SDG 15 aims to protect, restore, and promote the sustainable use of terrestrial ecosystems and forests, to halt and reverse land degradation, and to put a stop to loss in biodiversity. 

Forests are crucial for sustainable development. Covering almost one third (31 percent) of the Earth’s land surface, they offer a habitat to over 80 percent of all terrestrial species and are key to preserving biodiversity. Forested watersheds and wetlands supply three quarters of all accessible freshwater in the world. Worldwide an estimated 300 to 350 million people live in or close to forests and largely depend on them for their livelihoods, and over a billion people rely on forests for employment, forest products, and contributions to livelihoods and income. Many of those living in extreme poverty are highly dependent on forests for their livelihood. 

Forests also play a key role in the mitigation of climate change, removing an estimated 16 billion tonnes of carbon dioxide (CO2) from the atmosphere annually, equaling about half of the annual CO2 released from burning fossil fuels.  

As visualized in this map of the 2023 Atlas of Sustainable Development Goals, global tropical rainforests sequester more CO2 than boreal and temperate forests combined. CO2 emissions caused by loss of trees, for instance due to logging or wildfires, averaged 8.1 billion tonnes annually over the past 20 years, which is roughly half the CO2 that is removed from the atmosphere by forests. The CO2 released as a result of tree cover loss partially offsets the removal. The net effect is a removal of 7.6 billion tonnes of CO2 annually, which is about one fifth of the total global CO2 emissions from other sources. 

Deforestation is high in tropical rainforests. This causes the tropical rainforests in Southeast Asia to be a net source of CO2 emissions, with the remaining trees unable to absorb the CO2 released by forests lost in a given year. The rainforests in the Amazon and Congo river basins are still a net “sink,” meaning they absorb more CO2 than the amount of emission caused by forest loss. 

To slow climate change, critical steps include protecting forests, reforestation, and afforestation, as well as restoring degraded forests. These measures can increase the amount of CO2 sequestered by forests and reduce emissions caused by deforestation and forest loss. 

Explore the data stories and visualizations of the fifteenth chapter of the Atlas, to see how forest area is unequally distributed among regions, how deforestation and forest degradation undermine sustainable development, and how the deforestation rate has changed over time.