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How B.C.’s forests became a carbon-spewing liability

#1956 of 2515 articles from the Special Report: Race Against Climate Change
View of trees killed by fire, drought and insects in B.C.'s Stein Valley Park
Trees killed by fire, drought and insects in B.C.'s Stein Valley Park. Photo by Barry Saxifrage

British Columbia's forest has drawn a short climate straw. The polar amplification of global warming is altering the climate much faster here than in more southern forests. These rapid climate shifts are unleashing more wildfires, droughts and insects.

The province's magnificent forest is one of the most carbon-rich ecosystems on the planet. The towering old-growth trees, in particular, are champions of carbon storage. Decades ago, B.C.'s forest absorbed huge amounts of CO2 from the atmosphere. Its carbon sink provided an immensely valuable service to Canadians and its logging industry.

Sadly, that's now gone. Instead, the forest has transitioned over the last two decades into emitting CO2. Lots of it. And the wood harvested from it has been piling millions of tonnes more of CO2 on top of that. What started out as a worrying CO2 trickle has turned into a flood.

That's the grim story told by the government's forest carbon data in B.C.'s official emissions inventory report. To illustrate the startling scale and speed of what's unfolding, I created the chart below from that data. Here's the tale it tells.

Forest carbon collapse

Forests pull CO2 out of the air to create new growth. And forests emit CO2 back into the air when trees and plants die and rot. The balance of new growth versus new decay determines the net amount of CO2 a forest removes from the air.

British Columbia's valuable carbon sink is gone. Its forests are hemorrhaging CO2. And the wood harvested from the province is now adding fuel to our climate crisis, writes @bsaxifrage.
Net CO2 removed (carbon sink) or emitted (carbon source) by B.C. forest. Decade averages.

On my chart, the downward green bars show the annual averages for how much CO2 was removed in each decade. As you can see, net growth in B.C.'s forest has steadily collapsed to a fraction of what it was.

At the same time, wildfire has exploded. The orange bars show the average CO2 emissions from forest fires. This tripled during the 2000s and then tripled again in 2010s.

This one-two punch of declining net growth and surging wildfire has flipped the forest from a huge carbon sink into a huge carbon source.

The bars on the left side of the chart show that back in the 1990s, the forest removed an average of 84 million tonnes of CO2 (MtCO2) per year. The middle bars show that this shrunk to an average of just 38 MtCO2 per year in the next decade. Then in the 2010s, the trends continued past the tipping point. B.C.'s forest flipped to emitting an average of 42 MtCO2 per year.

On top of that is the additional CO2 emitted by logging.

Harvesting wood like it's still 1990

Harvested wood, and the slash left behind, emit CO2 when they get burned or eventually rot. The government tracks and reports the amount each year. Its data shows these logging emissions have stayed fairly steady over the last three decades, averaging around 46 MtCO2 per year. That's a lot of CO2, roughly equal to the emissions from all fossil fuels burned in the province.

Net CO2 removed (carbon sink) or emitted (carbon source) by B.C. forest and logging. Decade averages.

I've added brown bars to the chart to show these logging emissions.

Back in the 1990s, the forest removed more CO2 than harvested wood emitted. So, the logging industry called their wood products "carbon-neutral."

But during the 2000s, logging levels and emissions stayed high even as the forest failed to keep up. As a result, around seven MtCO2 per year, on average, was added to the atmosphere.

Then in the 2010s, as discussed above, the forest was unable to offset any CO2 from any source. It was emitting CO2 even before accounting for logging. Despite this, the industry and the B.C. government continued logging at old-climate, 1990s levels. The bars on the right side of the chart show the result. Harvested wood CO2 accumulated in the atmosphere — on top of what the forest was emitting. The CO2 trickle that started in the 2000s turned to a flood, averaging 89 MtCO2 per year.

In fact, the data shows that in every individual year since 2002, harvested wood emitted more CO2 than the forest removed from the air. Every year, more wood was being logged than the forest was growing back. When something happens every year for 20 straight years, it isn't an anomaly — it's the new reality. Does this sound like sustainable logging to you?

And does logging a forest that is hemorrhaging CO2 sound "carbon-neutral"? Not to me. It sounds like yet another form of climate delay and denial.

What now?

The just-released sixth assessment report by the Intergovernmental Panel on Climate Change says: "Increased heat waves, droughts and floods are already exceeding plants’ and animals’ tolerance thresholds, driving mass mortalities in species such as trees and corals."

It goes on to say that these threats are expected to continue: "Continued climate change substantially increases risk of carbon stored in the biosphere being released into the atmosphere due to increases in processes such as wildfires, tree mortality, insect pest."

In one example specific to B.C., the IPCC report said wildfires in 2017 burned "seven to 11 times the area that would have burned without climate change."

National Resources Canada also expects climate impacts to worsen in Canada's forests. Its State of Canada's Forests 2020 report opens with this warning: "Scientists predict that increasing temperatures and changes in weather patterns associated with climate change will drastically affect Canada’s forests in the near future. With the rate of projected climate change expected to be 10 to 100 times faster than the ability of forests adapt naturally."

The climate science and the government's data make it painfully clear that our forests are already struggling under an increasingly destabilized climate. And so are we. If we want any shot at avoiding a full-blown climate crisis, we need to stop pouring fuel on the crisis with our CO2.

That includes dealing with all the new CO2 we've started pumping into the atmosphere by logging our forests faster than they are growing back.

*****

Endnotes:

  • Since 2002, the wood logged in B.C. has emitted a total of 660 MtCO2. The forest has emitted another 325 MtCO2. Combined, they've pumped nearly a billion tonnes of CO2 into the atmosphere.
  • Nearly half of the wood harvested in Canada comes out of B.C.'s forest.
  • Overall, Canada's managed forest lands have lost three billion cubic metres of wood volume since 1990. That's a loss of more than two billion tonnes of CO2 storage.
  • The primary use of harvested wood in Canada is burning it as fuel. Burning wood is more CO2-intensive than burning coal per unit of energy. For wood to be a competitive fuel, its CO2 must be removed from the atmosphere somehow.
  • Removing a tonne of CO2 from the air with machines and sequestering it underground currently costs around $1,200. The lost carbon sink in B.C.'s forest was a valuable service that will be hard and expensive to replace.
  • Further reading: For those looking for more details on forest carbon in Canada, here's my in-depth explainer on forest carbon trends and the government efforts to shift responsibility for the rising flood of CO2.

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