Scientific American Frontiers on PBS

In “Hot Times in Alaska,” host Alan Alda surveys evidence of global warming, from the lack of sea ice in the Arctic Ocean to melting glaciers and thawing permafrost. “In less than one human lifespan we are witnessing geologic time,” says Army Corps of Engineers scientist Ken Tape of the changing landscape. And that's particularly bad news, because, as Alda puts it, “the north is the canary in the gold mine.”