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The story of Alaska鈥檚 glacial retreat is plainly written across the landscape. Melting has left these slow-moving rivers of ice, while still spectacular, much diminished. And it is forcing us to think differently about them.

无码视频 than mere sources of beauty, they now represent a collapsing system that for millennia has helped cool the globe and kept sea levels stable. This more systemic outlook on glaciers is important to adopt, say some experts, as it can help people understand and perhaps act upon the growing climate .

Today鈥檚 visitors to Alaska find a landscape transformed, with raw mountainsides only recently stripped of their ice. At visitor centers, they can watch the change unfold on time-lapse videos.  All the while, meltwater tumbles past in swift, cold rivers 鈥� destined for the ocean.

That was never truer than this past summer, when record-setting heat鈥攊ncluding temperatures in a region where 60s and 70s are more the norm鈥攕parked severe melting that pushed rivers toward flood stage.

I say this as someone who has witnessed the change up close. For nearly 30 years, I have lived and worked alongside Alaska鈥檚 melting glaciers. I began as a young Forest Service naturalist at the in Juneau, where my first experience with glaciers was all about wonder and adventure.

The ice was certainly receding, but the glaciers were still sprawling and mighty, filling valleys of their own making. Climate change was discussed, but it was peripheral to the experience and seemingly too far-off for alarm.

But the planet鈥檚 warming became a much more immediate concern for me in the ensuing years, as I watched the ice calve away. Over time, great glaciers where I had camped and worked slumped downward. They developed holes and fissures that never healed but only expanded until entire limbs of ice disappeared. Every year, seemingly incalculable torrents of meltwater poured into the sea.

Today, scientists are attempting to put hard numbers the amount of meltwater flowing from Alaska鈥檚 glaciers. Three studies published this year underscore not just the rapid loss of the globe鈥檚 glacial ice, but the rate of the melt and its contribution to sea level rise.

In April 2019, an international research team the world鈥檚 mountain glaciers, which do not include the massive ice sheets of Greenland and Antarctica, lost a hard-to-fathom 9,000 billion tons of ice over the past 50 years. Even though these mountain glaciers comprise only 4 percent of the world鈥檚 land ice, their melting has so far fueled up to of global sea-level rise, the research shows. Researchers pegged Alaska as the largest single contributor to the melting.

鈥淎laska鈥檚 glaciers are in kind of a Goldilocks position,鈥� says Twila Moon, a research scientist with the National Snow and Ice Data Center at the University of Colorado Boulder, who did not participate in the study. 鈥淭hey are far enough north that they get the snow necessary to form very large glaciers, but they鈥檙e also at that southern Arctic edge where we see so much change from warming.鈥�

Another study of the world鈥檚 mountain glaciers predicts that at the current levels of fossil fuel use their melting in the decades ahead will spill enough freshwater to raise seas by up to 10 inches. That amount alone is enough to inundate vulnerable coastal population centers from Florida to Bangladesh. In this research, too, Alaska鈥檚 glaciers emerged as the top source of meltwater, with up to half of their mass expected to melt in the coming years.

鈥淭he proximity of Alaska鈥檚 glaciers to the ocean puts them in an especially sensitive area,鈥� Moon says. 鈥淎s more precipitation falls as rain throughout the year [in coastal Alaska], they鈥檒l continue to be an important player in sea level rise.鈥�

The studies attempt to put tangible numbers on just how much Alaska鈥檚 melting glaciers affect global sea levels. Among the most of all climate change impacts, rising seas threaten to displace millions of people from coastlines across the globe. It is expected to contribute to famine, conflict, and other human migration crises in our lifetime.

In this light, Alaska鈥檚 glaciers stop being mere wonders of the world, showcased on tourism brochures, but instead are now seen as a vital part of the planet鈥檚 cooling system being critically damaged by burning fossil fuels.

Meanwhile, a third of Alaskan glaciers published in 2019 suggests scientists may still be underestimating the speed of their melting. While pioneering new techniques, including underwater sonar surveys of the ice, researchers discovered melt rates more than 100 times greater than those predicted by models.

鈥淥ur study calls for a reconsideration of melt rates calculated by theory,鈥� lead researcher David Sutherland wrote in an email. Sutherland, an oceanographer at the University of Oregon, explained that his techniques are likely to apply worldwide. It could affect predictions for sea level rise.

Back at the Mendenhall Glacier Visitor Center in Juneau, the U.S. Forest Service is demonstrating how melting glaciers provide an opportunity to connect people to the seriousness of climate change.

The center鈥檚 500,000 summertime visitors prominent displays linking the glacier鈥檚 retreat to climate change and naturalists trained to navigate the challenges of discussing the topic with the public.

鈥淰isitors are taught that the glacier is disappearing because of human-caused climate change,鈥� says John Neary, the visitor center鈥檚 former director, who recently retired. During his tenure, Neary ushered in a new era of more open dialogue about climate change at the Mendenhall.

鈥淧eople are stunned when they view our time-lapse video of the shrinking Mendenhall,鈥� Neary says. He recalls trying to give visitors 鈥渟omewhere to take that sense of loss.鈥�

鈥淒uring my time at the glacier, I tried to plant the seeds of hope by planning for changes in facilities and infrastructure that embraced sustainable energy principles,鈥� he said. 鈥淲e鈥檒l have to see if the Forest Service implements them.鈥�

Moon, the researcher, also believes in the importance of educating the public about melting glaciers. 鈥淚鈥檓 hopeful that it can make people understand that the future of ice is not set in stone,鈥� she says. 鈥淪o much depends on our actions today.鈥�

The opportunities for鈥攁nd the importance of鈥攕uch education is only growing. In October, researchers announced that Alaska鈥檚 massive has started retreating. Before this summer, it was the last major glacier in the Juneau area to remain stable in the modern era. As it retreats, it will steadily add to the fresh water Alaskan glaciers are spilling into the ocean.