The oceans are absorbing 90% of the excess heat caused by climate change, and the first to suffer are the small islands. All island communities are at risk. All but one, off the coast of Mexico. For 85 years, the Buzos y Pescadores cooperative of fishermen and divers has prospered on Isla Natividad: they fish sustainably and protect the marine ecosystem.

In 2009, an exceptional wave of deaths affected abalone and sea cucumbers, highly prized species and sources of income for the locals. The prime suspect: water acidification. This global phenomenon, caused by the dissolution of CO2 in the ocean, threatens shellfish in particular and, consequently, the entire marine food chain. ‘We decided democratically to stop fishing abalone for six years and to protect part of the concession as a marine protected area’, recalls Renée Mendoza, the oldest of the fishermen still working.

An unusual and painful decision, but one that has paid off. These molluscs have survived and, according to a team of researchers from Stanford University, they have probably evolved genetically to adapt.