As the first decade of the 21st century began, most major natural resources were on the verge of becoming scarce; while human-created waste, most of it greenhouse gases, began to overwhelm the biosphere. These factors were both influenced by, and contributed to, a large inequality in both physical wealth and social power on a global scale enabled by the dominant social and economic philosophy of maximizing personal gain. Attempts for more than 20 years by nations and international corporations to secure more access to natural resources led to the century's first wars.
Over the course of the decade, in response to the approaching resource limits, per capita consumption began to slow down. The financial sector of the U.S. economy, having amassed a great amount of debt in expectation of accelerating growth, was caught by surprise and suffered losses that triggered a world recession. Governments led by the U.S. attempted to artificially increase consumption by building infrastructure and assuming the financial sector's debt; but because they only peripherally addressed the resource and waste problems, the recession continued to worsen and by the early part of the second decade became a full depression.
Desperation led to acceptance that some natural and human services needed to be freely available to everyone without being diminished by their use; this included maintenance of the infrastructure, people, natural resources, and species that those services depended on (“the commons”). As a result, most nations instituted variants of the Commons Development and Maintenance Amendment to the U.S. Constitution (CDMA), which required all adult citizens to give one in seven days of their time to building and maintaining the commons. This joint project largely defined the rest of the century, narrowly averting climate catastrophe due to global warming and leading to achievement of near-total sustenance of the world's population by common services in 2100.
As insurance against extermination of humanity due to extraterrestrial events, a self-sustaining settlement was established on Mars which used and replaced what it needed with minimal impact to its environment based on the new understanding that to qualify as a highly evolved species, humans would be virtually indistinguishable from the rest of nature, whose principal goal is extension of life into the farthest future.