Is Climate Change the Reasons No Aliens Have Made Contact?

Read more of this story here from Truthdig RSS by Tim Radford / Climate News Network.

US scientists have calculated the conditions for the survival of a civilisation – all advanced civilisations across the vast universe. Their calculations may explain why, so far, extraterrestrial beings have failed to get in touch.

They may also help explain why climate change driven by global warming could be both inevitable and potentially calamitous.

Entirely theoretical research of this kind is the basis of astrobiology: the attempt to understand why life exists in a seemingly hostile universe, and why, if it exists on Earth, it is not visible everywhere. For practical data, astrobiologists have only one instance of life, and one of intelligent advanced civilisation to work with: planet Earth.

Adam Frank, of the University of Rochester, New York, and colleagues report in the journal Astrobiology that they considered the evidence of a vanished civilisation on Earth – the mysterious culture that flourished on Easter Island in the Pacific and then vanished by about 1500AD.

Better insight

“If we’re not the universe’s first civilisation, that means there are likely to be rules for how the fate of a young civilisation like our own progresses,” said Professor Frank.

“The point is to recognise that driving climate change may be something generic. The laws of physics demand that any young population, building an energy-intensive civilisation like ours, is going to have feedback on its planet. Seeing climate change in this cosmic context may give us better insight into what’s happening to us now and how to deal with it.”

The principle is that any civilisation must change its planet, and the most obvious way would be by exploiting resources in ways that might affect average planetary temperatures.

Under such circumstances the population could reach a peak – and then die off, leaving a few survivors. Or it could foresee the problems and go for sustainability rather than ever more growth. Or population and temperature could reach a peak, at which point the civilisation would collapse. Or – disconcertingly – the threatened civilisation could identify the looming disaster but fail to act in time.

Fatal delay

“The last scenario is the most frightening,” said Professor Frank. “Even if you did the right thing, if you waited too long, you could still have your population collapse.”

Geoscientists have already identified a new phase of Earth history: the planet has now entered an epoch informally called the Anthropocene. They have already established that, in principle, the build-up of greenhouse gases in the atmosphere as a consequence of the exploitation of fossil fuels could raise temperatures to a point that would make civilisation, and perhaps even life on Earth, unsustainable.

Professor Frank himself has explored these questions in earlier studies. In 2014, he and colleagues asked themselves how long an alien civilisation that had discovered fossil fuels, and therefore changed the conditions in which it evolved, could sustain itself.

Earlier this year he returned to the theme and asked how modern humans could ever know if some intelligent non-human civilisation had once ruled the planet and then obliterated itself. Easter Island’s vanished overlords, the people who built the vast stone statues that now stand in enigmatic silence over an impoverished landscape, become in such a case an object lesson.

Archaeological evidence suggests that a culture emerged perhaps 1600 years ago, population grew to a peak, resources were over-exploited, population collapsed and, with it, all memory of what once had been. If an isolated island had a maximum carrying capacity, then so ultimately would an isolated planet. Professor Frank sees global climate change as a planet’s response to civilisation.

“If you go through really strong climate change, then your carrying capacity may drop, because, for example, large-scale agriculture might be strongly disrupted. Imagine if climate change caused rain to stop falling in the Midwest. We wouldn’t be able to grow food, and our population would diminish,” he said.

“If you change the Earth’s climate enough, you might not be able to change it back. Even if you backed off and started to use solar or other less impactful resources, it could be too late, because the planet has already been changing.

“These models show we can’t just think about a population evolving on its own. We have to think about our planets and civilisations co-evolving.”

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Humans and Our Livestock Weigh Heavy on the Earth

Read more of this story here from Truthdig RSS by Tim Radford / Climate News Network.

The human load on the Earth, an audit of all life on the planet shows, is out of kilter with our numbers: we constitute a hugely heavier presence than all wild mammals together.

Israeli and US researchers found the whole package of living tissue – bone, blood, shell, chitin, collagen, timber, cellulose, muscle, blubber, teeth, hair, hoof, horn and all the myriad cells that make up self-replicating, greedy, carbon-based organisms – if tossed on the scales, would (if reduced to carbon) weigh an estimated 550 billion metric tons.

