Why do polar glaciers melt?

According to a research report of the United Nations Environment Programme, experts have observed 3,252 glaciers and 2,323 glacial lakes in Nepal and 677 glaciers and 2,674 glacial lakes in Bhutan through aerial survey, satellite observation and field investigation for three years. The results show that the temperature in these areas has increased by 1℃ compared with that in 1970s, and the fact that the melting speed of Himalayan glaciers has accelerated once again shows that global warming will be human in the coming decades. After photographing and analyzing 48 glaciers in New Zealand, scientists vividly compared them to "banks". In recent years, due to the prevalence of high air pressure, the decrease of westerly winds, dry weather and the obvious decrease of snowfall, the "bank" can't make ends meet, because the glaciers are supplemented by natural snowfall to maintain a dynamic balance, which reflects the balance of income and expenditure of glacier accumulation and melting. If the bad weather continues, the glaciers there will continue to shrink.

(2) Human causes

After studying the glaciers in Qilian Mountains, China scholars pointed out that besides the natural climatic factors, another main reason for glacier retreat is population expansion, overgrazing, over-reclamation, deforestation, indiscriminate excavation of Chinese herbal medicines and indiscriminate exploitation of groundwater. In the past 50 years, the population of Gansu has more than doubled, while the cultivated land has only increased by 4%. In the 20 years since the founding of New China, northwest China has successively carried out three large-scale deforestation and land reclamation. By the end of 1990s, the area of soil erosion in Gansu Province accounted for 85.6% of the total area, and sandstorms increased significantly, which further aggravated the glacier shrinkage.