Sixty years of observations and future projections of nine declining North American glaciers.

Warming climate has greatly affected the stability of the world's glaciers. In 1957, as part of the International Geophysical Year, nine North American glaciers were surveyed in great detail so that they could serve as future benchmarks. Since their initial survey, these nine benchmark glaciers have drastically decreased in volume and areal extent. This is a direct result of global warming. However, the exact amount of their change has never been fully documented and predictions of their lifespans in the wake of continued temperature increase has never been projected. In this study, we utilized advanced satellite techniques to quantify changes in the nine glaciers as well as assessed their long-term survivability. The methodology successfully used in this study can be applied to glaciers throughout the world, which would provide a cost-effective evaluation of past, present, and future glacial change at localized scales. We show that since 1957, the glaciers have lost 1.4 metric gigatons (Gt) of freshwater and have shrunk on average by 33%. Additionally, utilizing future temperature projections and cumulatively integrating temperature-driven volume changes over time, we show that only 3 of the 9 glaciers will still be in existence by 2100. These results paint a grim picture for the future generations observing glaciers in North America.