Ecuador has had the opportunity to bring about environmental change, but this has been thwarted. In mid-August, a plan to leave oil in the ground in one part of the Ecuadorian Amazon rainforest was dismissed by President Rafael Correa. He argued that the world has failed Ecuador by contributing little of the money the government had hoped to raise, and said the oil revenues would be used to end poverty.

We always knew it would be difficult to cut through the oil interests. Indeed, doubts had been voiced since 2007, when the Yasuní-ITT initiative was proposed. In an economy addicted to black gold, people were baffled by this proposal not to drill for the 850m barrels of heavy oil – 20% of Ecuador's reserves – in Yasuní national park. Crazy though the idea seemed, however, it attracted support and grew stronger.

The Yasuní initiative emerged from civil society, even before Correa became a presidential candidate in 2006. Its evolution was influenced by the Chevron Texaco disasters in the northern Amazon, and by resistance from the community of Sarayaku.

Yasuní-ITT would prevent 410m tonnes of CO2 emissions. In return, Ecuador expected a financial contribution from the international community, taking into account the principle of shared but differentiated responsibilities.

The idea was that all peoples of the world profoundly changed their relationship with nature by contributing to the establishment of a new global legal institution that transcended national and private interests. It would be a custodian for the atmosphere and biological diversity, areas in which all humanity has a stake. Most importantly, it would protect the land and lives of the Tagaeri and Taromenane indigenous peoples who live in voluntary isolation.

The proposal has followed a convoluted path since becoming part of official political discussions. There were steps forward and back, successes and contradictions, approval and controversies. Interestingly, the idea took root even though some people considered it far-fetched. After its official launch, support grew quickly.

Yet plan B – to drill in the park if contributions were not met – has long loomed large, and, after Correa's announcement, the proposal is on the brink of destruction. He blames the international community for not contributing the $350m (£225m) a year required to fund the innovative environmental plan.

Rather than blame the international community, which has supported the initiative despite the Ecuadorian government's inconsistencies, coherent and consistent government action was needed to support plan A – not to drill for oil instead. It is up to Correa to overcome the problems that he helped cause. He should have stayed committed to the initiative.

The activities linked to oil exploration and exploitation at the edges of ITT should not have been permitted either. Moreover, the government could have put a stop to other threats to Yasuní – deforestation, illegal logging, settling, illegal tourism – and prohibited the roads and waterways from Manta to Manaus, designed for commodity exports to Asia. Similar policies could be pursued in Peru's neighbouring oil fields. This area is also home to peoples who have had no contact with the outside world.

Oil production in Yasuní should take place only upon application by the president, and only on the basis of a declaration of national interest by the national assembly. Now a broad movement is preparing the ground for a referendum. Only then will the Ecuadorian people have the last word – to leave the oil in the soil, even without money from abroad.

Yasuní-ITT can still be achieved by civil society in Ecuador and around the world. We need other Yasunís too.

Alberto Acosta is an Ecuadorian economist, professor and researcher at Flasco-Ecuador. He is the former minister for energy and mining (2007) and ex-president of the assembly charged with drawing up the constitution (2007-2008) and ran for president (2012-13).