The agricultural expansion is often explained as a direct consequence of the global increase in food and energy requirements due to the human overpopulation (which in turn has been attributed to agricultural expansion itself), with an estimated expectation of 10 to 11 billion humans on Earth by end of this century. It is foreseen that most of the world's non-agrarian ecosystems (terrestrial and aquatic) will be affected adversely, from habitat loss, land degradation, overexploitation, and other problems. The intensified food (and biofuel) production will in particular affect the tropical regions.
Most modern agriculture relies on intensive methods. Further expansion of the predominant farming types that rest on a small number of highly productive crops has led to a significant loss of biodiversity on a global scale already. In the light of the already occurring and potential massive ecological effects, the need for sustainable practices is more urgent than ever.
The FAO predicts that global arable land use will continue to grow from a 1.58 billion hectares (3.9×109 acres) in 2014 to 1.66 billion hectares (4.1×109 acres) in 2050, with most of this growth projected to result from developing countries. At the same time, arable land use in developed countries is likely to continue its decline.
A well-known example of already ongoing agricultural expansion is the proliferation of palm oil production areas or the land conversion/deforestation for soy bean production in South America. Today's land grabbing activities are often a consequence of the strive for agricultural land by growing economies.
In the beginning of the 21 century the palm oil industry caused a massive deforestation in Borneo with a heavy consequences.
Human population growth has typically been seen as the primary causative factor of other ecologically destructive phenomena. Current human disease epidemics are explored as a function of population size. That human population growth is itself a phenomenon with clearly identifiable ecological/biological causes has been overlooked. Here, human population growth is discussed as being subject to the same dynamic processes as the population growth of other species. Contrary to the widely held belief that food production must be increased to feed the growing population, experimental and correlational data indicate that human population growth varies as a function of food availability. By increasing food production for humans, at the expense of other species, the biologically determined effect has been, and continues to be, an increase in the human population. Understanding the relationship between food increases and population increases is proposed as a necessary first step in addressing this global problem. Resistance to this perspective is briefly discussed in terms of cultural bias in science.
The human population is projected to reach 11 billion this century, with the greatest increases in tropical developing nations. This growth, in concert with rising per-capita consumption, will require large increases in food and biofuel production. How will these megatrends affect tropical terrestrial and aquatic ecosystems and biodiversity? We foresee (i) major expansion and intensification of tropical agriculture, especially in Sub-Saharan Africa and South America; (ii) continuing rapid loss and alteration of tropical old-growth forests, woodlands, and semi-arid environments; (iii) a pivotal role for new roadways in determining the spatial extent of agriculture; and (iv) intensified conflicts between food production and nature conservation
The recent intensification of agriculture, and the prospects of future intensification, will have major detrimental impacts on the nonagricultural terrestrial and aquatic ecosystems of the world. The doubling of agricultural food production during the past 35 years was associated with a 6.87-fold increase in nitrogen fertilization, a 3.48-fold increase in phosphorus fertilization, a 1.68-fold increase in the amount of irrigated cropland, and a 1.1-fold increase in land in cultivation. Based on a simple linear extension of past trends, the anticipated next doubling of global food production would be associated with approximately 3-fold increases in nitrogen and phosphorus fertilization rates, a doubling of the irrigated land area, and an 18% increase in cropland.