Can we save the world's coral?

Coral reefs, vital ecosystems supporting 25% of marine life and protecting coastlines, are facing extinction by 2100 due to climate change. The BBC's The Climate Question explores the science behind coral bleaching—triggered by warming oceans and ocean acidification—and the urgent efforts to save them. Ove Hergulberg, a pioneering marine scientist who first linked coral bleaching to rising temperatures in the 1980s, shares how his findings were met with fierce resistance from fossil fuel interests and political figures, delaying global action. Despite this, scientists and conservationists are now deploying innovative solutions: coral nurseries in Puerto Rico grow resilient coral fragments in controlled tanks, using genetically identical 'twins' to prevent internal conflict. Teams also breed sea urchins and crabs to naturally suppress algae that compete with coral for space. While these efforts offer hope, they are expensive and limited in scale. Still, the episode ends on an optimistic note—scientists like Hergulberg believe we can stabilize reefs if emissions are reduced to zero and we act with urgency. The future of coral may depend not just on biology, but on political will. The most striking revelation is that coral don’t just bleach—they fight each other. When genetically different coral pieces are brought together, they launch biological attacks using filaments and stings to kill rivals.