Transcript of the inside the Bureau's climates guide project webinar

Heather Field:

Our webinar today in our climate webinar series is on looking inside the Bureau's new climate guides project. Today Luke will run through the new regional climate guides, which aim to help farmers understand and manage their climate risk. Luke Shelley joined the Bureau in 2008, and in the last two years has been a member of the Bureau's new agriculture program, where he's currently the acting general manager. Luke has just finished traveling around the country to consult stakeholders on the design of the Bureau's new climate guides. I will now pass over to Luke Shelley from the Bureau of Meteorology.

Luke Shelley:

Thanks very much Heather, and thanks very much for having me on today as part of the seminar series. I'll have to admit this is a bit weird because I don't know if I'm just talking to myself or I'm talking to a hundred people out there, but we'll get cracking. So as Heather said, this today is about the Regional Weather and Climate Guides. I'm going to talk to you a little bit about what a climate guide is, some of the things that we did to develop the guides, and some of the things that we learned, and then we'll probably the second half or most of it, most of the presentation today, I'll walk you through an example of a climate guide and then I'll show you some of the trends and findings that we found in and across the guides. The focus will be on Victoria, and of course you could obviously do the same sort of thing with the guides, we're national, so today's focus is really just on the guides that were in Victoria. And then we'll have plenty of time for questions.

Luke Shelley:

The first thing is what is a climate guide? It's really a snapshot of the region's climate from 1959 to 2018, and it compares two 30-year periods in that range. When we started the project, we asked people what was going to be most relevant to present from a statistics point of view. And what came out fairly early on was that looking at two 30-year periods would cover two generations of farmers and their families, and that would probably be a reasonable estimate of how people remembered their business on the land. And so the whole idea behind this was that we could show people what happened perhaps in the previous generation, and then show them statistics on the more recent climate. The guides also feature a range of topics that are relevant to agriculture and I'll show you through those today, and also based on Australia's NRM regions.

Luke Shelley:

So in Victoria they're the CMA, the Catchment Management Authority, regions and other in parts of the country they're known NRM regions or as the for example, New South Wales called them LLS regions and so on. When we started the project, when we were asked to do this project by the Federal Government, the way they described it to us was they wanted to help agriculture in particular, but agriculture and regional communities understand more about their current climate risks and opportunities, and they wanted us to do that nationally. We envisaged that we'd be able to do something like 40 or 50 of these sorts of guides, and we made that up in our head before we had a look at specifically what regions we would do. And so given of course that the NRM regions are already existing, there's already a lot of work that's based on those regions, it made sense for us to try and do the guides based on those regions as well.

Luke Shelley:

All right. There we go. To develop the guides, we purposefully didn't want to just sit in an office in a capital city and produce a set of climate statistics. That actually would be fairly trivial for some organization like the Bureau to do. We really wanted to engage with people from those regions to understand what their needs were, and really learn more about how people use the information. So we engaged with farming representatives, agronomists, local state and federal government. It's worth pointing out that what we didn't do, is we didn't just send out a blanket invite for people in the regions to just come and have a workshop, we actually targeted people who were representatives. The reason why we did that is largely because we needed to do something that was representative of each region and representative of the nation, and to invite a whole heap of producers, often what happens is everybody has some needs for their own business and their own property, and we knew that we weren't going to be able to cater for those individual needs.

Luke Shelley:

And so from the very start we focused and honed in more on those regional representatives and some industry bodies. For each NRM we produced a four-page guide and the map there just really shows where we went out to engage and that we did all of that in 12 months, so we visited, we did 50, I think it was 52 workshops. It was actually 58 guides. You can see that Northern Territory we actually split that into some of their LGA regions and it just made more sense. The actual Northern Territory in our own region is the whole territory.

Luke Shelley:

And we also split the Northern WA into two halves as well. But I traveled, I think I facilitated 30 of those workshops that you can see on the map. Everywhere from, I did quite a number here in Vic, pretty much all the interior New South Wales and interior Queensland ones. And it was also when the heatwave was on at this time last year when I was doing those. So I had a pretty hot summer myself traveling up to the north there, but every workshop that we did we learned something new everywhere we went. It didn't matter if it was the first or the 50th workshop. A highly, highly valuable experience to be able to travel around the country and engage with people in each region.

Luke Shelley:

We had some pretty big challenges for this project aside from the expectation to do it all in 12 months, but there really is a strong desire out there for locally relevant information, and that's terrific, and to a certain extent we can offer that through the Bureau services. Some of the things that underpin that though are challenging, and one of those is that observations aren't equal around the country, and particularly if you want to look at a longer term record. So the Bureau has some infrastructure that it manages, and some of that goes back more than a hundred years, 120 years in some locations, but not every location. So if you're talking about rainfall records, there's a really rich history of 100 years around the country, temperature records really only go back 60 or 70 years. So it makes it a little bit more difficult.

