The re-greening of the world
by David Palmer
The scientific community warned that 400 parts per million (ppm) of carbon dioxide in the atmosphere was the threshold level that would lead to a potentially irreversible 1.5 degree C warming of the Earth’s temperature. That point was recently surpassed, not on the Hawaiian mountain top of Mauna Loa where carbon dioxide has been tracked for decades, but on a little known island in the Indian Ocean, far from local influences.
As carbon dioxide levels continue to climb, new reports offer hope and possible salvation to a world thought to be choking to death on it. The scale of decay from the Mountain pine beetle infestation (MPB) that turned 18 million hectares of B.C.’s interior pine forests from healthy carbon-storing warehouses into rotting carbon-spewing sources – which for a time rivaled carbon dioxide output from the northern Alberta oil sands – is reversing. Researchers are now finding that the rate of recovery from the MPB attack is faster than anticipated, partly due to increased global carbon dioxide levels.
“By 2020,” said Vivek Arora of the Canadian Centre for Climate Modelling and Analysis at the University of Victoria, “the enhanced growth due to climate change and increasing carbon dioxide more than compensates for the carbon loss from rotting trees. This turn-around will happen much faster than we had imagined.”
Other forest carbon researchers around the world are coming up with similar results. Trees and crops are growing faster, and green areas are expanding. While increased levels of carbon dioxide are one factor in the re-greening of the world, it’s by no means the sole factor, nor even the largest.
A decade ago, while visiting the Calakmul Model Forest in Mexico’s Yucatan Peninsula, I observed that small-scale agriculture was on the decline and that those tiny farm plots that used to barely support a family were reverting back to forest. The stereotypic image of the Mexican peasant, engaged in subsistence farming on his tiny plot of corn, had virtually ceased to exist. The gleam of jobs in tourism at the nearby resorts of Cancun and the Mexican Riviera had lured many from the country to the city. Almost overnight, a city of a million people (Cancun) had sprung up where none had existed 40 years before. Farmers had left their meager plots to live in the city, and the forest was growing back.
This urbanization trend is well known in the Maritimes, but the fact is, it is taking place world-wide at an unprecedented rate. According to the journal Nature Climate Change, a 20-year study to measure terrestrial biomass using satellite readings showed a decline in forested area from 1998-2002 due to large-scale deforestation in Brazil and Indonesia, but that trend was reversed from 2003-2012 as trees started to grow back.
The regrowth was attributed to several factors: increased urbanization; a higher proportion of intensive commercial agriculture; better growing conditions in the savannahs of Northern Australia and Southern Africa; a program to stop the clearcutting of the Amazon rain forest for soy and cattle production that has already reduced deforestation by 80 percent; and a major afforestation initiative in China.
GREAT GREEN WALL
The objective of China’s massive planting program is to reforest a 4,500-kilometre strip across the country’s northern region – an area of 400 million hectares – by 2050. Compare that number with Canada’s total forest of 348 million hectares, the 18 million hectares of forest affected by the Mountain pine beetle, and the half-million hectares that were burned in the Fort McMurray fire, and you get an idea of the scale of the undertaking.
Deforestation rates in Canada have declined over the last two decades, from 64,000 hectares/year in 1990 to 46,000 in 2010, according to Natural Resources Canada (NRC). According to NRC’s 2015 annual report, 41 percent of the decline is attributable to agriculture, 37 percent to resource extraction, and eight percent to forestry, primarily through the creation of forestry roads.
This is not to suggest that everything is beautiful and we can just forget about carbon dioxide and deforestation. Countries like Haiti, with only three percent of its forests intact, and El Salvador, with 10 percent, are clearly in trouble, and face huge development issues. It would be interesting to track the relationship between human progress and afforestation over the next decade or so, to see if trends observed elsewhere hold.
I’ve spent a good chunk of the past four months in B.C. looking after my dad, who is 96. Inside the house he gets about with a walker, while for longer jaunts he has a push wheelchair that we have used to explore the trails and byways of Victoria. Thus, I have become keenly aware of the importance of good, smooth, barrier-free, low-incline surfaces for accessibility, which has caused me to reflect on the curious assortment of forestry topics selected by the motley crew of colleagues who toiled away on their Master’s degrees in Room 311 of the old Forestry building on the UNB campus.
Although the topics were interesting, with perhaps one exception, relevance to traditional forestry subjects was at best peripheral. We weren’t studying stand dynamics or management systems. We had no interest in silviculture, forest fire retardants, or insect outbreaks. And here’s the wheelchair tie-in: Fran Robinson was investigating the rolling resistance of various gravel surfaces used for walking trails, specifically in relation to wheelchair traffic. She rigged up a winching system, piled weights on the chairs, and used a special meter to measure the resistance. It was great work, but I never realized its true value until I found myself wheeling my dad around, 30 years later.
One gusty, early spring day, I was walking with my grandson and my daughter in a raggedy, White spruce forest near the Huntsman Marine Science Centre, on the edge of St. Andrews, New Brunswick. The trees were being whipped around like a wheat field, and the ground under our feet shuddered as roots struggled to hold on. One big old bruiser of a tree had partially succumbed, and was leaning heavily into a neighbour. Its roots rose and fell with each passing gust, as though it had a set of giant lungs. I called to my grandson to come and ride the root wave. We stood on the uplifted roots as they heaved like an ocean swell for a minute or two, never thinking it might choose that moment to give up the ghost, and we then walked on. Seconds later, a big gust hit the stand, there was a thundering crack, and we wheeled around to see the big guy come down. The angled roots we had been bouncing on now pointed skywards, and I felt sheepish about the risk I had exposed my grandson to. Perhaps he will take that lesson, file it, and grow up more cautious than me.