Montana's melting glaciers: The poster-child for climate change

As recently as 100 years ago, Montana's Glacier National Park had more than 150 glaciers throughout its more than one million acres.

In 2005 only 27 remained. Today the total is down to a just 25 and those that are left are mere remnants of their former frozen selves.

With warmer temperatures and changes to the water cycle, scientists predict Glacier National Park will be glacier-free by 2030.

Daniel Fagre, a U.S. Geological Survey (USGS) ecologist who works at the national park believes that even those estimates are too conservative and says the park's namesakes will be gone about ten years ahead of their predicted demise. Fagre has been conducting research in the national park since the early 1980s.

Fagre's current research reveals that temperatures in Glacier National Park have risen higher than was predicted in 1992. The Montana glaciers are now expected to be gone by 2020. And that will dramatically impact the park's rare and sensitive plants and animals.

"The glaciers have been around for the last seven thousand years," he told CNN, "and if we are going to lose them in the next 10 or 20 years that is a pretty radical shift."

The rapid melting of glaciers has led scientists to believe that mountains are more susceptible to global warming than the lowlands beneath them.

"Mountain ecosystems have been changing about twice as fast as the rest of the globe. We have had temperature increases that are two times greater than the average," said Fagre.

Many scientists are now concerned about the cascading effects on the landscape and the consequences for all species -- including humans.

"Many people are directly dependent on the water coming out of mountains and in the arid western United States that figure is much larger, it is about 85 percent," said Fagre.

"So even if you live a long ways a way you are tied to the water in mountains and so we have a lot of concerns of future climate change scenarios."

Fagre says mountains are the "water towers of the world" with 70 percent of the world's fresh water frozen in glaciers.

Glacier National Park

CNN traveled to the edge of Grinnell glacier that is at an altitude averaging 7,000 feet (2,100 meters) and was named after George Bird Grinnell, an early American conservationist and explorer.

"When George Grinnell came here in 1887 he described this place as being a thousand foot high in ice and this entire basin was filled to the mountaintop," said Fagre. "Now I stand beside a lake that is 65 meters or 187 feet deep." (Click on image at right for a larger image).

We could see chunks of ice falling off, and others just dripping away. Fagre bent down to show us what's underneath the thin edge of the glacier.

"Look under here and you can see there is a lot of mucky sauce stuff and this is a lot of the rock flour ground by the glacier because it has been dragging rocks across the underlying rock layer and rubbing those two together creating this very fine material," he said.

"Many people would not be impressed by this little dirty glacier that seems to be obviously falling apart, that has become very tiny and decrepit -- and people often think about glaciers as these beautiful white expansive, blue colors - but those are healthy glaciers and this one is not. This one is on its last legs."

In 1997, USGS Physical Scientist Lisa McKeon and Fagre(at left, setting up photography equipment) started the Repeat Photography Project at Glacier National Park tracking down old photographs of the park's glaciers taken by first explorers in the 1900s and comparing them with their own images. View the historical images here (will require Adobe Reader).

McKeon and other USGS scientists try to re-photograph the exact spot where the historic photograph was taken, though it's not always possible when the original photographer was standing on ice that is now long gone.

"If you look at these pictures, you cannot say they haven't changed over time. It's very obvious," says McKeon.

Glacier National Park is celebrating its 100th anniversary this year but soon the glaciers that gave the park its name will be gone.

"Glacier National Park has been the poster child park for climate change for a lot of people in the country and I think that there has been pretty sensational news about the glaciers disappearing in fairly short order," says Chas Cartwright, Glacier National Park Superintendent.

"There is a lot less water coming off the mountain. There are dramatic changes in vegetation. It begs the question: how is that going to impact wildlife in this park?"

Many of the plant and animal species that call the park home require cold water, meaning the ecosystem of the park may change dramatically when the glaciers are gone.

There is a general consensus that man is contributing to the planet's changing climate. Some skeptics remain, but Dan Fagre isn't one of them.

"I think on a global scale when you look at all the ice disappearing all around the world, there is no other explanation for that then climate change that is driven by people," he said.

What is beyond doubt is that whatever the causes magnificent and environmentally crucial glaciers around the world are retreating: a loss to nature and to the human species.