Luke Shelley:

And then of course not every station... and that's at the most, not every weather station that we operate has that period of record, so trying to get information that's locally relevant, sometimes you have to choose a couple of locations that are representative across the region, rather than being necessarily the one in your backyard. Some of the regions are very large and agriculture within those regions is vast and highly differentiated. So I guess all of those things together, probably the biggest challenge that we had was communicating the concept of what we were trying to do, and managing those expectations about what we could actually do in the timeframe, and I guess in a guide, in a way that we can still help people nationally and in their region, but achieve something that's representative of a region without it necessarily being exactly what's happening in your backyard.

Luke Shelley:

I think when people ask me about what would be a successful outcome for the guides, the way I described that was that even though it might not be the information in your backyard, if you could pick up a guide and get an understanding of what's happening around you and around your region, and that then sparked you to have further questions about what might be happening in your backyard, that would be a really good outcome, and I think we did a pretty good job in achieving that.

Luke Shelley:

Some of the things that we learned from traveling around the country and listening to people and what their needs are, people are really, really attuned to change and variability. Talking in averages is just not relevant anymore if it ever was, and people really have a keen interest in learning more in that space. Something came across quite strongly actually, and I've just gotten quotes, "Stick to the weather and climate and leave ag to us." And that was a really good learning for us. They said that look, matter of fact is that ag Is highly differentiated. It's very different from property to property and region to region. The Bureau would be best to just stick to giving them that industry and Australians the very best weather and climate information that we can, and leaving them to decide how they use that information.

Luke Shelley:

I think that that was really, really relevant and certainly we don't want to move into that space, it's not our area of expertise, but we really do want to continue to engage and work with that customer group, give them the very, very best information that we can. It's pretty clear that, and I'm speaking now I guess, we certainly did our best to differentiate the climate guides product region by region and across the country, but what came out was this real need and desire for all of the products and services that the Bureau produces to be highly differentiated by customer-base and by region around Australia. So I'm talking not only about climate guides, but that our seasonal outlooks about our daily weather forecast, the whole lot. That was a really, really strong piece of feedback that we gathered around the country.

Luke Shelley:

And look, the other thing is that people have a lot more questions on their mind, more than what we can cater for in this project, no doubt, we're really only scratching the surface with the Regional Weather and Climate Guides, but there's a real appetite for people wanting to learn more, questions about certain processes that happen in their region. Again that goes back to the challenges that we had about the data and observations, and all that sort of thing, but there's no doubt there's a lot more that people would like to learn.

Luke Shelley:

So, I'm going to now give you a walk through of a climate guide. I've just got on the page, there is a bit of a space filler, but the three locations that you can actually get the guides, you can get them from the Bureau, you can download the PDF from the Bureau. You can also download the PDF from FarmHub, the National Farmers Federation, FarmHub. The FarmHub is building up to be a bit of a one-stop shop for farm support. It has a whole range of resources from mental health through to climate risk, so it makes sense for us to place the guides there and also Climate Kelpie, which I'm sure a number of the subscribers here today are familiar with. Climate Kelpie is actually a really nice, they've done a terrific job for us on Climate Kelpie with a feature on the climate guides, and there's a nice in page PDF viewer, that means you don't have to download the guide if you want to just read it online, so I'd recommend those three resources. I'm just going to click out of this and I'm going to get up a PDF to... Okay, this is an example of a climate guide, and I'm going to take you through The Mallee.

Luke Shelley:

The Mallee was where we started and I think I have some unconscious bias that whenever anyone asks me for an example of a climate guide, I straight away go to The Mallee. It was the first place that we engaged with, so they really gave us some frank... we had a really frank conversation with people in the Mallee about what this was going to be and that group along with a number of others around the country, I guess helped shape that early on, but really the guide-

Heather Field:

And Luke-

Luke Shelley:

Yeah.

Heather Field:

We're not seeing that on the screen at the moment, that guide.

Luke Shelley:

Sorry. You can hear me talking and I actually... All right, sorry. I'm sharing the wrong thing, my apologies. I'll stop sharing for one moment. There we go. How's that?

Heather Field:

That's great. Thank you.

Luke Shelley:

All right, that's good. Thank you. Well, I hadn't started describing the guide fortunately, but I will now. So the climate guide, like I said earlier, it's four pages. We know that as much as we might desire that everyone would read four pages, not everyone will do that. So the front page is really designed to be, if you're only going to read one page, the top of the front page, usually a bit of a snapshot and you can read some of those headlines, and if you go away having learned something in it, and you think a little bit more about some of those concepts, terrific job done.

