Earth’s Sixth Mass Extinction Event Already Under Way, Scientists Warn

ENVIRONMENT
Researchers talk of “biological annihilation” as study reveals billions of populations of animals have been lost in recent decades.

Photo Credit: Maggy Meyer/Shutterstock

A “biological annihilation” of wildlife in recent decades means a sixth mass extinction in Earth’s history is under way and is more severe than previously feared, according to research.

Scientists analyzed both common and rare species and found billions of regional or local populations have been lost. They blame human overpopulation and overconsumption for the crisis and warn that it threatens the survival of human civilization, with just a short window of time in which to act.

The study, published in the peer-reviewed journal Proceedings of the National Academy of Sciences, eschews the normally sober tone of scientific papers and calls the massive loss of wildlife a “biological annihilation” that represents a “frightening assault on the foundations of human civilization”.

Prof Gerardo Ceballos, at the Universidad Nacional Autónoma de México, who led the work, said: “The situation has become so bad it would not be ethical not to use strong language.”

Previous studies have shown species are becoming extinct at a significantly faster rate than for millions of years before, but even so extinctions remain relatively rare giving the impression of a gradual loss of biodiversity. The new work instead takes a broader view, assessing many common species which are losing populations all over the world as their ranges shrink, but remain present elsewhere.

The scientists found that a third of the thousands of species losing populations are not currently considered endangered and that up to 50 percent of all individual animals have been lost in recent decades. Detailed data is available for land mammals, and almost half of these have lost 80 percent of their range in the last century. The scientists found billions of populations of mammals, birds, reptiles and amphibians have been lost all over the planet, leading them to say a sixth mass extinction has already progressed further than was thought.

Nearly half of the 177 mammal species surveyed lost more than 80% of their distribution between 1900 and 2015

Percent of species which have lost more than 80 percent of their range

Billions of animals have been lost as their habitats have become smaller with each passing year. (Guardian graphic | source: PNAS)

The scientists conclude: “The resulting biological annihilation obviously will have serious ecological, economic and social consequences. Humanity will eventually pay a very high price for the decimation of the only assemblage of life that we know of in the universe.”

They say, while action to halt the decline remains possible, the prospects do not look good: “All signs point to ever more powerful assaults on biodiversity in the next two decades, painting a dismal picture of the future of life, including human life.”

Wildlife is dying out due to habitat destruction, overhunting, toxic pollution, invasion by alien species and climate change. But the ultimate cause of all of these factors is “human overpopulation and continued population growth, and overconsumption, especially by the rich”, say the scientists, who include Prof Paul Ehrlich, at Stanford University in the U.S., whose 1968 book The Population Bomb is a seminal, if controversial, work.

“The serious warning in our paper needs to be heeded because civilization depends utterly on the plants, animals, and microorganisms of Earth that supply it with essential ecosystem services ranging from crop pollination and protection to supplying food from the sea and maintaining a livable climate,” Ehrlich told the Guardian. Other ecosystem services include clean air and water.

“The time to act is very short,” he said. “It will, sadly, take a long time to humanely begin the population shrinkage required if civilization is to long survive, but much could be done on the consumption front and with ‘band aids’—wildlife reserves, diversity protection laws—in the meantime.” Ceballos said an international institution was needed to fund global wildlife conservation.

The research analyzed data on 27,500 species of land vertebrates from the IUCN and found the ranges of a third have shrunk in recent decades. Many of these are common species and Ceballos gave an example from close to home: “We used to have swallows nesting every year in my home near Mexico city—but for the last 10 years there are none.”

The researchers also point to the “emblematic” case of the lion: “The lion was historically distributed over most of Africa, southern Europe, and the Middle East, all the way to northwestern India. [Now] the vast majority of lion populations are gone.”

Current and historic distribution of lions

Historically lions lived across Africa, southern Europe, the Middle East, all the way up to Northwestern India. Today their habitat has been reduced to a few tiny pockets of the original area. (Guardian graphic | source: PNAS)

Prof. Stuart Pimm, at Duke University in the US and not involved in the new work, said the overall conclusion is correct, but he disagrees that a sixth mass extinction is already under way: “It is something that hasn’t happened yet—we are on the edge of it.”

Pimm also said there were important caveats that result from the broad-brush approach used. “Should we be concerned about the loss of species across large areas—absolutely—but this is a fairly crude way of showing that,” he said. “There are parts of the world where there are massive losses, but equally there are parts of the world where there is remarkable progress. It is pretty harsh on countries like South Africa which is doing a good job of protecting lions.”

