MONTREAL – In the tropical section of this city’s Biodome, essentially a museum of the environment, I felt very much at home. Outside, snow stretched in all directions, but the interior climate was warm and humid – just like Florida’s. And it reminded me of how clever people can be.

In this case, they creatively replicated not only the tropics but a northern forest, a marine ecosystem, and a side-by-side version of the Arctic and Antarctica.

Sadly, people also can be incredibly slow in responding to challenges that threaten the true-life versions of those ecosystems. I am thinking particularly of Antarctica, where a piece of ice about seven times the size of Manhattan collapsed from the Wilkins Ice Shelf just after my stroll through the Biodome.

Bear in mind that this is not the end of the problem – which many scientists attribute to climate change – but merely a fragment of the beginning. The rest of the Wilkins Ice Shelf, which compares in size to the state of Connecticut, reportedly is barely holding together. According to some scientists, such as David Vaughan of the British Antarctic Survey, one of the world’s leading environmental research centers, the collapse of the entire shelf is not far away.

How can policy-makers fail to view such developments with alarm and hasten decisions to ease their impact? Naysayers will no doubt swarm, as they typically do when I write about climate change, and chant a tired refrain about the lack of universal agreement on the causes of today’s environmental woes. I am fairly certain that some will even point out that icebergs naturally break away from the mainland. Fine, but that is not saying much in light of the highly unusual, dramatic events that we have been observing with disturbing regularity; moreover, it comes across as naive and stubborn.

How much more ice must break away or melt to get their attention – enough to cause dangerous sea-level increases and severe coastal flooding? And what about the other anticipated results of unchecked climate change: the worsening of weather of mass destruction, the disappearance of various species, more-frequent droughts, starvation on a mind-boggling scale, human migration in numbers that have never been seen before and a plague of diseases? Finally, let us not forget the tensions and violence that inevitably would follow in the scramble for remaining resources.

Americans and the rest of humanity have nothing to gain from waiting around to see what will happen. They should demand that their governments aggressively take on the challenge of climate change, and settle for no less than sound solutions and meaningful actions in the context of an international consensus. More specifically, they should expect a global strategy aimed at greatly reducing emissions, expanding conservation, boosting efficiency and accelerating the development of renewable energy sources.

Such thoughts surely were far from the minds of most visitors as they completed the Biodome tour in Polar World, watching penguins swim, snack and socialize in pleasant surroundings. But they should be a foremost consideration in the face of urgent signs that the world has taken ill, with the worst yet to come.