As trends in investment in agriculture in poorer countries edge up, the combined effects of climate change, energy scarcity and water paucity now demand that we radically rethink our agricultural systems.Business as usual will not do. An unprecedented combination of pressures is emerging to threatenthe health of existing social and ecological systems. Population and income growth, urbanization,changing consumption patterns, stagnant yields, demand for land, feed, and biofuels, and theimpact of climate change, biodiversity loss and environmental degradation are driving limited resources of food, energy, water and materials towards critical thresholds.The combined effects of climate change, land degradation, cropland losses, water scarcity and species infestations may cause projected yields to be 5-25% short of demand by 2050, and 600 million additional people could be affected by malnutrition as a direct result of climate change by 2080.The current food system is failing to feed the world adequately, and widespread poverty and inequality mean that many are too poor to access the food that is available. Despite there being enough food for everyone, an estimated 925 million people are hungry and another billion suffer from 'hidden hunger' and micro-nutrient deficiency, while 1.5 billion people are overweight and obese, and a third of all food for human consumption is lost, spoiled, or wasted.Productivity gains from the Green Revolution have not always been sustainable over time and often came at a high social and environmental cost, including the depletion of soils, pollution of groundwater, biodiversity loss, high household debts, and increased inequality among farmers.With case study evidences from Bangladesh, Cambodia, Indonesia and Pakistan, and citing global studies and surveys, this report argues that agro-ecology -- or ecological agriculture -- offers tools that can help the poorest communities to develop new, affordable, dynamic, low-carbon and locally-adaptable models of agricultural development to meet these multiple challenges. Recent research shows that agro-ecology is highly productive and holds great promise for the roughly 500 million food-insecure households around the world.Agro-ecology is the application of ecological science to the study, design, and management of sustainable agriculture, and it is based on practices such as recycling biomass, improving soils through green manures, mulches and bio-fertilisers, minimising water, nutrient and solar radiationlosses, intercropping, mixed farming with a variety of crops and farm animals, and minimising the use of chemical fertilisers, herbicides and pesticides