Robin Freeman, at the Zoological Society of London, U.K., said: “While looking at things on aggregate is interesting, the real interesting nitty gritty comes in the details. What are the drivers that cause the declines in particular areas?”

Freeman was part of the team that produced a 2014 analysis of 3000 species that indicated that 50 percent of individual animals have been lost since 1970, which tallies with the new work but was based on different IUCN data. He agreed strong language is needed: “We need people to be aware of the catastrophic declines we are seeing. I do think there is a place for that within the [new] paper, although it’s a fine line to draw.”

Citing human overpopulation as the root cause of environmental problems has long been controversial, and Ehrlich’s 1968 statement that hundreds of millions of people would die of starvation in the 1970s did not come to pass, partly due to new high-yielding crops that Ehrlich himself had noted as possible.

Ehrlich has acknowledged “flaws” in The Population Bomb but said it had been successful in its central aim—alerting people to global environmental issues and the the role of human population in them. His message remains blunt today: “Show me a scientist who claims there is no population problem and I’ll show you an idiot.”

Earth’s five previous mass extinctions

End-Ordovician, 443 million years ago

A severe ice age led to sea level falling by 100m, wiping out 60-70 percent of all species which were prominently ocean dwellers at the time. Then soon after the ice melted leaving the oceans starved of oxygen.

Late Devonian, c 360 million years ago

A messy prolonged climate change event, again hitting life in shallow seas very hard, killing 70 percent of species including almost all corals.

Permian-Triassic, c 250 million years ago

The big one—more than 95 percent of species perished, including trilobites and giant insects—strongly linked to massive volcanic eruptions in Siberia that caused a savage episode of global warming.

Triassic-Jurassic, c 200 million years ago

Three-quarters of species were lost, again most likely due to another huge outburst of volcanism. It left the Earth clear for dinosaurs to flourish.

Cretaceous-Tertiary, 65 million years ago

An giant asteroid impact on Mexico, just after large volcanic eruptions in what is now India, saw the end of the dinosaurs and ammonites. Mammals, and eventually humans, took advantage.

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Capitalism and mortality: Death rate soars for middle-aged US workers

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4 November 2015

A study published this week in Proceedings of the National Academy of Sciences documents a sharp rise in the mortality rate for white, middle-aged working-class Americans over the past fifteen years. The report’s authors are Nobel laureate Angus Deaton and Anne Case, both economists at Princeton University.

Their calculations show that the rising death rate since 1999 for this segment of the population translates into 96,000 more deaths than if the mortality rate had remained flat. Had the rate continued on its declining trajectory for the period 1978-1998, the authors state, there would be 500,000 more people alive today in the United States.

“Only HIV/AIDS in contemporary times has done anything like this,” commented Deaton.

The increase in the mortality rate is due mainly to a dramatic rise in the rate of deaths from suicide, drug abuse and alcoholism—all expressions of social and personal crisis.

Dr. Case and Dr. Deaton found that the overall mortality rate (measured as the number of deaths each year) for white, non-Hispanic adults between the ages of 45 and 54 increased by 34 per 100,000 between 1999 and 2013. For those with a high school education or less, the rate increased by 134 per 100,000 (reaching 735.8 per 100,000) over this same period. This is a rise of 22 percent. In the study, education level served as an approximate stand-in for income level.

The increase in mortality for middle-aged white Americans with a high school education or less is attributed to: poisonings (including drug overdoses), which rose from 13.7 to 58.0 deaths per 100,000 (an increase of 400 percent); suicide, which rose from 21.8 to 38.8 deaths per 100,000 (an increase of 78 percent); and chronic liver cirrhosis (caused by alcoholism), which rose from 26.7 to 38.9 per 100,000 (an increase of 46 percent).

The authors also document the growth of morbidity, or ill health, within this social layer, showing that reports of good health fell, while reports of physical pain, psychological distress and poor health rose sharply.

The study confirms and provides additional substantiation for the conclusions of previous reports, including one from September of this year that found a dramatic decline in life expectancy for poorer middle-aged Americans.

Behind these figures lies an immense social retrogression and sharpening of class divisions. They reflect a catastrophic decline in the social position of the working class resulting from the protracted decay of American capitalism and a relentless, decades-long assault by the ruling class on all of the past social gains achieved in the course of a century of bitter class struggle.

While white workers, particularly white men, are routinely denounced as “privileged” by the pseudo-left proponents of racial and gender politics, they have seen perhaps the most dramatic reversal in their conditions of life. Middle-aged blacks still have a higher mortality rate than whites, but the difference between the two groups is closing rapidly.

Consider the experiences of the age group involved. A worker aged 50 in 2013 was born in 1963, at the height of the postwar economic boom. He or she would have reached employment age around 1980, the onset of a ruling-class offensive aimed at driving down workers’ wages and living standards and dismantling social services and public infrastructure. With the “deindustrialization” of America, huge swaths of industry were shut down, working-class cities were devastated, and millions of decent-paying jobs were wiped out.

This social counterrevolution has only accelerated under the Obama administration in the years since the financial crisis of 2008. The Wall Street crash of that year, triggered by the greed and criminality of the financial elite, has been utilized by that same financial aristocracy to strengthen its control over every aspect of social and political life in the United States.

The number of manufacturing jobs in the United States peaked at 19.5 million in 1970, falling to 17.4 million in 1999 and collapsing to just over 12 million by 2013. The share of working-age men between the ages of 25 and 54 who are not working has tripled since the late 1960s. Those jobs that are available pay less and less. Households headed by someone with a high school education or less have seen a 19 percent decline in their inflation-adjusted income.

Immense resources have been diverted into financial speculation, with the stock market becoming the primary mechanism for redistributing wealth from the poor to the rich. The share of national income going to the top one percent has nearly tripled, increasing from about 8 percent in the 1960s and 1970s to more than 20 percent today.

The consequences have been disastrous for predominantly African American cities such as Detroit, but the most concentrated growth of poverty in recent years has occurred in the suburbs—an increase of 64 percent from 2000 to 2011, according to one study.

Workers who are now middle-aged have experienced an unending decline in living standards. They have had their homes taken away, their retirement and health benefits gutted, their life savings wiped out. Millions are drowning in debt, exhausted by overwork or scraping by on unemployment, often unable to provide for their families and facing the permanent stress of economic insecurity. The “American dream” has become the American nightmare.

The organizations through which workers previously resisted the dictates of the corporations have collapsed. The trade unions have become labor syndicates, serving as a police force for the corporations to suppress the class struggle and impose mass layoffs, wage cuts and speedup. Under these conditions, the anger and frustration of workers, unable to find any organized expression, have in many cases been turned inward and taken personally and socially destructive forms.

This, however, is not a permanent state of affairs. The increase in mortality for large sections of the American population testifies to the failure of the capitalist system and the bankruptcy of all of its agencies, including the official unions. The objective crisis of capitalism is already giving rise to a growth of social opposition and anti-capitalist sentiment, which will inevitably find expression in a new upsurge of class struggle.

That the ruling class has nothing to offer to address the spiraling social crisis is reflected in the lack of serious attention paid to the shocking findings of the Princeton economists. In an earlier period, they would have been treated as a national disgrace.

Today, the Democrats and Republicans compete with each other in slashing social programs. A decline in life expectancy is seen as a positive good by a ruling class that is determined to cut spending on health care and pensions in order to finance an ever-expanding stock market bubble.

Under capitalism, society is marching backwards. The only social force that can reverse this counterrevolution is the working class.

Joseph Kishore

 

http://www.wsws.org/en/articles/2015/11/04/pers-n04.html

New discoveries show that Mars may have once been habitable

By Bryan Dyne
28 March 2015

A recent study using data from NASA’s Curiosity rover and published in the Proceedings of the National Academy of Sciences present data showing the presence of nitrates on Mars. This molecule, composed of one nitrogen and three oxygen atoms, may indicate that there was once a nitrogen cycle on ancient Mars, one of the necessary mechanisms on a planet to sustain terrestrial-like life.

The Mars rover Curiosity. Credit: NASA/JPL-Caltech/MSSS

The research was undertaken with an international team led by Jennifer Stern using Curiosity’s Sample Analysis at Mars (SAM) instrument suite. In earlier studies of Martian soils and rocks at Gale crater, nitrogen was detected in both scooped and drilled sediment samples. However, it was not clear whether the nitrogen detected was from the surrounding atmosphere, indicating molecular nitrogen, or from the rocks themselves, indicating nitrates. Using SAM and subtracting out the known sources of nitrogen within the instrument, Stern’s team was able to show that there were still up to 1100 parts per million (ppm) of nitrogen remaining, depending on the sample analyzed. From this, Stern’s team concluded that the nitrogen originated from the sediments and thus from nitrates.

