Farmers now have the tools to measure their carbon footprint.

A carbon calculator's been developed which can compare a farm's greenhouse gas emissions to the distance travelled in a car.

AgriLink's Managing Director Andrew Barber says that the number is a simple tool for farmers.

"The farmer can enter in 100 dairy cows, and out pops a carbon number, how many emissions does that cow produce."

Barber told Mike Hosking that the calculator then converts the number into hectares of forest, which reveals a more sobering number.

He says it's changing the way we think about the environment.

"The idea really behind this was that it creates a conversation. It starts a conversation around a real area.

"We need to go from saying this is our number to saying this is what we're doing. They're planting trees, be that different management systems."

Barber says that if farmers are concerned about climate change, then people need to do more.

He says that they are receiving sponsorship at the moment to help launch the programme.

It follows a similar study done by the University of Manchester, which used sandwiches and chocolate to measure how much energy people use.

LISTEN TO ANDREW BARBER TALK WITH MIKE HOSKING ABOVE