In this week dedicated to climate rage, I decided to talk to you about these autumn colors that I particularly adore. Summer is coming to an end, the days are getting shorter and the deciduous trees are becoming more colorful. Soon, their greenery will be nothing more than a distant memory. In this cold country, to keep your greenery all year round, as in the popular Christmas song, it is better to look towards the beautiful fir tree, king of the forests.
And if I mix autumnal colors and environmental anger in my title, it is because I ironically think that this inevitable cycle of leaf loss perhaps explains why the Greens have so much difficulty winning over federal politics. When will there be a large fir tree rooted in Ottawa, a party very different from the dying formation of Elizabeth May, to unite these young people and these Mothers at the front who demonstrate their rage in the streets?
One thing is certain, while the dark green is invisible, the autumn shades are conspicuously displayed on the left. Think here of the orange color of the New Democratic Party (NDP) which is quietly being swallowed up by the Liberal red. In these two fall colors, we say we are seriously concerned about the environmental crisis. However, like the maple tree, as soon as the lack of light is felt in the polls, hiding the greenness of the program very often becomes a mode of political survival.
This surface environmentalism is that of Canada which welcomed the 24e World Petroleum Congress last week while boasting of being a leader in the fight against climate change.
We rolled out the red carpet for players in the gas and oil industry in Calgary and, around the same time, we participated in the United Nations (UN) summit dedicated to climate ambition and urgency to abandon fossil fuels.
However, even if economy and ecology come from the same Greek root oikos, which means “house or habitat”, we would benefit from prioritizing them in these times of great turbulence. For the policy maker considering our small oikos biospheric further than the generation of one’s children and grandchildren, putting ecology before economics is sometimes the only path to wisdom.
It is she who will make it possible to perpetuate this magnificent and enigmatic autumn spectacle for those who will come after us. I said enigmatic, because for science, this phenomenon has its bright side and its gray areas.
We know, for example, that the yellow and orange colors of carotenoids were simply hidden in the leaves during the summer. Therefore, by removing this inhibition, the disappearance of chlorophyll allows these colors to be expressed in the foliage.
But for the red color that we owe to pigments called anthocyanins, it is more complicated. Indeed, their appearance, which requires additional energy expenditure from trees, is still the subject of scientific debate.
“Why do trees spend so much energy coloring leaves that are getting ready to fall? » This is the question at the center of the lack of consensus in this story.
For a long time, hypotheses have followed and contradicted each other. A so-called physiological thesis presents these pigments as phytoprotectants and antioxidants which protect the tree from the effects of solar radiation when the greenness of the foliage has faded. Scientists also believe that red reduces the camouflage capacity of phytophagous insects which abundantly squat on deciduous trees in early fall.
Among the other attempts at explanation, that of the late Oxford University professor, the brilliant William Hamilton, appeals to me. In an equally criticized position, this biologist believes that trees invest in these bright colors to send a message to insects who seek to lay their eggs on their branches and bark at the end of summer.
The bright color of the maple would therefore be a military display of deterrence to particularly advise aphids to look elsewhere where the leaves are duller. The brighter the colors, the more the tree shows the critters that in the event of an infestation, it will be sufficiently armed with toxic tannins to attack their offspring en masse. In biology, this phenomenon is sometimes called that of the “honest signal”.
However, in the fight against climate change, Canada’s signal is not always honest.
It is for this reason that the UN Deputy Secretary General for Global Communications, Melissa Fleming, delivered a Jarnac blow to Justin Trudeau at the famous summit on climate ambition and the urgency of abandoning fossil fuels. . She presented the Canadian prime minister as one of the world leaders in the expansion of fossil fuels over the past year.
Because of its hydrocarbon-fuelled economy, Canada is a country torn between sustainable green and oil-brown. A dilemma which also recalls the destiny of autumn leaves.
Indeed, however colorful they may be, once on the ground, this foliage ultimately ends up displaying shades of bituminous brown, the colors that make conservatives salivate. In this other party, blue remains a primary color, but the environment is secondary. Which is not surprising, because traces of blue in the autumn maple leaf are as rare as traces of environmental will from conservatives.