June marks 20 years since the 1992 United Nations Conference on Environment and Development in Rio. Rio will again host world leaders this year in a follow-up Earth Summit, Rio+20.

This is a crucial opportunity. Indigenous people's rights must be recognised, strengthened and respected, in Brazil and in the entire world.

We need to raise funds to get tribal leaders to Rio+20. They need our support for travel and accommodation.

Please help us to make Rio+20 a landmark event. Indigenous people are the vital guardians of the forests and indispensible in maintaining the environment.

* £10 will provide one day's food for a warrior

* £75 will pay for the food for one leader for the whole trip

* £250 will sponsor one person's travel and stay in Rio

- but any donation will help. Pleasse be generous.