Spatial scenario of tropical deforestation and carbon emissions for the 21st century

Abstract

Tropical forests are disappearing at an alarming rate due to human activities. Here, we provide spatial models of deforestation in 92 countries covering all the tropical moist forests in the world. Our results question the global effectiveness of protected areas in decreasing deforestation and allow reinterpreting the impact of roads on deforestation in terms of both accessibility and forest fragmentation. Using our models, we derive high-resolution pantropical maps of the deforestation risk and future forest cover for the 21st century under a “business-as-usual” scenario based on the deforestation rates observed in the 2010s. Under this scenario, 48% (39–56%) of tropical moist forests are expected to disappear during the course of the 21st century, and many tropical countries will have lost all their forests by 2100. The remaining forests in 2100 will be highly fragmented and located in remote places. We also show that future deforestation will likely concern forests with higher carbon stocks, and hence that carbon emissions from tropical deforestation are expected to increase (up to 0.583–0.628 Pg/yr in 2100). Combined with the decreasing carbon absorption (down to 0.312 Pg/yr in 2100) due to the decrease in forest cover, tropical moist forests will likely become a strong net carbon source in the 21st century.Significance StatementUnder a business-as-usual scenario of deforestation (i.e. projecting the 2010–2020 deforestation rates at the country level in the future), three quarters of the tropical moist forests that remained in 2000 will have disappeared by ca. 2120, 2160, and 2220 in Asia, Africa, and America, respectively. By 2100, 41 tropical countries, plus 14 states in Brazil and one region in India, will lose all their tropical forests. Remaining forests will be highly fragmented and concentrated in remote areas (far from roads and towns), preferentially in protected areas, and at high elevations. Future deforestation will likely happen in forests with higher carbon stocks. In the absence of change in the deforestation rates, increase in carbon emissions from deforestation and decrease in carbon absorption due to reduction of forest cover will make tropical forests a major carbon source in the 21st century.