Climate change has been recognized by the World Health Organization (WHO) as the biggest health threat of the 21st century.

But what does it mean for Canada?

Canada has already seen increased wildfires resulting in smoke-related health impacts and stressful evacuations; an expansion in the spread of Lyme Disease; and food security and mental health challenges related to rapid changes in the far North, which is two to three degrees Celsius warmer than it was in the 1950s.

Climate change is no longer a suspected diagnosis. It's a health emergency that is already causing systemic damage to the health and well-being of many around the world.

Consequences reach beyond borders: climate-related drought and crop failure has been implicated as an exacerbating factor in the conflict in Syria.

The Lancet, one of the world's most respected medical journals, points out that based on current emissions trajectories, temperature rises over the next 85 years may bring such consequences in terms of sea-level rise, malnutrition, conflict and other destabilizing factors as to be "incompatible with an organised global community."

The flipside of crisis is opportunity. In fact, the central conclusion of The Lancet's 2015 Commission on Climate Change and Health is that tackling climate change may be the biggest health opportunity of our time. This report fused the knowledge of some of the world's most prominent economists, physicians, urban planners and other experts.

Their assessment? "The single most powerful strategic instrument to inoculate human health against the risks of climate change would be for governments to introduce strong and sustained carbon pricing."

The Lancet likened carbon pricing to methods already used successfully by public health departments across the world, such as tobacco taxation. Citing the Lancet, in 2015 the Canadian Medical Association passed a motion committing it to promote the health benefits of a strong, predictable price on carbon emissions.

The prescription of a critical treatment is a step towards better health. Given that, we applaud the Federal Government's recent announcement of a minimum price on carbon.

In British Columbia, per capita consumption of fossil fuels covered by their carbon tax decreased by 16 percent between 2007 and 2013, and a review of studies on the tax showed an overall 5-15 percent decrease in greenhouse gas emissions compared with what would have occurred with no tax.

Decreasing fossil fuel use decreases local air pollution, which has immediate benefits for health. The WHO attributes one in every eight deaths worldwide to air pollution. In 2008, the CMA estimated that air pollution resulted in 11,000 hospital admissions and 21,000 deaths in Canada annually, at a cost to the health system of over eight billion dollars. As a carbon price drives society towards decreased fossil fuel use, air pollution is expected to decrease, resulting in immediate health benefits.

Air pollution-related illness in Toronto has dropped in the years following the closure of Ontario's coal plants; what if all of Canada saw illness from air pollution decreasing? Any cost-benefit analyses of carbon pricing must include estimates of the impact of carbon pricing on rates and costs of asthma, chronic obstructive pulmonary disease and heart disease.

A formal health impact assessment at the provincial level at the time of consideration of individual policies would be helpful in order to ensure that new carbon pricing regimes are implemented in a way that does not penalize those with the least means, and which optimizes overall health.

Strategies to help with implementation include a predictable, reasonable rollout so that people can make progressively lower-carbon choices, tax rebates or a tax shift.

For example, the provincial government of British Columbia decreased personal and corporate income tax to compensate for their carbon pricing regime.

Other measures will be required to help us do our fair share and meet our international commitments, but a national minimum price on carbon is a significant step forward. There is much room for the provinces to each determine the best way to introduce carbon pricing and how to use the revenue generated for provincial coffers.

The world is going low-carbon. Canada has agreed to a G7 pledge to completely decarbonize by 2100 and has now ratified the Paris Agreement on Climate Change, which will enter into force on November 4th.

If climate change is the biggest threat to human health, a robust response is our greatest opportunity to make positive change. The institution of a national carbon price is a key step in the treatment necessary to keep us -- and our children -- alive and thriving.

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