The Role of Trees and Forests in the Earth’s Climate System

Frederik Vroom, Carbon Manager, Tree Canada

At Tree Canada we celebrate the beauty and influence of trees on our urban living environment — but trees and forests also play a crucial role at a global scale. Our planet’s climate is directly influenced through the composition of the atmosphere.

In 1897,a Swedish professor called Arrhenius tried to find an explanation for the ice ages and was able to prove that the amount of carbon in the atmosphere explained the variation in climate on our planet over time, what we call “ The Greenhouse effect”.

Since then scientists have been able to collect data and refine their understanding of how our planet and its climate has evolved. One of the main influences on the Earth’s climate is the carbon cycle. The carbon cycle consists of the carbon stored in soils, the Earth’s crust (including fossil fuels), vegetation, oceans, atmosphere and exchange of gasses between these so-called carbon pools.climate-change

Over the last 5000 years, humans, through their activities, have influenced the atmosphere by increasing the amount of carbon dioxide. Through land use and the burning of fossil fuels we annually played a small but significant part in changing the composition of our atmosphere; however, the use of fossil fuels is not the only reason for human induced increase of carbon dioxide in the atmosphere. Collectively, humans have also removed large amount of forests and converting them to grass and cropland. Scientists estimate that 33% of all greenhouse gas emissions that are attributable to humans come from land use conversions. At the moment 12.5% of annual human-caused greenhouse gas emissions are from land use[2].

By understanding the problem – that an increase of carbon in the atmosphere results in higher global temperatures distorting our climate and ecological processes – we can also find solutions.

We must reduce our emissions from all sources: by using less fossil fuels and stopping the conversion of our forests[3] to pasture and cropland. But we can also work on increasing and restoring the carbon accumulated in forests. Reforesting areas previously used for agriculture or uncultivated land will sequester carbon from the atmosphere and store it in the trees and soils. Not only does this contribute to reducing the carbon content of the atmosphere it will also provide the other valuable benefits of forests including: water retention, reduction of atmospheric pollution, provision of animal habitat, and rebuilding of soils.

Tree Canada believes it is important to share and spread the knowledge of the important role of our trees and forests. National and international programs are being developed to support better land use and protection of carbon stocks[4][5].  Tree Canada has developed a program to help establish forests and to increase sequestration as part of the solution.

Our Grow Clean air program provides individuals and organisations an opportunity to contribute to this effort. We calculate how much carbon is being sequestered by the trees planted, and allow those that support these reforestation efforts to compensate their emissions of travel or events. This is one solution of the many actions needed to be taken to shift our thinking and ways of practicing good business.

Further reading:

[2] Carbon emissions from land use and land-cover change

Houghton R.A et al 2012 

[3] Reducing emissions from deforestation and forest degradation and the role of conservation, sustainable management of forests and enhancement of forest carbon stocks in developing countries (REDD-plus)

[4] United nations program to stop deforestation

[5] British Colombia government initiatives to include forests in their climate action program


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