From oil palm to sugar to coffee and cocoa, commercial agriculture is expanding across the tropics, destroying valuable tropical rainforests, which store immense amounts of carbon and support half of the Earth’s plants and animals. A new paper published in Conservation Letters entitled, “Guiding Agricultural to Spare Tropical Forests,” identifies more than 125 million hectares (309 million acres) of already-degraded lands across the tropics most suitable for expanding industrial agricultural production over the next 25-50 years. Without continued deforestation, expansion on these degraded lands will keep over 13 billion tons of CO2 from entering the atmosphere to further exacerbate climate change.
For co-author Alessandro Baccini, Associate Scientist at Woods Hole Research Center, “A key point in this analysis is that it not only guides commodity production away from sensitive, high carbon and high biodiversity areas but also provides alternative locations for production, toward lands that are already low in carbon and biodiversity yet still suitable for agriculture.”
The team of researchers from Woods Hole Research Center, RESOLVE, World Wildlife Fund, and University of Minnesota identified degraded land by measuring the amount of carbon stored in trees in tropical rainforests. Called Above Ground Carbon Density (AGC), the AGC of intact tropical rainforests is approximately 250 metric tons per hectare (2.5 acres), a figure that decreases as trees are cut down. Areas considered in this study to be degraded were those with an AGC of 40 metric tons or less, a value agreed-upon by various organizations and oil palm producers as a guideline to avoid clearing high-carbon forests. The researchers added several safeguards that excluded protected areas, steep slopes, existing urban areas and agriculture, and sites with rare habitats or species found nowhere else from consideration. Of the 125 million hectares, about half is in tracts larger than 5,000 hectares and below 500 meters elevation, which are prerequisites for commercial-scale oil palm production, the fastest growing industrialized commodity crop in the tropics.
“The simplicity and transparency of this easily-monitored metric could prove useful to producers, governments, investors, environmental stewards, and consumers and enhance good governance in tropical regions,” said the study’s lead author, Eric Dinerstein, Director of RESOLVE’s Biodiversity and Wildlife Solutions program and senior fellow at the World Resources Institute.
Over the last century, industrial-scale agriculture has expanded rapidly into tropical rainforests. The loss of trees degrades the structure of the forest – far fewer species can survive in areas after the trees have been cut – and the clearing of tropical rainforests causes roughly 10-15% of global human-caused carbon emissions. Redirecting the planting of oil palm and other crops to areas already damaged by logging would substantially lower carbon emissions and the loss of rainforest species. Production of three key crops – oil palm, sugar cane, and natural rubber – alone is projected to increase 17% to 29%, and the estimated 60-66 million hectares (148-163 million acres) needed to accommodate the increase could easily fit within the degraded, low-carbon lands identified in this study for years to come.
In commenting on the analysis, Nigel Sizer, Global Director of World Resources Institute’s Forests Program said, “The study’s concrete recommendations will help to guide commodity producers, some of which are already taking steps to reduce their environmental footprint. By redirecting projected expansion to areas of lower conservation value, producers can help ensure more responsible and sustainable supply chains.”
WHRC is an independent research institute where scientists investigate the causes and effects of climate change to identify and implement opportunities for conservation, restoration and economic development around the globe.