The National Farmers' Federation has reacted with surprise and concern at speculation that the Federal Government may be about to set a start up date for agriculture's inclusion in an emissions trading scheme (ETS).

The Federal Government is due to release on Wednesday its green paper detailing its response to the Garnaut Report, setting out how it intends to establish an ETS.

Professor Ross Garnaut recommended that agriculture be initially excluded from the ETS due to the Government's inability to measure, monitor or verify the sector's true emissions profile.

But there is speculation will set a start up date, possibly 2013, for agriculture to be brought into the system, which will otherwise begin in 2010.

"It's news to us," NFF president David Crombie said.

"All indications have been that the Government recognises agriculture cannot be covered at this time – as both Professor Ross Garnaut and the Productivity Commission have made clear."

Mr Crombie pointed out that the challenges of covering agriculture within an ETS are not isolated to Australia.

"No country in the world has found a way to equitably include its agricultural production in an ETS," he said.

"That is, with the exception of New Zealand, where farmers are now looking at margins reducing by up to 160pc as a result.

"As Professor Garnaut and the Australian Government's Productivity Commission both found, measuring, monitoring and verifying agricultural carbon emissions across 155,000 farms is simply not possible to do accurately, equitably or cost effectively at this time – nor do many of our farmers have access to genuine low cost and accessible abatement options.

"The Government must be careful not to just pluck any date out of the air for agriculture's suggested coverage under an ETS without providing a clear demonstration of how and when the obstacles will be overcome."

Mr Crombie said there needs to be recognition of the sequestration and storage of carbon in soils, crops and pastures to take full account of agriculture's natural cycle.

"The science also has to catch up so farm emissions can be accurately measured, monitored and verified, and commercially viable options to reduce on-farm emissions need to be available," he said.

"Today, there are no definite indications that any of these needs can be met, nor is there any clear pathway for being able to achieve them. Much more research needs to be done.

"We hope the ETS Green Paper will show that an arbitrary date for covering agriculture, without iron clad guarantees of addressing these obstacles, is in no one’s interest."