Friday 4 January 2019

L'Apocalypse des Animaux.


I stole the title of this post from an old Vangelis album.

(source)

The dramatic Queensland bushfires monopolised the public’s attention during a few weeks in late November/early December. That’s understandable. Events of such magnitude, where human lives and property are visibly at stake in our own TV screens, have a way to grab our attention. The media coverage was extensive.

At about the same time, however, the Australian media reported other events. Although I’ve discussed them with some friends, I doubt the wider public really noticed, for they didn’t receive the same level of coverage.

Still, I feel obliged to not let those perhaps deceptively little tragedies pass unacknowledged.

(source)

Although my intention is to keep editorialising to a minimum, I think that note requires some remarks, almost as a digression to what’s the subject of this post (last year I reported on something similar).

Australia is a dry place: Second only to Antarctica. By 2012 over 50% of the continent received yearly rainfalls under 300 mm (source) and the Murray-Darling Basin accounts for a substantial fraction of whatever rainfall Australia does receive. The following map shows the geographical distribution of the Fire Danger Index (source). It might seem like a curious choice to locate the Basin.


You see the large brown area towards the southeast of the continent? The one encompassing the Australian Capital Territory (Canberra), most of New South Wales and Victoria, plus southern Queensland and eastern South Australia? Well, that’s the Murray-Darling Basin (see also): With a population in excess of 2 million people, the Basin’s also where 40% of Australian agricultural production by value comes from (source).

The Darling River (where that photo was taken) collects the rainfall on the northern reaches of the Basin and discharges it on the Murray River. Unlike in the cases shown below, the ultimate cause of those deaths is well-known: Lack of water.

Fish aren’t the only ones affected. Virtually every community in that area is already feeling the pinch, even those whose water consumption is minimal:


(source)

Now, for the really bad news: Because of its fragility and strategic importance for the Australian economy, the Murray-Darling Basin is -- and has been for a number of years already -- under Commonwealth administration. Lots of money have been spent to achieve those results.

And water availability won’t be increasing any time soon as average rainfall on SE Australia is declining, due to climate change, as the chart below (from the same State of Climate report) indicates:


----------

(source)


(source)

(source)

(source)

----------

In their recent paper “Trajectories of the Earth System in the Anthropocene” (PDF) Will Steffen and co-authors warn about “tipping points”: Critical thresholds, which, once crossed lead to self-reinforcing changes in a system. (This is what tipping point means in a biodiversity context. A previous article on tipping points). The paper made some ripples a few months back.

Its authors, however, never explained how one, on the ground and in real time, could tell when those tipping points were being crossed.

I don’t think that lack of precision is their fault. I suspect that question has no general, clear-cut answer. That’s my point precisely: We could be seeing it without being aware of it.

UPDATE:
 I forgot to mention this above, but this is a good place to do it: Average temperatures in Australia -- according to the State of Climate report -- have increased by 1ºC above the 1910 level. That’s still below the lowest tolerable temperature increase level established by the IPCC: 1.5ºC.

No comments:

Post a Comment