A new study covering forty years of satellite observations confirms that the melting of ice has been involving the Himalayan glaciers for several years already. The new study, published in Science Advances, refers to data collected by satellites in recent decades in India, Nepal, China and Bhutan and shows that glaciers in mountain areas in these regions have dropped by an average of 45 cm every year since 2000.
It is the equivalent of eight billion tons of water per year or 3.2 million Olympic size pools formed by melted ice every year. This is the double the ice that these glaciers have lost from 1975 to 2000, data that shows how the dissolution in these areas is accelerating and certainly cannot be classified as stable.
Often referred to as the “third pole” of the Earth, the Himalayas contain more than 600 billion tons of ice and already several estimates made in previous studies showed that 2/3 of this ice could disappear by 2100 already. There are studies in this particular area that are sometimes contradictory, while this study, carried out by Joshua Maurer, a researcher at Columbia University, is a summary of all the previous studies, fragmented both geographically and temporally.
And the results certainly do not seem encouraging. Another example is also given by the analysis of temperature alone: from 2000 to 2016 the average temperature of all these areas taken together has increased by one degree centigrade compared to that recorded from 1975 to 2000. This is the “clearest picture of how much quickly the glaciers of the Himalayas are melting in this interval of time,” as Maurer himself declares.
The researcher, to analyze the large mass of data, has created a new automated system that has transformed satellite images into 3D models to better show the changing elevations of glaciers over time.
The situation is serious for several reasons, perhaps the main one is linked to the seasonal outflow of the Himalayan glaciers that serve to irrigate the cultivated fields that feed hundreds of millions of people in the area: when the glaciers begin to lose many parts of their mass, these natural irrigations will be greatly reduced and this will lead to lack of water and cultivated food.