Someone told me recently that I should see Glacier National Park before the glaciers are all gone. I see now I'm nearly too late. A warming climate has erased more than 80 percent of the 150 named glaciers mapped in 1850. Most of the survivors are barely one third the size they were then. Scientists expect they'll all be gone by 2030.

Since 1997, US Geological Survey officials in Montana have undertaken a project to photograph glaciers that were documented on old pictures of the park. Carrying copies of the archival photos, photographers have found the spots where the original pictures were taken. Their images provide a dramatic comparison, and hard evidence of the glaciers' disappearance.

Here is a link to the project's results so far. And here is a brief outline of the program. Since 1997, more than 60 photographic pairs have been assembled showing 17 glaciers. Hurry, while they last.