Tropical deforestation, a significant driver of climate change, could be cut in half by 2020 if countries follow Brazil's example in protecting the rainforest with better law enforcement and more transparency, a study released on Monday said.

Brazil cut more than a billion tons of annual carbon emissions by reducing the rate of deforestation in the Amazon by nearly 80% since 2003, said the study, based on an analysis of new satellite images of the world's forests.

Tropical forests play a crucial role in sucking carbon dioxide out of the atmosphere and scientists say that conserving them is the key for combating climate change.

A reduced rate of deforestation in Brazil, however, has been largely offset by increased logging in the Democratic Republic of Congo, Peru and other tropical countries where governments haven't taken the problem as seriously, said the study published in the journal "Global Change Biology".

"Forests are cut down because someone profits from selling the wood, or the cattle or crops that are grown on the deforested land, or from speculating in poorly regulated land markets," Daniel Zarin, the study's lead author said in a statement.

"Market failures and governance failures are part of the problem."

In 2003 deforestation in Brazil was responsible for emitting 1.76 gigatonnes of carbon dioxide, a similar amount to Russia's 2013 emissions from fossil fuels and cement production, the study said.

Brazil's deforestation emissions fell to 0.428 gigatonnes in 2012 as a result of public policy changes, better law enforcement and action by the private sector, researchers said.

However, the destruction of Brazil's Amazon forest, the world's largest intact rainforest, increased by 16% in the year to July 2015, bucking the longer-term downward trend.

Despite big reductions in the rate of deforestation over the last decade, Brazil managed to increase agricultural output, showing that economic growth and combating climate change aren't mutually exclusive, researchers said.

The study comes at the beginning of UN climate change negotiations in Paris where governments are hoping to reach a new deal to tackle global warming.

Fifteen tropical countries have pledged to cut carbon emissions from deforestation in half by 2020, although some countries who signed the New York Declaration on Forests last year have actually increased their forest emissions.

If that agreement is kept, 1.135 billion tons of carbon dioxide would be kept out of the atmosphere, contributing significantly to efforts to limit the global temperature rise to less than two degrees Celsius, the study said.