SAO PAULO, Brazil -- A Brazilian network of environmental groups says emission levels of greenhouse gases in Latin America's biggest country fell last year to their lowest in two decades.

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

It says in a report released Thursday that 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.

Gas emissions caused by deforestation, farming, the energy and industrial sectors and the burning of crop residues were measured.

It says emissions from deforestation have dropped, but emissions from the other activities have risen and could rise more because of gasoline subsidies and increased use of thermal power.