You might call it the ultimate cold case. In a time when glaciers are quite literally melting before our very eyes, one glacier in the Himalayas has been doing quite the opposite.
“It’s been a source of controversy that these glaciers haven’t been changing while other glaciers in the world have,” Sarah Kapnick, a postdoctoral researcher in atmospheric and ocean science at Princeton University, told livescience in October. She and her colleagues recently journeyed to the Himalayas to discover why the Karakoram Glacier has not lost volume over time, unlike so many other glaciers around the world. Though it melts a little in the summer, the melting is offset by snowfall in the winter.
Many attempts have been made to explain the “Karakoram anomaly.” Kapnick and other researchers published a paper in the journal Nature Geoscience last month which unearthed the secret for this phenomenon. Their answer: the area has a unique weather pattern that keeps the ice cold and dry during the summer months.
How this detail has escaped notice for so long has as much to with a lack of detail in previous climate models as anything else. The Princeton team’s new climate model has a resolution 17 times more detailed that the one used for the Intergovernmental Panel on Climate Change (IPCC) (2,500 square kilometers compared with 44,100 square kilometers).
The new model simulated temperature and precipitation changes in three major Himalayas regions (Karakoram, the central Himalayas, and the south-east Himalayas which included parts of Tibetan Plateau) from 1861 to 2100. Global climate models from the IPCC overestimated the temperature in the Karakoram region because they could not properly account for the topographic variations in the Karakoram region. As a result, the models also underestimated the amount of snow that falls on the glacier. The new climate model successfully simulated seasonal cycles in temperature and precipitation due to its finer resolution.
“The coarser resolution ‘smoothed out’ variations in elevation, which works fine for the central Himalayas and southeast Himalayas,” Kapnick said in the Live Science interview. “However, the Karakoram region has more elevation variability than the other two regions.”
Unlike the rest of the Himalayas, the Karakoram region is not negatively affected by summer monsoon season, Kapnick discovered. The precipitation that occurred during the summer in the rest of the Himalayas never reached the Karakoram regions until winter when the temperature was already cold. The temperature in the Karakoram region on average is below freezing, which contributes to the excess snow it received in the winter when the western winds from Afghanistan bring in precipitation to the mountains.
This advantage from the western winds may not hold on long, though. If climate change continues on its current path, even the Karakoram region would be affected. Kapnick believes that as climate changes the Karakoram region can continue this advantage through 2100, but after that it’s unclear. “Understanding how that changes into the future is important from a climate perspective, but it’s also important from a societal perspective,” she said.
Understanding the snowfall patterns in the Himalayas can contribute to better understanding of variations in regional climate change. Moreover, the findings in this research can make a difference in water management processes regionally. Glaciers in the Himalayas serve as the primary water reservoir for many people in India, Pakistan, and China.