Primary production
in a changing
environment

GAVIN
Kia ora. We’re here to talk about climate change – how it works, and how it relates on-farm.

CARRIE
We’ll also reveal New Zealand’s biggest contributor to climate change. It might not be what you think, and it’s rather close to home.

COW 1
[Belch]

COW 2
[Belch]

COW 3
[Is she looking at us?]

CARRIE
Our atmosphere is a magnificent cocktail of gases, water vapour and particles that constantly mix and mingle. It gives us our oxygen, protects us from radiation from the sun, and controls our weather. It’s a delicate balance, and all life depends on it.

GAVIN
But we’re doing things down here which are really upsetting the balance up there. Human activities are rapidly increasing the concentration of greenhouse gases in the atmosphere. They’re called greenhouse gases because they trap the heat and warm the planet. The main greenhouse gases that we produce are carbon dioxide, nitrous oxide and methane. Globally, carbon dioxide is the most important because it stays in the atmosphere a very long time.

CARRIE
Here’s what’s going on.

GAVIN
Incoming solar radiation warms up the surface of the Earth. The Earth’s surface then sends this heat back through the atmosphere and most of it goes out into space. But some of this heat is trapped by greenhouse gases, and this extra heat warms up the atmosphere.

So, the more greenhouse gases we emit into our atmosphere, the more it’ll warm up and affect our climate.

CARRIE
And it’s already having a big impact. Earth’s temperature has warmed by about one degree Celsius since humans started using coal, oil and other fossil fuels. Globally, 18 of the hottest 19 years on record have occurred since the year 2000.

Here in New Zealand, temperatures are about one degree hotter than they were a century ago. We’re seeing more extreme weather and that’s before we talk about rising sea levels, melting glaciers and polar ice. 

SHEEP 1
Indeed, the evidence is compelling.

CARRIE
As our climate in New Zealand changes, it might not be possible to farm in the same ways or the same places as we do now. A couple of degrees of warming might not seem like much, but it has a big impact on crop and pasture growth, and on pests and diseases. More extreme weather also creates bigger problems.

GAVIN
Now it might surprise you to learn that New Zealand’s biggest current contribution to this isn’t carbon dioxide at all.

CARRIE
Nope. It’s methane from animals.

COW 1
[Belch]

COW 2
What the?

CARRIE
You can find out more about how methane affects climate change in our next video.

Produced by the New Zealand Agricultural Greenhouse Gas Research Centre. Funded by the New Zealand Government

CARRIE
So how exactly is methane produced, and how does it contribute to climate change? There are a lot of different stories out there, but this is how it actually works.

GAVIN
Methane comes from several places, including wetlands, landfills, forest fires, agriculture and fossil fuel extraction. But here in New Zealand, the largest proportion by far is belched out by livestock.

COW 1
[What, all livestock?]

SHEEP 1
[Not us, surely!]

CARRIE
It’s perfectly natural. Microbes in the fore-stomach of ruminant animals, like cows and sheep, break down the pasture the animals have eaten and produce methane. And, well, it has to come out somehow.

COW 1
Great … but it breaks down though, right?

GAVIN
Well, it’s true that methane released into the atmosphere breaks down much faster than other greenhouse gases like carbon dioxide. But while it exists, it has a big impact. Tonne for tonne, methane is actually many times more effective at absorbing heat than carbon dioxide.

CARRIE
An emission of methane will mostly disappear from the atmosphere within 50 years. But while it’s up there, every molecule traps lots of heat. An equivalent emission of carbon dioxide traps less heat, but stays around much, much longer. Thousands of years in fact.

GAVIN
We’ll show you what it looks like. Let’s say filling up the board with symbols is equivalent to a certain temperature increase.

I’m emitting carbon dioxide into the atmosphere every year. Because CO2 takes so long to break down, every emission adds to the warming caused by previous emissions. The amount of CO2 increases over time, and the effects become bigger and bigger.

CARRIE
Okay. I’m emitting methane into the atmosphere. Each emission makes a big contribution to warming, but fortunately we’re not emitting nearly as much methane as we are carbon dioxide.

