This is The Guardian.

Red by Reese Weathers, produced by Tony and the Chugu.

One of the first scientists to realise that something was wrong with the lakes was a geologist named Simon Oniwari.

He came to the topic by accident.

Between 2010 and 2013, he had been studying Lake Boringo, Kenya's fourth largest lake by volume.

The bones of residents of the area around the lake weakened uncommonly fast,

and Oniwari was investigating whether this may be linked to high fluoride levels in the water.

Then, in early 2013, while he was meeting with residents of Marigat, a town near the lake, one old man stood up.

''PROF'' he said.

''We don't care about the fluoride. What we want to know is how the water has entered our schools.''

Curious to know what the man was talking about, Oniwari visited the local Salabani Primary School.

There he found the lake lapping through the grounds of the school.

Non-plussed he took out his map.

He looked at the location of the lake and the location of the school, and wondered how the lake had moved two kilometres without it becoming news.

Oniwari rushed back to Nairobi, where he and his colleagues at several Kenyan University studied recent satellite images of the lake.

The images showed that the lake had, in the past year, flooded the area around it.

Then, Oniwari searched for images of some of the lakes nearby.

Lakes Borgoria, Navasha and Nukuru.

All of these had flooded.

As he extended his search, he saw that lake Victoria, Africa's largest lake, had flooded too.

So had Lake Takana, the largest desert lake in the world.

By September 2013, after further investigation and mapping, it was clear to Oniwari and his colleagues how extreme the damage was.

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