Luke Shelley:

So really, it's just some headlines at the top, which we go into more detail throughout the guide. A bit of a description about the region, which is probably not telling anyone anything who lives in that region. But interestingly, we got some feedback earlier on around this and it's utility for using the guide to describe to people who are outside of the region.

Luke Shelley:

So, lots of regions apply for state and federal government grants and sometimes having this sort of information can go a long way to supporting those grant applications and whatnot, and so we've just put a little bit in there, based on some ABARE stats and things like that, and then it's just a little bit of a spiel about what the climate guides are and what to expect. So then we pretty much go straight into some of the key content. We start with rainfall, a bit of a no-brainer that rainfall was going to appear, everyone's interested in rainfall. And really what we're doing here is we show the full... This was also a really important piece of feedback that we got earlier on, which was that people want to see the full record of the rainfall in their region, and that we shouldn't just jump to periods that are shorter than that, we should at least show the whole record, and then the commentary focuses not on the whole record, but on those two 30-year periods. So the two 30-year periods that we compare in the guide, 1959 to 1988, and 1989 to 2018.

Luke Shelley:

And really the reason for those two was we're in 2019, we wanted to choose exactly 30 years backwards, so that's the reasoning behind those two periods. You could choose any periods that you like to make a comparison. But this is what made the most sense and certainly made the most sense with the customers that we asked. So those charts here really just show the full history with a 10-year running average, so you can see what's happening at a sample of some weather stations in that region. It's not necessarily every weather station, and you could go away and have a look at other weather stations in the region and they vary, with the length of record, we wanted to choose some that... Everywhere we went, we asked people, "What would be a weather station that would resonate with people in this region?"

Luke Shelley:

And so that was our first selecting criteria. If they said, "You'd be mad if you didn't have the Birchip post office records in here." And then we'd go away and investigate whether or not that weather station actually had that record for us to be able to do some meaningful analysis. And so, in some cases like Birchip is a good 120 years of data, in other places where even though people would request a particular location being included, it just didn't have enough data or the quality of that data wasn't adequate for us to be able to do the analysis. Throughout the guide, and I guess I didn't mention earlier I've talked about what the guide is, but what it's not, and the guide does not address future climate projections.

Luke Shelley:

It only goes so far as to make some links. And there's a couple here, one here is to the climatechangeinaustralia.gov.au website, and there's another location in the guide, that is a link out to the state of the climate report that the Bureau and CSIRO do. And that's as far as we go with climate change projections. Another aspect to rainfall, and I will show you I'm sort of just going to skip through, but I'm going to show you a couple of examples later on across all of the guides, but this is a part where we talk about rainfall reliability, and so you get each season and try and understand about how reliable the rainfall is across each of those seasons. I'll go into more detail about that in a minute.

Luke Shelley:

Then we talk through rainfall timing, again the same as the rainfall records we choose the previous annual rainfall. We actually choose a couple of locations where we can show more of a breakdown, not only what was your annual rainfall, but when did it fall on average? And this is where we start to get into some of the detail of comparing those two periods. Depending on where you are in the country. So obviously across Victoria, the autumn break is something that people use, it's a notion that people use in the cropping season and pasture seasons. But that's not the case across the whole country. So in the Victorian guides we have a focus on the autumn break, and I'll show you an example of that later, it'll be the same example, but other parts of the country, this is where we started to vary things a little bit. So for example, up north of the country focused more on heavy rainfall events and more on things like the onset of monsoon and the wet season. Finishing off from the rainfall, we then start to talk about temperature, and this is where we really hone in on things that are relevant to agriculture, and this was from direct feedback from our customers again.

Luke Shelley:

So we have a focus on frost in a couple of weather stations again, and then are focused on higher temperatures. One of the things that we don't present in the guides, that's actually the last page, that we don't present in the guides here is we don't do a commentary on average temperature increases. Some really good reasons for that, and this again came back from the customers that we asked, and that was that you might've had an increase of a one degree or half a degree or one and a half degrees at your location in your region, but that doesn't really mean much for people if you're talking about an average. What they told us was that it's those thresholds that matter the most.

Luke Shelley:

So rather than doing a chart and some analysis on average temperatures, we asked people in each region what did they consider to be a hot day? What was that threshold? And then we plotted how many times that was happening over that period. And you can see the example there and I've got a couple more later on. So I'll go back to my... I'm sorry, there might a better way to do this, but... Here we go, we're back. Can I just check that you can see the content again?

Heather Field:

Yes, we can. Thank you.

