Preface

Land degradation is a major concern globally and is accepted as one of the most serious ecological and socioeconomic problems worldwide. The subject has received and will con‐ tinue to receive a lot of international attention in the twenty-first and twenty-second centu‐ ries, respectively. Available data show that in dry areas of the world, for example, degraded lands amount to 3.6 billion ha out of 5.2 billion ha and that the global extent of land degra‐ dation by all processes is about 1.9 billion ha. Furthermore, the current rate of agricultural land degradation worldwide by soil erosion and other factors is leading to an irreversible loss of productivity. It is estimated that human-induced soil degradation has affected more than 24% of the inhabited land area and the values of individual continents range from 12% in North America, 19% in Oceania, 26% in Europe, 27% in Africa, to 31% in Asia (Lal, 1993).

Despite the use of different methods and techniques to halt the problem, the world contin‐ ues to witness loss of vegetation cover, loss of land productivity, increased soil erosion, and increased poverty. The problem is more serious in developing countries where the majori‐ ties depend on natural resources for livelihood. Understanding the relationship between land cover and other environmental processes could be an eye-opener to scholars, land-use planners, and land users in addressing the problem and restoring and/or conserving de‐ graded lands.

This book highlights the scope and extent of land degradation and desertification and landatmosphere interaction in both developing and developed world and how contemporary methods and techniques can play a great role in understanding and mitigating the problem. The methods and techniques used among others include remote sensing, GIS, modelling, and the use of land quality.

The contributors in this book are renowned scholars and researchers with vast experience in the disciplines of land degradation and desertification. I hope that this book will be a very useful reference material to environmentalists worldwide who wish to see the world being a better place to live in now and in the future.

> **Abiud Kaswamila** Professor of Land-Use Planning Department of Geography and Environmental Studies The University of Dodoma Dodoma,Tanzania

**Remote Sensing and Modeling**
