US President Barack Obama has viewed Alaska's Exit Glacier, in a bid to drive home the impact climate change is already having on America.
Obama visited the Kenai Fjords National Park in southern Alaska, where he stood against the backdrop of the vast, but receding, Exit Glacier.
He pointed to signposts marking the glacier's retreat since 1815.
"This is as good of a signpost of what we're dealing with when it comes to climate change as just about anything," Obama said on Tuesday (local time).
"This place has lost about a mile and a half over the last couple hundred years."
Obama is in Alaska to build support for domestic carbon reduction rules, and for a global pact to cap global temperature increases by two degrees Celsius over pre-industrial levels.
In December, representatives from around the world will gather in Paris to try to thrash out the deal.
On Monday, Obama warned that climate change is no longer a problem of the future, but rather a challenge for now and one that will define the next century.
Describing the "urgent and growing" threat he said is not being addressed quickly enough, Obama sketched the problems already facing people living in one of America's last wilderness frontiers.
"[The challenge] will define the contours of this century more dramatically than any other," the US president told a conference in Anchorage.
"Human activity is disrupting the climate, in many ways faster than we thought."
With one eye on Republicans who reject man-made climate change, he added: "The deniers are increasingly alone, on their own shrinking island."