Obede Loyla Souza is the latest person murdered by illegal loggers. It is a battle for the forest but also for the idea of progress without destruction

Obede Loyla Souza is the latest tragic death in the war of Brazil's forests, shot in cold blood for taking a stand against illegal loggers. His killing is the sixth in a month, and another grim addition to a death toll of over 1000 in the last two decades.

But do not think that this war is only between heroic activists, frequently landless and poor, and rapacious, murderous loggers. It is, of course, but it is also a war of ideas. Chico Mendes, the rainforest campaigner infamously slaughtered in 1988, put it succinctly: the fight is to "demonstrate that progress without destruction is possible", he said shortly before his death.

Twenty years on the concept of sustainable development is far better known, if not much better practised. But in the Amazon, it is a matter of life and death.

Brazil has shouldered the burden of the world in acting to cut deforestation. Losing the Amazon would tip the global climate into chaos with consequences for us all. When I went to the Amazon last year, and to Brasilia to meet ministers, the crackdown on logging was impressive. Satellite technology had helped cut deforestation radically.

At Brazil's space institute, its head, Dr Gilberto Câmara, explained to me how he believed his nation could become becoming the first environmental superpower, the first nation to grow rich from its natural resources without destroying them.

There are plenty of catches of course, not least Brazil's huge oil finds, as I wrote about then. In the Amazon, the first obstacle is simply scale: the rainforest is bigger than western Europe. Furthermore, much degradation of the land in Brazil takes place outside the Amazon - in a nation four times the size of western Europe.

The government has about 800 officers tasked with enforcing laws against deforestation. That's roughly one officer per 10,000 square kilometres. And it's terrifying work. Raquel Taitson told me she loggers had tried to run her down in a car, attacked her with an axe and set fire to the guest house she was sleeping in.

Land rights are another issue. The long-term falling trend in deforestation has sharply reversed this year, most probably as illegal loggers grab land ahead of changes in Brazil's Forest Code that might legitimise such plots. Environmental campaigners rightly denounce the changes.

But do not underestimate the power of the voices of Brazil's many poor, who in desperation back any economic development over green concerns. Brazil's president Dilma Rouseff has to balance these voices - and the corrupt local politicians that ruthlessly exploit them for their own profit - with forest protection.

In the rich world, Brazilian leaders who say foreign aid to stop deforestation should not be laden with strings of conditions are seen as arrogant beggars. Blunt speaking, such as in 2009 when former President Luiz Inácio Lula da Silva said "I don't want any gringo asking us to let an Amazon resident die of hunger under a tree", is seen as needlessly aggressive.

But remember, Brazil is battling to do what no western nation ever did: lift its citizens from poverty without destroying the future prosperity of others.

That is why men like Obede Loyla Souza are so extraordinary. They toil to feed their families and yet are still prepared to face death protect the forest that protects us all. It is deeply humbling.