ENVIRONMENTAL AND NUTRITION OUTCOMES - Food Security, Food Prices and Climate Variability - page 157

• reductionsinbiodiversity;
• changesinlanduseandecosystemfunction;
• alterationsinthewaywildlife,domesticatedanimalsandhumansinteract;
• climatechange.
The transformation of the natural world has been done to serve human needs. These changes
have led to enormous increases in the amount of food available per capita, allowed access to
minerals and metals needed for industrial activity, increased access to energy and water sources
and allowed harvesting of all manner of renewable resources, from trees, kelp forests, shellfish,
to a wide variety of fish stocks (Kates et al ., 1990). This transformation has allowed the human
population to increase exponentially while simultaneously increasing the standard of living
and reducing the poverty rate (Myers and Patz, 2009).
The Millennium Ecosystem Assessment focused attention on the damage all this develop-
ment has done to ecosystems around the world, stated that without a change in the way
people used natural resources, it was likely that the progress seen in human welfare over the
past centuries could not be sustained (Reid et al ., 2005). The accelerating degradation of
natural resources and ecosystems drives an urgent need to alter policies to ensure that the risk
of catastrophic changes to ecosystems is averted. As ecosystems transform, they become more
vulnerable to perturbations of climate, reducing their resilience and productivity. The assess-
ment brought together literature on the likely impact on human health caused by degraded
resources, and focused attention on the impact these changes would have on the poorest and
most vulnerable groups. Researchers began focusing on providing quantitative evidence that
links environmental change to human health, an effort that is still ongoing.
Environmental change and nutrition
Food security and nutrition linkages are strong, particularly for the need to provide adequate
calories and protein to the world's growing population. Because most chronically hungry
people in the world are also among the over one billion people who live in absolute poverty,
increasing global food production is only part of the solution (Myers and Patz, 2009). Many
of the food insecure are too poor to access global food markets and depend on local food
production. Local ecological constraints can drive hunger, disease and death in these poor
communities, even if global food production exceeds demand in the aggregate (Myers and
Patz, 2009). Nutrition is the intake of food, considered in relation to the body's dietary needs.
Good nutrition, or an adequate, well-balanced diet combined with regular physical activity,
is a cornerstone of good health. Poor nutrition can lead to reduced immunity, increased sus-
ceptibility to disease, impaired physical and mental development, and reduced productivity
(WHO, 2013).
Soil infertility is already driving reductions in yield in regions that do not use adequate
fertilizer and can significantly impact local food production (Sanchez, 2002). Rates of land
degradation in agricultural regions are not well known, but recent work on erosion rates
indicate that modern, mechanized tillage agriculture is causing erosion at rates that exceed soil
formation by one to two orders of magnitude (Montgomery, 2007). The long-term impact
of these changes is poorly understood.
For example, in savanna regions of Africa, land degradation has long been conceptually
difficult to assess, since in many non-equilibrium systems the likelihood of the transition of