On way to achieve those outcomes was through bipartisan politics said Mackay, who praised Environment Minister James Shaw for his work on the Zero Carbon Bill.
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Mackay agreed, saying Shaw's wish for something "enduring" and National's support for the Bill was a "mature" way to come to consensus over such an important global issue.
Although there was no denying climate change was "the big challenge of our generation", water continued to be a "multifactorial" issue for farmers said Mackle.
"There are so many things in there, for example, there's a bunch of different contaminants and you've got to manage them differently too and also different farming systems and different contributors whether it be urban, municipal town waste ... so a lot of things to work through".
Climate change and water concerns were at the forefront of many farmers' minds this year, but there was also the challenge faced by some from cattle disease Mycoplasma bovis.
Mackle thought "things were getting better" with M. bovis, although that might be "cold comfort" for some farmers.
"I think in the new year we'll have a much better idea of where exactly are we on this journey towards eradication, towards freedom from M. bovis if you like.
"Overall I've got no doubt that the response is getting better at a general level, better people coming on board, better systems and processes".
Farmers also had a role to play in the battle against M.bovis said Mackle, especially when it came to traceability.
"I think a team effort in 2020 [is needed] to push ahead with this one".
Also in today's interview: Mackle recapped a successful revenue year for dairy and said he thought Te Papa's "brown water" display was "very disappointing".
