to environmental issues.

“Put your Stanford education to work and help us meet this critical global challenge,” she said. “You have a responsibility to those who come after you.”