Marty Matlock, Ph.D., P.E., C.S.E. Professor and Area Director, Center for Agricultural and Rural Sustainability Ecological Engineering Group Biological and Agricultural Engineering Department University of Arkansas Global Agriculture and Water Use

Agricultural use accounts for over 70 percent of all human use of water. Agricultural water use is predominantly from rainfall. Water scarcity is experienced by humans as famine. Demand for food, feed, fiber and fuel from agriculture will double by We have to meet that need without one drop more of water, one hectare more of land. We must freeze the footprint of agriculture Global Agricultural Water Use

World Wildlife Fund Encyclopedia of Earth World Resources Institute The Millennium Ecosystem Assessment Report Sources of Information

Everything is Connected Source: Ricklefs Economy of Nature

Everything is changing

We’re all in this together

Global Freshwater Resources, in KM 3

Water Use by Sector

Water Resource Use by Sector

Availability of Fresh Water

Water Resource Scarcity

Water Resources and Prosperity –5 to possibly 25% of global freshwater use exceeds long-term accessible supplies (low to medium certainty) – % of irrigation withdrawals exceed supply rates and are therefore unsustainable (low to medium certainty)

Water Resources Per Capita

Sustainability 2050: The Challenge

What we do in the next 10 years will shape Earth and Humanity for the next 100 years

Source: Population Reference Bureau, 2005 World Population Data Sheet. Projected Population Change by Country Percent Population Change,

Billions Less Developed Regions More Developed Regions Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), Growth in More versus Less Developed Countries

Association Between Fertility and Education Percent of Girls Enrolled in Secondary School Source: Population Reference Bureau, Population & Economic Development Linkages 2007 Data Sheet. Total Fertility Rate Palestinian Territory Uruguay Morocco

Association Between Fertility and Poverty Percent of Population Living on <$2 per Day Source: Population Reference Bureau, Population & Economic Development Linkages 2007 Data Sheet. Total Fertility Rate Niger Jordan Mongolia

Sustainability 2050: The Challenge

Ecological Services

Millions Source: United Nations, World Urbanization Prospects: The 2003 Revision (medium scenario), Largest Cities, Worldwide

The largest cities in the world are growing rapidly, and they are shifting from the more developed regions to the less developed regions. In 1950, New York was the largest city in the world, with a population of about 12 million. By 2015, the largest city worldwide is projected to be Tokyo, with triple this population size: 36 million. Largest Cities Worldwide

Published by AAAS J. A. Foley et al., Science 309, (2005) Worldwide extent of human land-use and land-cover change

Human Activities Dominate Earth Croplands and pastures are the largest terrestrial biome, occupying over 40% of Earth’s land surface

Meeting Food Needs by 2050 Jason Clay The role of research

Water Footprint Concepts Water footprint is the amount of water required to produce a unit of product. 1 Kg Corn requires 900 L water. 30

Water Footprint Concepts Blue water is water that is collected for use (river, reservoir, groundwater) Green water is soil moisture from precipitation Grey water is water to dilute pollution concentration 31

2000 Corn Yield Data (SAGE)

Blue vs Green Water from Water Balance Model

Water Stress Index 35 A WSI of 0.5 is the threshold between moderate and severe water stress. The WSI the ratio of water use to availability with a weighted factor dependent on watershed variations in annual water availability. Pfister, S; Koehler, A; Hellweg, S. Assessing the Environmental Impacts of Freshwater Consumption in LCA. Environ. Sci. Technol. 2009, 43, The above represents climate data from

Water Use Impacts on Ecosystem Quality 36 In places where plant growth is water-limited, withdrawals of blue water may eventually reduce the availability of green water and thus diminish vegetation and plant diversity. Ecosystem Quality (EQ) is represented as the area-time ecosystem damage as a function of water use availability and potentially disappeared fraction of species. Pfister, S; Koehler, A; Hellweg, S. Assessing the Environmental Impacts of Freshwater Consumption in LCA. Environ. Sci. Technol. 2009, 43,

Water Use Impacts on Human Health 37 The damage induced by water consumption in a watershed or country is measured in disability adjusted life years (DALY) as outlined in the Eco-Indicator 99 method. The impact on human health is a function of expected specific damage per unit of water consumed Pfister, S; Koehler, A; Hellweg, S. Assessing the Environmental Impacts of Freshwater Consumption in LCA. Environ. Sci. Technol. 2009, 43,

Agricultural use accounts for over 70 percent of all human use of water. Agricultural water use is predominantly from rainfall. Water scarcity is experienced by humans as famine. Demand for food, feed, fiber and fuel from agriculture will double by We have to meet that need without one drop more of water, one hectare more of land. We must freeze the footprint of agriculture Global Agricultural Water Use