Delegates from 179 countries meeting at the Convention on Biological Diversity (CBD) in Nagoya, Japan, agreed to "take effective and urgent action to halt the loss of biodiversity" to try to ensure the resilience of ecosystems by 2020.
Too much of a good thing can be bad. A new study of marine aquaculture around the world finds that even the most efficient operations—think industrialized salmon farms—can cause large environmental harm if there are too many of them.
With global population expected to reach 9.2 billion by 2050, food production will need to double worldwide. Meeting this challenge without causing more environmental damage—cutting down rain forest, for example, or using more groundwater—will be even harder.