For many British Columbians, smoke from the wildfires in Washington and Oregon states filled our lungs and burned our eyes for several days — a potent reminder of how inextricably linked the U.S. and Canada are when it comes to the climate crisis. Scientists agree that things are only going to get worse. But Americans in Canada could hold the key to how much worse they get. The catch? They have only a week or two to take what could be the most impactful climate action in their lifetimes — voting in the U.S. presidential election — and many of them don't even know it.

People often focus on personal action to mitigate climate change — reducing flying, driving and cutting out factory-farmed meat. Unfortunately, the public has not fully embraced voting and other forms of civic engagement as critical climate actions, in part because of the fossil fuel industry's push to focus policy debate on individual consumer actions. But the climate consequences of not voting in the U.S. presidential election are truly staggering. Here are three reasons why.

Voting in the U.S. election is important because it's likely that a tiny fraction of votes will decide whether it's a Trump or Biden administration that shapes climate justice policy in our rapidly closing window for action. Fewer than 80,000 voters in three key swing states decided the U.S. election in 2016, and it is likely that this election will once again come down to only tens of thousands of votes. But fewer than six per cent of the estimated one million Americans and dual citizens living in Canada who are eligible to vote in the US presidential election actually do so. If more of them turned out, they could be the decisive factor in defeating Trump and staving off climate catastrophe.

Because the U.S. produces such a massive share of global greenhouse gas emissions, a shift in its climate policy could have more impact on Canada than Canada's own climate policies. Scientists agree that the slower we act, the harder it will be to prevent a truly apocalyptic future and that we are fast running out of time. Rather than advancing U.S. climate policy, the administration of Donald Trump has actually dragged it backward, slashing key environmental regulations and withdrawing from the Paris Agreement, a global accord to cut greenhouse gas emissions.

After being appointed to Democratic presidential candidate Joe Biden's climate task force, climate justice champions, including Rep. Alexandria Ocasio-Cortez and Varshini Prakash, executive director of the Sunrise Movement, helped push the Biden campaign to release a sweeping, ambitious, $2-trillion climate plan. In contrast, Trump has called climate change a hoax and just this month refused to link the wildfires to climate change, saying that "science doesn't know." This election may be our last chance to get the U.S., one of the biggest global emitters and climate action holdouts, on board soon enough to stave off the worst of the climate catastrophe.

With COVID-19, this isn't going to be an ordinary election, and there are serious concerns about postal delays. That's why American and dual citizens should request a ballot and use the federal write-in absentee ballot as an emergency backup to ensure their vote is counted. Instructions for all states are here.

The last day to request a ballot from certain states is as early as Oct. 3. The critical window to request a ballot is now.

Many dual citizens who have never lived in the U.S. are eligible to vote, and voting in federal elections will not change your federal or state tax liability.

If you're a Canadian reading this, text, call and email American friends and family in Canada and elsewhere to confirm they're registered to vote and have a voting plan. Call on behalf of a campaign, write letters to and text voters in swing states. Experts agree that Canadians are allowed to do this kind of routine volunteer work, and it doesn't count as foreign interference.

If the wildfire smoke made you feel helpless and fearful for you and your loved ones' future, these are concrete steps you can take to profoundly shape the climate future of Canada, the U.S. and the world.