Q&A Climate change: recent effects on crop yield and productivity
ROSEMARY LOTT: Hello, I'm Rosemary Lott from ABARES. I wondered-- probably anyone of the three in the panel could answer this. What's your sense of the capacity of farmers to continue to adapt in the future as climate continues to throw increased variability, and decreased rainfall, increased temperature at us?
ZVI HOCHMAN: Sorry, I can't see you, so there's-- yeah, OK. Well, it seems that farmers are adapting at a rate of around 25 kilogrammes per hectare per year. But there is a ceiling to that. And that ceiling is that they will reach 80% of yield potential. So you've got one train, which is the rising capacity, if you like, of farmers to make the most of what's happening. That will come to a plateau when it reaches 80%. There's literature from lots of places around the world that supports that, including from Australia.
At the same time, what we don't know is if there is a ceiling on how much the climate will become more adverse. If it continues at the current rate-- and that's an if, because I don't think anyone would be brave enough to say whether it will or it won't. In terms of climate change projections, that rate is actually at the more negative side of predictions. But if it does continue, then in the next 26 years, we will have crossed the line. And we will be seeing reductions in yields.
LEIGH RADFORD: So that means, when you get to that point, it doesn't matter how hard you try, that's it. You're going backwards whether you like it or not.
ZVI HOCHMAN: Unless prices go dramatically higher. And none of the economists are predicting that.
LEIGH RADFORD: Neil, the new model that you were showing us-- obviously, that is a tremendous step up. Is that fully operational now? And what else is in the pipeline? If you're doing stuff that is that impressive, and is already being used, what else is coming, too?
NEIL PLUMMER: Yeah. Thanks, Lee. It's not operational right now. We'd expect to get it operational later this year. That's the hope. So the early signs is, as I showed, a positive thing. We've seen some-- we actually expect improvements. But there's got to be some management of expectations around here. There's still uncertainties-- you know, the probabilities. We're not going to get to the 90%. We're getting to the 80% in some areas.
But the next lot has really taken this model from the UK, and just tweaking it slightly for Australia. So that's what will come out this year. And then there'll be a lot more tailoring, or Australianising, of the model in future years. And I think we'll see some better improvements there.
And then, beyond that, it is, how can we continue to improve our supercomputing, our science, the modelling, and so forth? But there's a lot of advancements going on around the world, so they expect that improvement to progress for a good few years. Yeah.
LEIGH RADFORD: Great. Now another question here. And please don't hesitate to put your hand up. It's actually quite difficult to see you with the bright lights, so you may need to sort of wave your hand around a little bit. But a question over here.
DAVID CAMPBELL: That's on. David Campbell, agribusiness freelance. Two questions. They're related, and they are linked to the earlier question about farmers adapting. So first, to Zvi, the focus on your potential-- have you been able to discern whether there's been a significant change in water use efficiency underpinning what you're seeing? Because it would seem to suggest that that is happening. I'm not sure whether you factored in what was going on with genetic potential, and whether you've been able to take that out. So that's my first question.
The second one is to Neal Hughes. There seems to be a lag affect between when we introduce new technology and farmers learn to use it, and their advisors learn, and working with variability. And from the commercial side of input industries, I certainly saw that over about a 30-year period in our commercial experience. Have you been able to factor that in at all, somehow, in your analysis? And if so, does it give us some insights about how we actually improve the speed and rate of adoption, which has been one of the underlying issues in extension, traditionally, in agriculture, is how do we get these innovations, both rate and speed, much more into agriculture?
LEIGH RADFORD: Thank you. Two good questions. Zvi, we might go to you firstly with the yield potential one.
ZVI HOCHMAN: So the first half of that water use efficiency, yes. The answer is yes. The two are almost inseparable. In terms of separating the genetic effect, I have no update on that. But other work suggests that that's about half of the progress that we see in technological improvement.
So you have kind of system improvements, you have genetic improvement. The two often leverage each other. And so even distinguishing between them is a bit fallacious. But certainly, the assumption would be that genetic improvement's about half of that story.
LEIGH RADFORD: And the second one, Neal?
NEAL HUGHES: Yes. So the idea that there are lags between research, development, and extension is something that ABARES has looked at in a lot of its research. It's not something that is explicitly built in to the model in this study. But certainly, the idea that there are lags between the productivity growth that you see in the model-- so the rebound over the last 10 years-- and the research and development activities that led to that.
So it suggests that there was a period where productivity was stagnant. So presumably, there was a lot of activity going on during that period. But it may not have taken effect until later. So yeah.
