The global landscape: outlook on a worldwide forest transition

Background/Question/Methods

The decline of the Earth’s forest cover and other natural habitats has been a subject of great concern in recent decades. According to the Food and Agriculture Organization of the United Nations (FAO), the global forest cover was reduced by more than 70 MHa since 1990, an area larger than France and roughly 0.5% of the global land area. The main driver of deforestation is agricultural expansion. Despite the apparent demise of the world’s forests, over the last two centuries many countries, particularly in the industrialized world, have experienced a forest transition (FT); that is, a transition from a period of shrinking forest area to a growing one. Most studies of the FT and forest decline focus on spatial scales at the national and sub-national levels, and on temporal scales of a few decades, but there are some important notable exceptions. In particular, these studies have focused on policies and drivers that could potentially either trigger or inhibit a global forest transition in the future, but few quantitative claims have been made pertaining to the timing of the forest transition and to the ultimate scale of deforestation. Here, we develop a mathematical model to address these issues.

Results/Conclusions

We show that the world food equation accounts for almost all of the land use changes that have occured during the past millenium. Our model fits surprisingly well historic data on forest cover, human population and agricultural yield dynamics. We extrapolate on these findings to postulate conditions under which a global forest transition may occur. We find that under most circumstances a forest transition is not likely to occur without radical new advancements in agricultural technology. However, if agricultural yields and per capita consumption continue to increase as they have in the last half-century, then a forest transition may occur within the next century, depending on the level to which per-capita food consumption increases during the same period. We discuss that reducing food wastage and consumption is just as effective for land sparing as is increasing yields.