TEN years ago, at the famous Earth Summit in Rio de Janeiro, Brazil, the term "sustainable development" was first adopted.
As an all-Wales Member of the European Parliament, I will be present at the second Earth Summit in Johannesburg next week.
Labelled "Rio + 10" it will review progress over the past 10 years and discuss new initiatives to tackle the world's problems.
The outlook is not encouraging. More people than ever suffer poverty, hunger, environmental devastation, war and repression. Globalisation has surged forward. The gap between rich and poor grows wider every day. Climate change continues unabated. Vital bio-diversity resources are being dangerously depleted.
A study published by the National Academy of Sciences in June showed that human beings are using about 25pc more natural resources than the Earth can replenish.
More than a billion people are still without clean drinking water. More than 8pc of children born in developing countries die before their first birthday. The poorest 40pc of people have access to a mere 11pc of the world's resources. Against this background, the promises of Rio seem empty.
There has been limited progress. Both the Kyoto Protocol on climate change and the Cartagena Protocol on international trade resulted from the Rio summit.
But the fact that neither of these has yet been fully implemented shows that putting agreements into practice can be difficult.
Hopes for success at the Johannesburg Summit declined every time the parties to international agreements failed to fulfil their promises, and powerful countries like the United States try to hijack the process.
So a great deal is at stake in Johannesburg and only political will can make it succeed.
We cannot afford another summit full of fine speeches but with very little content or results. Many are already predicting "Rio + 10" will be a failure because of the lack of agreement by governments in the preparatory meetings. It is even being labelled "Rio minus 10" to reflect this lack of progress.
That is why I and many others are travelling to Johannesburg to put pressure on the decision makers. We have to make them keep faith with the aims adopted at Rio and, this time, come up with effective action.
Action plans for sustainable development must focus on the needs of people: sustainable communities working in partnership across the world, respecting democracy, human rights, equality, languages and cultural values.
The environment is not the only aspect of life that needs to be sustained. As well as bio-diversity, cultural and linguistic diversity must be preserved.
Hundreds of indigenous languages and native cultures are in danger of extinction worldwide. Today, of the 6,000 or so languages spoken in the world, a staggering 3,000 are in serious danger of dying out. Over the past three centuries, languages have disappeared at a dramatic and increasing pace.
In Wales, strategies for the survival of the Welsh language - which is a key element of our national identity - and to protect the cultural diversity of Wales, can be much better appreciated in this global context.
There are literally thousands of other peoples like us. We are not alone.
Sustainability, in all its aspects, begins at home. Due to our own experiences, Wales can have an important role in achieving progress. The National Assembly has a duty to promote sustainable development.
Many organisations in Wales took up the challenge of Local Agenda 21 - part of the Rio Agenda - for local and regional strategies to promote environmental, social, economic, linguistic and cultural diversity.
This shows that solutions must be found as close as possible to the communities they affect. People must be given incentives to become key players in ensuring that their own development is sustainable.
A successful outcome at Johannesburg is as relevant to communities in Wales as to everywhere else in the world.
In Johannesburg, we will be joining thousands of people. Not only heads of state and governments, but also non-governmental organisations, industry, children and young people, local authorities, farmers, women, trades unions.
In fact, major groups from all over the world. As well as the summit itself there will be events co-ordinated by the United Nations and others.
The European Free Alliance - the political group to which Plaid Cymru, The Party of Wales belongs in the European Parliament -
has organised meetings and visits in Johannesburg to discuss cultural diversity, minority rights and the rights of indigenous peoples.
I am certain that learning about the experiences of others will benefit us in Wales.
I'm particularly looking forward to visiting a school in Alexandra Township that teaches through the medium of four different native languages.
The debate on sustainable development in Johannesburg must focus on respect for all people - their values, cultures and environment.
It is not just about economic growth, but about changing the global agenda so that economic and trade policies serve rather than dictate social, environmental and cultural objectives. It is a unique opportunity to improve the conditions of life for people everywhere in the world, including Wales.
Failure at Johannesburg will mean a setback in the battle for a fair and safe world for everyone.
Ten years from now, today's children will be asking what progress has been made since Johannesburg. I will do all I can to en-sure that the answers will be more positive next time around. The United Nations World Summit on Sustainable Development is in Johannesburg from August 26 to September 4.