Donana National Park in southwestern Spain — one of Europe's most important wetlands, home to millions of migratory birds and threatened species like the Iberian lynx — is running dry. But rising temperatures and drought caused by climate change are only part of the problem.

The UNESCO -protected region on the Atlantic coast relies on an underground aquifer that's been tapped by hundreds of illegal wells. The reason: Europe's fruit and vegetable supply. Spain provides one-quarter of Europe's fresh produce, supplying colder parts of the continent with fruit and vegetables year-round.

The scale of water extraction in Spain is staggering: In 2016, WWF Spain estimated that the Donana wetland was home to over 1,000 illegal wells and more than 1,700 ponds illegally irrigating an area as big as 4,200 football fields.

The 'sea of plastic' in Almeria is a massive expanse of plastic-covered greenhouses key to Spain's agricultural production Image: Viajar24h/Pond5 Images/IMAGO

"It's gotten hotter every year.…