Global tree canopy cover increased by 2.24 million square kilometers (865,000 square miles) between 1982 and 2016, reports a new study in Nature. These new findings contradict earlier studies that reported a continuing net loss of forest cover.

Researchers using satellite data tracked the changes in various land covers to find that gains in forest area in the temperate, subtropical, and boreal climatic zones are offsetting declines in the tropics. In addition, forest area is expanding even as areas of bare ground and short vegetation are shrinking. Furthermore, forests in montane regions are expanding as climate warming enables trees to grow higher up on mountains.

Tree canopy in Europe, including European Russia, has increased by 35 percent—the greatest gain among all continents. The researchers attribute much of that increase to the “natural afforestation on abandoned agricultural land,” which has been “a common process in Eastern Europe after the collapse of the Soviet Union.”

The researchers’ satellite data also confirms the effectiveness of China’s large-scale reforestation and afforestation programs, leading to a tree canopy gain of 34 percent in that country. Declining forest cover in the western United States, meanwhile, has been offset by increased tree canopy cover in the eastern part of the country. The result is that overall U.S. tree cover increased by 15 percent in the study period.

… If the Nature study is correct, the world gained 2.24 million square kilometers rather than lost 1.29 million square kilometers in forest area in the past three decades.

Full story at Reason Online

The study: https://www.nature.com/articles/s41586-018-0411-9

Global land change from 1982 to 2016

Abstract

Land change is a cause and consequence of global environmental change. Changes in land use and land cover considerably alter the Earth’s energy balance and biogeochemical cycles, which contributes to climate change and—in turn—affects land surface properties and the provision of ecosystem services. However, quantification of global land change is lacking. Here we analyse 35 years’ worth of satellite data and provide a comprehensive record of global land-change dynamics during the period 1982–2016. We show that—contrary to the prevailing view that forest area has declined globally—tree cover has increased by 2.24 million km2 (+7.1% relative to the 1982 level). This overall net gain is the result of a net loss in the tropics being outweighed by a net gain in the extratropics. Global bare ground cover has decreased by 1.16 million km2 (−3.1%), most notably in agricultural regions in Asia. Of all land changes, 60% are associated with direct human activities and 40% with indirect drivers such as climate change. Land-use change exhibits regional dominance, including tropical deforestation and agricultural expansion, temperate reforestation or afforestation, cropland intensification and urbanization. Consistently across all climate domains, montane systems have gained tree cover and many arid and semi-arid ecosystems have lost vegetation cover. The mapped land changes and the driver attributions reflect a human-dominated Earth system. The dataset we developed may be used to improve the modelling of land-use changes, biogeochemical cycles and vegetation–climate interactions to advance our understanding of global environmental change.