Planting massive numbers of trees as a strategy to combat the climate crisis can be said to have its roots (groan) in a program begun in Africa but which has grown (groan) into a global effort involving governments and organizations all over the world.

According to its website, the Green Belt Movement was founded by Wangari Maathai in 1977 to respond to the needs of rural Kenyan women. Their streams were drying up, thereby threatening their food supply, and they had to walk long distances for firewood. So, a simple solution: plant trees to stop erosion, store rainwater and provide food and firewood. The GBM has planted more than 30 million trees.

A zero was added to the goal in 2006 when the UN Environmental Programme (that’s how they spell it) launched the Billion Tree Campaign, a target they reached in 2007. So they upped the goal again, to 7 billion trees, and met that in just over a year. The goal skyrocketed when, in the opening speech at the meeting of the UN International Year of the Forest, the Trillion Tree Campaign was announced.

By 2011 more than 12 billion trees were in the ground when the UN formally turned management of the TTC over to the “youth-led not-for-profit Plant-for-the-Planet Foundation.” Finally, at the 2020 meeting of the World Economic Forum, a One Trillion Tree Initiative specifically for governments and businesses to contribute to the UN’s “Decade of Ecosystem Restoration.’

It’s not clear to me how rigorous the monitoring and accounting has been or will be for these huge projects, but somehow the tree-planting programs are credited with planting 13.6 billion trees in 193 countries since last November.

This gained saliency in July of 2019 with research published in Science magazine with the “mind blowing” conclusion that planting trees could offset two-thirds of all the greenhouse gases human activity had emitted in the past 200 years. And it could do so without intruding on land used for cities or food production.

Basically, according to this research, there’s a huge vacant lot out there on the planet that no one is using and is suitable for trees. This got people excited. According to the lead researcher, “This new quantitative evaluation shows (forest) restoration isn’t just one of our climate-change solutions, it is overwhelmingly the top one.” Further, “It is available now, it is the cheapest one possible, and everyone of us can get involved.”

Lofty and hopeful as it sounds, and backed up with extensive data and analysis, it didn’t take too long for it to start raining on the parade. No one disputed that trees can be a significant contributor to mitigation of the climate crisis by pulling carbon out of the atmosphere but, there were many holes to poke in the research.

A scientist at UC Santa Barbara summed it up: “We found that there’s a real need to better understand how much risk forests face due to climate change-driven mortality factors like fire, insect outbreak and drought before we can ensure how appropriate forest carbon-storage projects are to meet ambitious aims for mitigating climate change.”

For one thing, trees grow slowly, and it might be 30 or 50 years before they are sequestering substantial amounts of carbon. And during that time all sorts of things can happen to a forest. The biggest example is the Amazon rainforest, long regarded by the world as a climate crisis hero, as the “lungs of the planet,” drawing in CO2 and exhaling oxygen.

But just one election of a president in Brazil who favors the economic potential of chopping down that rain forest and all those well-intentioned dollars spent on “saving the rainforest” are going up in smoke, losing an area the size of a soccer field every minute.

The Amazon isn’t the only trouble spot. There are huge fires in Indonesia set by humans to clear land for growing palm oil, an ingredient in an estimated 50 percent of supermarket products. There are wildfires in huge swaths of Siberia too remote for firefighters to extinguish. Fires rage across Europe, Africa and Asia and, goodness, we can’t forget the recent infernos in Australia. And, not to leave out the US, roughly half the land area prior to the arrival of Europeans was forest. We have room to grow.

The thing is, the world is getting hotter and dryer We’ve seen evidence of the effect of climate on fires in California. The state has experienced half of its largest wildfires, and three quarters of the most destructive since 2010. The U.S. Geological Society calculated that California wildfires in 2018 contributed 15 percent of total CO2 emissions produced by the entire state.

The clear message in all of this is that yes, we do need to plant trees and, yes, they can contribute to offsetting to some degree human-caused greenhouse-gas emissions, but we should not fool ourselves that planting trees can, by itself, be the answer to the climate crisis. Equal or even greater emphasis should be given to listening to our inner Lorax and speaking for the trillions of trees that are already here.

— John Mott-Smith is a resident of Davis. This column appears the first and third Wednesday of each month. Please send comments to johnmottsmith@comcast.net.

Crossposted from the Davis Enterprise

Published online on June 30, 2020 | Printed in the July 01, 2020 edition on page A6