Most of it would be foliage, wood, root and fruit: the green plants that have colonised the terrestrial globe account for about 450 billion tons, or gigatons, of carbon. Another 70 gigatons would be composed of bacteria, and most of that would be invisible: at work beneath the surface of the land and sea.

And although the oceans cover 70% of the globe, the share of marine life is much smaller: the blue water is home to a mere six billion tons of living things. The fungi that colonise the forests and grasslands alone account for twice that mass.

Top mammal

Mammalian life in sharp contrast to all this sheer weight of living things is almost inconsequential: even so, one mammal dominates.

The mass of all the humans on the planet – just humans, not their livestock – is more or less 10 times the mass of all other living wild mammals.

Research like this is fundamental. It is vital. And it is provisional.

It is fundamental because, ultimately, it can help answer questions about how life survives: how the energy of the sun is turned into, and then sustains, life everywhere. That is because, ultimately, all the carbon in living things is derived from atmospheric carbon dioxide, in a process powered by photosynthesis.

It is vital because to make long-term reliable calculations about the carbon budget, and therefore calculations about the future rate of global warming and climate change as factories and exhaust pipes pump ever more greenhouse gases into the atmosphere, climate scientists need to understand the big picture: how life sequesters and recycles carbon on a massive scale.

And it is provisional because some of the calculations are almost certainly wrong: estimates of global plant life can be checked by satellite data and national forestry accounting, but some questions have barely been addressed. The authors concede – “our work highlights gaps in the current understanding of the biosphere”, in their words – that their estimates for the mass of bacteria could be wrong by a factor of 10, and viruses by a factor of 20.

But the researchers report in the Proceedings of the National Academy of Sciences that they see a full census of life on Earth as key to understanding how the biosphere works, and a step towards that would be a better understanding of how biomass – the sheer weight and substance of life – is concentrated, and shared.

Insects abound

And the sums are bewildering. Insects make up the richest group of creatures, with so far one million described species. But their fraction of biomass, say the authors, is negligible. Some single species contribute much more than entire families or even classes.

The Antarctic krill Euphausia superba adds up to about the same mass as humans, or cows. The measure of a huge variety of termites far surpasses the entire biomass of birds. The nematode worms contain more individuals than any other species, but their collected mass is only about 1% of the grand total for all life.

There are entire environments, the authors say, “for which our knowledge is very limited.”

The research also assesses the impact of Homo sapiens – one mammalian species among many – on all other life on Earth. The biomass of domesticated poultry is three times that of all other birds. “In fact”, the authors say, “humans and livestock outweigh all other vertebrates combined, with the exception of fish.”

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Long-Lived Civilization May Be a Pipe-Dream

Read more of this story here from Truthdig RSS by Tim Radford / Climate News Network.

Humanity’s cherished hope that we are building a long-lived civilisation may be nothing more than a pipe-dream. Human endeavour, two scientists argue, may carry within it the seeds of its own destruction.

The two astrophysicists have turned one of the great questions in science into a way of examining the down-to-earth consequences of global warming, the pollution of the oceans with indestructible polymers, and the wholesale destruction of species in the last 300 years.

They put an innocent question: if there had been an advanced technological and industrial civilisation on Earth several hundred million years ago, how could anyone know? What marks would have been left by a race of intelligent reptiles with motorised transport, housing estates, international trade and an arms race?

In what they call the Silurian hypothesis – a reference not to the geological period long before the first creatures crawled from the sea onto the empty continents, but to a 1970 episode of the British television serial Dr Who – they turn to the only testbed available to contemporary Earthlings: the evidence of the Anthropocene, the geologists’ name for a new era that could be considered to have commenced with the Industrial Revolution.

If some alien or distant-future civilisation set out to study the Earth’s geological record, what signs would humans have left in the strata?

And almost immediately, their study confronts a paradox. “The longer human civilisation lasts, the larger the signal one would expect in the record. However, the longer a civilisation lasts, the more sustainable its practices would need to have become in order to survive,” they write in the International Journal of Astrobiology.

But the more sustainable a society, the smaller the footprint its agriculture, manufacture or energy generation would have made, and the smaller the signal in the geological record.

So the researchers, Adam Frank from the University of Rochester, New Yorkand Gavin Schmidt, director of the Nasa Goddard Institute for Space Studies, set out to calculate the future signature of long-vanished human society.

