The carbon ice-age cycle

The drifting continents
Clash and pull apart
As the pulsing polar ice-caps
Beat on like a heart

Expanding as the carbon drops
And shrinking as it rises
This carbon linked great cycle
Is one of earth’s surprises

Driven by great algal blooms
That peak in times of cold
And die away to little
As the seas grow hot and old

The earth and its biosphere are intimately linked. The ancient dance of ice-ages and interglacial warmth cycle on and on in response to Milankovich orbital cycles or the episodic rising and falling of atmospheric carbon dioxide levels.  Sharp falls in atmospheric carbon dioxide levels can occur when massive oceanic algal blooms suck up billions of tonnes of CO₂ . This could occur for many reasons including continental drift modifying ocean currents, volcanic eruptions or fractures in the earth’s crust releasing billions of tonnes of natural gas.  This in turn can trigger an ice-age which reinforces itself with the albedo of marching glaciers and is accompanied by dramatic drops in sea-level. But as the nutrients in the ocean slowly deplete the algal blooms reduce and atmospheric carbon-dioxide levels start to rise. The world begins to warm and rain returns to shrinking drought stricken continents reducing the volume of iron-rich dust settling on the oceans.  The oceans become clearer as the continental vegetation flourishes and the ice-caps retreat.

 The massive release of carbon from the burning of billions of tonnes of fossil fuel by our industrial world is, unfortunately for us occurring at and intensifying the hot part of the cycle. To a large extent the rapidity of the current rise is uncharted territory. It may not, as the geologists tend to argue, make too much difference in the longer term but the short term impact if left unmitigated will be profound and include both mass extinction of species and the potential collapse of our civilisation.  Time will tell if we, like our ancestors who repeatedly abandoned and reinhabited places like the Unite Kingdom through the ice-ages, can also adapt.  We probably can but there won’t be many of us left.

But we do have the option of mitigating the degree of global warming by reducing our emissions and we also have the option of artificially triggering oceanic algal blooms through the addition of iron to upwelling zones to reduce atmospheric CO₂ levels.  We have to be careful before launching global bioengineering initiatives as the consequences of this are not fully predictable but it is something which should be looked at and business as usual no longer an option.

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Sepik River Piranha

The people of the Sepik
Are hungry and need fish
Let's introduce the Pacu
That's a tasty dish

It may be a piranha
But it doesn't feed on meat
It mostly crushes nuts
With its large and fearsome teeth

Now the ball-cutter piranha
Feeds on other nuts
As it lurks in shallow water
Close to peoples huts

No one likes to see hungry people but the decision to introduce piranha into Papua New Guinea's Sepik River as a food source beggers belief. Yes, they may be vegetarian in their native Amazon but they are still piranha and nobody should have been surprised when they became carnivorous when their natural diet of nuts and river vegeation became scarce. Referred to a "The Mutilator" in Jeremy Wade's River Monster programme they appear to be responsible for at least two deaths in the Sepik when they bit off the genitals of men wading in the shallows. It is unsurprisingly now referred to as the "ball-cutter" throughout PNG and it is greatly feared. It is a large and hardy species that has spread throughout theSepik River system since fingerlings were introduced into the river by the misguided "FishAid" Project in 1994 and then into the Ramu in 1997. They will undoubtably infest all PNG rivers in the longer term.

The ecological and social cost of active introductions of invasive exotic fish species into Papua New Guinea's river systems has been enormous and yet the introduction programmes continue with the latest menace being the genetically modified GIFT Tilapia. Crocodile populations have plummeted as the river vegetation that they need for nesting is consumed by introduced tilapia and carp. Freshwater prawns are also vanishing and so are iconic game fish species such as the Black Bass and the Sepik Grunter. It is a tragedy unfolding.

We seem incapable of learning and keep making the same mistakes again and again with the same predictable consequences. The long term answer lies in education but by then it will be far too late for many river catchments and their unique species of fish.

