The 21st century will be marked by a crucial debate: how can we make economic and social development compatible with the preservation of our natural environment?

The challenge is faced by developed and developing countries alike, but the burdens need to be more equally shared. The width of the divide between rich and poor countries has doubled over the last 40 years. While the developed world has benefited from the prosperity generated by economic progress, poor countries suffer the consequences of environmental degradation resulting from uncontrolled growth. Rich countries have unsustainable patterns of production and consumption. They are responsible for 41% of total carbon dioxide emissions, and their overall consumption of raw materials is four times greater than that of all other countries combined. With those conditions, there is no possibility of a sustainable future.

The scale of Brazil's natural assets is extraordinary: the Amazon region contains 20% of the planet's fresh water, and almost two-thirds of the country is still covered by natural vegetation. Against this backdrop we have been implementing policies that directly address our most pressing environmental concerns.

When I began my term of office, the rate of deforestation in Brazil had been increasing by an average of 27% per year. From the second half of 2004 onwards, however, we put measures in place to monitor tree-felling and to address the issue of land distribution, with the result that the rate of deforestation has fallen dramatically. In a country that suffers from profound social inequalities, however, the success of environmental policy ultimately depends more than anything on economic and social measures that are themselves geared towards the preservation of our environment.

Over the next 10 years we will place an additional 13m hectares of the Amazon region under a management regime that will guarantee the forest's regeneration cycle. And our commitment to a responsible approach extends well beyond our own territory. It is imperative that we put into practice the commitments of the Kyoto protocol to combat the potentially devastating impact of global warming.

In the search for new, sustainable economic models, the international community is coming to recognise the need for a radical rethink in relation to the generation of energy, and Brazil is responding by using clean, renewable, alternative energy sources to an ever-greater extent. More than 40% of Brazil's energy comes from "green" sources, in comparison with around 7% in rich countries.

The ethanol Brazil produces from sugar cane is attracting worldwide interest, for it is one of the cheapest and most dependable types of fuel derived from renewable sources. Three-quarters of the cars now being produced in Brazil have "flex-fuel" engines, capable of running on either ethanol or petrol, or any mixture of the two.

The government has implemented environmental initiatives that are also bringing social benefits - for example in the form of the biodiesel project. Produced from oil-bearing plants, biodiesel is significantly less polluting than conventional petroleum-based diesel. As it can easily be produced by small farmers in some of the poorest regions of the country, the project combines environmental protection with rural development, and reduces social inequality. There is a great potential for biodiesel in Africa.

Brazil is actively preparing itself for a new development paradigm that will meet the environmental and social challenges of the coming decades. Ethanol and biodiesel are the key components of our approach, and we are determined to "plant the oil of the future". I invite you to join us in our endeavours.

· Luiz Inácio Lula da Silva is the president of Brazil. Email: imprensa@planalto.gov.br