Trees: The silver bullet for fighting climate change?

By Laura Nikinmaa & Maria Schlossmacher

International climate action and therefore climate negotiations are not only about fossil fuels. Forest conservation or forestations became strategies that are (sometimes more and sometimes less) acknowledged around the globe and strategies that are here to stay. The Paris Agreement promotes forest management as a pathway towards halting climate change through the reduction of CO2 emissions. At the end of the climate negotiations, more than 50 countries have pledged to protect existing forests and add tree cover in order to reduce greenhouse gas emissions. However, things might not be that simple.

Science writer and reporter Gabriel Popkin recently released an article in NATURE with the provocative title How much can forests fight climate change?”. In his text, he examines several studies arguing that trees do not only influence the climate in one direction. Planting trees in order to take more carbon out of the atmosphere is a highly practical way to combat climate change – as long as the trees are planted in the right place. In boreal forests for instance, forests do cool the climate, so reforestation there is one crucial and applied way to meet the climate goals. However, the question how big of a role forest have in fighting climate change is at the same time diverse and complex. Although forests suck carbon dioxide from the air, they also affect the climate in various ways. For example, trees absorb and reflect light differently. The light-green broadleaves reflect more sunlight back to the atmosphere than the dark conifers and therefore have more cooling effect during the summer. All the trees emit chemical compounds that affect the climate in different ways: some cool the climate, some make it warmer. Planting trees in tundra might not be efficient when aiming at cooling the climate.

Popkin illustrates the hot debate on the topic amongst the scientists. Some argue that questioning the positive-only effect trees have on climate might dilute reforestation and forest management policies or – in the worst case – lead to more deforestation, this time in the name of climate. In contrast to this, the other side of the debate insists that trees have a much more complex and uncertain impact on climate, and that planting them in a wrong place might not support the efforts of combating climate change. However, it is not all dispute and quarrel: scientist agree that forests are good for the environment. Nobody denies the role of trees when it comes to biodiversity protection, and research does not suggest cutting down existing trees. And no matter in which direction scientists argue, they are eagerly waiting for more data coming from long-term studies, for instance from the Amazon, where researchers are tracking the gases and chemicals that trees emit and absorb.

To sum it up: Trees and forests do provide a crucial part of the solution when it comes to  mitigating climate change. They help us  to adapt to the global challenges we are all facing. We need to manage our forests properly to be more resilient to the changing climate. Reducing trees to their climate-limiting capabilities, will not do them justice.

Image by @Aris Sanjaya/CIFOR

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