BONN: The global agricultural sector can curb emissions immediately and provide a window for fossil fuel-guzzling energy and transport sectors to decarbonise before global warming spirals out of control, the United Nations said on Friday.

"In the next few years ... agriculture ... could produce early results immediately, cost-effectively and all over the world," said René Castro of the UN's Food and Agriculture Organisation (FAO) at climate talks in Bonn.

That will give energy and transport sectors time to switch to renewables "to really take us out of the precipice and the path we are going on which is far beyond the goal of 2 degrees Celsius", he said.

Global temperatures are expected to rise 3 degrees above pre-industrial levels under current plans to curb emissions. This is far above the goal enshrined in the 2015 Paris climate agreement which limits warming to well below 2 degrees.

Scientists say that any rise above 2 degrees takes the planet into dangerous weather patterns with increased droughts, more frequent and powerful storms, and floods.

Small island states, many of which are already suffering the effects of rising sea levels and powerful storms, want the warming limited to 1.5 degrees.

"Agriculture is a large source of powerful greenhouse gases ... but has great potential to store carbon and reduce greenhouse gases in our lifetime," said Helena Molin Valdes, head of the Climate and Clean Air Coalition Secretariat.

Agriculture, forestry and changes in land use together produce 21 percent of global greenhouse gas emissions, making them the second largest emitter after the energy sector, according to FAO.

At the same time, the global demand for food is expected to soar as the population is projected to grow to 9.7 billion people by 2050, up from 7.6 billion today. "We need to feed them, and at same time we need to curb emissions from agriculture ... We think it's doable," Castro, FAO's assistant-director general, said on the sidelines of the UN talks.

Livestock account for nearly two thirds of agriculture emissions, says FAO. But changes in the way livestock are raised have been successfully piloted and could be scaled up.

Recent projects in Brazil and Argentina, for example, have managed to increase livestock productivity from one cow per hectare to four cows per hectare, and at the same time absorb carbon dioxide and methane emissions by better managing grasslands and soils and planting trees, Castro said.

Costa Rica already grows carbon dioxide-neutral coffee, and China says it plans to do the same with tea, he said.

"So if a small country like Costa Rica can do it, and a big player like China can also do it, in the middle you have every other country," said Castro, who is a former minister for environment for Costa Rica.

Christian Schmidt, Germany's federal minister of food and agriculture, said: "(Agriculture's) potential to offer climate change solutions is enormous."