Signs of change

They conclude that the burning of fossil fuels has already changed the carbon cycle in a way that would be recognisable in records of carbon isotopes. Global warming – a consequence of that fossil fuel combustion – would be detectable in the rocks.

Global agriculture would be signalled by increases of erosion and sedimentation rates over time, and plastic pollutants would be detectable for perhaps billions of years. And all-out thermonuclear war – were it to happen – would leave behind some unusual radioactive isotopes.

“As an industrial civilisation, we’re driving changes in the isotopic abundances because we’re burning carbon,” said Professor Frank. “But burning fossil fuels may actually shut us down as a civilisation. What imprints would this or other kinds of industrial activity from a long-dead civilisation leave over tens of millions of years?”

The latest study is not the only one to contemplate the paradox of a self-destroying civilisation. Last year an Arkansas mathematician considered the silence of the extraterrestrials.

Nothing heard

For 40 years, humans have been listening for the noise of other intelligent civilisations in the galaxy, and have heard nothing. Maybe, he suggested in the same journal, modern humans are typical of technological civilisations, and destroy either their planet, or themselves, almost as soon as they exploit technology.

Perhaps, he suggests, a technological civilisation that lasted for millions of years would not be typical.

The latest study, in essence, pursues the same logic. Human advance for the moment is not sustainable. The people of the Anthropocene have already tipped 12 billion tonnes of indestructible plastics into landfills, and created a technosphere that totals about 30 trillion tonnes. And by 2050, humans will have built another 25 million km of roads.

“You want to have a nice, large-scale civilisation that does wonderful things but that doesn’t push the planet into domains that are dangerous for itself, the civilisation,” said Professor Frank. “We need to figure out a way of producing and using energy that doesn’t put us at risk.”

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Erosion May Be Carbon Source, Not Sink

Read more of this story here from Truthdig RSS by Tim Radford / Climate News Network.

Researchers have challenged one of the few certainties of earth and climate history: the link between erosion and the drawdown of carbon dioxide from the atmosphere.

For decades, it has been a given that heavy rainfall on steep mountain slopes is likely to chemically weather the exposed rock and precipitate a chemical reaction that ends with carbonate minerals on the ground and with less of the greenhouse gas carbon dioxide in the atmosphere.

So geochemistry and the weather between them help moderate the planet’s climate.

But geologists and oceanographers who took another and closer look at the process in action – in the central mountains of Taiwan, hammered by three or more major typhoons each year – say they are not so sure.

They report in the journal Science that the same erosion process could be a source of carbon dioxide, releasing it into the atmosphere far faster that it can be absorbed by the newly exposed rock.

And the agency at work in this unexpected process could be biology: the researchers found evidence that tiny microbes in the mountain soils were consuming sources of organic carbon trapped in the rock, and releasing CO2 into the atmosphere.

On the face of it, the process may not be severe enough to upset the global calculations that add up to what climate scientists call the carbon budget – the annual traffic of carbon in the form of greenhouse gases from atmosphere to living things and then into the rocks and oceans – but it is yet another reminder that the climate machinery is still incompletely understood.

“This goes against a long-standing hypothesis that more mountains mean more erosion and weathering which means an added reduction of CO2. It turns out it’s much more complicated than that,” said Jordon Hemingway, of Harvard University, who led the study.

The Earth’s crust, powered by heat from the mantle below, is permanently in a state of levelling and reconstruction: powerful subterranean forces build mountains and the steady attrition of wind and rain immediately begin the process of wearing them down.

Complicated picture

But mountains are part of the climate machine. There is a theory that the rising of the Himalayas and the Tibetan plateau provided the barrier that made the South Asian monsoons possible, and a secondary theory that the increased rainfall on the freshly raised mountain slopes weathered so much rock that the planet’s levels of atmospheric carbon dioxide took a dive, to precipitate 30 million years of Ice Ages.

A closer study of the soil, bedrock and river sediments in Taiwan revealed a more complicated picture. The scientists found that almost 70% of the organic carbon initially present in the weathered bedrock had been oxidised by soil microbes, to put, for every square kilometre they measured, somewhere between six and 18 tonnes of carbon back into the atmosphere.

This is not enough to set alarm bells ringing. But it does suggest that the intricate details of the carbon budget depend not just on what happens on the planet’s surface, but also in the teeming life beneath – and sometimes far beneath – the surface.

