Scientists predict human beings will die out by the end of the century because of what they've done to the planet, David Suzuki says. But he wants Burlington high schoolers to remember two words: sockeye salmon.

In 2009, the fish dwindled to such low numbers that the famed environmentalist feared they wouldn't reach their Fraser River spawning beds. Then the next year, for no apparent reason, the numbers swelled.

That shows nature, no matter how battered, brings pleasant surprises, Suzuki told about 700 students at the Burlington Performing Arts Centre Tuesday.

"I believe if we give nature a chance, she will be much more forgiving than we deserve."

It was a moment of levity in an hour-long talk focused largely on how baby boomers and people of Suzuki's generation — he's 81 — have failed youth with their inaction on climate change.

David Suzuki

"We are part of and utterly dependent on the rest of the natural world for our well-being and our survival," David Suzuki told the students. "Only when you look at the world that way will you begin to behave in a very different way." (Samantha Craggs/CBC)

"I'm up there because I am apologizing," Suzuki said afterward.

"I feel that my generation and the boomers that followed, we partied as if there was no tomorrow." But "when the party's over, you've got to sober up and clean up the mess."

Suzuki said retirees with the freedom to speak their minds now have to "get off the couch" and "get off the golf course" and act as elders in the environmental movement. 

The state of climate change, Suzuki said, is undeniably grim. He told students that some scientists predict humans won't see the end of the century.

He also referenced a recent update to the 1992 "World Scientists' Warning to Humanity" document. In the new version, 15,000 scientists from 184 countries say resources are dwindling to the point where the planet cannot sustain humanity.

Monica Mahut and Makayla Dang

"It is quite frustrating that everything’s been so postponed," says Makayla Dang, right, with Monica Mahut. Both are in the M. M. Robinson Secondary School eco club. (Samantha Craggs/CBC)

While sockeye salmon is still struggling, Suzuki said he tells the story because he's not ready to call it a day yet. Perhaps, he said, the melting of Arctic ice won't release as much methane into the environment as anticipated.

"We don't know enough to say it's too late," said Suzuki, who was the long-time host of The Nature of Things. "Nature shocked us with the sockeye salmon."

He tells the story, he said, "to motivate us to keep going."

It worked for Makayla Dang and Monica Mahut, both 15, from M. M. Robinson Secondary School in Burlington. Both are involved in their school's eco club.

The story, they said, made them feel hopeful.

"I feel inspired to help in some way," Mahut said, "no matter how small."