UN warns fresh water supplies under threat

Valerie Sanderson (0:00)

This is the Global News Podcast from the BBC World Service. I'm Valerie Sanderson, and at 1300hrs GMT, on Thursday 17th September, these are our main stories. The United Nations is warning of a serious decline in the amount of fresh water stored on the earth's surface, increasing chances of flooding and drought. In South Africa, police discovered the body of a woman to the east of Johannesburg, the ninth killing in two months. Canada's Prime Minister Mark Carney welcomes the European Union's proposal of associate membership.

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Valerie Sanderson (1:10)

We find out how people on the streets of Moscow view Russia's upcoming parliamentary elections. We begin with a stark warning from the United Nations about the earth's dwindling water resources.

Celeste Silo (1:26)

Last year was one of the driest years for river discharge in 35 years. The past seven years have been abnormal river flows.

Water related extreme events continue to devastate communities and economies.

Valerie Sanderson (1:40)

Celeste Silo, the Secretary General of the World Meteorological Organisation. The organisation's annual report says water storage, including groundwater, fresh water on land and the water in rivers and lakes across the earth's surface is declining. Extreme weather patterns caused by climate change are predicted to cause more floods and drought. And unreliable water resources disrupt the balance of earth's natural water cycle by altering how water moves and evaporates. Our Global Affairs reporter Paul Moss told me more.

Paul Moss (2:12)

The water cycle sounds simple. It's the process by water evaporates from the earth and then comes down again as rain. But what this report says is that it's become increasingly erratic. And that's because what can change is where the water comes from and how it falls. What happens is because we've got increasingly high temperatures because of climate change, fresh water is vanishing up into the sky from lakes and rivers. Many people, of course, depends on lakes and rivers for fresh water, both for drinking and for crops. And those levels in lakes and rivers, the report shows have fallen. But then there's the question of how and when the water falls. What goes up, of course, must come down. And if there's more water in the sky in terms of clouds and humidity, more water will fall and that can cause flooding.

And I think this sometimes causes problems for people to understand. How can climate change cause both drought and flooding? Well, that's because first of all, the water may go up slowly and then all fall in one go.

Or of course, there may be more water loss in hot places, more water loss through evaporation, which then falls in colder countries as flooding.

Valerie Sanderson (3:17)

The UN report is focusing particularly on the changes to glaciers. Why are they so important?

Paul Moss (3:25)

Glaciers, it explains, work as a buffer. And in fact, in a rather good graphic phrase, what it says is glaciers operate as the world's savings account in terms of water. They freeze. Obviously, when the weather is cold, more water freezes. And then when it's warmer in the summer, that water is released again. The trouble is, the glaciers are retreating. And it has a very good way of visualizing it. What it says is that every year, the Earth's glaciers are losing water equivalent to 500 million, half a billion Olympic swimming pools. So what does that mean? Well, first of all, that current account I was describing to you is depleted. We don't have it anymore. Secondly, those glaciers may break up and melt with catastrophic consequences, which we of course saw last month in Nepal, when what was probably the cause by a glacier melting and then breaking off caused the flash flooding, which resulted in thousands of deaths and also towns and villages completely destroyed.

Valerie Sanderson (4:20)

Paul, it's an obvious question this, but can anything be done to avoid these water related disasters?

Paul Moss (4:27)

One of the few pieces of good news in this report is that there is better monitoring of water levels and so we can at least warn of trouble ahead. The problem is that there is poor warning systems in place in Africa and Asia and those are precisely the areas which are going to be worse affected by all of this.