On the steps of the Capitol, the president declared, "Some may still deny the overwhelming judgment of science, but none can avoid the devastating impact of raging fires, and crippling drought, and more powerful storms."
His visit to battered Staten Island in the wake of Hurricane Sandy gave the president a firsthand look at the terrible impact of America's emerging weather patterns.
Mr. Obama's dire warning on climate change echoes the growing alarm by experts. Scientists overwhelmingly believe climate change is not only real, but the result of human activity.
Of course, no single occurrence of violent weather — not even Hurricane Sandy — can definitively be attributed to climate change, much as some want to do that. But the overall, long-term pattern is certainly troubling.
The hottest year ever recorded in the continental United States was 2012. And before that, nine of America's 10 hottest years ever had occurred in the period since 2000. Clearly, the norm has changed.
Rising world temperatures — blamed to a large degree on the greenhouse effect caused by burning fossil fuels — have penetrated even to the ocean depths.
With nearly 4 million Americans — including thousands on Staten Island — living within a few feet of high tide, there is good reason to ponder the future impact of rapidly melting polar ice caps and higher sea levels.
Scientists say the sea level along New York's shoreline and much of the Northeast coast is about a foot higher than a century ago, mostly because of man-made global warming that worsened the damage from Sandy.
The record storm surge brought unprecedented flooding on our East and South shores. The hurricane destroyed some 200 buildings on Staten Island alone, and another 300 are still without heat and power and are all but uninhabitable. About 2,400 or so structures in the borough have been registered for the city's Rapid Repair program.
So we have every reason to hope that Mr. Obama succeeds in his effort to train the nation's focus on climate change, however belatedly.
The president has pledged to boost renewable energy sources, such as wind and solar power, in addition to more traditional energy sources, such as natural gas. But alternative energy remains problematic and costly, so the outcome of those hopeful initiatives remains far from certain.
Mr. Obama tried and failed during his first term to obtain legislation to curb greenhouse gas emissions. He was opposed not only by Republicans, but some members of his own party: Conservative Democrats and those from energy-producing districts.
And it's telling that climate change was never a key issue in the 2012 election campaign. That's undoubtedly a good indication of the difficulties surrounding it, despite mounting evidence.
After his re-election, Mr. Obama said that thinking about the future of his two young daughters had inspired him to take a closer look at long-range issues.
"We will respond to the threat of climate change, knowing that the failure to do so would betray our children and future generations," Mr. Obama promised during his inaugural address.
As we have learned only too well on Staten Island, our fate is tied to the state of the environment.
America had better deal with the man-made elements of climate change sooner rather than later.