David Miller is the president and CEO of World Wildlife Fund Canada

The new records humanity is setting are frightening: Arctic sea ice at an all-time winter low; 2016 as the hottest year on record; and a new high in the amount of carbon released into the atmosphere in millions of years.

As climate change unfolds before our eyes, the climate deniers now include a small but powerful number of global leaders, people who think climate change isn't worth spending time or money fighting. This wasn't the case when the global agreement to fight climate change was signed in Paris in December of 2015.

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So, it can be easy to despair and think that the problem is too big for individual Canadians, or anyone, to tackle. In the face of disregard for science and for the impact of climate change on people and wildlife, what can the average person do? Can Earth Hour actually help move the needle on climate change?

Earth Hour isn't about reducing emissions for a single hour on a Saturday night. Emissions aren't the metric by which to measure this event.

Yes, Earth Hour is symbolic, but it's not trivial. By disconnecting, we're connecting with the biggest issue confronting the world today.

In Canada, we can take that hour to talk about the impact climate change is already having – entire communities forced to relocate because of permafrost melt, extreme weather events causing massive upheaval and habitat destruction, wildfires and floods causing people and wildlife to flee their homes.

We can take an hour Saturday night to talk about the impact climate change is having on narwhals, those almost-mythical unicorns of Arctic seas that are now prey for transient orcas no longer stopped by ice.

We can talk about polar bears, and the fact that in some populations, sea ice loss has contributed to fewer cubs surviving into adulthood.

We can talk about barren-ground caribou and the fact they're facing disastrous declines partly because climate-change driven weather events make it harder for them to get food.

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Through Earth Hour we are reaffirming for each other, and for our leaders, that we trust the science, that we want action, that we believe in joining together to put the brakes on climate change.

And when we see a candle in our neighbour's window, when we see our communities go dark, when we see that our small, symbolic actions are visible from outer space, we see we're not alone in this fight. Earth Hour is a visual signal that ordinary people the world over resist opposition to halting climate change.

It's a sign we haven't forgotten about the Paris Agreement, and our determination to halt the degradation climate change causes to our environment.

Symbolic actions demonstrate what the public cares about. Today there is clear public acceptance for the need for action. And we have seen action: Canadian cities are acting (Toronto alone reduced its GHG emissions by over 15 per cent); led by B.C., many Canadian provinces have acted; and our current federal government has shown leadership. Most important, people and businesses are changing their habits to move toward a lower-carbon world.

In a literal sense, Earth Hour itself won't make an ice cube's worth of difference in limiting warming to 1.5 C. But because it deepens the commitment of ordinary people to stand up against those who actively promote increased emissions, it's worth it.