Tuesday August 14, 2012 Kenneth Kidd Feature Writer
A funny thing happened on the way to climate-change policy in Ontario — nearly everyone forgot their elementary-school lesson about photosynthesis and how plants remove carbon from the atmosphere.
That’s something the David Suzuki Foundation now hopes to rectify with “Carbon in the Bank,” a report released Wednesday on the greenbelt’s role in mitigating the effects of climate change.
Click here to download the report
“It’s a massive carbon storehouse,” said Faisal Moola, the Suzuki Foundation’s director of science.
Covering 750,000 hectares (1.8 million acres) from Rice Lake to the Niagara River, the greenbelt’s farms, forests and wetlands not only remove carbon from the atmosphere via photosynthesis, they store it in their biomass for extended periods.
The forests alone, which cover 24 per cent of the greenbelt, are effectively banking about 40 million tonnes of carbon, the equivalent of 147 million tonnes of carbon dioxide.
The wetlands store a further 6.7 million tonnes of carbon or roughly 25 million tonnes of carbon dioxide.
Combined, that’s the same amount of carbon dioxide released annually by 33 million cars and trucks.
“This is definitely low-hanging fruit, and yet it seems the role of the greenbelt (in fighting climate change) has been downgraded by the provincial government,” said Moola.
One problem, which the report seeks to solve, may be the traditional difficulty in measuring and putting an economic value on the amount of carbon that green areas remove from the air and store through photosynthesis.
Young forests, for instance, consume and hold a lot of carbon while mature ones mostly just store it rather make any net additions to their carbon content.
“There’s that adage that you can’t manage what you don’t measure,” noted Moola. “This report begins that process.”
The Suzuki study, prepared by McGill University’s Ray Tomalty, synthesizes a number of existing estimates and measurement models to come up with a total of 86.6 million tonnes of carbon now being stored in the greenbelt.
Estimates of how much all that carbon is worth — based on the damage it would do in the atmosphere — vary widely. So the Suzuki Foundation used the average of peer-reviewed estimates, or $53 per tonne of carbon (in 2005 Canadian dollars).
That puts the entire greenbelt’s carbon value at $4.5 billion or, treated like an annuity, nearly $370 million annually over 20 years.
Nor is this just an academic exercise. If Ontario adopts a cap-and-trade system for controlling carbon, then putting a value on the role of forests and green space in mitigating climate change will be crucial.
“If you drain, pave over and dug up wetlands or clear-cut old growth forests, all that carbon gets released back into the atmosphere,” said Moola.
But any moves to increase the greenbelt’s ability to store carbon could also have saleable value as so-called “carbon offsets” under cap-and-trade.
Farmers and large landowners, for instance, could create offsets by planting more trees on their property or adopting no-till farming techniques. Hence the need for established measurement tools to make sure the carbon offsets are credible.
“I think that’s going to be a game changer,” said Moola.
But the Suzuki Foundation also cautions that the greenbelt isn’t immune to threats. Proposals for new highways and quarries will reduce the greenbelt’s ability to act as a carbon sink.
And additional golf courses, through forest removal and ongoing maintenance (including fertilizer and pesticides) can actually cause a net increase in greenhouse-gas emissions.
By the numbers
24 — Per cent of the greenbelt now forested.
35 — Per cent the Suzuki Foundation would like to see by 2025.
7,100 — Number of farms.
$1.5 billion — Annual farm receipts
260 — Number of licensed quarries in and around the greenbelt.
41 — Number of golf courses on the Oak Ridges Moraine alone