Luke Shelley:

Terrific. Thank you. Leading off from there, now I'm going to talk about what were some of the actual findings in a data, in a statistic sense about Victoria's climate. We'll start with the rainfall. When we compare annual average rainfall between 1959 and 1988, and 1989 and 2018, just those two periods, it's not a comparison of the full record, it's just those two 30-year periods. And what we found was that there was some slight decrease across Victoria, say from the north and the northwest, you can see that Mallee is seven percent, where in north central six, seven across. But where I put the equals, there was still some slight changes there, and that's basically anything less than five per cent. So Northeast Vic, and Corangamite, and Glenelg, I think they were around they did have a slight decrease it was one or two percent.

Luke Shelley:

You have to be pretty careful with the messaging around that, because we're only talking about two 30-year periods and whether or not one or two percent, that can sometimes be in the noise in the area so it doesn't necessarily mean there's a huge change in those areas, and look, even some of the others, five, six, seven, it's not so much whether or not that's a huge increase but it is about when it falls, and it's also about I guess how it's been trending. We're breaking this down into wet and dry years, so what we've considered here is that a wet year would be the top 30% of annual rainfall in those periods, and the dry year the bottom 30%. Everything else in between being considered average. And there's a couple of really clear things that have happened here between those two 30-year periods.

Luke Shelley:

One thing we have to keep in mind is that the most recent period did include the millennium drought, so that would obviously have an impact on the results, but really if you look at the wet years, between those two thirty year periods there's been a drop in the number of wet years, but then there's been an increase in the number of dry years. So in some ways you can see some of those regions there have almost take something like The Mallee, from the '60s, '70s, '80s, there were out of a 30-year period, a little bit more than a third of those were wet years, and then flip that relationship or that pattern over, they now are only not even a third of wet years... it's a fifth actually, and then having more than 30% of those dry years. And you can see that there's a pattern, not everywhere at the same but that was quite a pattern across most of Victoria.

Luke Shelley:

And then if we have a look at the breakdown, so I've just grabbed a few of those regions. So yes, they might have decreased by five, six, seven per cent, but when we actually broke down the records to have a look, what we did see is that this area here, which is the autumn and into early winter in some and you can even see with Birchip in the top left, there's also some decreases coming out late winter through to spring.

Luke Shelley:

Just focusing on that autumn period, autumn was the one that had I guess the most replicated pattern across Victoria, particularly Northern Victoria, but you still can see some changes down there in Orbost, and so when we talk about that, there's slight decrease in an annual rainfall, it's actually that most of that decrease has happened in a particular period, and that period is obviously quite relevant for agriculture. I should say, of course, I've just picked four, so not every rainfall station shows that and it's worth having a look at the guides, your local region a little bit more closely to see if that's apparent in your region or it may be a different pattern.

Luke Shelley:

This is what rainfall reliability looks like across Victoria, and this isn't a comparison of the two periods, it's just the most recent period. When we say rainfall reliability, what we've actually done with the stats here is we're just showing the fluctuation from year to year. The average fluctuation from year to year. It doesn't show an extreme fluctuation, but basically the colour grading is anywhere that's that sort of a light beigey-brown, it could fluctuate on average in that season at that location, plus or minus 50%. And red is where it can fluctuate much higher. So it's less reliable. It doesn't mean that you get consistent rainfall throughout that period, this is about, the annual average variability from year-to-year. So if you've got an area that's the blue and the darker blue, then on average through that 30-year period, the rainfall only fluctuated by plus or minus 10, 20, 30% from year-to-year.

Luke Shelley:

So winter is the obvious standout and I know that that's not telling anyone anything new because that's the winter, that's the southern cropping season down here, the most reliable areas tending to be in the southwest of the state, but generally speaking, most of the states are fairly reliable through winter, less so in spring for the southern half of the state and pattern which is similar in autumn. And a question that often does come up, and it's also why we wanted to show people this, is that people often ask the question, "Oh, gee, we've had a couple of summer storms the last couple of years, maybe we should start thinking about what we can do. Can we put something in then, etc." But the reality is that despite that, we have to tease out recent memory versus the actual stats, and despite that it shows, particularly for the northern part of the state, summer rainfall remains unreliable.

Luke Shelley:

I can tell you that we have done it. It doesn't appear in the guides, but we have done a minor... we did compare the two periods and there's really no difference between the two. So there hasn't been any change, anything significant between the reliability of those seasons. The only very minor thing that came up, was that in actual fact the summer rainfall is slightly less reliable than it used to be. So it's actually, I'm going the other way, but we're only talking about five, five to 10% at most change. That's different for other parts of the country, particularly the north, but down south there's really no change.

