Glaciers are often regarded as the immediate indicators of climate change. With the recent completion of an extensive inventory of the world's glaciers, scientists may now be able to uncover with precision the impacts of climate change on sea level rise.

In fact, it could even provide glaciologists accurate information on each and every glacier on the list, with its comprehensive digital vector outlines offering a glacier's total extent and volume measured up to the last inch.

Thanks to a group of geologists from the University of Colorado Boulder and Trent University, plus the 74 scientists from 18 countries and a community of glaciologists, the Randolph Glacier Inventory (RGI) now holds a total record of approximately 727,000 square kilometers glaciers, which is estimated to be the same size of Switzerland, Germany and Poland combined.

"I don't think anyone could have made meaningful progress on projecting glacier changes if the Randolph inventory had not been available," said lead author and professor Tad Pfeffer of the University of Colorado.

Named after one of the places in New Hampshire where the group would usually meet, RGI was collated to complete an anthology of 198,000 glaciers worldwide aside from the ice sheets intended for use in line with the Fifth Assessment of the Intergovernmental Panel on Climate Change (IPCC), an international forerunner of climate change assessment.

Glaciers are the largest reservoir of freshwater on Earth. They are formed when snow from an entire year accumulates and re-crystallizes due to compression of layers. Then the snow develops firn, midway before it turns into glacier ice. In some cases, glaciers are formed more than one hundred years.

Glacial ice is mostly situated in the Polar Regions amid ice sheets, in mountain ranges in each continent except for Australia, as well as in some islands in higher latitudes. The researchers mapped out glaciers of every size in the Himalayas and central Asia, Alaska and Patagonia of the Americas, and Greenland and Antarctica.

With satellite images and maps, the team outlined the areas and location of the glaciers then combined the data using "power law scaling" to determine volumes of the glaciers.

The numbers will change in time, as some small glaciers may thaw while others may break at their foot. These small glaciers are the main reason behind today's sea level rise and may persist in the coming years, according to Pfeffer.

Should every glacier in the world except in Greenland and Antarctica melt all at once, the current sea level is expected to rise by 14 to 18 inches.

The compilation can be found in the publication Journal of Glaciology.

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