Mangroves

The rhythm of the sea
Pulses through the trees
While the leafy canopy
Rustles in the breeze

The fish and crabs are feeding
Among the mangrove roots
While birds and bats are breeding
In their leafy roosts

But now the trees are dying

In a smelly stagnant pond
Because their roots need drying
And they’ve lost their tidal bond

 Mangroves are marvellous! A productive tidal forest adapted to the rhythm of the sea. But to conquer this niche they had to first overcome the challenges of salt and waterlogging. Salt is excluded at the roots but also accumulates in the leaves which shed and in turn support a detritus food chain feeding crabs, prawns and fish. The tidal pulses on the other hand provide regular respite from waterlogging.

Marvellously adapted they may be but like many organisms living on the edge they are close to their upper tolerance limits. They are hence vulnerable to both waterlogging and hyper-salinity should the tidal flushing be inhibited. Great care is therefore necessary in the construction of causeways and other tidal barriers to ensure adequate flushing and complete drainage which in turn will prevent the death of mangroves and the loss of fish, crabs and prawns. It is very sad to see a marvel of nature transformed into a stagnant, foul smelling and mosquito infested swamp dotted with dead skeleton trees.

Soldier Crabs

You will not see the blue crabs
When the tide is high
They are hiding in their burrows
Safe from fishy eyes

 And even when the tide is low
There still are hungry spies
And the blue crabs in their borrows
Avoid the sea-birds eyes

But sometimes if you’re  lucky
When the tide is on the ebb
You may see the blue crab army
Emerging from their beds

They march across the mud flats
Grazing as they go
Before retreating to their borrows
Before the tide is low

The behaviour of the blue Soldier Crabs of Coochiemudlo Island in many ways mirrors that of the human inhabitants of the island. For most of the time both are snug inside their houses and the streets and sandy mudflats are still and quiet.  But at set times both groups emerge from their homes to forage before retreating to the safety of their houses. For the human inhabitants the sound of the barge is the signal to emerge and go shopping. For the crabs it is ebbing of the tide.

The sight of the blue crab army emerging from their burrows on the ebb tide is truly amazing. The grey sandy mudflats transform to glittering blue as the soldier crabs march across the mudflats grazing on the algae scum and leaving behind small balls of sandy waste. They feed quickly ever alert for avian predators before retreating to their burrows before the bird tom-tom triggers the arrival of  all kinds of hungry birds looking for a feed of crab. And there they remain through the tidal change until the next ebb tide.

Flying fox lament

People do not like me
They hate my noise and smell
And many batty orchardists
Wish I was in hell

Some may think me vermin
And a vector for disease
But I really am quite useful
As I pollinate the trees

I'm intelligent and sociable
And pretty as can be
And turning sunset sky to black
Is marvellous to see

Few creatures are as unfairly maligned as the flying fox.  In a country awash with ferals it is a great irony that a protected and ecologically important native animal is the brunt of so much hatred and hysteria.  The media has a lot to answer for by deliberately stirring up controversy and giving air time to the profoundly ignorant. And then the politicians get involved and it is a free for all. The one group no one listens to are the scientific experts.  If the experts state that you won’t catch Hendra Virus from a from a flying fox you will be sure to see an opinion piece by someone with no credentials  shrilly denouncing the flying fox as a danger to public health. The current trend of opinion taking precedence over science in a host of areas including climate change, ecology and even medicine and sociology is extremely worrying. We are headed back to the dark ages when a Galileo could be imprisoned for daring to suggest that the earth travelled around the sun.

Yes, flying foxes are noisy and messy but few ask the right question of why they are establishing colonies in towns. They falsely assume that the population is too high and demand that they be culled when the real reason for their presence is that their habitat is vanishing and they are looking for food and a place to live.   Far from being overpopulated the flying foxes are in decline despite their increasing presence in towns. And yes they will maraud fruit crops but many species of flying foxes are primarily nectar feeders and they are important pollinators. They are intelligent and  sociable and the sight of them taking to the sky in their hundreds at dusk is magnificent.  I’ll bat for the flying fox any day.

