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Earth, with its core-driven magnetic field, oceans of liquid water, dynamic climate and abundant life is arguably the most complex system in the known Universe. Life arose on Earth over three and a half billion years ago and it would appear that despite planetary scale calamities such as the impacts of massive meteorites, runaway climate change and increases in brightness of the Sun, it has continued to grow, reproduce and evolve ever since.

Has life on Earth simply been lucky in withstanding these events or are there any self-stabilising processes operating in the Earth system that would reduce the severity of such perturbations? If such planetary processes exist, to what extent are they the result of the actions of life?

Forty years ago James Lovelock formulated his Gaia Hypothesis in which life controls aspects of the planet and in doing so maintains conditions that are suitable for widespread life despite shocks and perturbations. This hypothesis was and remains controversial in part because there is no understood mechanism by which such a planetary self-stabilising system could emerge.

In research published in PLOS Computational Biology, University of Southampton lecturer Dr James Dyke and PhD student Iain Weaver detail a mechanism that shows how when life is both affected by and alters environmental conditions, then what emerges is a control system that stabilises environmental conditions. This control system was first described around the middle of the 20th Century during the development of the cybernetics movement and has until now been largely neglected. Their findings are in principle applicable to a wide range of real world systems — from microbial mats to aquatic ecosystems up to and including the entire biosphere.

Dr Dyke says: “As well as being a fascinating issue in its own right, we quite desperately need to understand what is currently happening to Earth and in particular the impacts of our own behaviour.

“Pretty much whatever we do, life on Earth will carry on, just as it did for the previous 3.5 billion years or so. It is only by discovering the mechanisms by which our living planet has evolved in the past can we hope to continue to be part of its future.”

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The research, published in Nature Geoscience and led by researchers from the Université Libre de Bruxelles, the University of Exeter, Laboratoire des Sciences du Climat et l’Environnement, the University of Hawai’i and ETH Zürich, has for the first time shown that increased leaching of carbon from soil, mainly due to deforestation, sewage inputs and increased weathering, has resulted in less carbon being stored on land and more stored in rivers, streams, lakes, reservoirs, estuaries and coastal zones — environments that are together known as the ‘land-ocean aquatic continuum’.

The study reviewed previously published data and showed that a significant fraction of the carbon emitted through human activity that is taken up by the land is not actually stored there, but in the aquatic continuum.

Pierre Regnier from Université Libre de Bruxelles said: “The budget of anthropogenic CO₂ reported by the Intergovernmental Panel on Climate Change (IPCC) currently does not take into account the carbon leaking from terrestrial ecosystems to rivers, estuaries and coastal regions. As a result of this leakage, the actual storage by terrestrial ecosystems is about 40% lower than the current estimates by the IPCC.”

The ‘land-ocean aquatic continuum’, has not previously been considered an important carbon sink. Future assessments of carbon storage must now take into account the surface areas of the land-ocean aquatic continuum to ensure accurate estimation of carbon storage. This will also require an improved knowledge of the mechanisms controlling the degradation, preservation and emissions of carbon along the aquatic continuum to fully understand the impact of human activity on carbon transfer.

Professor Pierre Friedlingstein from the University of Exeter said: “Carbon storage in sediments in these rivers and coastal regions could present a more secure environment than carbon stored in soil on land. As soil warms up stored carbon can be lost to the atmosphere. The chances of this occurring in wet sediments are reduced.”

A fraction of the carbon that leaches from land to the land-ocean aquatic continuum is emitted back to the atmosphere, while another fraction is sequestered in sediments along the continuum. Only a minor part, about 10%, eventually reaches the open ocean.

Philippe Ciais from the Laboratoire des Sciences du Climat et l’Environnement said: “Our revisited global carbon budget which includes the land-ocean aquatic continuum is still entailed with significant uncertainties. It is however fully consistent with the observed growth rate of atmospheric CO₂. Our downward revision of the land carbon storage is also in agreement with very recent results from forest inventories.”

A significant part of the carbon storage thought to be offered by ecosystems on land — mainly forests — is thus negated by this leakage of carbon from soils to aquatic systems, and to the atmosphere.

Garry Shilson-Josling, AAP Economist, AAPJune 11, 2013, 3:14 pm

Let’s talk about the latest trend.

No, not shoes, clothes, music, social media or smart phones.

Let’s talk about the trend in gross domestic product.

If it makes you feel better, be assured that GDP includes shoes, clothes, music, social media and smart phones.

Along with lots of other stuff.

Stuff made by people.

People with jobs.

Accordingly, the trend in GDP is important, more important than anything else, in creating jobs.

More GDP equals more jobs.

But that means too much GDP creates too many jobs, a squeeze in the labour market and, potentially, a surge in wage costs feeding through into rising prices and, Hey Presto, you have rising inflation.

At least, that’s how it works in the nightmares of central bankers, and that’s important because central bankers decide whether interest rates are high or low.

Too-fast GDP growth means rising interest rates, in order to slow things down, and too-slow GDP means falling rates.

But just what growth rates for GDP would be seen as too fast, too slow or just right – or “trend” – is subject to a lot of guesswork.

You have to guess how fast the population will grow.

And the proportion of it in each age group.

And the proportion of each age group active or “participating” in the jobs market.

Then, once you’ve guessed all that, you need to guess how much stuff can be produced by each worker.

To do that, you have to guess how many hours each worker will put in.

And their productivity – how much they produce per hour.

Put all those guesses in the pot, give it a stir and Bob’s your uncle, you have a trend rate of GDP growth.

Chances are, it will be much like the average annual growth rate of the past few decades, somewhere in the 3.0 to 3.5 per cent range, depending on the time frame you’re looking at.

Policymakers have become rather gloomy in the past few years about the trend growth rate from now on, though.

First, we had a bout of slow productivity growth, largely the by-product of the mining boom.

But in the past two years labour productivity growth has been at its fastest for a decade, so those fears – always overblown – have mercifully died down.

And then there’s the ageing of the population.

Older people are less active the labour market.

That’s lowering the growth rate of the available labour force by about a fifth of a percentage point a year and, if nothing else changes, will reduce the potential or trend GDP growth rate by the same margin.

But there are some cross currents at work.

The participation rate for women, for example, is still inching higher, and so is participation by older workers.

At last count in April, for example, 55 per cent of the 60 to 64-year-old age group was active in the labour market, compared with 47.5 per cent five years earlier.

Those factors alone will offset much of the effect of the ageing of the population.

And then there’s population growth.

In the past two decades, mainly thanks to changes in immigration rates, working-age population growth has varied from 1.1 per cent to two per cent a year.

It’s very easy for the government of the day to turn on the immigration tap, inducing a minor variation in the rate of immigration that would overwhelm the effect of the ageing of the population.

Whether it will or not is another matter.

But it’s too early to assume the ageing population has lowered the potential for economic growth over the coming few years.

In their official forecasts these days, the RBA and Treasury are taking a conservative line and pencilling in three per cent as their trend growth rates.

And, who knows, maybe their guesses will be right this time.

But always bear in mind that they’re just that – guesses.

Image Credit: Donarreiskoffer

Posted by Antony Green on June 10, 2013 at 09:31 AM in Election Date Speculation, Federal Politics and Governments | Permalink