Up close: Alaska's majestic, melting glaciers

They’re large, rock-hard and grand spectacles — but Alaska’s great glaciers are in grave danger. The glacier recession rate accelerates every year, losing an average of 20 inches — almost twice the rate of loss seen in the 1980s and 1990s. Weekend TODAY’s Lester Holt joined acclaimed scientist Dr. Doug Causey, professor of biology at the University of Alaska Anchorage, for a close look at Alaska’s great natural wonders. They visited Spencer Glacier, which is now breaking off and calving due to rapid melting. While calving is normal for glaciers, the melting has been accelerated by climate change.

“This is truly one of nature's most magnificent shows and one not to be missed,” Lester said of his mission to Anchorage, Alaska. “Scientists say it's a show ending a lot sooner than they ever imagined.”

Sensitive to climate change, glaciers heavily depend on their climate conditions — and changes in temperature, precipitation, solar radiation, humidity, and wind speed could leave serious effects. Many scientists believe that global warming is to blame for the glaciers’ abnormal melting and retreating, contributing to sea level rise and placing communities that rely on glaciers for water at risk. Although Alaska’s many glaciers are currently vast and plentiful, they’re at risk of disappearing within decades.

"In Alaska, glaciers are a source of water and water is one of the very important, limited resources in the Arctic," Dr. Causey said. "Probably most important is that glaciers are the canary in the mine — they show what's happening to the earth's climate." Causey explained that scientists recognized the climate was changing, with evidence from over 50 years ago, but that every time that they re-assess the data, they find "that things are moving faster — partly because it's moving so fast that our data is lagging behind."

According to an AP/MSNBC environment report, glacier wastage added 73 trillion gallons of new water to oceans, and scientists believe water levels are rising one to two millimeters per year, with glacial wastage directly responsible for as much as 30 percent of the increase. And with glaciers melting earlier in the year than usual — leaving inhabitants without enough water during warmer summer months — it has become a serious, troubling issue.

Check out photos of Lester’s trip to Anchorage, Alaska to witness the great glaciers.

More from TODAY MySpace victim's mom disappointed by ruling Makeover! Wife renews vows — and her looks Jermaine Jackson: ‘I wish it was me’   Exclusive look inside Jackson’s Neverland   Celebrity sightings: Jessica Simpson, Kate Moss and more

MORE FROM TODAY

Today Section Front

Ruling disappoints MySpace victim's mom Jermaine Jackson: ‘I wish it was me’ To-die-for pie is testing Obama’s discipline James Frey turns to teen science-fiction novels Publisher releases S.C. governor from book contract McDonald’s to debut $4 Angus burgers Poo brew: Premium coffee is dung to a turn Looking at Lady Liberty from fresh perspectives July 4 is about more than fireworks — Ask Kitty Blanket’s godfather: I’m not his biological dad Today Section Front   Add Today headlines to your news reader: