Celebrated scientists and development thinkers today warn that civilisation is faced with a perfect storm of ecological and social problems driven by overpopulation, overconsumption and environmentally malign technologies.

In the face of an "absolutely unprecedented emergency", say the 18 past winners of the Blue Planet prize – the unofficial Nobel for the environment – society has "no choice but to take dramatic action to avert a collapse of civilisation. Either we will change our ways and build an entirely new kind of global society, or they will be changed for us".

The stark assessment of the current global outlook by the group, who include Sir Bob Watson, the government's chief scientific adviser on environmental issues, US climate scientist James Hansen, Prof José Goldemberg, Brazil's secretary of environment during the Rio Earth summit in 1992, and Stanford University Prof Paul Ehrlich, is published today on the 40th anniversary of the foundation of the UN environment programme (Unep). The paper, which was commissioned by Unep, will feed into the Rio +20 earth summit conference in June.

Apart from dire warnings about biodiversity loss and climate change, the group challenges governments to think differently about economic "progress".

"The rapidly deteriorating biophysical situation is more than bad enough, but it is barely recognised by a global society infected by the irrational belief that physical economies can grow forever and disregarding the facts that the rich in developed and developing countries get richer and the poor are left behind.

"The perpetual growth myth ... promotes the impossible idea that indiscriminate economic growth is the cure for all the world's problems, while it is actually the disease that is at the root cause of our unsustainable global practices", they say.

The group warns against over-reliance on markets but instead urges politicians to listen and learn from how poor communities all over the world see the problems of energy, water, food and livelihoods as interdependent and integrated as part of a living ecosystem.

"The long-term answer is not a centralised system but a demystified and decentralised system where the management, control and ownership of the technology lie in the hands of the communities themselves and not dependent on paper-qualified professionals from outside the villages," they say.

"Community-based groups in the poorer most inaccessible rural areas around the world have demonstrated the power of grassroot action to change policy at regional and national levels... There is an urgency now to bring them into mainstream thinking, convey the belief all is not lost, and the planet can still be saved."

The answer to addressing the critical issues of poverty and climate change is not primarily technical but social, say the group. "The problems of corruption, wastage of funds, poor technology choices and absent transparency or accountability are social problems for which they are innovative solutions are emerging from the grassroots."

To transition to a more sustainable future will require simultaneously redesigning the economic system, a technological revolution, and, above all, behavioural change.

"Delay is dangerous and would be a profound mistake. The ratchet effect and technological lock-in increase the risks of dangerous climate change: delay could make stabilisation of concentrations at acceptable levels very difficult. If we act strongly and science is wrong, then we will still have new technologies, greater efficiency and more forests. If fail to act and the science is right, then humanity is in deep trouble and it will be very difficult to extricate ourselves.

The paper urges governments to:

• Replace GDP as a measure of wealth with metrics for natural, built, human and social capital – and how they intersect.

• Eliminate subsidies in sectors such as energy, transport and agriculture that create environmental and social costs, which currently go unpaid.

• Tackle overconsumption in the rich world, and address population pressure by empowering women, improving education and making contraception accessible to all.

• Transform decision-making processes to empower marginalised groups, and integrate economic, social and environmental policies instead of having them compete.

• Conserve and value biodiversity and ecosystem services, and create markets for them that can form the basis of green economies.

• Invest in knowledge through research and training.

"The current system is broken," said Watson. "It is driving humanity to a future that is 3-5C warmer than our species has ever known, and is eliminating the ecology that we depend on for our health, wealth and senses of self."