Coral reefs are the rainforests of the ocean. They exist on vast scales and are equally important havens (避风港) of biodiversity. Reefs occupy 0.1% of the oceans. 【小题1】

【小题2】 Without the protection which reefs afford from crashing waves, low-lying islands such as the Maldives would have flooded long ago, and a billion people would lose food or income. However, reefs are under threat from rising sea temperatures. Heat causes the algae(海藻)with which corals are living together to generate toxins (毒素) that force those coral to leave. This can cause a coral’s death.

Research groups around the world are coming up with plans of action to see if that will help, such as identifying naturally heat-resistant corals and cross-breeding such corals to create a new type. 【小题3】 Without carbon reduction and decline in local, coral-killing pollution, even resistant corals will not survive the century.

Doubters doubt humanity will get its act together in time to make much difference.

【小题4】 Carbon targets are being set and ocean pollution is being dealt with. Countries that share responsibilities for reefs are starting to act together. Scientific workarounds can also be found. Natural currents can be applied to facilitate mass breeding. Sites of the greatest ecological and economical importance can be identified to maximize bang for buck.

This mix of natural activity and human intervention is important. 【小题5】 Hard-coregreens-those who think that all habitats should be kept unspoiled-may not approve. But when entire ecosystems are facing destruction, the cost of doing nothing is too great to bear.