Source:
Cable Network News, "Montana's melting glaciers: The poster-child for climate change", accessed October 9, 2010
LA Times, "Glacier National Park's vanishing ice sheets", accessed October 9, 2010

Record heat recorded for Africa's greatest lake

Africa's deepest lake is warming at an "unprecedented" rate thanks to man-made climate change, scientists have warned. Lake Tanganyika, which stretches from Burundi and DR Congo on its northern shores to southern Tanzania and Zambia, is the second largest lake in the world by volume. The lake is 420 miles long, making it the longest fresh water lake in the world, and the second deepest.

Lake Tanganyika is also the oldest of the East African Rift Valley Lakes. It is also the second deepest lake in the world (after Lake Baikal) and has become a "hot spot" of biological evolution during its lengthy and complex geological past.

Roughly 600 species of vertebrates and invertebrates are endemic to the lake. Lake Tanganyika is home more than 350 species of fish. Another remarkable property of the lake is that the water temperature is almost uniformly consistent even in the deepest part, 4,700 feet down. The difference from the surface temperature is only about 3 degrees centigrade.

Hundreds of species of fish and invertebrates may be found along the lake's rocky shorelines, often at a single submarine boulder or outcrop. More than 1,500 species of animals and plants have been described from the lake, making it biologically one of the richest lakes on earth.

The 420-mile-long finger of water in south-central Africa is now warmer than at any point in the last 1,500 years, according to research published in the journal Nature Geoscience, and the consequences could be dire for the 10 million people who live around it and depend on its fisheries.

"Our records indicate that changes in the temperature of Lake Tanganyika in the past few decades exceed previous natural variability," the paper found. "We conclude that these unprecedented temperatures and a corresponding decrease in productivity can be attributed to anthropogenic global warming."

Geologists from Rhode Island's Brown University and the University of Arizona took samples from the lake floor. By carbon dating these "lake cores", taken from depths of up 4,700 feet, and testing fossilized micro-organisms, they were able to create an accurate picture of temperature changes since AD500.

What they found was a gradual warming that accelerated alarmingly in recent decades as heat-trapping gases in the atmosphere have driven global climate change. The scientists were also able for the first time to link the warming to lower productivity in the lake, concluding that higher temperatures were killing life. The study found that the warmer the surface of the lake has become, the harder it is for cold currents to rise from the bottom and penetrate and recharge warmer layers.

A less productive lake means fewer fish and therefore less food and income in one of the poorest regions on earth. "The people throughout south-central Africa depend on the fish from Lake Tanganyika as a crucial source of protein," said Andrew Cohen, professor of geological sciences at the University of Arizona. "This resource is likely threatened by the lake's unprecedented warming since the late 19th century and the associated loss of lake productivity."

The surface temperature of the lake has risen by two degrees in the last 90 years to 26C, while the levels of algae that indicate the productivity of the lake have dropped.

The vast body of water, which at some points is more than 45 miles across, produces some 200,000 tons of fish annually, mainly sardines. Dagaa (right) is a tiny sardine. They have it in other lakes, too, but Kigoma dagaa from Lake Tanganyika is widely acknowledged to be one of the best. Unfortunately, there seem to be less Dagaa now than in the past. The lake is also the region's main source of freshwater.

While scientists have previously focused on the Earth's atmosphere to understand the extent and consequences of climate change, they are increasingly looking to its lakes and seas, which absorb tremendous amounts of heat.

Jessica Tierney, from Brown University and the lead scientist on the paper, said: "We're showing that the trend of warming that we've seen is also affecting these remote places in the tropics in a very severe way."

The Great Lakes region of Africa – Lake Malawi, Lake Victoria and Lake Tanganyika – were formed after Eurasia and Africa collided some 25 million years ago, creating the Great Rift Valley stretching from Syria to Mozambique.

Officials from the UN Environment Program (Unep) in Nairobi, Kenya, have warned that Tanganyika is not alone among Africa's Great Lakes in being threatened by climate change. Lake Victoria, the continent's largest by surface area but shallow in comparison with Tanganyika, has registered record temperature rises since the 1960s, which have added further stress to an ecosystem already under attack from human waste, agricultural run-off and invasive species.

With the fastest-growing population of any lake basin in the world, Victoria is offering what some scientists are calling "an accelerated preview of the great environmental challenges" of the coming century. More than 30 million people already live around "Victoria Nyanza", as it is known in Kenya, and that figure is projected to double by 2025, according to UNEP.

Source:
The Independent, "Record heat recorded for Africa's greatest lake", By Daniel Howden, accessed May 19, 2010