So as we do this, Gavin is going to rub out the methane symbols to show they break down at a much faster rate in the atmosphere, and I’m going to continue emitting at the same rate.

GAVIN
So if we keep emitting the same amount of methane, the amount in the atmosphere levels out, because the new emissions by and large just replace the previous emissions that have now disappeared.

COW 1
[So, what’s the problem?]

COW 2
[New burps replace the warming caused by old ones.]

CARRIE
But, we’ve increased our methane emissions a lot over the past century. This has pushed temperatures up already, and globally they’re still going up.

GAVIN
If we keep emitting methane at the current rate, that will keep the atmosphere a lot warmer than it used to be.

CARRIE
So, at a minimum, if we want to stop additional warming from methane we need to reduce the amount of emissions.

GAVIN
They don’t have to be stopped completely, but the more that they’re reduced, the less warming is caused and the better for the climate. How far could we go?

COW 1
[I don’t mind a change of diet!]

CARRIE
Climate change is a complex challenge. But we’ve already achieved heaps thanks to some clever Kiwi innovation and farmers becoming more and more efficient. But there is more that we can do. New technology will play its part, but there’s more that you can do now. Find out what in our next video.

 Produced by the New Zealand Agricultural Greenhouse Gas Research Centre. Funded by the New Zealand Government

GAVIN
Farmers have been asking: what can I do to reduce emissions on my farm? Well, there are three gases we need to reduce: carbon dioxide, nitrous oxide, and methane. But on-farm, it’s particularly about the last two. Lots of small steps can add up to make a big difference.

CARRIE
The good news is that combined greenhouse gas emissions from New Zealand agriculture are no longer going up, thanks to farmers’ efforts to become more and more productive and efficient over the years. As a result, the greenhouse gases emitted per unit of product are going down.

GAVIN
Without all this great work, emissions from agriculture in New Zealand would be about 30 percent higher than now, to produce the same amount of food.

COW 1
[But there’s a lot more of us now.]

SHEEP 1
[And a lot fewer of us!]

GAVIN
But we need to reduce emissions, not just keep them steady. There’s no magical formula here, but there are several things that can be done on farms right now – and some will have other benefits too.

You know your business better than anyone, so you’re in the best place to work out which of these are achievable.

CARRIE
Here’s what some farmers are doing already, that you might want to consider for your farm.

First, find out what your farm’s greenhouse gas emissions are and include them in your planning. Depending on the farm, it might be that some of those options can save you time, and money.

In a nutshell, methane emissions are related to the total amount of dry matter eaten. Nitrous oxide emissions depend on the total amount of nitrogen going through your farm via feed and fertiliser. So, what steps can be taken to change these quantities, while still running a profitable business?

GAVIN
Look carefully at the feeds used. Can you use feeds with lower nitrogen or higher energy content to get animals to market quicker? Would a less-intensive system work for you? It might be reducing fertiliser inputs and stocking rates, changing the ratio of your stock type, or once-a-day milking.

You could try using precision technologies for improving the amount and timing of your fertiliser application.

CARRIE
Look at the balance between individual animal performance and stocking rate. Could you run slightly fewer animals and focus more on getting the most out of each animal to keep production up?

You could also consider the balance of your land use to reduce livestock emissions. Many farmers are now integrating trees onto their less productive land, and there is Government support to help do this.

For some farms, diversifying some of the land use to cropping or horticulture could reduce overall emissions and dependence on one income stream.

GAVIN
Rest assured, you’re not alone in your efforts. Scientists are working hard on new solutions, with some very promising results. Some of them are being trialled already. In the future, it’s likely we’ll be able to breed low-methane animals or use inhibitors and vaccinations to reduce the amount of methane that animals belch out.

We’re all working towards the same goal, and any small step is a step in the right direction.

CARRIE
Remember to check out our website for lots more information. Thanks for watching.

Produced by the New Zealand Agricultural Greenhouse Gas Research Centre. Funded by the New Zealand Government