This is basic research at a down-to-earth level: climate science can’t make sense of what is happening now without a better understanding of what has always happened, and of the swings in planetary temperatures over the past 4.5 billion years.

Clear understanding

Researchers are confident that they understand the cycle of Ice Ages, and they also have a clear idea that the biosphere plays a hand in keeping the planet at liveable temperatures, but they also know that the high altitudes are more than usually affected by climate change driven by ever-higher ratios of greenhouse gases released by the combustion of fossil fuels by seven billion humans.

Their fears extend to Alpine economies and the plants and animals that live in the mountains. Now it seems clear that some long-term questions require explanation at the microscopic level.

“Looking backwards, we’re most interested in how these processes managed to keep the levels of CO2 in the atmosphere more or less stable over millions of years. It allowed Earth to have the climate and conditions it’s had – one that has promoted the development of complex life forms,” Dr Hemingway said.

“Throughout our Earth’s history, CO2 has wobbled over time, but has remained in that stable zone. This is just an update of the mechanism of geological processes that allows that to happen.”

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Shell’s Knowledge About Climate Crisis Is a ‘Big Concern for Shareholders’

Read more of this story here from Truthdig RSS by Eric Ortiz.

Climate change deniers often make the claim that more research is needed to determine if fossil fuels are warming the earth. But while the energy industry foments scientific uncertainty, internal research from Royal Dutch Shell confirms the company knew about the science of global warming decades ago and then hid the knowledge.

Dutch journalist Jelmer Mommers of De Correspondent, unearthed a Shell report from 1988 called “The Greenhouse Effect” that calculated Shell’s contribution to global warming and anticipated the multinational oil and gas company could be sued in the future over environmental damage.

According to Climate Files:

The confidential report, “The Greenhouse Effect,” was authored by members of Shell’s Greenhouse Effect Working Group and based on a 1986 study, though the document reveals Shell was commissioning “greenhouse effect” reports as early as 1981. Report highlights include:

  • A thorough review of climate science literature, including acknowledgement of fossil fuels’ dominant role in driving greenhouse gas emissions. More importantly, Shell quantifies its own products’ contribution to global CO2 emissions.
  • A detailed analysis of potential climate impacts, including rising sea levels, ocean acidification, and human migration.
  • A discussion of the potential impacts to the fossil fuel sector itself, including legislation, changing public sentiment, and infrastructure vulnerabilities. Shell concludes that active engagement from the energy sector is desirable.
  • A cautious response to uncertainty in scientific models, pressing for sincere consideration of solutions even in the face of existing debates.
  • A warning to take policy action early, even before major changes are observed to the climate.
  • In short, by 1988 Shell was not only aware of the potential threats posed by climate change, it was open about its own role in creating the conditions for a warming world. Similar documents by ExxonMobil, oil trade associations, and utility companies have emerged in recent years, though this Shell document is a rare, early, and concrete accounting of climate responsibility by an oil major.

    Mommers partnered with Damian Carrington, the Guardian’s environment editor Damian Carrington, to produce a comprehensive investigative report on how Shell has conducted business as usual investing in fossil fuels for over 25 years, despite knowing about the dangers of climate change.

    In fact, in 1991, Shell made a 28-minute film about climate change called “The Climate of Concern” that warned about climate change. De Correspondent made the film public again.

    Shell, like Exxon, is among a growing list of oil corporations that has spent millions to mislead the public about climate change while profiting off the destruction of our planet.

    Truthdig contributor Sonali Kolhatkar spoke about the Shell scandal on “Rising Up With Sonali” with Cassady Craighill, the media officer for Greenpeace USA.

    “This is a big concern for shareholders,” said Craighill. “About a year ago, a different company, Exxon, its shareholders had a big revolt at its annual meeting in Dallas and passed a historic resolution that demanded the company account for climate change and its impact on Exxon’s business model. That was very ill-advised from Exxon’s executives. It was not what they wanted, but the shareholders did it anyways, so these things are very important to these companies. Of course, you and I are thinking about the catastrophe that is climate change and its global impacts, but there is a whole other side of this to audiences like shareholders who know that these products are not sustainable.”

    To learn more, visit climateinvestigations.org and read other internal Shell climate documents.

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