The Curlews of Coochie

Does the sound of eerie shrieking
As you lie there in your bed
Wake you from your sleeping
And fill your soul with dread

Your terror is in error
There is nobody dying
Relax enjoy the pleasure
Of the Coochie curlews crying

We have recently relocated to beautiful Coochiemudlo Island nestling in a sheltered corner of Moreton Bay. It’s a place of sun soaked beaches, clear seas and lazy days. It is also home to a large population of Bush Stone Curlews who spend their days hiding in the thick forest which covers much of the island and emerge at dusk. They are strange long legged ground-dwelling birds with large yellow eyes and stand about 55 cm high. They are very graceful and have the capacity to stand very still and blend into the background and their screeching call has to be heard to be believed. At intermittent times throughout the night the silence of the Coochie night is shattered by a chorus of piercing shrieks and wails that sound like someone is being murdered. Long term residents no longer notice them but visitors can find them very disturbing. I love their eerie call and the reminder of wild nature outside our window in this special place. 

Most residents of Coochie would be very surprised to learn that their “Curlews” are not really curlews but Bush Stone Curlews or Thick-knees. It is a dry-land species despite its relationship to Oyster -catchers and Avocets. They are common across NE Australia where they forages for frogs, spiders, insects, molluscs, crustaceans, snakes, lizards and small mammals and particularly on moon-lit nights but are now rare and endangered in Victoria due to predation from foxes.

Carbon tax

Remember when the earth was cool
And consequences rare
When we could burn up energy
Without a thought or care

We did not know the Piper
Who piped his Siren’s song
Would one day demand payment
To make us right the wrong

We must now pay the Piper
Who piped our song of greed
And now demands his payment
If we are to be freed



The sea-level rose an average 1.8 mm a year last century but the rate of increase is accelerating alarmingly and currently exceeds 3 mm a year and three times that in some places. And as the icecaps melt and the warming seawater expands it is set to get a lot worse. Modelling showing metres of seawater rise by 2100 was recently considered pessimistic by but increasingly looks like being in right ball park. We are on the verge of global catastrophe. And if you doubt that, spare a thought for the people of PNG’s Carteret Atoll who are the world’s first Climate Change refugees. They have already relocated to Bougainville as their islands disappear beneath the waves and they will soon be followed by many others across the rising Pacific. This is a key point that seems to be lost in the current carbon tax debate. We don’t have time to argue the point about disadvantage or to delay action until other nations take action. We must start moving to a low carbon economy and Australia as a world eco-power with so much to lose from sea-level rise and climate change in general must show leadership.

I think the government is going about it the right way. Put a price on carbon to provide reasonable incentives to industry to reduce emissions without wrecking the economy whilst protecting the vulnerable as we transit to a low carbon economy. Moving too far too quickly will be political suicide and doing nothing is not an option. My guess is that we will end up with a carbon price of about $25/tonne similar to Europe. Australia missed a golden opportunity to take bipartisan action on climate change a couple of years ago and history will vilify those responsible for the demise of the Emissions Trading Scheme that followed the demise of the then Leader of the Opposition.

But while we consider the negative consequences of a carbon tax we should also think about opportunities. Investments in alternate energy and agro-forestry will likely prosper but our real advantages are in less obvious areas such as environmental science and technological leadership. Our geographical location close to the booming economies of China, India and SE Asia also gives us a significant advantage over our competitors with respect to mineral resources. The embodied emissions in a tonne of Pilbara iron-ore over its life cycle from mine to China will for example be much less than a tonne mined in central Brazil and shipped half way around the world.

Yes, it will be difficult to ensure adequate compensation for vulnerable groups impacted by a carbon tax. Industry will also be disadvantaged in the short term by moving more quickly than our competitors but there is a place for leadership and most industrial leaders understand the opportunities associated with first mover advantage. What should be obvious to everyone is that this is not an issue which will go away. We can take decisive and early (already a bit late for that) action or we can play catch up later when forced by circumstance. The main difference between climate change and natural disasters like cyclones and floods is the time scale. But unlike a flood or cyclone situation when everyone pitches in and helps regardless of cost we seem content to sit back and ignore the situation. We have enjoyed the dance and it is now time to pay the band.