President Obama issued a stark warning on climate change Monday, stating that future generations will face harsh consequences if we don’t fix the issue soon.

“Climate change is no longer some far-off problem. It is happening here. It is happening now,” he warned the representatives of more than 20 countries attending the Conference on Global Leadership in the Arctic: Cooperation, Innovation, Engagement and Resilience, or GLACIER.

“The time to heed the cynics and critics and the deniers has passed. The time to plead ignorance has surely passed,” Obama said. “Those who want to ignore the science, they are increasingly alone. They are on their own shrinking island.”

“Any so-called leader who doesn’t take this issue seriously or treats it like a joke is not fit to lead,” he said. “On this issue, of all issues, there is such a thing as being too late, and that moment is almost upon us.”

While discussing the rising sea levels, Obama cited a study published in the journal Geophysical Research Letters that estimates Alaskan glaciers lose 57 gigatons, or 75 billion tons, of ice per year. To describe the size he explained it as a block of ice the of size the National Mall in Washington, D.C., stretching from Congress to the Lincoln Memorial, that is four times as tall as the Washington Monument.

Speaking in Alaska, he emphasized the already disappearing Alaskan villages and native cultures threatened by global warming; while adding that climate change affects every facet of life on the planet.

“Climate change is a trend that affects all trends. Economic trends, security trends, Everything will be impacted and becomes more dramatic with each passing year,” he said. “Desperate refugees seeking the sanctuary of nations not their own, political disruptions that could trigger multiple conflicts around the globe, that’s not a future of strong economic growth. That’s not a future where freedom and human rights is on the move.”

And while he issued warning of the need to act, he also cited that the technology exists to help solve the problem and it’s not “simply a danger to be avoided, this is an opportunity to be seized.”

Obama highlighted the agreement between the U.S. and China, the world’s two largest economies and emitters, to limit emissions, while touting that the ability to grow economies and protect the environment are no longer at odds with one another. The U.S. economy has grown nearly 60 percent over the past 20 years, while carbon emissions have dropped to levels from two decades ago, he said.

But he was cautious to emphasize that no nation was “moving fast enough.”

“If we were to abandon our course of action—if we stopped trying to build a clean energy economy and reduce carbon pollution—if we do nothing to stop glaciers from melting faster and oceans from rising faster and forests from burning faster and storms from growing stronger, we will condemn our children to a planet beyond their capacity to repair it,” he said.

Obama added that the political will may finally be upon the world to act on the issue.

“We know that human activity is changing the climate. That is beyond dispute. Everything else is politics,” he said.

President Obama continues his tour of the 49th state Tuesday when he tours a glacier in Seward, Alaska.