The following is an excerpted essay from John Ikerd, Professor Emeritus of Agricultural Economics at the University of Missouri. You can read the full essay and his other works at his faculty page here. The bolding is mine.

Adam Smith, the father of contemporary economics, in his landmark book, Wealth of Nations, wrote: “No Society can surely be flourishing and happy, of which the far greater part of the members are poor and miserable.”  …[D]istrust and dissention [sic] are inevitable consequences of substantial and persistent economic disparity among members within a society.  Economic disparity inevitably creates a sense of social injustice, and an unjust society is neither stable nor sustainable.  Distrust and dissention ultimately lead to civil unrest, which disrupts the economy and ultimately leads to exploitation and destruction of the natural ecosystem.  Eastern Europe and Sub-Sahara Africa provide two prime examples of the widespread ecological destruction that results from persistent social injustice.

 A market economy will not ensure social justice.  A market economy provides for people only in relation to their willingness and ability to pay, not in relation to their basic needs.  The abilities of people to earn money and to pay for food, clothing, and shelter do not necessarily match their needs.  All people have a basic right to sufficient food, clothing, and shelter to ensure survival and normal physical and mental growth and development, although we are just beginning to accept this fact in America.  Our market economy will not ensure those rights.  Inevitably, equity and justice must be ensured through conscious, purposeful actions by the members of society – by our individual acts of human compassion and by our public acts, through government, to ensure the general welfare.  Both are necessary and neither absolves our responsibility for the other.  A society that does not accept this responsibility for social justice is not sustainable. 

Equity and justice do not require that everyone have access to the same quantity, quality, and variety of food, clothing or shelter, or that food, clothing, and shelter be equally convenient or effortless for all.  Equity and justice are matters of ensuring equal access to specific things to which all have equal rights – not equal access to all things.  A right to safe, nutritious food, for example, does not imply a right to prime rib and artichoke hearts nor to packaged or pre-prepared foods.  However, food and farming systems that do not accept responsibility of ensuring that all have adequate food, clothing, and shelter are not sustainable.

Each of us must accept our ethical and moral responsibility to help ensure the sustainability of human life on earth. …[S]ocial justice also demands that all people have adequate food, clothing, and shelter.  Sustainability is a question of environmental integrity and economic viability, but sustainability is also a question of social justice.

Read the full essay: Sustainable Agriculture: A Question of Social Justice.