Intensive farming and warming seas spark toxic algae crises across Europe's coasts

Across Europe, toxic algal blooms are spreading as warming seas combine with nutrient-rich runoff from intensive livestock and fertilizer use. In France’s Brittany, “green sludge” on beaches has been linked to pig farms, while Spain’s Mar Menor lagoon—despite legal personhood—suffers from manure-driven cyanobacteria, prompting massive algae removal and shrinking fish catches. Northern Ireland’s Lough Neagh faces similar blue-green blooms, threatening its role as a drinking-water source and crippling local fisheries.

Scientists attribute the blooms to climate-induced temperature rises and cite studies showing agriculture supplies up to 85 % of nutrients in affected waters. National programmes, such as Spain’s €675 million lagoon recovery plan and German projects to curb Baltic nutrient loads, have so far spent only a small share of allocated funds. Environmental groups and citizen-science apps are monitoring water quality, but experts warn that only sweeping changes to farming practices can halt the escalating pollution.