Kambarang, Birak and the encroachment of summer

Round about the first of November we had a day with a dry easterly wind blowing. The easterlies bring over the warmth of the inland, but it’s still early in the bright half of the year and the Earth has a rather large amount of thermal mass so it was a much cooler breeze than I expected. Even though it wasn’t particularly hot the kids were ratty as expected – something about the dryness, the potential for static, or the scent of dust. Northerlies in Melbourne are the same, they bring in the restlessness. Working in informal education over there you always knew it would be a tougher day than most if the north wind was blowing in spring. I commented about the weather online and a friend replied that climate change seemed to mean we were losing Kambarang.

Kambarang is the Nyungar name for the season I refer to as secondspring. It’s the one we’re in now, notionally, it started at the beginning of October and would reasonably run through to around the end of November. Then there’s Birak or firstsummer, followed by Bunuru or secondsummer which last year started three weeks early on Christmas Day so I thought Bunuru was claiming Birak’s time. But the more I think about it, the more I start to wonder how true my friend’s comment is. It’s a funny old time of year right now. This week is all mid-30s, give or take, getting to high thirties at the end of the forecast range. Every day is a dry easterly. When I first learnt the local seasons twenty years ago, I associated November with grey, overcast, humid days. Days where it’d threaten rain but you’d mostly just get lightning, maybe a few spitting drops if you were lucky, maybe a little more but it’d evaporate off almost as soon as the rain stopped leaving the air even thicker. It was the time when all that moisture from August was getting sucked out of the ground but it hadn’t quite gone out of reach yet. The next season, firstsummer or Birak, was characterised by the clockwork pattern of warm easterly winds in the morning followed by an afternoon westerly sea breeze. What we’re seeing this week is kind of in between – easterlies, but not enough heat in them to generate the westerly in response. And I know that’s within the normal range for November, because among my imprinted sense of the seasons (and most redolent memories of this city) is that easterly wind, not too warm but quite a bit dry, that brings the smell of the harvest and dumps it on Perth for a week at a time. And it’s harvest time, and we have a week of easterlies ahead. But still.

A couple of weeks ago in the local paper there was an article about bushfire risk and controlled burning. Again, another feature I learned to associate with this season twenty years ago – the smoke rolling in over the city from controlled burns in the escarpment, and staying here until the easterlies could take it away. I’ve only seen the smoke once this year. The fire people were talking about how they haven’t been able to do anywhere near enough controlled burning this season, and maybe the last few either. They need the days of this season that don’t have the easterly in order to burn safely. And there’s fewer and fewer of those days. This year they’ve had less than a double handful. The areas of bush needing urgent protective burning are increasing. The local Nyungar people did their burning in Birak or firstsummer, with its predictable wind patterns. But if we’re losing or at least significantly shortening Birak too/instead…

Christmas Day last year was the first heatwave of the season, the 40-degree-plus temperatures that I associate with the heatwaves of secondsummer (or Bunuru) and the end of firstsummer. And which I associate with not happening before the middle of January on average. It’s that thermal mass thing again – you actually have to get well past the summer solstice and longest day of the year before the amount of stored energy builds up enough to make this end of the planet feel really hot. My husband spent his teenage years earning pocket money in the family’s window cleaning business, working through his summers. He commented that he’d worked in days that hot many times, but never in December. For once his parents actually agreed with something he said, which I’ve come to realise is a rarity unless they say it first.

I assumed from that and other signs that Bunuru was lengthening and extending earlier, which is very predictable from a tiny increase in average global temperature, and that Birak was the season we were losing. But with the Birak-like-weather this week I’m not so sure. Or maybe I am. It’s hard to say. See, the seasonal indicators don’t just include weather patterns, they include flowering times of plants and behaviour of wildlife. And the flowering times of our native plants haven’t changed as noticeably. Maybe a little. Several of the non-native trees in my mental floral calendar have distinctly changed, with trees I associated with the end of Kambarang or beginning of Birak already in flower now. But not so much the locals, they’re still suggesting we’re in the tail end of Kambarang. Climate change is screwing with the pattern by moving some parts of the system and not others, in particular accumulated stored heat vs day length, which means the indicators don’t happen at the same time anymore. I have no idea how disruptive this is going to be to the local ecosystem, if things that normally happen together and have formed a subtle relationship over time (eg chicks fledging and food sources appearing) start regularly happening at different times.

This year, it’s just going to be about waiting to see what the weather does, and looking in hindsight to determine when the changeover is. It might not have happened yet. It might have happened at the beginning of November. It might be happening at the end of this week. Hindsight will tell.

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