How melting glaciers contributed to floods in Pakistan

AYESHA RASCOE, HOST:

Extreme flooding has left roughly one-third of Pakistan underwater. The flooding comes after monsoon rains that are typical for the summertime broke records this year. But there's also another factor - melting glaciers and snow. Pakistan is home to the most glaciers in the world outside of the Arctic and Antarctic. Joining us now is Ulrich Kamp. He's a geographer and has studied glaciers for the better part of his career. He joins us now. Welcome.

ULRICH KAMP: Thank you. Thanks for having me here.

RASCOE: So first, help us to understand the role of glaciers in larger ecosystems around the world.

KAMP: So in high alpine environments, so glaciers are the main source for freshwater. And fauna and flora depend directly on the meltwater from glaciers but also snow. Then, for example, you know, you find wetlands in high altitudes that are very important as a freshwater resource for animals. These wetlands are directly fed by meltwater.

RASCOE: So I'm going to ask you kind of a very glaciers 101 question, but how do glaciers melt? Can you talk a bit about what's actually happening there?

KAMP: So a glacier is a larger mass of ice that is moving along a slope. And it can be a steep slope, like in the mountains, or it could be a more gentle slope, maybe like on Greenland or in Antarctica, but it has to move. So in the high mountains, precipitation during the winter months falls then as snow and not as rain, like, during the summer. So that snow accumulates over the winter months. And that ice mass now increases in volume and extent, and it's getting heavier. Then it starts moving. And then it reaches in lower elevation areas. You know, it moves down the valley where it is warmer. So in these areas where it's warmer now the ice starts to melt. But there is also another factor, and that is sublimation. So some of the ice also evaporates directly into the atmosphere.

RASCOE: Can you talk to me about, like, how that is connected to the type of flooding that we're seeing in Pakistan? How is this contributing to the flooding that we're seeing there?

KAMP: So Pakistan - you mentioned that already earlier - has over 7,200 glaciers. So these glaciers are sitting in the Hindu Kush, Karakoram, Himalaya in northern Pakistan and, you know, in a yearly rhythm increase in volume during the winter months, mainly, and then, you know, lose ice mass during the snowmelt season. So the snowmelt season is a little bit ahead of the season when the summer monsoon, you know, hits the mountains in Pakistan. So that's also important. So you have different peaks now of the meltwater flow but also then rainfall, you know, that feeds into the river systems. And usually, they are separated. So with climate change now, the monsoon, that is, of course, mainly responsible for the flooding - you know, we have on top of that now accelerated glacial melt. And, sometimes, it could happen that the meltwater peak and the monsoon peak actually are closer together. And that's then, you know, a particularly high amount of water that goes through the entire stream system.

RASCOE: With what you're seeing happening with glaciers at this moment on this planet, are you alarmed?

KAMP: Oh, I'm very alarmed. So we know that when we start globally that - you know, over the last 35 years, there's an accelerated loss of global glacier ice. So when we compare the period from 2000 to 2004 with the period of 2015 to 2019, we have 70 billion tons of ice that melted in this period every year more than it did in the earlier period.

RASCOE: Who do we expect to be most impacted by this glacier loss?

KAMP: First, of course, local communities. So when we think about the entire Hindu Kush, Karakoram, Himalaya range, probably, you know, around a billion people in the area depend on the fresh water from the water towers, you know, more or less directly. These are, you know, population in Pakistan and in India, Bhutan, Nepal, Bangladesh. So we are talking here about South Asia and Southwest Asia.

RASCOE: Ulrich Kamp is a professor of Earth and environment at the University of Michigan-Dearborn.

Thank you so much for speaking with us.

KAMP: Thank you very much. Transcript provided by NPR, Copyright NPR.