Luke Shelley:

So we'll move on to temperature and I've already given away the answer there in highlighting what we're going to be focusing on, but what I'm showing here is the comparison of the frequency of frost and just note that the scale is different on each of the charts here. So somewhere like Boort doesn't have as many frosts as somewhere like Rutherglen, so that the chart isn't equal, just keep that in mind. But really the blue bars here represent the frequency of frost for the period 1959 to 1988, and the orange bars are the recent period, '89 to 2018, and then along the bottom you've got the time of year. So the charts starts for most of them in April and finishes in November, but again that scale is different for each of them, depending on what their frost season's like and as you would imagine the start of the season anywhere you start to see the little parts of the histogram crop up is where the season kind of officially starts, and then there's more frost or more cool temperatures, in the middle of the season.

Luke Shelley:

I should just say when we say frost here, this is because this is not actually based on observations of frost occurring, it's based on observations made at a bureau weather station, and we make the observation if a zero occurs at a bureau weather station, that's what we call screen height, and that's a little bit about the ground, and that normally means minus 2 at the ground level, and so that's what we've used as a surrogate for frost. Keeping in mind, we're really just trying to show some patterns here of the potential for frost, not necessarily exactly what happened on the ground at that location, at that time, but anywhere you can see where the bars of one period taller than the bars of the other highlights a change.

Luke Shelley:

So if we have a look at, say I'll take Birchip on the left you've got Birchip, and you can see that those orange bars tend to be quite a bit higher than the blue bars from the previous period. So that really shows that in the last period there were more frosts throughout that time of the year, and you can also see maybe a little bit skewed by the red circles ovals, I've got on there, but you can also see there's been a few instances of frost later in the season, particularly at Birchip and Boort, and then again highlighting that these are just a sample of locations, and every location is different. But there's an example there of Hamilton where frost has I guess receded a little bit through some parts of the season.

Luke Shelley:

I think that I was going to mention something else about frost. With the Birchip and Boort, you have to remember that we have had the dry period as well, and so generally speaking, frosts tend to occur when it's been dry, clear skies, and no moisture, no rainfall. So that's actually a good explanation for why we might have seen an increase in the frost, during the most recent 30-year period compared to the previous one.

Luke Shelley:

And now we'll finish off with the hot days, and again, this is where we focused on the number of hot days above a particular threshold. So when we traveled around the state, people in the north and to the west mostly told us that 38 degrees was a good threshold, and then down south 35. So I've just got that line across the state, I'm showing that. And then the numbers for each region and the name of the weather station that we used for those records. So the first number on the left is how many times on average, in a year, that temperature met or exceeded. So we take 38 degrees and we'll use Mildura as an example, so between 1959 and 1988 it got to at least 38 degrees 10 times, and between 1989 and 2018 it got to 38 degrees at least on 16 occasions.

Luke Shelley:

And you can see for every one of the locations, there was an increase, sometimes not by much, because in some areas it doesn't happen that often, but in others I guess reasonably substantial. It might not seem like a lot if you're going from say three to five, but I guess what that means is that if you're running cattle, or you've got a particular activity, having that across summer or maybe light spring, it means you've now got two extra days you have to worry about looking after your stock or managing that activity better than you used to in hot condition. In general, the pattern has been for an increase across the state and that's a pattern that we've seen across many parts of the country.

Luke Shelley:

Here's, again, I've just plucked out a few examples from the guides and you can get the individual ones in each of the guides, and not all of them show the same, but this is the number of days over that threshold, and they're all based on 38 degrees and the 10-year running average. So take Rutherglen for example, it's not like it's never gone over 38 before. You can see in the late thirties, it definitely did that, and there's other examples in some of the others as well where that temperature has certainly been exceeded in the past, but it's more about the frequency and how often that's happening and how the increase in the number of times that we're seeing that happen. And to finish with it, just a couple of little stats on some of the more extreme temperatures. So in Bairnsdale, since 1999 has recorded 43 degrees, seven times, and there's been no prior observation in the history of the record of that temperature being there.

Luke Shelley:

Rutherglen recorded 44 degrees eight times since 1989, and I should also note that this doesn't include 2019 or 2020 data, this is only up to the end of 2018, and it's only recorded 44 degrees at Rutherglen three times prior, in the history of the record. Some of those were in the '30s as well, early '40s I think. And Horsham 45 degrees six times since '89, and only once in the previous period, I don't know about the whole record for Horsham. And Mildura, 46 degrees six times since '89 and only twice for each period. So in some ways the temperature is probably, of all the things I've shown you in the guide, I guess temperature is the one that's the most hard hitting fact, I guess and it's probably a fitting way to finish with the climate guides, so that's it for my presentation, it is, and I am happy to take some questions. I'll stop sharing my screen.

Heather Field:

Oh no, leave it on there in case you need to flick back to anything, but thank you Luke for your great presentation today and giving us a better and more detailed look into the climate guides, it's been great. We've had 155 people registered for today's webinar, and we've got about 87 people online at the moment.

