The philosophy behind achieving sustainability through scarcity was expressed by Rev. Thomas Malthus who theorised since the Earth's resources were finite while population grew exponentially, the world would inevitably run out of resources. The Malthusian theory is a favourite theme of environmentalists and other doomsayers. Eventually the Earth, depleted of resources, will enter a new dark age in which human existence will be under constant threat. To be sure, there has been famines, which cause enormous suffering, for reasons of weather, natural disasters and geo-politics. But the problem is not our inability to grow enough food. It's uneven food distribution and our inability to get food to people who need it.
The theory of unchecked population growth itself overwhelming the capacity of the Earth to sustain life has also been discredited. As nations develop and their economies grow, birth rates decline. This because parents no longer feel the need to have large families to provide for their old age, which liberates women from their traditional role as child-bearers to enter the workforce. Projections are the Earth's population of 6.5 billion today will grow to 9 billion by 2050 and stabilize at 11 billion by 2200. Considering global standards of living continually rose as the Earth's population increased to its present level, there's reason for optimism about its capacity to sustain 11 billion people two centuries from now. This isn't to minimise human suffering or suggest there will not continue to be famines, disease and poverty. But it does refute the idea population growth itself poses an existential threat.
Today's doomsayers make the classic mistake of predicting the future based on the present.
The production of food has been the domain of the farming and fishing communities from beyond history. The strong links that farmers had to their land was severed by the introduction of industrial farming and the ‘Green Revolution’. Traditional knowledge that has sustained humanity for over three thousand years was discounted and replaced with a high energy dependent, biodiversity poor, toxic method of farming which has been supported and financed by the capitalist system. A Consultative Group on International Agricultural Research paper explains “The primary objective of agriculture is not to enhance the resource base on which agriculture depends, and certainly not to enhance environmental quality." http://groundviews.org/2011/06/18/right-to-food-ecologically-based-agriculture/
‘Modern’ agriculture discounts traditional approaches. In Sri Lanka the tradition of selective hand weeding resulted in a crop increase of over 400% in Rice paddies. In Africa It has been shown that a 79% increase crop increase has been obtained through cultural and ecological approaches to agriculture. Tree planting methods have changed the environments of thousands of hectares of Sahelian desert to more sustainable ecosystems in Tanzania, Senegal and Mali. Projects in Sri Lanka, Guatemala, Cuba, Ecuador and Viet Nam have increased both crop and non-crop biodiversity by over 150%. Agrarian societies with long histories, posses the credibility of having sustained themselves successfully under the rigor of survival in a natural world. The concern for the future is that the model chosen for sustaining future global agrarian society is an energy and resource demanding production system. it is becoming evident that the present resource expensive system of agrarian production will become increasingly more expensive to maintain. This phenomenon is a result of increasing input costs and decreasing productivity of the land. The predicted global climate effects will also make large areas of monocultures risky.