Introduction

Changes in land use and land cover constitute one of the major drivers of Earth system transformation (Foley et al. 2005; Turner et al. 1990). Land not only provides major resources such as food and forest products, it also interacts with the Earth system in complex ways. Managing the land, so as to continue our access to resources while minimizing Earth system degradation, has become one of the major challenges of this century.

Today, nearly one-third of the world's land is occupied by agriculture; forests make up another third; savannas, grasslands, and shrublands constitute a fifth of the land; the remainder is sparsely vegetated or barren, with urban areas occupying a very small portion (Ramankutty et al. 2008; Potere and Schneider 2007). Most croplands have expanded at the expense of forests, while pastures have primarily replaced former savannas, grasslands, and shrublands (Ramankutty and Foley 1999). Currently, the most rapid changes in land— deforestation and agricultural expansion—are occurring in the tropics (Lepers et al. 2005).

These changes are the result of meeting the resource demands of a growing population. Food, freshwater, timber, and nontimber forest products are all valuable resources that are needed by human society and provided by the land. Can the land continue to provide enough resources for a growing, and increasingly consuming, population? In this chapter, I examine the data on land area, food production, and forest production to assess the recent trends of, and future prospects for, our land resource base.

0 0

Post a comment