Tropical forests are losing their capacity to absorb C02

ProPopulus Team

Tropical forests in Africa and Amazonia will stop absorbing carbon dioxide of the atmosphere by 2035, according to a new research published by Nature on March 4^th, that analysed 565 forests over the last 30 years. The conclusion is nothing but saddening and alarming. Until now, scientists had developed their climate models under the premise that carbon sequestration by tropical forests would remain steady, but this new study demonstrates that it is not so. Consequently, climate models must be re-evaluated, and new ones drawn up.

Tropical forests have a crucial role in tackling climate change: they act as global carbon sinks, taking CO₂ from the atmosphere and storing it in the trees’ biomass. The research published by Nature, in which almost 100 institutions around the world took part, monitored the evolution of over 300.000 trees in Africa and Amazonia since 1983, revealing that tropical forests reached their maximum CO₂ absorption capacity in the 1990s. By the year 2000 it had fallen by a third.

In the 1990s virgin tropical forests removed 17% of humanity’s carbon dioxide emissions worldwide from the atmosphere, but only 6% in the 2010s, “because the pan-tropical weighted average per unit area sink strength declined by 33%, forest area decreased by 19% and anthropogenic CO2 emissions increased by 46%”, says the article.

High temperatures and droughts also have a negative effect on trees since they slow down their growth and can even kill the trees.

According to the researchers, tropical forests are undergoing a change and will stop being global carbon sinks to become CO₂ producers. This effect will take place faster in the Amazon tropical forest than in African forests. South American forests suffer higher temperatures, more sudden temperature changes and more regular and severe droughts, which accelerate the decline. According to the study, by the mid-2030’s, the Amazonian forests will become a source of carbon dioxide.

Thus, it is becoming evident that the tropical forests’ capacity to be carbons sinks is declining and it will occur decades sooner than the most pessimistic models predicted.

Planted forests on the other hand, are increasing worldwide and they could be a way to help counteract the effects of a decrease in tropical forests CO₂ consumption capacity. A new paper in Science, titled “The global tree restoration potential”, shows how much additional tree cover could exist outside of existing forests and agricultural and urban land, stating that there is potential for 0.9 billion hectares.

Creating and implementing new policies and aids to boost planted forests in Europe and around the world are becoming a must in the global task of tackling climate change.