Every age has had its great moral issues. Slavery, colonialism, civil rights, women’s rights, freedom of religion or belief, social and economic justice. But no issue has ever threatened the entire human race in a way that our unsustainable lifestyle threatens the future of our existence on this planet, or the many other life forms that share it with us. So what is so unsustainable about the way humans live and interact with the natural world?

The sheer size of the human population makes it difficult for nature to maintain her generous ability to supply us with natural resources and absorb the wastes that we emit when we are finished using them. Each year the world’s population grows by 80 million people and we must make further incursions into the natural world to support them. We have devised a very efficient economic system which brings wealth and benefits to huge numbers of people around the world but it only stays strong as long as it continues to grow.

Most of our politicians see their role as doing whatever it takes to keep this growth going but only a modest amount of reflective thought leads to the conclusion that this is not a situation that can continue indefinitely. A truly sustainable world can only be achieved by stabilising population and making the transition to an economic system where steady levels of production and consumption have replaced growth as the main goal. How can we make this happen? Tell anyone who will listen.

If you were on the Titanic and you thought you could see an iceberg ahead, would you race up to the bridge and shake the captain’s shoulders furiously or would you trust his judgment and hope you were mistaken? Would you place blind faith in the ability of modern technology to keep the ship from sinking? If we don’t become sustainable, the future seems very unclear.

Water, food and energy shortages have the potential to threaten the fabric of civilized society and set us on a course to dangerous conflict and the complete breakdown of law and order.

The inability of many of our leaders to see this danger ahead gives them something in common with the captain of the Titanic. Their calls for more and more growth have in them a faint echo of that blustering order to run the engines at full steam ahead- there are never any icebergs this far south at this time of year.