Soon after taking my first good look at the barren and alien orange landscape of the Tablelands, I held a heavy chunk of rusty-looking peridotite in my hands and tried to absorb its global significance.

The UNESCO World Heritage Committee has added Hopewell Ceremonial Earthworks, a group of eight ancient earthwork sites in southern Ohio, to the World Heritage List. Among the eight sites is Hopewell Culture National Historical Park.

Along the windswept northwestern coast of Newfoundland where four ancient cultures once lived off the sea’s bounty, a lone caribou grazed, indifferent to my family’s delight and seemingly safe in the knowledge that it can no longer be hunted in this protected landscape. We held up a card from Port au Choix National Historic Site that warned us to stay at least three bus lengths away from this gorgeous species at risk. There was a thumb-size rectangle cut out of the cardboard.

Across the country, national park units are grappling with the likelihood that a portion of their land could become inundated and their habitats significantly altered by sea-level rise in the not-too-distant future