雅思阅读 55: Asia's Vanishing Water Tower（亚洲正在消失的水塔）

改编自 ICIMOD / Down To Earth / UNDP（2025-2026）。雅思阅读 Section 3 难度，约 1050 词。 素材来源：https://www.downtoearth.org.in/climate-change/the-himalayas-laid-bare-how-vanishing-snow-and-ice-are-reshaping-asias-water-tower

Reading Passage

A. Stretching across eight countries, from the rocky ramparts of Afghanistan to the eastern folds of Arunachal Pradesh, the Hindu Kush Himalayan range holds the largest mass of ice anywhere outside the polar caps. It is, in effect, an immense natural reservoir, frozen in winter and released in summer, feeding the headwaters of the Indus, Ganges, Brahmaputra, Yangtze, Mekong and Salween rivers. Those rivers, in turn, supply drinking water, irrigation and hydropower to somewhere in the region of two billion people downstream — farmers on the Indo-Gangetic plain, cities strung along the Yangtze, fishing communities in the Mekong delta. For centuries this system worked on a predictable rhythm: winter snow fell, spring and summer melt fed the rivers, and the flow peaked just as the planting season demanded it. It is precisely this predictable rhythm that climate change is now dismantling. The mountains are warming roughly faster than the global average, and the reservoir they hold is draining out of step with the seasons that human agriculture was built around.

B. The scale of the loss has become unmistakable. In March 2026, the International Centre for Integrated Mountain Development released two reports marking the World Day for Glaciers, drawing on half a century of monitoring. Their central finding was blunt: the rate at which the region's glaciers are losing ice has doubled since the year 2000. Earlier analyses had already shown that glaciers disappeared 65 percent faster in the 2010s than they had in previous decades, and that roughly 9 percent of the ice area present in the early 1970s had vanished by the early 2000s. The 2025 Snow Update added a further warning: snow persistence — how long snow actually lingers on the ground — across the range had dropped to its lowest point in 23 years, sitting 23.6 percent below normal, with four of the past five winters classified as below-normal in snow cover. The pattern is not a single bad season but a trend measured over decades, in which winter arrives later, retreats earlier, and the frozen buffer that used to hold water back is steadily thinning.

C. The consequences are paradoxical, and they arrive in two opposite waves at once. In the near term, faster melting means more water in the rivers, not less. Glaciers are like a savings account being spent down: while the ice lasts, the meltwater payments grow. Scientists call the moment at which that spending peaks "peak water," and most Hindu Kush Himalayan river basins are expected to reach it somewhere around the middle of the century. After that, as the glaciers shrink to a fraction of their former size, summer flows are forecast to decline, leaving downstream farms dependent on rainfall alone. At the same time, the extra meltwater does not stay in the rivers. It collects behind natural dams of rock and ice, forming thousands of new glacial lakes. When one of those dams bursts — a glacial lake outburst flood, or GLOF — it releases a wall of water and debris downstream. A 2025 event near the village of Thame in Nepal swept away more than 459,000 cubic metres of water and rock, an example of a hazard that researchers warn is becoming more common as the lakes grow.

D. What is at stake is not merely scenic wilderness. The rivers that rise in these mountains irrigate land tied to a large share of the region's economic output, and their summer flow fills the reservoirs of dozens of hydroelectric schemes. The ICIMOD projections are stark: under a high-emissions future, the Hindu Kush Himalaya could lose up to 80 percent of its present glacier volume by the end of the century. Even in an optimistic world where warming is held to 1.5 degrees Celsius, a loss of 30 to 50 percent of that volume is still expected. Nepal alone is estimated to hold about 3,252 glacial lakes, many of them expanding as temperatures rise, each a potential source of a sudden flood. Farmers who have always planted according to the calendar now face rivers that peak earlier and shrink faster, while cities that count on dry-season meltwater are building infrastructure for a flow that will not last. The adaptation problem is made harder by the fact that the most affected countries are often among the least equipped to monitor high-altitude ice, which is why much of the early evidence has come from satellites rather than ground measurements.

E. Monitoring, early warning and careful water planning are the tools now on offer. Sensor networks, satellite imaging and community-based flood-warning systems can reduce the immediate danger from outburst floods, even if they cannot stop the glaciers from shrinking. Longer-term answers lie outside the mountains altogether: slowing global emissions determines how much ice survives, and investing in water storage, drought-resistant crops and efficient irrigation determines how well downstream societies cope once the peak-water peak has passed. The story of the Hindu Kush Himalaya is in one sense a parable of climate change in miniature. A resource that two billion people treated as permanent is, on the timescale of a single human lifetime, turning out to be finite. The choice now is not whether the water tower will drain, but whether the countries that depend on it will plan for the dry season that comes after — or be taken by surprise when the rivers run low. Farmers on the Indo-Gangetic plain, engineers designing reservoirs that will outlive the glaciers that fill them, and cities already rationing water in the driest months are all, in effect, gambling on a future flow that the ice can no longer guarantee. What makes the mountain's retreat so hard to govern is that its causes lie thousands of miles away, in emissions the highland countries can do little to control, while its consequences arrive on the fields and in the homes of people who never fly.

Questions 1-4

Choose the correct heading for paragraphs B, C, D and E from the list of headings below.

List of Headings i. Measured over decades: the loss is accelerating ii. The peak-water paradox and sudden flood risk iii. Why two billion people stand to lose iv. How monitoring and adaptation might help v. A brief history of Himalayan mountaineering vi. How hydroelectric dams are constructed vii. The economics of mountain tourism

1. Paragraph B: ____
2. Paragraph C: ____
3. Paragraph D: ____
4. Paragraph E: ____

Questions 5-8

Choose the correct letter, A, B, C or D.

5. According to ICIMOD's 2026 reports, how has the rate of ice loss changed since 2000? A. It has halved. B. It has doubled. C. It has stayed constant. D. It now occurs only in summer.

6. What does the term "peak water" refer to in this passage? A. The highest mountain summit in the range. B. The point at which glacier runoff peaks before declining. C. A new brand of bottled mineral water. D. The moment rivers freeze over in winter.

7. What happened near the village of Thame in 2025? A. A glacial lake outburst flood released water and debris downstream. B. The village was abandoned after a long drought. C. A new glacier formed in the valley. D. A hydroelectric dam was completed.

8. Under a high-emissions scenario, what share of present glacier volume might the HKH lose by 2100? A. About 5 percent. B. Up to 80 percent. C. Exactly 100 percent. D. No loss at all.

Questions 9-13

Do the following statements agree with the claims of the writer?

Write:

• TRUE if the statement agrees with the information
• FALSE if the statement contradicts the information
• NOT GIVEN if there is no information on this

9. The Hindu Kush Himalaya holds the largest store of ice outside the polar regions.
10. Across the range, snow persistence reached its highest level in 23 years.
11. Even if warming is limited to 1.5 degrees Celsius, all of the present glacier ice is expected to disappear.
12. Nepal is estimated to contain roughly 3,252 glacial lakes.
13. Every country downstream has already installed an effective flood-warning system.

Questions 14-15

Complete the summary below using NO MORE THAN TWO WORDS from the passage.

The rivers rising in the mountains supply water to about (14) __________ people downstream, and scientists project that most river basins will reach (15) __________ around the middle of the century before flows decline.

答案与解析

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