European leaders have thrown the Amazon rainforest under a Volkswagen bus in a massive cows-for-cars trade deal with Brazil and three other South American nations.

The EU-Mercosur agreement – the largest in Europe’s history, according to officials – will make it cheaper for Brazilian farmers to export agricultural products, particularly beef, despite growing evidence that cattle ranching is the primary driver of deforestation.

In return, European businesses get greater access to the markets of Brazil, Argentina, Uruguay and Paraguay, which will benefit producers of vehicles, chemicals, machinery, wine and cheese.

Negotiations took almost two decades, which may explain why the outcome signed last week reflects the pro-industry values of the past rather than the environmental concerns of the present.

Europeans know the risks. Many more people here are adopting a vegetarian diet as it becomes clear that consumption of beef – particularly from Brazil – is a cause of forest clearance, which is destabilising the climate.

The clearest proof yet is contained in a new investigation by the Stockholm-based NGO Trase, which tracks supply chains and the impact of the beef on our plates, in our burgers and on our barbecues.

Even before the new trade deal, the country-by-country breakdown by Trase – reported exclusively by the Guardian – reveals that meat consumers in Britain were indirectly responsible for up to 500 football pitches of land clearance in Brazil last year. Italy – the biggest Brazilian beef buyer in the EU – chewed through about four times as much. With the agreed reduction in tariffs, the volume in all European countries is likely to increase.

The trade deal was celebrated by the Brazilian president, Jair Bolsonaro, who has put agriculture and mining at the vanguard of a strategy to open up the Amazon, the Cerrado and other forests. His government has neutered the environment ministry and pushed proposals to remove the protected status for indigenous territory and nature reserves.

Last month, a record surge of deforestation prompted concerns that Bolsonaro is giving a free pass to illegal logging, farming and mining. Last year saw a 13% increase to the highest level in a decade.

Not coincidentally, this comes at a time of record beef exports. Brazil is now the world’s slaughterhouse. Last year, 1.64m tonnes of steak and other cuts were sent overseas, beating the previous record in 2007, which followed the peak of forest clearance. The Trase study shows 5,800 sq km – 100 times the area of Manhattan – was cut down last year to create pastures.

European leaders have downplayed the environmental impact of the deal. Despite the cheaper tariffs, they claim beef imports are unlikely to rise significantly and insist the deal locks Brazil into the Paris climate agreement. The European Commission president, Jean-Claude Juncker, told reporters the historic deal highlighted a commitment to “rules-based trade”.

Yet there are countless reports of rule-breaking by Brazilian meat companies. An investigation published this week by the Guardian, in conjunction with Repórter Brasil and the Bureau of Investigative Journalism, shows how the global market leader JBS is still selling meat from companies that have been fined for deforestation. This follows similar revelations two years ago, connected to a senior member of the Brazilian cabinet. The farmers involved denied the claims.

Revealed: rampant deforestation of Amazon driven by global greed for meat Read more

Many European politicians and environmentalists are furious about the trade deal and sceptical that it will increase leverage over Bolsonaro. They see the agreement as a form of appeasement at the behest of corporate interests.

Behind this are bigger geo-strategic concerns. In recent years, China (particularly Hong Kong) has become Brazil’s biggest customer by far for beef and soy, which is used to feed livestock. According to Trase, China is responsible for 60 times more deforestation than the UK. Without support from Beijing, efforts to promote greater supply-chain transparency and sustainability in the Amazon and Cerrado will come to nothing.

The US is also expected to announce that it will resume imports of fresh beef from Brazil for the first time since July 2017, which will add to pressure on the forests and give Bolsonaro further cause to abandon the battle against deforestation.

Business and politics as usual cannot fix this. The world’s greatest rainforest is a globally essential source of oxygen, carbon sequestration and biodiversity, but as long as these benefits are omitted from trade balance sheets, it will continue to lose out to steakhouses and burger joints. The Amazon needs to be at the centre of a change of values, not a peripheral concern that can be bartered away for a consignment of auto parts and delicatessen fillers.