Life evolved to live within limits. It's a delicate balance. Humans need oxygen, but too much can kill us. Plants need nitrogen, but excess nitrogen harms them, and pollutes rivers, lakes and oceans. Ecosystems are complex. Our health and survival depend on intricate interactions that ensure we get the right amounts of clean air, water, food from productive soils and energy from the sun.

Salmon have been swimming in Pacific Northwest waters for at least seven million years, as indicated by fossils of large saber-tooth salmon found in the area. During that time, they've been a key species in intricate, interconnected coastal ecosystems, bringing nitrogen and other nutrients from the ocean and up streams and rivers to spawning grounds, feeding whales, bears and eagles and fertilizing the magnificent coastal rainforests along the way. For as long as people have lived in the area, salmon have been an important food source and have helped shape cultural identities.

In July, Solar Impulse 2 became the first airplane to fly around the world without using fuel. At the same time, the U.S. National Aeronautics and Space Administration has been working on electric planes. These developments mean air travel and transport could become more environmentally friendly, with less pollution and fewer greenhouse gas emissions, and planes would be quieter.

Like this article? rabble is reader-supported journalism.Chip in to keep stories like these coming.

Humans are the world's top predator. The way we fulfil this role is often mired in controversy, from factory farming to trophy hunting to predator control. The latter is the process governments use to kill carnivores like wolves, coyotes and cougars to stop them from hunting threatened species like caribou -- even though human activity is the root cause of caribou's decline.

Like this article? rabble is reader-supported journalism. Chip in to keep stories like these coming.

It’s been shocking to watch news of the Brexit vote in Britain, Donald Trump's promise to build a wall between Mexico and the U.S. and the ongoing threats and violence against ethnic minorities in many parts of the world. I'm not a political or social scientist, but my training as a biologist gives me some insight.

Like this article? rabble is reader-supported journalism. Chip in to keep stories like these coming.

Like this article? rabble is reader-supported journalism. Chip in to keep stories like these coming.

The Arctic's Baffin Bay and Davis Strait region is home to seals, bowhead whales, polar bears and up to 90 per cent of the world's narwhals. The area's marine waters also provide habitat for 116 species of fish, such as Arctic char, an important dietary staple for Nunavut's Inuit communities.

Like this article? rabble is reader-supported journalism. Chip in to keep stories like these coming.

Canadians of all political persuasions care about climate action. Watching Canada fall behind the rest of the world over the past 10 years has been deeply disturbing to many. We became climate laggards. We yearn to be leaders.

Like this article? rabble is reader-supported journalism. Chip in to keep stories like these coming.

Alberta is home to two of Canada's imperilled caribou populations: the southern mountain and boreal woodland herds. Both are threatened with extinction.

Like this article? rabble is reader-supported journalism. Chip in to keep stories like these coming.

The shift from fossil fuels to renewable energy is occurring mainly at the power plant level. But what about transportation? Can we significantly reduce greenhouse gas emissions by switching to cleaner fuels? Or is this just an attempt to keep 20th century technology chugging along while trading one set of environmental problems for another?