Are trees efficient in capturing CO2 and fighting climate change?

Forests, together with oceans, are by far the two main and best carbon capture systems we know. But we only know how to use forests to capture more CO2 and slow down climate change.

Trees extract CO2 from the air and convert it into oxygen and plant material through photosynthesis. This process involves plant cells that convert the carbon from carbon dioxide into a solid form of sugars (the carbohydrates glucose and starch) that can be stored in leaves, stems, trunks, branches, and roots, to contribute to tree growth. Oxygen is released back into the atmosphere as a by-product of photosynthesis, which animals depend upon for survival.

Trees have evolved for millions of years to perfect this photosynthesis process. It is estimated worldwide that there is a total carbon sink of 2.4 petagrams of carbon per year. It makes forests, together with oceans, by far the 2 main and best carbon capture systems we know. Unlike with the oceans, it's easy to plant trees at a mass scale and increment the total amount of CO2 we can capture.

In 2019, a scientific report by the Crowther Lab concluded that planting trees is possibly the cheapest and most effective way to fight climate change.

The Paris agreement (COP21) recognizes that carbon capture is essential to keep global temperature rise below 1.5ºC above pre-industrial levels, a task the reduction of emissions alone could not achieve.

Carbon capture alone (by planting new trees) would not be sufficient to fight climate change. But, in the race against irreversible and irreparable damages (the tipping points), planting trees can help slow down the climate change process, which gives us more time to complete our transition to a sustainable society.