Emissions from burning fossil fuels are projected to be up 0.6 per cent in 2019, to reach almost 37 billion tonnes of carbon dioxide, scientists from the University of East Anglia (UEA), University of Exeter and the Global Carbon Project said.

The annual rise in carbon dioxide, the main greenhouse gas driving rising global temperatures, is less than increases of 1.5 per cent in 2017 and 2.1 per cent in 2018.

Levels of pollution are growing more slowly because of falling coal use in the EU and the US and slower growth in the use of the fossil fuel in China and India.

But worldwide emissions from gas and oil are up, according to the assessment which is published as countries meet in Madrid for the latest round of UN talks on tackling climate change.

A shift from coal to less-polluting gas has been backed by some as a "bridge" to a cleaner future, but the experts warn emissions must fall to zero and switching to gas is no long term solution.

The researchers' analysis shows how far the world is from achieving the steep emissions declines of 7.6 per cent a year to 2030 that the UN has warned are needed to curb global warming to 1.5C and prevent the worst impacts of climate change.

Three years of almost no growth in emissions between 2014 and 2016 raised hopes that carbon pollution had peaked - hopes undermined by the last two years of increases.

Emissions are set to be 4 per cent higher than they were in 2015, when countries negotiated the Paris Agreement to limit global warming to "well below" 2C above pre-industrial levels and to pursue efforts to curb rises to 1.5C.

But the annual average rise over the past decade has been lower, at 0.9 per cent, than in the 2000s when carbon pollution was growing at around 3 per cent a year.

The researchers behind the project called for more policies to make sure clean technologies such as wind, solar and electric vehicles are replacing fossil fuels, rather than coming online alongside existing fuels to meet growing demand.

"The current climate and energy policies are clearly not enough to reverse the trends in global emissions," Prof Corinne Le Quere, from the UEA, said.

She said stronger policies are needed to accelerate the deployment of low carbon technology and "very importantly" to phase out the use of unabated fossil fuel.

There was a delay in the sense of urgency in taking action, and there was a need to take a more systematic approach to tackling emissions across society, such as transport, heating and cooling buildings and industry.

Burning fossil fuels for electricity, transport and heating, as well as using them for industrial processes such as making steel and cement, has accounted for 86 per cent of carbon emissions over the past decade.

Some 14 per cent comes from deforestation and changes to the way land is used, and emissions were up 0.8 billion tonnes above 2018 levels, to six billion tonnes, with more fires in the Brazilian Amazon and Indonesia.

Overall, global carbon emissions from human activity are set to reach 43.1 billion tonnes in 2019.

In Europe, policies to increase the cost of carbon pollution drove a big drop in electricity generation from coal, while in the US, the economics of cheap natural gas and more solar and wind have seen coal use fall despite President Donald Trump's attempts to boost the sector.

China saw modest growth in coal, with low growth in electricity demand but stronger growth in energy-intensive products that use coal such as cement and steel.

A slower economy in India, coupled with a strong monsoon which flooded coal mines and boosted hydropower generation, also saw emissions grow more slowly there.

Data for the Global Carbon Budget 2019 is being published in the journals Nature Climate Change, Earth System Science Data and Environmental Research Letters.

Australian Associated Press