Tragedy silently unfolded in Rio de Janeiro this spring. Twenty years ago, at a global summit held in the same Brazilian city, world leaders agreed that economic justice and environmental stewardship were the twin challenges faced by humanity, and that solving them did not have to be at the expense of a healthy economy. This year, at Rio+20, they changed their minds. Economic growth was put back on its pedestal as the gold standard of global policy objectives, effectively abandoning 20 years of progress.

This about-face comes at a time when the diagnosis of the current global crisis points toward the need for accelerated action on the sustainability vision first agreed to in Rio de Janeiro. What has been sold as an economic crisis is, in fact, a sustainability crisis with social and ecological dimensions at its core.

The social dimension is about the increasing gap between the rich and the rest. Since Rio 1992 the gap has grown to levels not seen since the lead up to the Great Depression.

In End This Depression Now, Nobel economist Paul Krugman writes that “to understand the deeper reasons for our present crisis we need to talk about income inequality.” Krugman argues that inequality fuels bitter partisanship and has resulted in the hijacking of the political process by wealthy people who never hesitate to spend vast sums of money to get what they want.

Krugman’s analysis confirms the exhaustive research contained in the book The Spirit Level: Why Equality is Better for Everyone. Unequal societies suffer from higher rates of obesity, mental illness and crime, and lower levels of trust, literacy and social cohesion.

Tragically, the lack of trust and social cohesion make it much harder for societies to act on the economic and ecological fronts.

There are many manifestations of the ecological crisis, but it is summed up in the United Nations Environment Programme’s Global Environmental Outlook, released in June, which reveals the world has made progress on only four of 90 of the most pressing environmental goals and “continues to speed down an unsustainable path.”

This spring also marked the 20th anniversary of the decimation of the North Atlantic cod stock and subsequent cod fishery moratorium in Newfoundland that threw 60,000 rural Newfoundlanders out of work. That ecological tragedy is a microcosm of the current global crisis — unsustainable economic growth drawing down the last of the planet’s resources, bringing the Earth’s capacity to renew itself to the breaking point and wreaking havoc on the economy. As ecological economist Herman Daly has pointed out, we have crossed a threshold — growth is now uneconomic.

Meanwhile, world leaders remain myopically fixated on growth. Just this week the European Central Bank, the Bank of England and the People’s Bank of China took co-ordinated action to boost it. Yet not a word has been heard from these leaders about the unconscionable appropriation of wealth by the very few or the breaching of the limits of global ecosystems and the twin threats these pose to a truly sustainable economy. Tragically, it would appear that our leaders, while paying lip service to sustainability for 20 years, have understood nothing of what it tells us about the interrelationships between social, ecological and economic systems, or the limits to growth on a finite planet.

But why should Calgarians care? Seemingly impervious and oblivious to this unfolding tragedy, we celebrate 100 years of the Calgary Stampede as we ride the Brahma bull of oil wealth with gusto. We are touted as a global energy superpower. Our material standard of living increases relentlessly, and we are now among the wealthiest on the planet.

Our provincial government and our corporate leaders seem singularly concerned with increasing the pace of economic growth — import more workers, leave ecological restoration for the next generation, roll back regulation of coal-fired electricity generation, and on and on.

Sadly, Canada was once considered one of the good guys, and a key architect of the Rio Summit in 1992. Today we slash environmental legislation, actively undermine global environmental agreements and twist arms to persuade others to do the same.

This week Prime Minister Stephen Harper called Calgary the greatest city in the greatest country in the world. But are we just another decadent, opportunistic society endowed with impressive but fleeting wealth, content to ride the wave while it lasts?

Fifty years after the launch of the modern environmental movement with the publication of Rachel Carson’s Silent Spring, we find ourselves at a fork in the road. As Carson wrote, we have “sugarcoated an unpalatable truth” that our wealth is founded on an unsustainable economic model.

We have a moral obligation to change the model and honour the definition of sustainable development agreed to in Rio 20 years ago — to not compromise future generations by our actions today. We have a historic opportunity to show international leadership. If we fail to take up the sustainability challenge, we will be a lesser city for it.

Geoff Ghitter teaches urban studies at the University of Calgary. He can be reached at geoff.ghitter@gmail.com. Noel Keough is an assistant professor in the faculty of environmental design at the university, and is co-founder of Sustainable Calgary Society. He can be reached at nkeough@ucalgary.ca.