Whether nitrogen is found in the atmosphere or in other forms plays an important role in biochemistry on Earth. While the majority of terrestrial nitrogen is in the atmosphere, making up 78 percent of the air we breath, it is in the inert form of molecular hydrogen (N2). To incorporate nitrogen into more complex molecules—such as nucleobases, amino acids, DNA, RNA and proteins—it must be in more accessible forms. The nitrate molecule (NO3) is one of the most prevalent and useful molecules seen on Earth for this purpose.

As such, the strong evidence of nitrates in a variety of different rocks and sediments on the Martian surface implies that, at a very early point in the planet’s history, there could have been large amounts of biologically useful nitrogen on the Red Planet.

Stern’s research complements a report released three weeks ago in Sciencewhich provides strong support for the existence of an ocean of liquid water on the surface of Mars during the planet’s early life. The ocean is estimated to have held more water than Earth’s Arctic Ocean. That is enough water to cover the entire surface of Mars in liquid 137 meters deep. More likely, the ocean covered almost half Mars’ northern hemisphere and reached depths greater than 1.6 kilometers.

This is much larger than previous estimates of a primordial Martian ocean, meaning that the planet’s surface could have been wetter for much longer than estimated, perhaps 900 million years. Combined with a thicker, warmer atmosphere, volcanism on the surface and the presence of nitrates, this likely led to rich reservoirs containing the diverse chemical elements needed for life.

Artist conception of the primitive ocean the NASA suspects once existed on Mars

This second discovery was made by a team led Geronimo Villanueva, working with the European Southern Observatory’s Very Large Telescope in Chile, and the W.M. Keck Observatory and NASA Infrared Telescope Facility in Hawaii. Using detailed maps of the Martian atmosphere, the scientists were able to distinguish the chemical signatures of two slightly different isotopes of water. The first is the familiar H2O. The second is the more exotic form HDO, in which one hydrogen atom is replaced by one its more massive forms, deuterium.

By taking the ratio of H2O and HDO in Mars’ atmosphere and comparing it to those values found in water trapped in a 4.5 billion-year-old Martian meteorite, Villanueva’s team was able to measure the atmospheric change in the intervening time span and determine how much water escaped to space. The forthcoming MAVEN probe will take similar measurements.

These maps were made over the course of three Martian years, amounting to six years on Earth. Beyond showing that Mars once housed a massive ocean, the research also revealed seasonal changes and local weather patterns across what was previously thought to be a mostly homogenous desert climate.

Mars’ polar ice caps were also studied, using the same H2O and HDO ratio, as they are suspected to contain a more direct record of water on Mars from 3.7 billion years ago to the present. The researchers found that Mars once had at least 6.5 times the amount of water currently contained in the ice caps, meaning a volume of water on ancient Mars of at least 20 million cubic kilometers. This is in general agreement with the atmospheric study.

Both the nitrogen amounts and water levels now thought to have existed on ancient Mars lead to the question: Where did this all go? Mars today is a barren world with an atmosphere that is 96 percent carbon dioxide and less than 1 percent as thick as Earth’s. There is no liquid water on its surface and one has to dig before finding any indication of biologically useable material.

It is suspected that Mars lost its atmosphere to space. The results gathered by the Curiosity rover as a whole are in agreement with in situ atmospheric measurements made by the Viking landers from 1976 to 1982, when this idea first gained traction. The three main mechanisms for losing atmosphere include interactions between the atmosphere and the solar wind, a massive impact by an asteroid or other body, and/or the atmosphere escaping as a result of thermal motion and the planet’s relatively low gravity. It is not clear which of these mechanisms (if any) is primary.

The loss of the ocean is somewhat more mysterious. Neither the solar wind nor low Martian gravity can account for the loss of liquid water. As the planet cooled and the water froze, one way for the ocean to have disappeared is for the frozen water to sublime into water vapor in the atmosphere and then into space. A more interesting hypothesis is that the ocean didn’t go anywhere at all, but was covered up by sediment and dirt as it froze. If so, this would mean that a great deal of water ice is under the northern lowlands of Mars, the Vastitas Borealis basin. It is unknown how far down a probe would need to drill in order to test this idea.

A further question is posed: What is the possibility that life developed on early Mars?

While a great deal more research needs to be done on this subject, these two results are further evidence that at the very least, the conditions once existed on Mars for a life cycle to begin.

 

http://www.wsws.org/en/articles/2015/03/28/mars-m28.html