Despite overwhelming scientific evidence – and growing public concern – that our present development path is headed for calamity, governments are still not taking the challenge of achieving sustainable and equitable world development seriously: short-term national and financial concerns are consistently given top priority.  As a result, the scale of resource use is escalating and the crucial issues that will determine the future are not being effectively addressed.

There is an increasingly urgent need to act on the structural, fundamental causes of the deteriorating situation, primarily the excessive consumption, waste and the current unsustainable model of economic growth.

This requires transformational change. So far we have mainly seen a lot of rhetoric and political grandstanding about change. But leaders must walk the talk.

The world’s population will be over 9 billion by 2050. Every day, there are 220,000 more people at the global dinner table, many of them hungry, thirsty and desperate. Almost all (95%) urban expansion during coming decades will take place in the developing world, putting strains on already overcrowded cities and settlements, including grossly under-serviced and over-populated slums.

Exploding growth in the developing world will also create a vast new middle class, which could reach five billion people by 2030 (66% in Asia). This means increased buying power and need for resources, consumables and services, placing new strains on the planet.

And how is the world coping? To sustain our current 7 billion-strong population, resources equivalent to more than the world already possesses are needed. We are stretching the planet to breaking point. With GDP predicted to increase from $US60 trillion to $US200 trillion by 2050, it means – in resources terms – that we will need the equivalent of three planets to meet energy, consumable and other needs.

Clearly, unlimited growth is not possible on a limited planet. And raising efficiency will not be the silver bullet.

What is needed is nothing less than a revolution in the way we use natural resources. Our economy will require a fundamental transformation within a generation – in energy, industry, agriculture, fisheries and transport systems, and in producer and consumer behaviour.

When I joined Green Cross, shortly after its 1993 founding, I knew we had a long battle ahead to influence a change in the values of people, business and government, to turn sustainability into a development pillar.

This is taking hold but much slower than needed. President Obama is committing to fight climate change. Europe is championing green energy. China has de-facto recognized its development must be sustainable. The UN adopted the right to water as a human right. Oil multinationals, car manufacturers and chemical companies are parading their environmental credentials. Pollution, climate change and the depletion of natural resources have replaced nuclear weapons as the existential threats keeping voters awake.

There is awareness, and there are many examples of what is needed, being undertaken by companies, governments and individuals. But this has to be stepped up, and governments have to facilitate this expansion with incentives for circular economic and business models, green and smart energy and technologies, while turning back the clock on outdated approaches, like subsidizing fossil fuels.

New thinking and engagement are needed to break the “deadlock” of impotent political will and inadequate intellectual inquiry.  Leaders must rise to this challenge. To do less now – when so clearly confronted – is to dishonor our past, disgrace our present and devalue our future. In order not to fail, they must start walking the talk today.