London’s River Thames comes back from the ‘biologically dead’

Some 60 years ago, parts of the River Thames were declared biologically dead. But the famous waterway that cuts through London has been revived and it is now home to hundreds of wildlife species, such as seahorses and sharks.

The latest State of the Thames report, released by the Zoological Society of London on Wednesday, found cleanup efforts over recent decades have brought down levels of chemicals like phosphorus and conserved salt marshes for birds and fish, making the river “home to myriad wildlife as diverse as London itself.”

The report also highlighted many challenges the Thames faces, including rising water temperatures and sea levels due to climate change. Summer temperature in parts of the river have increased an average of 0.19 degrees Celsius (0.34 degrees Fahrenheit) each year since 2007, researchers found. Even slight alterations in seasonal heat may upset the river’s ecosystem and erode living habitats.

The Thames hasn’t always been a model for environmental protection. It became heavily polluted during the Industrial Revolution by toxic runoffs from tanneries and human waste. The “Great Stink” of 1858, caused in part by human sewage flowing into the Thames, forced the British Parliament to build better wastewater disposal systems.

In 1959, oxygen levels in the Thames had dropped so low the British Natural History Museum declared it biologically incapable of sustaining marine life. Authorities invested in better sewage treatment facilities and monitoring key environmental indicators, sparking a turnaround.