Luke Shelley:

Terrific.

Heather Field:

We do have a few questions coming in, and a reminder if you do want to ask a question you can either write that in the chat box or in the question box, and if you want to ask it verbally, I can try and unmute you to ask that verbally. But our first question is from John and he wants to know what measures of variability did you find most useful? He's used to thinking about SD and variants, but maybe deciles will work better.

Luke Shelley:

We just use co-variants on the East, but there definitely might be other ways of looking at it, and given that we only did the snapshot for the 30-year period of variability, that was just the technique we used to show that one image, so it's a spatial analysis for one image, deciles are definitely a very good way to show, more often we use those just to show where we're at now in comparison to history and that's absolutely valid way and terrific way to show that. But that we didn't have the space to just put everything I guess in the guides, we just wanted to show that snapshot.

Heather Field:

Okay, great. John says thank you, fantastic presentation. Maria would like to know, does the fact that the 30-year periods add up to only 21 wet and dry years mean that nine were neither wet nor dry?

Luke Shelley:

Yes, correct. What I didn't show you was the number of average years. So if out of 30 years, if it added up to 21 that meant nine were average, and average is anything higher than 30% of your longterm rainfall and less than... sorry, what was that? I'm getting that the wrong around. Less than 70% of your long term average rainfall and higher than 30%. So yes, definitely in that range, there would be a number that would just be consider it to be average. You could write that down, and this is I guess one of the challenges with the climate guides, is we had sort of had to choose something that was going to work for everyone. If you were really interested in understanding that more, I would recommend people to look at more detail into their actual local weather station records and work out what would you consider average?

Luke Shelley:

Because if we sit here at the Bureau, and we say, that's an average rainfall year, and it's quite a broad range, it might be that some of those years where you said actually you wouldn't consider average, you might consider that to be dry or you might consider that to be wet and a good year. We didn't really have the ability to do that. So yes, the rest are average.

Heather Field:

Right. Thank you. We've got a question or a statement and a question from Bronwyn. The BoM did a great job at workshops. I went to two of them. There were common threshold producers were interested in which were hot days, health frost days, animal health and crop production. We'll say the common factors did not have time to analyze or what were the common factors that the BoM did not have time to analyze and include?

Luke Shelley:

Good. I think there's a few I think one of those would have been showing a difference between the rainfall variability, so I showed you just what the last 30 years were, but I think generally speaking, people were interested in what we could show, but if there'd been any change, that was one. I think the other one particularly for down south was the autumn break and whether or not the autumn break was actually getting later or earlier, and actually I didn't get to more detail on that, but I should explain what we did for the autumn break was everywhere we traveled around people would say to us, "In our heads, we get autumn break on this day, and that's what we plan to." So what we did for the analysis was chose that date and then actually mapped when they would get that break, and showed it on the map how many weeks it was after that specific date, and you can see that in the guide.

Luke Shelley:

But that would be... and again that's based on average, so if we were to say, The Mallee tends to get its autumn break six weeks after the 1st of April, it's not always going to be like that, and so that was definitely an area where I think could be really useful to do some further analysis to show, I guess what the variability of autumn break is, but also has that been changing compared to the previous period or compared to the historical record? They were some of the really common ones? I think other areas were, temperature was a tricky one because we know that different thresholds relate to different industries and different businesses, so I think it would be nice to do... because you can pick any threshold you like and do the analysis. So we picked 38, that seemed to be the most generally accepted one, but you could choose 35, you could choose 42, you could choose a whole range of those. It'd be good to have those available to people.

Luke Shelley:

The rest of the requests tended to be fairly specific to those regions and they were very challenging, because that would only be for that region and it also would have been our research project on its own. I think the only other one that came up was about streamflow and water availability in dams and through allocations. That is definitely an area I think would be very useful to do, and we didn't really have the time, mostly because it's a different sort of set of data, compared to weather station data. It relies on a whole different range of factors when it comes to rivers and allocations, and that's a complex problem, but it's not one that can't be done, it would just take a little bit more time. But that was certainly common across the nation.

Heather Field:

Okay, thank you. We've got a question from Graeme Anderson. Are local people able to share or use some of the local graphs in their own extension materials, and if so, how best to go about it?

Luke Shelley:

That is a fabulous question and I must admit that is something we always aspired to making available, the individual images and charts that people can use. I would say, the best way you can go about that right now is to send an email to agriculture@bom.gov.au, and we will be able to facilitate that for you. So I'd be delighted to pass on any of the raw images or information for you to use and please do use them, we did this because we wanted it to be a valuable resource for everyone and that'd be terrific if you felt that it was worthy of using.