LEIGH RADFORD: Yeah, right off the back.
JIM PRATLEY: Jim Pratley, Charles Sturt University. Neil, I was wondering whether you could just--
NEAL HUGHES: Which Neil?
JIM PRATLEY: --give us the numbers on the improvement from what we have now to what the new model will give in terms of accuracy or confidence, from what to what?
NEIL PLUMMER: Yeah. So we don't have the numbers to see it, and we're not likely to have for awhile. But it's a bit of a blunt measure to put a single number on this. And just to explain why-- and we track this. So we track the accuracy across Australia, which in one way is a measure of how well the model's going. But in another, it's blunt. It doesn't actually mean anything.
Because what's important is how well we're forecasting at certain areas of Australia and at certain times of the year. So we know that that blunt measure, the national measure, is a lot lower than when you unpack it for key areas.
And it's also more important is that, when you're getting extremes in the climate, and they're impacting on rainfall and temperature in an extreme way, is that you forecast them events better. And we know that these models do that, so that, when we've got an El Nino or La Nina, will things happen in the Indian Ocean? We've got more confidence in those models.
Get back to your original question, though. We're targeting national average, 10% increase. But that will have more impact when you look regionally and at certain times of the year.
JIM PRATLEY: 10% Of what?
NEIL PLUMMER: Well, that's between 60% and 70% now. So the 65%, again, it's a bit meaningless in itself. That understates the improvements that we're likely to make for the reasons I just gave.
LEIGH RADFORD: And Zvi, this past year's been quite extraordinary. Clearly, it's a case of, add water, it will grow. But from the research you've done, would it appear to you, given the trends that you were showing us, that it really is just kind of one of those one-off events or years?
ZVI HOCHMAN: Well, I wouldn't say one-off. But I'd be surprised if we get, say, more than three of those in the next 26 years. So don't hold your breath waiting for that. Already, we're hearing from Neil that, perhaps, we're moving into an El Nino event, which doesn't necessarily mean low yields, but yeah. It was an exceptional year, and there's no reason to think we're likely to repeat it too often into the future, just as we wouldn't have even if there was no climate change.
LEIGH RADFORD: That wasn't what I was hoping you were going to say. Neil, though, given the exception of year, from a layman's perspective, it kind of looked like a lot of tropical activity was really responsible for the tidals that we saw, and ultimately, the season that we've had. The predictions have all been about hotter and dryer. But if oceans are warming-- if the Indian Ocean was such a big driver for this past period-- is there a possibility that we could see wetter summers in future, and more of this kind of thing, in your opinion?
NEIL PLUMMER: There were certainly-- some of the extremes-- and unpacking this one with that shift in the Indian Ocean, that was unprecedented. So we don't really have a historical analogue to see how that impacts on climate. But we know from the models that there's likely to be higher rainfall. Places a lot like Tasmania, during winter, the flooding-- the high rainfall they were getting-- was subtropical rainfall. It wasn't winter rainfall. So we're seeing lots of unusual things happen.
Agree with Zvi, though. The last 20 years, above average rainfall over southeast is about three or four. 16 have been below average. That fits with the atmospheric circulation changes we've spoken about. So I'd say, yes, we're still going to get these wet events. But they're unlikely to be as frequent as what we've had in the past.
LEIGH RADFORD: OK. Any other questions? What an extraordinary year it was. Well, if that's the case, we're-- oh, no. I beg your pardon. One more over this side of the room.
SUE BESTOW: Sue Bestow from the Department of Agriculture. You've spoken about how farmers have started to adapt to climate change over the last 20, 25 years. What you described is incremental change. When do you think we're going to see transformational change?
NEAL HUGHES: I think the thing about transformational change is that it doesn't necessarily happen suddenly. And to some extent, you might only be seeing that in the data showing movements of cropping. So the transformational change will take 50, 100 years. It will happen very slowly. So to some extent, we may already be seeing it.
Having said that, what's hard is to say where we'll end up in 50 years. And it's extremely hard to predict what the long-run changes in land use are going to be. We don't know what the future climate will bee. We don't know what climate change policy will look like. And these things will have a big bearing on all of that.
So my opinion is that we have to really focus on the trends that you're seeing in the short run, because that's-- predicting what's going to happen in 50 years is very difficult. And you can see the startings of movement in cropping activity.
LEIGH RADFORD: Fascinating hour and a half. Thank you so much for your presentations. Thank you for your questions. Can you please thank them?
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