Toward a stewardship of the Global Commons:

engaging “my neighbor” in the issue of sustainability


By members of the Critical Issues Committee, Geological Society of America

Part VII


A. R. Palmer, Institute of Cambrian Studies, Boulder, CO

Space travel has stirred our imaginations for more than a century and inspired not only writers of science fiction, and trekkies, but also the scientists and engineers of space agencies worldwide. At frequent intervals, presentations in various media speculate about human travel far beyond the international space station to other planets in our solar system in the not-too-distant future.

To some people, this could solve Earth’s population problem because they believe we will be able to emigrate to other worlds when push comes to shove. Space travel may be the special privilege of a few adventurous astronauts, but as a solution to our earthly problems, there is need for a reality check.

Let’s start with a trip to the moon and a look back to our Blue Planet – a spectacular view now common on many advertising pages. But look elsewhere in the Universe. Nothing else that we see looks any bigger than it did from Earth. Planets are still points of light, as are the stars and galaxies. We are a long way from even our nearest planetary neighbor!

And then there’s simple math. Earth’s current population (about 6 billion) is increasing by about 1% annually. The U.S. Census Bureau projects that by 2050 there will be a somewhat smaller rate of increase of 0.46%, and a probable median population of nearly nine billion people. The ANNUAL population increase in 2050 (9 billion X .0046) will be an estimated 41.5 million persons, down from the present annual increase of about 60 million. On a DAILY basis (41.5 million ÷ 365), population increase in 2050 will be about 115,000 persons, down from the present DAILY increase of about 170,000 persons. Daily permanent emigration of that many people, even given possible technological advances in space vehicles and propulsion by 2050, might be a bit optimistic.

For all practical purposes, we must internalize and make plans for Spaceship Earth as the only realistic habitation for humans. Bringing human occupancy of this planet into balance with available ecological areas and terrestrial and oceanic resources, must be one of our highest priorities if we wish a sustainable future for our descendants.

DEMONSTRATION 1. - Have your students check the Web for information about the energy and material requirements, including support infrastructure, for a single Space Shuttle launch. Have them consult the World Resources Institute’s annual compilation of human demands for resources and estimate how emigration of all excess population, if possible, would affect the present crunch on Earth resources..

DEMONSTRATION 2. - Have the students calculate how far from Earth, within our solar system, an astronaut would have to travel so that Mars, or one of Jupiter’s moons, would look the same size as the Blue Planet does from our moon. What does this tell us about the reality of regular daily exodus of humans (and their life support) on such trips?

Return to Introduction
Guidelines to Sustainability Literacy
Part I: Stewardship of the Commons
Part II: Understanding Deep Time
Part III: Doubling Time
Part IV: Sustainability and Resources
Part V: The Connectedness of Everything
Part VI: Ecological Footprint and Carrying Capacity
Part VII: Spaceship Earth: There's No Place Left to Go
Part VIII: Part of the Global Ecosystem
Part IX: We Live in a World of Change
Part X: What Do We Mean by Sustainable World?
Part XI: Cultural Context of Sustainability
Part XII: We Have The Option of Choice

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