SAO PAULO — Emission levels of greenhouse gases in Latin America’s biggest country fell last year to their lowest in two decades, a Brazilian network of environmental groups said in a report released Thursday.

The Observatorio do Clima, or Climate Observatory, network is comprised of more than 30 non-governmental organizations focused on climate change.

It said greenhouse gas emissions amounted to 1.48 billion metric tons in 2012 compared to 1.43 billion metric tons in 1992. Their highest point was 2.86 billion metric tons in 1995.

The report measured gas emissions caused by deforestation, farming, the energy and industrial sectors and the burning of crop residues. Emissions from deforestation have dropped, but emissions from the other activities have risen and could go up more because of gasoline subsidies and increased use of thermal power, it said.

Although they have dropped sharply, emissions from deforestation are still responsible for most of the country’s greenhouse gases.

The report shows that in 1990, deforestation accounted for 815.8 million metric tons of greenhouse gases, a figure that plummeted to 476.6 million metric tons in 2012 largely because of increased government efforts to curb the activities of illegal loggers and other culprits. It is estimated that close to 20 percent of the Amazon rain forest has been destroyed.

Emissions from the energy sector soared more than 125 percent between 1990 and 2012 thanks to increased use of thermal power plants and fossil fuels need to feed industry and a growing fleet of vehicles.

Carlos Rittl, executive secretary of the Climate Observatory, told Brazil’s state-run news agency Agencia Brasil he fears that emissions by the energy sector will continue growing.