Trees to Combat Global Warming

‘The restoration of trees remains among the most effective strategies for climate change mitigation.’ This is the opening line of a report called ‘The Global Tree Restoration Potential’ published in July this year in the Science journal.

The study measures the cover of the forest canopy rather than the area of the circumference of the tree trunk. The forest canopy is made up of the tree crowns in a forested area, regions or globally. This is effectively the green tree cover as seen from the sky. The study also takes into account that there are different forest types in which trees are closer together or more sparsely spread.

The process of photosynthesis is what enables a tree to live and grow. Water is absorbed by the tree’s roots and is carried to the leaves where it comes in contact with the layers of chlorophyll. Simultaneously, air containing carbon dioxide is absorbed by the leaves through the leaf pores. It is at this point that the extraordinarily important chemical reaction takes place that we call photosynthesis. Water is broken down into its oxygen and nitrogen elements, and it combines with carbon dioxide in the chlorophyll to form glucose.

This oxygen is released by trees and becomes a part of the air we breathe, while the glucose is carried to the other parts of the plant as nourishment. This essential process is what creates ninety five percent of the wood mass in a tree, and photosynthesis by trees and other plants is what contributes nearly all the oxygen in the air we breathe.

The study has developed unique modelling techniques based on an analysis that includes the direct measurement of the tree cover in protected areas that are free from human activity, based on around 80,000 photo-interpretation measurements. Amongst the critical factors taken into consideration are climatic conditions, such as rain, humidity, weather and temperature ranges as well as the topography and the soil qualities pertaining to these areas. This model was then used to predict areas worldwide where forests could be grown. The Food and Agricultural Organisation of the United Nations defines a forest as land of at least 0.5 hectares covered by at least 10% tree cover and without agricultural activity or human settlements.

The study reveals that there is in fact a huge potential for rewilding large areas around the globe as forests. The study goes much further than arguing in favour of reforestation. It actually identifies the precise areas around the world where this can take place successfully. The areas identified are areas with sparse vegetation, grasslands and land with degraded bare soil amounting to 1800 million hectares that would translate into 900 million hectares of actual tree cover.

Another extremely interesting finding is that of the 900m ha, 53%, or 479m ha, are found in just 6 countries, Russia (150m ha), USA (103m ha), Canada (78m ha),  Australia (58m ha), Brazil (50m ha) and China (40m ha).

A 2018 report by the Intergovernmental Panel on Climate Change (IPCC) said that the planting of 1 billion hectares of additional forest would be needed to curb global warming. Following this study on restoration potential we can see in concrete terms that this target is definitely achievable.

The study emphasises that “The restoration initiatives must not lead to the loss of existing natural ecosystems, such as native grasslands, that can support huge amounts of natural biodiversity and carbon.”

The vegetation in the potential restoration areas described could store 205 billion tonnes of carbon when restored to the level of existing forests. Let’s put this number into perspective. The current level of carbon in the atmosphere placed there by human activity is about 300 billion tonnes. We are currently releasing 37 billion tonnes of carbon into the atmosphere annually. The reforestation of the planet needs to start with extreme urgency coupled with a substantial reduction in annual carbon emissions.

As weather conditions become more extreme as a result of global warming. we are really running the clock down to the point of no return. The reforestation estimates presented by this study are calculated under current climatic conditions. With the advance of global warming the greatest forest losses will be in the tropics where the forests are densest and therefore where the tree cover is greatest – this is bad news as much less carbon would be absorbed.

The potential land available for reforestation will also decrease the more time passes, as reforestation could no longer be carried out in the tropics because of future weather conditions. It is estimated that humanity’s inaction will result in global tree cover that can potentially be restored decreasing by 223m ha or 25% by 2050. This translates into losing the potential to take 46 billion tonnes of carbon out of the atmosphere.

The study concludes that “This places ecosystem restoration as the most effective solution at our disposal to mitigate climate change.”

It clear that the natural solutions to the problems of extreme weather, global warming and the mass extinction of species (land and marine animals and plants) are there for all to see. There are two principal obstacles that stand in the way of the survival of sentient life on Earth. The first feeds into the second.

Firstly we have humanity’s ignorance of the self-evident fact that people are part of nature. We stand or fall with nature. It is difficult to comprehend how on the one hand parents undergo hardship and work and strive hard to give their children the best future possible and on the other hand with their lifestyle, and the belief systems they adhere to, they are robbing there children of the very future they need to exist.

The second obstacle is what is euphemistically call ‘the lack of political will to act’. We must stop voting for people who do not fully understand that we are part of nature and that we must stop degrading and must urgently restore the ecosystems that our very existence depends on.

An ignorant person is able to learn but lacks knowledge or is uniformed. On the other hand a stupid person is unintelligent and in a state of stupor and is incapable of acquiring knowledge, let alone act upon it.

I delved into these definitions to say that we, the common people, may have been to an extent ignorant and therefore easily led in the past. We are however now on the fast track acquiring knowledge about the real state of the world and how we have been led by the nose for thousands of years. On the other hand our representatives, their entourage and cronies and the political and business elites worldwide are mostly just stupid – I say this in the kindest way possible. Their stupidity arises from the fact that they are unable to see the existential crisis we are all facing as they follow their petty minded greed and misguided strategies.

In the relatively short period of time since our emergence on this Earth, an odd two hundred thousand years ago, we have brought a temperate and welcoming Earth to the point of collapse. The responsibility to act without delay and hesitation to remedy this situation lies with each and every one of us. The time of followers is over. Enter the age of leaders.

Main Source: ‘The Global Tree Restoration Potential’ published in July 2019 in the Science journal. Authors: Jean-Francois Bastin, Yelena Finegold, Claude Garcia, Danilo Mollicone, Marcelo Rezende, Devin Routh, Constantin Zohner, Thomas Crowther.