Answers to planet's ills are out of this world

As Earth struggles with climate change and overcrowding, Charles Cockell recommends we look to the final frontier

The ongoing exploits of two tiny rovers on the surface of Mars seem like an indulgence of space engineers and schoolboys. But such Martian expeditions are as important as our efforts to provide food to starving people in Africa.

Since the launch of Sputnik in 1957, environmentalists and space explorers have been asking about the value of each other's endeavours. To many prospective space settlers, environmentalism is introspective - focused on looking to the wounds of Mother Earth and neglecting the visionary advance to new homes in the cosmos. Conversely, many environmentalists feel that space exploration is a waste of money when there is so much to deal with at home.

Earth's environmental problems are hardly in dispute. Pollution, overpopulation and lack of basic sanitation for billions are indisputable challenges and barriers to the improvement of the quality of life. By contrast, space exploration seems more like a luxury; a dream for a few select nations and private individuals. When some of its fruits, such as Martian rocks that resemble human faces, are printed in our newspapers, it may appear irresponsibly wasteful - even immoral.

But the exploration of space has been one of the great catalysts of our environmental awakening. Consider the satellites without which we could not monitor the burning rainforests to understand our impact on them and mitigate it. The boundaries of national parks are now patrolled from space while the human impact of the most ferocious environmental disasters are routinely ameliorated by warnings sent to our television screens.

The mapping of the ozone hole by satellite has informed policy to reduce the use of ozone-depleting substances and now that hole is on the mend.

That is a stunning vindication of what can happen when space explorers and environmentalists work together. Satellites watch our world continuously and cleanly.

Even probes sent to distant worlds such as the searing hell of Venus and the frigid, radiation bombarded planet Mars have opened our minds to the fragility of our environment and why we must care for it, lest we go the same way.

These revelations, however, are a mere taste of what we could do. The great resources of space might be used to solve some of our wants on Earth. Many asteroids contain metals and mineral wealth on an almost unimaginable scale. Some people estimate that easy-to-access iron on the Earth will last for about another 300 years; then we will have to start mining much poorer quality ores. However, our solar system's asteroids contain at least another 300 million years worth of iron - much of it in pure form. The same goes for many other metals that we find most useful. To stay only on Earth and to reject the vision of space exploration is like locking yourself inside your home and watching its resources dwindle, when a simple push of the door will reveal an entire high street with its diversity of produce.

This is not fantasy - it is a very real opportunity for our civilisation to embrace, and it offers remarkable solutions to some of our most pressing resource limitations. The intellectual and economic effort required to bring this to fruition would not be insubstantial, but it requires a long-term vision of our future that the payoff would make such a commitment worthwhile. Environmentalists and space settlers could work together to bring this solution to bear on our troubles here on Earth, keeping our planet a green haven. Perhaps these space resources might offer us the chance to remove many polluting industrial processes to beyond our atmosphere.

It is no small irony that many environmentalists have chosen to call our planet "Spaceship Earth". They care about recycling, clean air and water, and making plenty of food for everyone in harmony with the rest of the biosphere. It may be surprising, but space settlers care about exactly the same problems on their spacecraft.

By settling and exploring space, particularly in environments far more extreme than the Earth, we will learn much about our home world. From this perspective the division between environmentalists and space explorers becomes so blurred that their ambitions become the same.

The opportunity to bring both communities together is not open ended. If they remain separated, space settlers - both government and now private - will leave the Earth and write it off as a lost cause while pursuing worlds beyond. Similarly, one could envisage an environmental future when space is regarded as a luxurious distraction for the wealthy, ignored as an irresponsible indulgence even as the Earth becomes more impoverished and overcrowded.

Now, while we have a resource-rich world and access to space, we have a brief opportunity to forge the two activities into a single vision of our future, each one strengthening the success of the other. We should use this window in history to transform ourselves into the space-faring guardians of a planetary oasis in space.

Charles Cockell is professor of microbiology at the Open University. His book, Space on Earth: Saving our World by Seeking Others , is published by Macmillan, £16.99.