Heather Field:

Okay, great. We've got question from Rob. Do you have any data on changes in wind speeds and humidity in your 60-year period?

Luke Shelley:

That would be one I left out of the list of things that commonly came up. Wind is very difficult data to work with, it's very messy. It can be inconsistent. The Bureau does record that information, and humidity information, but it tends to, I guess not being the same state as rainfall and temperature records, it's a bit harder to measure, and so we haven't done any further analysis on wind or humidity, although I should say some of the guides we did through THI, I can't remember if that specifically appeared in Victorian Guides, but a number of them we did a THI index, so we might have some of those for some of the big ones potentially. We definitely have them for a range of others, particularly as you go further north.

Heather Field:

I've got a question from Jamie. Can you comment on the extreme events?

Luke Shelley:

That's a tough one to... as much as we've gone into extreme events is what I showed you today. In the guides, the way we cater for that is to choose a threshold, and to analyze how many times that threshold has been met. And that's what I showed you with the temperature. We haven't done any further analysis on whether or not, there's been more or less of those and there's a whole range of things that people consider to be extremes, and so I don't have any further comment other than what's in the guides, and largely that was done around temperature, some parts of the country, particularly further north, we did a little bit more on... You wouldn't call them extreme, but people ask for information on the start or end of the wet season, and we just chose a figure, a number of 50 millimeter rainfall days or things like that. That's the approach in a guide like this. You can't do much more than that.

Luke Shelley:

The other... often when you see information about extremes, it tends to be at the national level, and there's a good reason for that, and that's because it is quite hard to tease out extreme events at a local level, because they don't happen that often, and so we could look into say observations, let's just pick Tatura for an example, and see how many times was there an event that it was 50 millimeters in a couple of hours, and let's call that an extreme event. That might have only happened a couple of times in the last 30 or 50 years, and so making any meaningful sense out of two or three occasions is really challenging. I'm not debating that it's not happening or that it is happening, but it's just a really challenging topic.

Luke Shelley:

The other thing that, what we're finding, and this certainly was feedback that came to us was that these things are happening, and they don't always happen where we've got a weather station. And so people are talking about extremes and yes, we've got this huge downpour but the property down the road didn't get anything and it certainly didn't fall on the weather station. So that makes it very difficult as well. Having said that, just at the Bureau level, it's probably worth mentioning that we certainly have a change in focus about observations in the future, and we're certainly looking at how we can better incorporate on-farm observations into the Bureaus data sets. Of course though we do need longer term records to be able to make meaningful sense of some of the data. So it'll just take us time to build up more of that information.

Heather Field:

Thanks Luke. We've got lots of people saying great presentation and they've really enjoyed it, and they also want to know is it possible to receive your slides, your PowerPoint slides, they understand there's going to be the recording, but are they able to access the slides? Can you share that?

Luke Shelley:

I can make them available to you. If you like, we can have a chat about what... Or we can do on a mass email out to everyone who subscribed or registered, I don't mind, but yes, you can. No trade secrets in there, you can go for your life.

Heather Field:

All right, I'll work something out there. We have Jess who would like to know if she can share the PDF online. For instance a link to display on cams or websites, assuming she's talking about the guides.

Luke Shelley:

Yeah. Look, everything you can share, go for your life. If there's anything I can do to help, let me know you can get in touch with me at agriculturebom.gov.au, so I'll give you an example, local councils, some in NRM regions etc. CMAs, LLS, they've contacted me and just asked if they can actually host the guide online or use a link, you can do all of those things, you can download the guide if you want and go for your life. You don't have to let me know if you want to, that'd be great, if I can help you in any way, terrific. If you're from a regional body and you are interested in getting some printed, I've got high resolution print files and things like that, so please get in touch to see if there's anything I can do to help you out.

Heather Field:

Thanks Luke. We've got a couple more questions, we've got a few minutes to go... I'm just trying to find it again. This is from Graeme again. For the temperature increases, is there a season where this is happening more than other seasons? And also do you expect the frost trend to continue in each region? Any thoughts for Victorian and frost next 30 years in terms of trends?

Luke Shelley:

You're asking questions above my pay grade Graeme. With the temperature, we didn't break it down by season, so I couldn't honestly answer that. I think that would absolutely be a good thing to do just like we did with rainfall because as we know a cow can tolerate high temperatures once it's acclimatized it might be that one of those hot days, early spring is the killer. So no I couldn't comment on that, and I certainly couldn't comment on the frost, but going back to what I said earlier, which is that frost does tend to occur and we did do, and it is in the guides, we did do a little piece of analysis around frost and dry years, and generally speaking, if you have a dry year, you will get three or four more frosts in the spring period. And if we were to continue to have dry spells and dry runs like what we've seen around the country in the last 12, 18 months, in some parts a little bit longer, if we continue to have those extended droughts like the millennium drought, yes I would expect to see frost pattern to continue. I guess just talking, addressing future projections a little bit here.

