Croppers adapting to a drying Wimmera

He said GRDC had partnered with the CSIRO to come up with more specific and accurate information, to help set the target.

"They are also doing some thinking as to how they can invest in assisting growers to make that emissions mitigation, without sacrificing vast amounts of productivity."

He expected that GRDC would have answers, by the end of the year.

"The biggest hurdle we have, as does all of agriculture, is understanding exactly where we sit," Mr Hosking said.

"There is a whole heap of modelling out there, and every model gives you a different answer."

It comes as the Intergovernmental Panel on Climate Change has warned within the next two decades temperatures are likely to rise by more than 1.5 degrees above pre-industrial levels.

Read more: NFF puts farmers' climate voice to the fore

Mr Hosking, Quambatook, said from an industry point of view, farmers wanted to be confident whichever net zero emissions model they chose was the correct one "even if it's not the information they want to hear".

Farmers realised the climate they were farming in today was different to the one many of them began their careers in.

He said when it came to land and soil, farmers considered the sustainability of their properties and ensuring they were "every bit" as productive in the future as they were today, if not more so.

"This year was a classic example in Victoria, we didn't receive and autumn break, but we've had an extremely wet winter," he said.

"Now practices farmers have put into places means we are actually looking at some really good crop potential, without the so-called vital autumn break we normally rely upon."

Most farms in Australia were owned and run by families.

"You are very conscious of making sure you are leaving your children something that is productive, sustainable and in the best possible condition," Mr Hosking said.

"It's not just an asset you buy and sell, with little regard to what happens to the next owner."

David Drage grows cereals and pulses and runs dual-purpose sheep at Lah.

"We are learning to farm with a variable climate - it's got its challenges," Mr Drage said.

"It's not just what can you do to make the farm work, it's also managing the financial implications that come along with that.

"When I plant a crop, I am expecting a yield of somewhere between zero and five tonnes to the hectare - and that range is a significant thing to manage."

He said he'd traditionally relied on Medic pastures, to feed sheep, but with the shorter growing season, they were not performing as well as before.

"Hence there is a lot of vetch being planted, to be grazed off, or cut for hay - vetch has become the number one legume in my cropping rotation."

It made management decisions, during the cropping season, difficult.

"At the moment, we have had an extremely dry start so I am not prepared to give any more nitrogen to any crops.

"I have committed some, I know what the soil test results were, I know how much moisture I have got."

He said he had been using multi-peril crop insurance, but it was no longer available.

"So it comes back to the choice of crops and how we run the livestock operation," he said.

He said he'd switched to a self-replacing Merino flock, in an area which was not known for breeding.

"I can, through selective choice of rams and setting my own breeding values, produce a Merino ewe that is significantly more productive than whatever I used to buy."

Mr Drage said about two-thirds of the farm was planted to cereal crops, with the balance devoted to long fallows and forage crops, which were either grazed or cut for hay.

He aimed to run 500 breeding ewes.

"But a third of my breeding ewes are currently in NSW, because that's where I sold them in mid-May when things got tight.

"We have to be better at planning.

"I knew how much hay I had in the shed, earlier this year and no I had desire to purchase any more because if I did that it wasn't going to be viable."

John Renney, Berriwillock, grows wheat, barley, canola and lentils and said he believed there had been changes in climate and the weather.

"We tend to see these extremes they talk about - we get the longer periods of dry weather and then heavy rain," Mr Renney said.

"Temperatures, too, are probably a bit higher.

"In saying that, we have had a run of good years, so it's easy to put it in the back pocket.

"Our adaptations have made a massive difference, that's how we are keeping ahead of it at the moment, I reckon."

New plant varieties were a significant part of staying ahead of changes.

"We are basically moisture farmers now, we farm to store moisture for the crops, so we don't like any weeds over summer, even in-crop," he said.

"We sow earlier and no-till has been a massive plus - it allows us to get crops up and away and get their growing done, in that winter period."

He said 20-30 years ago, dry sowing the crop would have been unheard of.

"I have no doubt things are changing.

"I think they (the scientists) are fairly confident about the temperature side of things, it's just the rainfall that's hard to model."