A new study underscores the climate threat to Arctic breeding birds, while also emphasising how important habitat conservation will be to preserve their shrinking breeding grounds.

Each Arctic summer hundreds of millions of birds arrive in the tundra, to spend long days breeding in this vast treeless plain between polar deserts to the north and the tree line to the south.

Yet as the climate warms, the tree line is expected to march north, radically reducing breeding habitat for many birds rel...