The Himalayan range is home to around 15,000 glaciers, holding around 3000 cubic miles of freshwater. Some of the well-known ones in the region include Gangotri, Yamunotri and Khumbu glaciers. Recently, owing to effects of climate change and global warming, the glaciers around the world have been receding at an alarming pace. The Earth however has gone through multiple cycles of warming and cooling periods, causing glaciers to recede and form.
A new study has now shown that, in one such cooling phases, called the little ice age (LIA), a significant amount of mass was lost by the Himalayan glaciers. Although not a true Ice age due to the short duration for which it existed, the little ice age was a period between the 16th and 17th centuries when the temperature of the earth fell significantly. Particularly three short intervals of cooling occurred in 1650s, 1770s and 1850s. It was during the later stages of the LIA that the glaciers are said to have lost their mass, mainly due to the warming weather melting the glaciers.
The scientists used tree ring sampling method to reconstruct the mass balance record for the Western Himalayan glaciers starting from all the way back in 1615. Mass balance approach allows the scientists to estimate how much mass a system has gained or lost, in a given period. The study revealed that the later phase of the LIA was brief and weak in the Himalayas compared to the Arctic. It also showed that glaciers receded much faster, with considerably less glaciation or new glaciers forming. Scientists believe a combination of the El-Nino Southern Oscillation, a phenomenon known to cause variations in winds and sea surface temperatures in the Pacific Ocean, combined with Total Solar Irradiance - the amount of sunlight received at a region, could be the reasons for the decreasing glacial cover in the region. Today, many of these factors are still in play, with the El-Nino phenomenon still in effect and the glaciers still receding, the study can provide us clues to help us make better predictions to overcome global warming.