Why do 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 is 1℃ higher than that in 1970s, and the fact that Himalayan glaciers are melting faster once again shows that global warming is the biggest threat to mankind 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 weakening of the west wind, dry weather and a significant decrease in snowfall, "banks" have been unable to make ends meet.

Because glaciers are supplemented by natural snowfall to maintain dynamic balance, it 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 factors

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.

Extended data:

Global climate change is one of the main reasons for glacier melting.

About13 of the world's population lives within 60 kilometers of the coastline, with developed economy and dense cities. The expansion of ocean water bodies and the melting of ice and snow at both poles caused by global warming may raise the sea level by 50 cm in 2 100, endangering the global coastal areas.

Especially those densely populated and economically developed estuaries and coastal lowlands. These areas may be submerged or invaded by seawater, beaches and coasts will be eroded, land will be degraded, seawater intrusion and floods will be intensified, ports will be damaged, coastal aquaculture will be affected, and water supply and drainage systems will be destroyed.

The global climate system is very complex, and there are many factors affecting climate change, including solar radiation, atmospheric composition, ocean, land and human activities. There are still uncertainties in the scientific understanding of climate change trends.

In particular, it is impossible to make a more accurate judgment on the climate change trend and its specific impact and harm in different regions. But from the perspective of risk assessment, most scientists assert that climate change is a huge environmental risk facing mankind.

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