Kelp surveys on England's south coast monitor a key climate defence

In the 1980s, so much kelp washed onto beaches west of Brighton that the “unsightliness” of the seaweed and the flies it attracted made it a problem worthy of debate in the UK parliament. Farmers took the abundance of washed-up brown algae for fertiliser. Locals talked of the “kelp problem”. Today, the problem is too little kelp, says Mika Peck at the University of Sussex, UK.

Kelp matters because it locks up millions of tonnes of carbon globally, provides a nursery for fish and a buffer against coastal flooding. While climate change has played a role in…