GlacierHub News Report 06:21:18

GlacierHub News Report 06:21:18

The GlacierHub News Report is a bi-monthly video news report that features some of our website’s top stories. This week, GlacierHub News is featuring an assessment of the environmental impact of tourism in Tibet, deforestation on Mt. Kenya, cryoacoustics, and the adventures of a Filipino world traveler.

This week’s news report features:

 

Assessing the Environmental Impacts of Tourism in Tibet

By: Yang Zhang

Summary: In a paper published earlier this year in the Journal of Mountains, six researchers from the Tibetan Plateau provide science-based suggestions for policymakers to decide where and how ecotourism should be conducted. The construction of the Qinghai-Tibet Railway in 2006 gave people across the globe access to this cut-off region. By 2017, Tibet was the host of 25.61 million travelers worldwide, a 12-times growth compared to a decade ago. The exponential increase in tourism raises significant concerns about environmental degradation in this fragile ecological hotspot.

Read more about the research here.

Is Deforestation Driving Mt. Kenya’s Glacier Recession?

By: Jade Payne

Summary: Mount Kenya’s glaciers are rapidly receding. A new study published in the American Journal of Environmental Science and Engineering found that forest cover has the highest correlation with Mt. Kenya’s glacier coverage. The study found that the current trend in glacier thinning will continue until the glaciers completely disappear by 2100. In addition, the research found forest cover to be responsible for 75 percent of changes in glacier coverage during the study period, from 1984 to 2017.

Read more about Mt. Kenya’s glacier recession here.

Pioneer Study Sounds Out Iceberg Melting in Norway

By: Sabrina Ho

Summary: Last month, a team of researchers published their work on the intensity, directionality and temporal statistics of underwater noise produced when icebergs melt. The study is a pioneer in the field of cryoacoustics research still in its early stages since existing studies largely focus on larger forms of ice such as glaciers and ice shelves instead of icebergs.

Read more about the study here.

From the Philippines to Glacier Grey

By: Brian Poe Llamanzares

Summary: Rocco Puno, a Filipino world traveler, shared his story about traveling to Glacier Grey, a massive 1,200-year-old glacier that stretches 350 km long in the Chilean side of Patagonia.

Read the full story here.

Video Credits:

Presenters: Brian Poe Llamanzares & Jade Payne

Video Editor: Brian Poe Llamanzares

Writer: Brian Poe Llamanzares

News Intro: YouTube

Music: iMovie

Pioneer Study Sounds Out Iceberg Melting in Norway

It is not difficult to envision how ice melts— just imagine a solid cube of water transforming into a liquid mess. Perhaps more surprising, this transition also produces sounds that are audible to human ears, if we listen carefully. The sounds occur because ice traps air bubbles as they are escaping from freezing water. The bigger the ice— glaciers or ice shelves, for example— the greater the number of air bubbles that it contains. Last month, a team of researchers published their work on the intensity, directionality and temporal statistics of underwater noise produced when icebergs melt. The study is a pioneer in the field of cryoacoustics research still in its nascence, since existing studies largely focus on larger forms of ice such as glaciers and ice shelves instead of icebergs.

Air Bubbles Frozen in Ice (Source: Francisco Letelier/Pinterest)
Air bubbles frozen in ice (Source: Francisco Letelier/Pinterest).

In fact, different forms of ice produce different noise signals when melting. The key, in this case, according to Oskar Glowacki, the lead author of the paper, is the quantity of air bubbles trapped in ice. “Glaciers contain more bubbles than icebergs, which is obvious taking into account differences in size,” he explained to GlacierHub. “When the glacier is melting, millions of bubbles are released into the water at the same time. As a result, what we hear is a loud, constant noise described by a normal distribution (typical in nature). But when approaching melting icebergs, we can hear individual bursts of bubbles, and so the noise is much more impulsive.”

The study was conducted at Hornsund Fjord in Svalbard, Norway. The researchers gathered measurements for icebergs in four locations by deploying hydrophones at a depth of 1m from a boat during the spring and summer seasons. Hydrophones are devices that are used to record underwater sounds. Glowack said researchers can hear the sounds even while onboard the boat. But nothing beats diving in the cold waters of the Arctic fjords and listening to the noise of melting ice, an opportunity Glowacki recalls fondly as “the most amazing experience.”

Measures of underwater hissing produced during iceberg melt at the ice-ocean boundary pointed to the need for a remote method to gather quantitative data on the rate of subsurface melting. Iceberg melt has proven to be an important parameter in regional ocean models to estimate ocean circulation patterns and local hydrographic conditions such as in Greenland. However, it is still not easy to record underwater sounds in the harsh environments of the Arctic.

“The main difficulty is to really understand what we are listening to. When the goal is to accurately measure iceberg and glacier melting using underwater sound of bursting bubbles, we need to discover the exact relationship between the intensity of melt noise and exact ice loss,” Glowacki said.

Deploying a hydrophone to measure ice sounds (Source: Phys Org)
Deploying a hydrophone to measure ice sounds (Source: Phys Org).

In the study, the researchers noted that the cackle of icebergs changes based on its relative position to the hydrophone and speed of melting. Care must be taken to remove recordings that are made within 20m of an iceberg to avoid the effects of near-field noise interference, while calls from bearded seals also had to be excluded from analysis.

Moreover, this relationship can be different according to environmental conditions, as changing water temperature causes variation in the shape and size of air bubbles trapped in the ice, and hence the specific song that the ice sings under different conditions. Other complications include sound reflection from the sea surface or ocean bottom and changes in the direction of wave propagation driven by spatial and temporal differences in water temperature and salinity.

“Fortunately, we can take into account all of these factors using accurate mathematical models, which are available as computer programs,” Glowacki said. However, he reckons that transferring cryoacoustics into a real tool in glaciology may take a few years of intensive research, requiring laboratory experiments and studies in other ice-covered regions of Greenland, Alaska and Antarctica.

With more work, noises of melting glaciers might not only identify, but also accurately measure glacier retreat. Nevertheless, the sounds of melting ice are an obvious call from nature that climate change is real.