"About 400,000 people live on the tiny island of Malta. It is one of the most crowded spaces in the world."
"It is also highly vulnerable to climate change. Rising sea levels in the Mediterranean caused by global warming are threatening to submerge parts of the island."
"But there is another aspect to sea level rise that is already having a significant effect on Malta. It is the impact on the supply of drinking water."
"About 97m (320ft) beneath the surface of the island lie the Ta' Kandja galleries. Reached by a lift, the tunnels stretch out for several kilometres like the spokes of a wheel, all half filled with water that is pumped up to the surface and then to homes and farms around the island."
"The water in the tunnels is fresh. But just 10m below it is salty. And thanks to climate change the brackish water is rising."