The number of salmon in the Pacific Ocean is twice what it was 50 years ago. But there is a downside to this bounty, as growing numbers of hatchery-produced salmon are flooding the Pacific and making it hard for threatened wild salmon species to find enough food to survive.

Our high-tech products increasingly make use of rare metals, and mining those resources can have devastating environmental consequences. But if we block projects like the proposed Pebble Mine in Alaska, are we simply forcing mining activity to other parts of the world where protections may be far weaker?

As burgeoning human populations place greater pressure on wild areas, a strategy is emerging for preserving threatened lands and wildlife. Known as ‘rewilding,’ it involves expanding core wilderness areas, connecting them via corridors that allow humans and animals to co-exist, and protecting and reintroducing top predators.

Paul Ehrlich still believes that overpopulation imperils the Earth’s
future. But the good news is we are approaching a demographic turning
point: Birth rates have been falling dramatically, and population is expected to peak later this century — after that, for the first time in modern history, the world's population
should actually start to decline.