Brazil's annual greenhouse gas emissions increased last year for the first time since 2004 after years of reductions as deforestation and the use of thermal power plants rose, a new study found.

Latin America's largest economy generated 1.56 billion tonnes of carbon dioxide equivalent (CO2e) in 2013, a 7.8 percent jump over the previous year, according to a report released Wednesday by the Climate Observatory, a network of civil society organizations.

Emissions from deforestation rose 16 percent over the previous year while those from the energy sector climbed 7.3 percent.

The numbers can be expected to fuel criticism from environmental groups over the government's Amazon protection policies and its increasing use of fossil-fueled power plants.

The report also suggests that Brazil could fail to meet its goal of reducing emissions by 39 percent by 2020.

"We see the tendency for emissions to rise again in 2014 even considering a stagnant economy, so if Brazil manages to resume economic growth in the future it will be hard to meet the target," said Tasso Azevedo, the study's coordinator.

The government, however, does not see a new trend for emissions.

"You have to consider longer periods of time to conclude that a new trend is in place," said Adriano Santiago, the government's climate change director.

"Several sectors are indeed increasing emissions, but inside an expected range that will still allow us to meet our commitments."

Brazil found success combating deforestation in the last decade, cutting carbon emissions in the process.

Compared to a peak of 2.86 billion tonnes of CO2e emitted in 2004, the 2013 number is still 45 percent lower.

But deforestation rose again last year by 16 percent, as current policies failed to deter forest destruction caused mainly by illegal logging and cattle ranching expansion.

Besides that, a large part of the country faces a third year of drought that depleted reservoirs for hydro power plants, forcing the government to use an expensive network of pollution-producing thermal plants.

The Climate Observatory report was published 10 days before the United Nations global climate conference starts in Lima, Peru, where countries will negotiate a new pact to reduce greenhouse gases.

Carlos Rittl, executive secretary of the Climate Observatory, sees Brazil as unprepared to compromise on a new and more ambitious agreement.