Joy and hope are all too rarely associated with the environmental movement, but both have been in abundant supply since Ecuador’s people voted on Sunday to keep the country’s oil in the subsoil of the Yasuní national park. The question now is whether this is a one-off triumph, or something that can be replicated in other countries. The referendum result obliges the state oil company to dismantle operations – 12 drilling platforms and 225 wells that produce up to 57,000 barrels a day – in block 43 of the Ishpingo-Tambococha-Tiputini (ITT) project, an area of the Amazon rainforest famed for its ecological diversity, and which is home to two tribes that live in voluntary isolation. With more than 5.4 million votes in favour of halting production and 3.7 million against, this is the most decisive democratic victory against the fossil fuel industry in Latin America and, arguably, the world. It is the fruit of years of dogged campaigning by the Yasunídos collective and other civil society groups, and will surely inspire climate activists in other parts of the world. But arguably the greatest lesson from the referendum is for other governments, which have just been given a glaring example of the cost of stranded assets when the social mandate for fossil fuels is suddenly removed. The Ecuadorian authorities did everything in their power to prevent this happening. The government initially refused to accept a petition with 750,000 signatures, even though this was nearly double the threshold needed to initiate a referendum. Years later, when the courts ruled the proposal was finally to be put on the ballot, the campaign was vehemently opposed by the president, Guillermo Lasso. The head of Petroecuador warned his state-run company would lose $13.8bn over 20 years from denied income and the cost of blocking the well and clearing the site. Proponents successfully argued that these figures were exaggerated. A “keep-it-in-the-ground vote”, they said, would save Ecuador money in the long term as it would reduce damage to the country’s main guarantors of sustainable wealth and health, which are a healthy forest and clean rivers. It should also help to reduce climate damage, which will cost far more than decommissioning oilfields. The global fossil fuel industry will be hoping the referendum is an isolated case. Ecuador, after all, is virtually unique in having a constitution that recognises the rights of nature and promises to protect sensitive ecosystems from “activities that could lead to species extinction, the destruction of ecosystems, or the permanent alteration of natural cycles”. Yasuní is also an exceptional area of natural vitality. Recognised by Unesco as a world biosphere reserve, it is home to at least 1,300 native tree species and more than 100,000 different types of insects per hectare. As I noted after a first visit to the area in 2012: “In their first hour in Yasuní’s Amazonian forest, many people will see more creatures than they have seen in their entire lives, including some that have yet to be documented by science. To paddle up the Ayango creek that leads from the traffic and pollution of the Napo river into the most biodiverse region on Earth is to encounter a wall of noise, frequent bursts of colour and unimaginable combinations of life.” The discovery of a $7.2bn oil reserve inside the park prompted a fierce debate. In 2007, Ecuador’s then president, Rafael Correa, proposed to the United Nations General Assembly that the fossil fuels could be left in the ground if the international community would provide half that amount to that state. Donations poured in, though never in quantities close to the necessary amount. And even before the initiative wound up, oil firms began building roads to the drilling site. The real costs of drilling do not appear on national and corporate balance sheets. In the forest, roads open the ways for loggers and poachers, oil spills contaminate the earth and water, and the increased noise and light disturb wildlife. According to the Andean Amazon Monitoring Project, more than 600 hectares have been deforested in Yasuní, mostly by the oil industry. The social impact is also immense. Along with the additional pressure on the two uncontacted groups – the Tagaeri and Taromenane (whose plight is thought to have persuaded many voters) – other Indigenous communities have grown divided between those who are given mining jobs and those who chose traditional ways of life and forest protection. Within Ecuador, the ramifications will partly depend on the run-off vote in the presidential election in October, when the leftwing frontrunner, Luisa González, will face Daniel Noboa, the son of one of the country’s richest men. The winner should be obliged to shut down production at block 43, but past history suggests there will be a pushback from the oil industry and the financial markets. Regionally, the vote may not have a direct impact on the other Amazonian nations such as Brazil, Peru, Venezuela and Guyana that are pushing ahead with development of oil and gas fields in and around the rainforest. But it may make leaders such as Lula think twice about the risk of stranded assets, and it will strengthen the efforts of Colombia’s Gustavo Petro to keep the rainforest free of new oil and gas projects. Further afield, Ecuador’s vote to put the forest and its people above petrodollars certainly casts a harsh, if distant, light on the British government’s decision to rush ahead with North Sea oil and gas licences, despite dire warnings about the climate risks involved. Globally, though, the most important message from Ecuador’s referendum is the simplest: it is possible to say no to oil. Jonathan Watts is the Guardian’s global environment editor