The year is 2019 – before the pandemic, the good old times when climate change was the only existential threat we faced. A paper was published by a research group in Switzerland on the carbon mitigation potential of planting trees. The paper stated that there are enough non-forested, non-urban, and non-cropland areas on Earth to plant a trillion trees. Plant a trillion trees, and we can remove two-thirds of all emissions humans have ever put into the atmosphere.

Suddenly, international organizations, governments and corporations sprang into a flurry of activity. Lo and behold, here is the magic bullet that solves all the woes of our planet while we go about business as usual.  We just have to plant a bunch of trees. One of the authors of the paper claimed that it would take less than 300 billion dollars to do this. That is one-third of the annual defense budget of the USA; a relatively small amount of money to save the planet. The World Economic Forum started the 1 trillion trees initiative with the support of government leaders and corporations from around the world.

Finally, we were climbing out of the pit that we had dug for ourselves. There is one solution, and the world is coming together to achieve it. Except this was not the silver bullet that we needed. The paper gained immense popularity, and a lot of people learned about it through popular articles, but soon, there was a massive backlash from the scientific community against the claims made by the paper. The solution that sounded too good to be true was, in fact, too good to be true. Over-estimation of carbon storage, consideration of pasture lands, grasslands and savannas as places with tree plantation potential, and an overall exaggerated claim for the efficacy of tree plantation as a mitigation measure were some of the criticisms levelled against the paper. Since then, the authors have made corrections to the paper and responded to criticisms. But the damage was already done.

The silver bullet that isn’t

The conservation advocacy organization Greenpeace has a sentence in their ad campaign against plastic pollution: “If your bath was overflowing, you wouldn’t reach for a mop, you’d turn off the tap.” It conveys the message that we cannot recycle our way out of plastic pollution. We make way more plastic than we can ever hope to recycle. The case with trees is similar – we make way more carbon dioxide than trees can absorb. For instance, on average, a tree can absorb about 48 pounds of carbon dioxide a year. The average annual emission of a US citizen is about 16 tons of CO2. It would take more than 700 trees to absorb just a year’s worth of emissions of one US citizen. Add to this the fact that a newly planted sapling will take many years before it can reach its full carbon sequestration potential. We start to see the problem here.

In the discussion about global warming, there is one factor that is often underappreciated – the reflectiveness of the Earth to sunlight. The more light Earth reflects into space, the less energy reaches the Earth’s surface to heat it, and the cooler the Earth gets. An interesting consequence of this is that reducing sulfur pollution from ships and developing countries can accelerate global warming, because the pollutants help the Earth reflect more sunlight.      

Trees are rather dark and do not reflect a lot of light. On the other hand, snow and ice are extremely reflective and help to keep things a bit cool on Earth. Planting trees in places that have snow and ice for a large part of the year can make the overall landscape darker, leading to a greater absorption of light and subsequent warming. In fact, Colossal, the company behind the creation of woolly mice and the alleged de-extinction of the dire wolves, has put forth a wild proposal. They want to bring back large herbivores like the woolly mammoths and woolly rhinoceros that disappeared thousands of years ago to reduce tree cover and bring back sprawling grasslands in the snow-covered regions of the world. This will increase the reflectivity of the planet, thereby cooling it down.

Reflectivity of the Earth and surface temperatures. Courtesy: Luke Stone, opensnow.com

Even in regions of the world that do not have a lot of snow, trees are not always an effective mitigation measure for climate change. Planting trees in grasslands and savannas, which naturally do not have many trees, can lead to the loss of carbon stored in the soil. These ecosystems generally have a lot more carbon stored below ground than forested ecosystems. Disrupting these ecosystems by planting trees can lead to more carbon loss than gain over time. In addition to this, planting trees in these naturally treeless landscapes can harm the unique biodiversity of these ecosystems.

Greenwashing

The European Union provided funds to make a canopy walkway in Hungary. The politicians in charge of the project took the money, built a canopy walkway, and then cut all the trees and sold them. Courtesy: Akos Stiller for the New York Times

Tree plantation in Turkey. Courtesy: Daily Sabah

Despite all this, it has become fashionable for governments and corporations across the world to pompously announce and implement massive tree-planting campaigns. Many authoritarian leaders (of countries like India, Hungary, Turkey and Saudi Arabia) use these grandiose projects to bolster their image. These projects are relatively cheap and easy to implement, can garner a lot of publicity, and are generally an easy way to tick the environmental checkbox. What does not garner as much public attention is the fate of the saplings. More often than not, most of the saplings in these afforestation drives die due to the harsh conditions of the sites that they are planted in, making the plantation a waste of time, effort, money, seeds and water. The plants used in these campaigns are often fast-growing, non-native species planted in grasslands, which can adversely impact the local water table and livelihoods.

Deadly distraction

The harm done by such thoughtless plantation projects is not just the waste of resources. It distracts us from the most important aspect of climate mitigation – cutting emissions and preventing further deforestation. It allows us to plant a sapling, pat ourselves on our backs and sleep easy at night when we should really be squirming in bed, worrying about a way out of the mess we have created for ourselves. It gives us a false sense of safety – that we have planted this tree, and now everything will be alright. In the worst cases, reforestation has been used to justify the deforestation of old-growth forests. Governments and corporations act like this is a harmless transplant of an entire forest to a place of convenience, when in reality, the newly planted forest will take centuries, if not millennia, to store as much carbon as an old-growth forest. And that is if the saplings survive to become trees.

Maybe the thoughtless tree plantations by big actors and corporations come from a genuine concern about the planet, but they are misguided due to ignorance. Or maybe it comes from a place of malice – it suits the powers-that-be to do lip service to the environment by announcing big numbers, one-time spending of small sums of money, and go about their lives without doing anything meaningful. It allows big polluters to keep polluting and big deforesters to keep deforesting without any consequences.

What should we do then?

This is not to say that we should stop all tree planting today. Planting trees is useful for many reasons, like conserving biodiversity, reducing air pollution and reducing soil erosion in addition to carbon sequestration. We need to do it carefully. We must plant species that are native to the region and make sure they survive for many years after planting. But when it comes to CO₂ emissions, tree planting plays only a supporting role to that of cutting emissions. Shifting to cleaner energy sources like solar, wind and nuclear power and introducing incentives to cut emissions in the transportation sector (eg, electric and hydrogen cars) and food production (eg, reducing meat consumption) should be of the highest priority.

Next time you hear about a massive afforestation drive, delve deeper. Ask questions like “Is this place supposed to be a forest?”, “Are the species being planted native to the area?”, “Are there systems in place to ensure the continued survival of the saplings?” and more importantly, “Is this being used as a justification to cut down forests elsewhere?” and “This is all amazing, but are we doing something to reduce emissions?” We must let the people in power know that we are not falling for this trick. We should not go for the mop before we turn off the tap.