Luke Shelley:

There's two key things that have come out, at least from the last run of projections. The current global projections, new ones have just been finished and there'll be some analysis work done on those over the next year or so. But the two clear things that have come out are that what we expect over the next 10, 20, 30, well at least 10 to 20 years is that rainfall signal will continue to be highly variable. So it's really hard to pin down any particular trends there. But everything that I've shown you in the climates guides today, from a temperature perspective, is very consistent with the messaging and the current set of projections. So whether it's probably what's the relationship between the temperature and the rainfall is I guess the bit to tease out to try and understand whether the frost, that profile will continue. But certainly I think there's more than enough there for people to have a look and take notice and see what that means for your business.

Heather Field:

Thanks Luke. We've got two more questions. If you've got time to hang on for a couple more minutes.

Luke Shelley:

I'm happy to take questions for as long as people would like, and I'm happy for people to ask me questions beyond today's seminar if they like, I'm happy to facilitate any way I can. So just to say again, agriculture@bom.gov.au, and I'll do my best to get back to you when I can.

Heather Field:

Fantastic. Rob, he's made a comment and a question. Interestingly, if I heard right, your figures show only a small drop in rainfall in North East Victoria, yet MDBA figures show a significant drop in inflows into the Upper Murray... I've lost my question. Upper Murray in the last couple of decades, would you put this drop in inflows down to an increase in evaporation rates over the 60 year period.

Luke Shelley:

Possibly, and this goes back to one of the reasons why we weren't able to tackle questions like that. Rainfall at a location or on a new area is one thing, inflows into a system or a storage is a whole range of factors. Evaporation could absolutely be one of those. Certainly some of the analysis we did, some areas asked us for an understanding of if evaporation's changed in some parts it has and that definitely has an impact on water resources. There's a whole range of other things including land use, allocations, actual sources, what sources go into each system. That might set a challenging question to answer, and so the answer is it's not ever going to be a direct relationship with rainfall declines, it's a whole host of factors that impact on that.

Heather Field:

Thank you. Scott would like to know, is it possible for you to come to a workshop to present the climate guides to farmers?

Luke Shelley:

It's actually a challenging question and I'd love to say yes. I'm actually not an extension officer, I'm more of an industry liaison officer. So it does make it difficult for me to be able to come out and do presentations around the country. I guess if you think about my role, it's less about coming out to talk and more about negotiating with government to get funding to do another version of climate guides, if that makes sense, but I'd be happy for you to email me and we can have a further conversation about how I might be able to help, but just to manage expectations, it is a bit challenging for me to do that sort of work.

Heather Field:

Absolutely. Thank you. Richard, does Bureau of Meteorology gather radiation data and use that to indicate changes in carbon sequestration and potential for crops, and the way changes in total radiation might be influencing crop productivity over seasons.

Luke Shelley:

We definitely record solar radiation, I don't know the extent to which our network does that though. So, I couldn't comment whether or not that's every weather station, I doubt whether it would be. My current understanding, I have a counterpart. My role is in ag, I have a counterpart that works in energy and resources and I know that recently they've been highlighting the lack of observations that we have that suit planning for solar, solar electricity and things like that, so I know that we do have some, it possibly isn't adequate to meet the demands of what you're talking about, but that's certainly the sort of thing that we're looking into, into the future. I'd be very interested to learn more about how you would use that information and what the value would be. So please feel free to get in touch.

Heather Field:

All right. Thank you. And I think that was the last of our questions. We do have just a couple of comments from Dale Grey. Relationship between runoff and rainfall is not a straight line relationship and sunlight hours is at very few stations across the country.

Luke Shelley:

Great. Thanks Dale.

Heather Field:

Okay, well we might take it and close there. I think we've answered all the questions and a lot of interests there, which is fantastic. I do want to just remind everyone that we do have a survey at the end, so when you close out of the webinar, please take a minute just to complete that. And I just want to thank Luke again for his valuable time and answering all those questions and providing a very detailed presentation, and looking a lot closer into those climate guides. Thank you.

Luke Shelley:

Thanks.

Heather Field:

Before I do close, I just want to let everyone know that the next webinar in our series will be on the 11th of March, and we'll hear from Graeme Anderson from Agriculture Victoria on weather forecasts, seasonal outlooks and climate change projections and what they can and can't do. So if you have subscribed to the climate webinar series, you will be receiving some more information about that next webinar shortly. If there's no other questions and it doesn't appear to be, I'll close out now and thanks again, Luke.

Luke Shelley:

Thanks.

Page last updated: 23 Jul 2021