Over 10 million families in Mesoamerica (Mexico, Guatemala, El Salvador, Honduras and Nicaragua) are subsistence hillside farmers who grow their own food, primarily maize and beans: They face serious challenges to be able to produce enough to feed their families; most own 0.5-4 hectares of highly degraded hillsides (80% of the soils are degraded) (1), which is farmed using traditional farming techniques of slash and burn or more recently slash and chemicals. They are food insecure, having high levels of chronic malnutrition. It is estimated that farmers make a loss two years out five from maize production and studies show that rural families have incomes less than expenditures (2). It is no accident that this is a region of high levels of food insecurity (3) the rural population face an even more serious threat and that is climate variability. This region is one of the world’s most susceptible to growing climate instability (4) and studies indicate that yields are threatened to decline by 30% over the next thirty years (5).