Looking to Forests During Heat Waves

“Congratulations to whoever invents forests.” So read a viral tweet last January from actor-writer Cody Johnston in response to Elon Musk’s Twitter announcement: “Am donating $100M towards a prize for the best carbon capture technology.” In internet-time, this exchange is practically ancient history; quoting a 6-month-old tweet defies our expectation of the modern soundbite’s instant gratification and instant vanishment. But as this story asks for your attention to longer, ecological timescales, such a deviation seems appropriate. For decades the slow churn of geologic time has barely registered in our news cycles, with the exception of natural disasters, sensational stories which burst like fireworks just to fade away.

Except that in the past few years, the fireworks haven’t stopped. Natural disasters come one after another, breaking record after record. On the west coast of the United States, wildfire season lengthens while the wet season shrinks. As June turned into July, a Pacific Northwest heat wave killed hundreds of people, cooked more than a billion sea creatures to death, and sparked dozens of wildfires. As of right now, over one million acres of land in the United States are on fire. The day after the town of Lytton reached the highest temperature ever recorded in Canada of 49.6° C/121° F, it was gone—devoured by a wildfire. And this heat wave was only one of four in five weeks in the western US and Canada. The heat exacerbates other disasters: damage to ecosystems, wildfires, crop failures, droughts. It is all connected—but that doesn’t mean the web of relation can’t be untangled.

In the midst of this scorching summer, it seems pertinent to trace cause and effect between forests and weather patterns. The planet is warming, in part because of deforestation. (It’s estimated that tropical deforestation accounts for around 10% of the world’s heat-trapping emissions, a statistic which does not include the impact of deforestation in non-tropical regions.) The increased global temperature contributes to increased drought and wildfires, both of which compound forest degradation, particularly as dried-out vegetation is more flammable. Humans are responsible for the majority of wildfires—in the United States, 84% of fires are caused by human activity—as well as all deforestation for timber and agriculture. The more forests we lose, the more carbon we release into the atmosphere, increasing the heat of the planet, and thus exacerbating drought, wildfires, and forest degradation.

Degraded forests at a certain point no longer function as the carbon sinks we need them to be. A study published this summer found that parts of the Amazon Rainforest have been degraded so much by deforestation, fires, rising temperatures and moisture stress, they now release more carbon than they absorb. This is a dangerous sign, and hardly the only one we’ve been presented with. But it comes at the same time that “natural climate solutions,” meaning ecosystem conservation and restoration as a way of mitigating climate change, are gaining ground in global conversations.

Cody Johnston’s quip that forests are the best carbon capture technology is an opinion shared by many scientists. “The most mature carbon dioxide removal method is improved land stewardship,” writes a coalition of scientists. At the same time that forest loss is compounding, we are recognizing that forest ecosystems are one of our most vital tools to fight climate change. The more we lose, the more we will lose; but the more we save, the more we can save.

The notion that “trees bring rain” sounds almost fanciful. But conclusive evidence shows that forests have a significant impact on rainfall. Transpiration is the way that water moves through plants: water is absorbed from the soil by their roots, and released as vapor into the air by their leaves. The water vapor released by a forest accumulates in the clouds above it and creates rain, which falls on the forest and is carried on the wind to other regions. Fred Pearce writes that this “hitherto neglected impact of deforestation”—losing the water vapor released by trees into the air—“could in many continental interiors dwarf the impacts of global climate change. It could dry up the Nile, hobble the Asian monsoon, and desiccate fields from Argentina to the Midwestern United States.” Forests play a crucial role in the water cycle, and deforestation leads to desertification not only because of topsoil erosion in the absence of plant roots, but insufficient moisture in the air to make rain. The loss of major rainforests would disrupt weather patterns in far-flung regions sufficient to “pose a substantial risk to agriculture in key breadbaskets halfway around the world in parts of the U.S., India, and China.”

At the same time that Lytton, BC was engulfed in flames, 400 km west of the devastated town, police and protesters faced off in one of Canada’s last old-growth forests. The forest defenders at Fairy Creek, many of whom belong to First Nations, are fighting to protect the last 1% of old growth trees in Canada from being logged. Some detractors emphasize the damage to Canada’s logging industry if old growth forests—27% of British Columbia’s annual cut—were protected from logging. Other commentators point to the urgent necessity of a paradigm shift in our valuation of forests, especially in light of the universal need for a stabilized climate.

As the Pacific Northwest is ravaged by wildfires, attention should be drawn to the potential to fight fires with forests. Conserving and expanding forests, like the temperate rainforests of British Columbia, protects against worsening drought and heat waves. Old intact forests create their own microclimates which are cooler and wetter in every season, and during forest fires, “these old-growth refugia provide an island of safety for species, but also a firebreak that can reduce risk to communities.” And for the stubbornly fiscal-minded, the $1.3 billion in annual revenue from the Canadian forestry sector is matched by the up to $1.5 billion a year in wildfire damages, which is only one quantifier of the toll of ecosystem destruction.

American Forests issues this warning about deforestation: “You need trees in order to have the moisture to grow new trees: if you cut them all down, you might not be able to get them back.” Reforestation efforts do indeed face an upward climb, and much is irreplaceable. Yet there are successful re-greening efforts that prove we can still turn back the clock of environmental destruction. The Loess Plateau in China stands among the most remarkable success stories. The 12-year project which ended in 2009 transformed 920,000 hectares of desert in western China into fertile farmland through focusing on restoring soil health. Inspired by this success, a team of Dutch engineers called The Weather Makers has plans to re-green the Sinai Peninsula over a few decades, asserting that a “regreened Sinai would alter local weather patterns and even change the direction of the winds, bringing more rain.” Conserving the ecosystems we have, and restoring the ecosystems we’ve lost, can—slowly but surely—bring us the weather we need to quench this drought.


Image courtesy of Flickr. Originally published by S&S on Aug. 4, 2021.

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