Though large glaciers in the Karakorams look stable, some of them are sinking in the middle, while others are losing mass, as new studies show. Contrary to recent claims, the Baltoro Glacier is not growing, but reducing.
Pakistan is home to the most heavily glaciated area outside the Planet’s polar regions. The massive glaciers of Baltoro and Biafo stretch for over 60 kilometres each in the Karakoram Mountains. In fact, the area designated as the Central Karakoram National Park in Pakistan has around 711 glaciers, which is double the number of glaciers in the Alps. Today, Italian scientists involved in the SEED (Social Economic Environmental Development) project (funded by the Pakistani and the Italian governments and managed by the Ev-K2-CNR Committee based in Italy) are focusing on developing a glacier inventory using remote sensing and some field surveys. The goal is to describe the whole glacier coverage in the Central Karakoram National Park and evaluate glacier changes on a time frame of about a decade. This is important because unlike in the Alps (which cover 2,500 square kilometres) where each and every glacier has been measured and monitored there is not much research that has been done in the Karakorams (which cover 16,600 square kilometres).
“There have been few focused studies in these mountains,” says Christoph Mayer of the Bavarian Academy of Sciences and Humanities who is currently doing field research on high altitude glaciers and is working with the SEED project. He points out that in the high mountain areas of Nepal and Bhutan; the glaciers tend to receive accumulation through snow in the summers while in the Karakorams we receive the most accumulation in winters. In his view, which is backed up by other scientific studies done in this region, “the Karakoram glaciers are more stable”. This is good news for Pakistan, because scientists say that glaciers in neighboring Himalayan Mountains (where Nepal and Bhutan are located) are rapidly losing mass, which seems to be the global trend due to warmer temperatures caused by climate change. The Karakorams are in fact the Asian exception and an earlier study from 2001-2010 of glacier changes in the Central Karakoram National Park, described the phenomenon as the “Karakoram Anomaly”, “a regional glacier behaviour contrasting with the general glacier shrinkage which has been occurring in all the other glacierised zones of the Planet”.
The response of the Hindu Kush/Himalayan/Karakoram glaciers to global warming has of course been a controversial topic in the media ever since the 2007 report of the UN’s Intergovernmental Panel on Climate Change (IPCC) was found to have contained the erroneous claim that ice from most of this mountain region (also known as the Third Pole) could disappear by 2035. There was an outcry when the mistake was detected and the IPCC had to retract the claim. Clearly, the region’s glaciers are poorly studied and yet, they provide a vital water source, acting as giant water tanks, for more than a billion people living below in the basins of Asia’s mighty rivers such as the Indus and Ganges.
It is of course extremely difficult to study the high altitude glaciers of the Hindu Kush/Himalayan/Karakoram Mountains, given the rugged and remote terrain and the fact that mass balance studies are so time demanding. For example, Christopher Mayer is currently surveying the Baltoro Glacier, where his team (which includes three Pakistani colleagues) has fixed poles in the ice to measure the melt of the ice. The stakes will eventually move with the ice, so they will know the velocity of the ice movement (which can be up to 150 meters per year) as the glacier moves. By measuring the height of the stakes they can also tell if the glacier is sinking or rising. This summer, his team is going back to the field to maintain the network of poles, measure elevation profiles and monitor debris thickness, all of which is hard work since it will take them 4-5 days of trekking just to reach the snout of the Baltoro Glacier.
According to Mayer, “Alpine glaciers, when they lose mass, the snout retreats back as it melts, but in the Karakorams the glaciers are covered by debris which protects the snout of the glacier from retreating”. His team is studying the role of the debris cover in protecting melt and he says that: “debris cover is actually very effective in protecting glaciers from melting”. His team is also studying two accumulation basins found in the Godwin-Austen Glacier and the Gasherbrum area. They are studying the snow layers by digging snow pits and doing core drills from the surface to a depth of 8 metres. They are researching the accumulation history and by comparing it with climatic records, they can even trace individual precipitation events. This gives them an idea of how precipitation and temperature affect these glacier locations.
Mayer and his team have discovered that while it seems like the large glaciers in the Karakorams are stable and there is not much happening, there is however, “a lot happening on the local scale”, with some glaciers sinking in the middle, while others are losing mass in their snouts. “With dedicated studies, the dynamics of glaciers need to be better understood,” he explains. In some cases there are special advances of glaciers while in other cases glaciers are trying to recuperate. “However, we can only work on a small number of glaciers since it is so time demanding. We will try to extrapolate our measurements”.
While research is still underway, what his team has found out about Baltoro is alarming – “Baltoro is not growing, it is reducing. We need more profiles of elevation but the trend is that Baltoro is reducing”. This latest research is in contrast with earlier studies that claimed that the Baltoro Glacier was still growing.
Is this part of a wider new trend in the Karakorams? We don’t know as yet, but given that research suggests that larger glaciers across Pakistan may be particularly important to melt volume contributions for the Indus River, we need to support more field surveys of our large glaciers for better understanding of the links between climate change and glacier dynamics.