Human Overpopulation and Food Security: Challenges for the Agriculture Sustainability

Introduction

Agriculture is the oldest way where humans interact with natural systems for crop and livestock production by alteration of natural resources (land, water, nutrients, biomass and energy) for their well-being (Dale et al., 2013). It is the world’s largest industry occupying about 38% (including cropland and pasture land) of the Earth’s terrestrial surface (Robertson & Swinton, 2005; Ramankutty et al., 2008; FAOSTAT, 2011; Foley et al., 2011). In addition, it utilizes about 70% of global water withdrawals from freshwater bodies (FAO, 2011). It involves various interrelated activities like land management, settlement patterns, crop selection and livestock production throughout its span (Dale et al., 2013). It supports basic human needs and is governed by human activities (Figure 1) (Robertson & Swinton, 2005). For example, the interrelationship of human and agriculture can be visualized by the present growth of human population (during Industrial Revolution, 1750) followed by increased agricultural production (during Green Revolution, 1950) (Eikelboom, 2013). The present human population of more than seven billion is impending pressure on the capacity of agriculture to fulfil the food requirements without compromising the natural resources for their ability to nourish future generations (Robertson & Swinton, 2005). Moreover, the relative increase in urban population (about 55% of total population) is of more concern in this regard (Figure 2) (Eikelboom, 2013; Milder et al., 2014). A 2/3^rd increase in urban population is expected by the year 2025 (Hamlett, 2011; Eikelboom, 2013). It would cause a pressure on agriculture due to mass transition from producer to consumer category, thus loss of agricultural workforce and production. It may have severe consequences as the present overpopulated world is already facing twin challenges of food security and environmental degradation.

Figure 1.

General overview of the population growth, agriculture and its imperative effects

The environmental degradation has been regarded as the prime cause of collapses of several past civilizations (Ehrlich & Ehrlich, 2013). Therefore, to satisfy the basic demands (food, fibre and fuel) of the ever-growing population and its collapse, an intensive agriculture production is urgently required (Barea, 2015). However, the expansion of intensive agriculture for meeting these demands at the cost of compromised ecosystem services may further lead to severe environmental degradations (Figure 3) (Laurance et al., 2014; Milder et al., 2014). For example, the present agricultural production attained a pace with the present growing population due to various external inputs in the form of synthetic chemicals (especially N-fertilizers and pesticides) (Srivastava et al., 2016a). Such externalized control of agriculture is deleterious to the soil productivity and causes environmental pollutions (Erisman et al., 2013; Seneviratne & Kulasooriya, 2013; Alqarawi et al., 2014; Lal, 2015; Singh, 2015). Therefore, there is a great pressure on agriculture to meet various socio-economic and climatic challenges with minimal environmental impacts (Foley et al., 2005; Bommarco et al., 2013). Moreover, to attain the future food security, the future agriculture production should grow faster than the population growth by adopting resource-intensive agriculture practices (FAO, 2011). Therefore, there is an urgent need for sustainable thinking in agriculture (Srivastava et al., 2016a).