"It is accepted now that high economic growth rates do not necessarily translate into positive social developments but, for lack of consensus on what we should be measuring instead, our leaders remain obsessed with it." Fernando Henrique Cardoso calls for a rethink on how we measure economic success and social wellbeing. If measuring the GDP growth of individual countries gives a very limited outlook, what do we replace it with? Pedro Telles, Sara Svensson, Esther Agbarakwe and Gro Harlem Brundtland offer their responses.

I look forward to welcoming you all to Brazil next month for the Rio+20 conference.

While I haven’t yet met the ‘Youngers’ (except Pedro, whom I met by chance two weeks ago!), I have been told by my fellow Elders that you are a remarkable group. I am very pleased to be joining this debate with all of you at this important time.

I noted that last week’s discussion was about achieving change. But let me suggest that there is a vital step right before change can happen, which is for people’s thinking to evolve. In other words, to build a vision of the future that questions people’s fundamental beliefs – and makes clear the need for change.

My first question to you is this: what ideas and assumptions do we most urgently need to challenge?

Brazil is an interesting example, and it is fitting we should be meeting here in June to make progress towards sustainable development. I have said before that, for better or for worse, the fate of Brazil will be strongly linked to this moment in our humanity’s history.

We are a democracy, an open society with a vibrant civil society enjoying strong economic growth, but we are also facing enormous social and environmental challenges with dramatic human impacts: youth unemployment, corruption, violence, inequality, poverty and the degradation of our rainforests.

It is a moment of both huge opportunity and danger. But it is also as if two different histories of my country are being written at the same time.

At a time when we need to make life-and-death decisions on the future of our planet, such confusion is deeply worrying. It tells us we need tools to show that these two stories are not separate.

Our reliance on measuring GDP growth is a perfect example of this. It is accepted now that high economic growth rates do not necessarily translate into positive social developments but, for lack of consensus on what we should be measuring instead, our leaders remain obsessed with it.

Crucially, this narrow focus tells us nearly nothing about our successes and failures in assuring human wellbeing and environmental protection. Moreover, the GDP growth of a country will tell you very little about how countries’ fates are all interconnected. It is not designed for the deep challenges we face together: the threats faced by the lush rainforests of Brazil are interconnected with the expanding, roaring factories of China, America’s automobile industry and a million other issues, but we struggle to find better tools that capture the whole picture; that both improve our knowledge and change fundamentally the way we think.

I am sure you have spent many waking hours reflecting on this, and I look forward to hearing your ideas. What tools do you think we need to understand how our societies are performing?

And how can we ensure that these tools help promote greener, fairer and more sustainable economies?