The Royal Botanic Gardens and climate change

We had to get to the Australian Museum a few weeks back, but the night was warm and we had some time to spare, so we took the scenic route.  From the ferry, we strolled around the harbour's edge to the Opera House, and on through into the Royal Botanic Gardens.  It took us a little longer, but we knew in advance that it would be worthwhile.  It always is, and not just because my wife and I both took our first degree in botany.

It is suffering right now, from one of the effects of climate change, but I will come to that in a moment.

Sydney's Gardens were founded in 1816.  They aren't the oldest in the world, for Padua, Paris, Edinburgh, Cambridge, Rio de Janeiro and Munich are all older, but few gardens could have such a fine setting.  Certainly the greatest of them all, Kew, has less to offer in the way of vistas.

It was probably fitting that Australia should establish Botanic Gardens so early, since so much of the history of white exploration and settlement was tied up with botanists and naturalists.  Not only was there Sir Joseph Banks, who sailed with Cook to Botany Bay, but Robert Brown (who told physicists about what we now call ‘Brownian motion’, and who also told biologists about the cell nucleus), Allan Cunningham, and any number of other botanists who spent time in the young colony: you can find traces of some of them in the gardens.  The tradition was later to lead Charles Darwin, T. H. Huxley to our shores, and the naturalists are still coming, even today.

At first, the gardens were seen as little more than a glorified and official vegetable garden, but slowly the plant collection developed.  The name of the water near the gardens is a reminder of this earlier role, as it is still called Farm Cove.  Six months after the first settlement, there were ‘nine acres in corn’ at the first farm, but the soil was poor, and the crop was a failure, so agriculture moved elsewhere, and the area became a centre for acclimatising new plants from overseas.

If you visit the Gardens and find a poor and unkempt looking garden bed, you are looking at a reconstruction of this first ‘farm’, but that was soon displaced by other activities.  People who wanted to grow oaks to remind them of ‘home’ could obtain acorns there, and those with damp patches on their farms could get bamboo plants.  By 1816, it had become more of a plant collection, and by 1825, there were more than 3000 plant species in the collection.  Many of our worst modern plant pests came into the country this way.

Even so, Allan Cunningham, whose tomb is to be found in the gardens, still referred to it slightingly in 1838 as the ‘Government cabbage-garden’.  The science of botany had come to take second place to horticulture, with convicts being trained in practical farming there.  The gardens declined until 1848, when Charles Moore, a trained botanist, started a 48-year reign as Director of the Gardens, and from then on, they were to be truly Botanic Gardens, as well as being the home of the National Herbarium.  This is a research collection of dried plant specimens, used in the identification of unknown species.

Moore's successor, Joseph Maiden, was also a botanist, and it showed: one of Maiden's daughters was actually named Acacia!  This is the scientific name of what we plebs call a ‘wattle’, and I have this theory about the family sitting around, asking each other, ‘What'll we call her, what'll we call her?’  Well, it's only a working theory . . .

Botanic or Botanical Gardens?  Most Sydneysiders call them the ‘Botanical Gardens’, so I asked a friend who works there, and I was told that ‘botanic’ is the old-fashioned adjective which is part of their official name.  The gardens are indeed ‘Botanical Gardens’, but not in formal matters, it seems.  Still, Sydney people aren't all that formal at the best of times.  Even so, to most people there is only the one ‘Botanical Gardens’, and that is the one at Farm Cove, just to the east of the city.  As you will read in the next paragraph, we actually have three official ‘Botanical Gardens’.  I will say more about the other two branches of ‘The Gardens’ some other time.

Entry to the gardens is free to all.  There may be an entry fee for one or two spectacular temporary displays, but it is well worth paying to see the contents of these.  On the other hand, if you are in a hurry or on a tight budget, there is a great deal more to be seen for free, out of doors, including more than a hundred bird species: you can hope to see at least twenty on any given day.

Sadly, you will also see evidence of climate change there, and two days ago, I went there to record a tidal incursion. The highest "king tide" of the year comes when the planet is closest to the Sun, which happens on January 2. On January 3 this year, there was a high tide in Sydney of 2.07 metres, and the following day, when I was there, it was 2.05 metres.

Along Farm Cove, there is a sandstone wall to stop waves breaking in, and at the bottom, there are drain holes to let rain water out, but if the tide is high enough, the sea comes in. The wall is 86 cm: remember that number.

Here is what I found:

Now just to show how bad it might have been, here is some wave action at the western end, near the Sydney Opera House (or for Sydneysiders, near Man o' War Steps).

The wall is much higher there, but it was easily overtopped. Given the right wind, this would have happened all along. Now here is what I photographed the day before, when the tide was 2.07 metres: this was at North Harbour Reserve, where I have played for 70 years, and I have asked old people, when I was young, about its history.

In the 1930s, the local civic fathers saw fit to "reclaim" a former bay to make North Harbour Reserve. They built a seawall, higher than the highest tide, and pumped in mud to make a level playing field. Some years ago, as the sea started running in, they raised the sea wall and topped it with a path. Well, that defence is failing.

Our local champion of scientific idiocy, Tony Abbott, trumpeted overseas that he had looked at local historical photos of the area, and could find no evidence of climate change.

I have lived and played around North Harbour for 70 years, and I rather think this counts as evidence. That's a king tide that could easily have been 15 cm higher, if there had been a sou'easter blowing: the old men told me all about that happening, and floating one boatshed away. We got off lucky, this time, because the weather was mild.

In 1957, when I was a teenager, a super-high tide at our standard spot for the harbour (Fort Denison) was 6 feet 1 inch, or 185 cm: now, 60 years on, it is 22 cm higher. Two days ago, the CSIRO published estimates that by the end of this century, within the likely lifetime of my grandchildren, tides will be between 45 cm and 88 cm higher than now.

Those tides will be unstoppable, all around the world, and if the upper level is reached, that increase will overtop the highest point of the Gardens' stone wall by 2 cm. Seawater will extend well into the Gardens, killing and ruining our heritage.

One wonders if our do-nothing, look-at-me polly will seek funding to raise both the seawall and the park surface, or if he will just scream "fake news!".

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