Bronze Age lost its cutting edge before climate crisis

Bronze Age lost its cutting edge before climate crisis

Archaeologists claim to have unearthed evidence in Ireland that it was the rising power of iron, not climate change, that brought about the collapse of many ancient civilizations.

LONDON, 23 November, 2014 − Climate change – so often and so recently coupled with the decline of early civilizations in the Near East, the Indus Valley and the Mediterranean – may not have ushered in the collapse of the late Bronze Age after all.

A new study suggests that Bronze Age cultures everywhere collapsed not because of sustained drought or flooding, but because of technological change. The gradual spread of iron foundries and smithies, they say, undermined the economic strengths of those centres with monopolies on the production of, and trade in, copper and tin − the elements in the alloy bronze.

Ian Armit, an archaeologist at the University of Bradford in the UK, and colleagues base their argument on careful studies of ancient climate, using a combination of pollen data and other evidence, plus 2,000 precision-dated archaeological finds from Ireland, from between 1200 BC and 400 AD. This evidence tells a different, but equally familiar, story.

Went wrong

They report in the Proceedings of the National Academy of Sciences that although there was indeed a climate crisis around 750 BC – an event linked to the end of the cultures associated with Knossos in Crete and Mycenae in the Peloponnese – things had started to go wrong two generations or more before.

There had been a clear peak in human activity between 1050 and 900BC, followed by a steady decline and then a rapid fall between 800 AD and 750BC. Since copper was mined in Ireland – and alloyed with tin from Britain to make bronze – the Celtic populations of the place and time enjoyed high socio-economic status and power.

“The impact of climate change on humans is a huge concern today as we monitor rising temperatures”

They were involved in international trade, and at the heart of a global culture. Bronze, both literally and metaphorically, gave the Irish of the time a cutting edge. Such power and status started to evaporate with the advance of iron smithies. Copper and tin are relatively rare metals, but iron is found almost everywhere.

“Our evidence shows definitively that the population decline in this period cannot have been caused by climate change,” Professor Armit concludes.

But he says that the switch to increasingly rainier conditions in Ireland in 750 BC would have had its own impact. “It is likely that poor climatic conditions would have affected farming. This would have been particularly difficult for vulnerable communities, preventing population recovery for several centuries.”

Archaeology is a combative science: the evidence is preserved only precariously and a new discovery can, and often does, change the picture.

Contributing factor

Written records are fragmentary, interpretations open to dispute, and artefacts are often difficult to date. So reconstructions of the distant past are always tentative, and other groups have been careful to “link” or “associate” climate change with historical conflict. Climate would be a contributing factor, not necessarily a prime cause.

But the British scientists argue that, on the evidence from Ireland, a global bronze age civilization was coming to an end for reasons that were ahead of, and independent of, drought or flood, heat waves or sustained cold.

Professor Armit says: “The impact of climate change on humans is a huge concern today as we monitor rising temperatures globally.

“Often, in examining the past, we are inclined to link evidence of climate change with evidence of population change. Actually, if you have high-quality data and apply modern analytical techniques, you get a much clearer picture and start to see the real complexity of human/environment relationships in the past.” – Climate News Network

Share This:

Green Revolution trebles human burden on planet

Green Revolution trebles human burden on planet

American researchers say seasonal swings in temperatures and CO2 levels are evidence of how agricultural advances and the population explosion have tilted nature’s balance.

LONDON, 22 November, 2014 – Humans are changing not just climate overall, but also the difference between seasons in any given year.

Researchers in the US believe they now know why global warming has begun to announce itself both in annual rises in temperature and in the seasonal records of carbon dioxide in the northern hemisphere − the same seasonal variation in atmospheric chemistry that also contains within it the signature of the Green Revolution and the 20th-century population explosion.

And it’s all because the natural swing from high carbon dioxide levels to low each year has become more dramatic in the last 50 years.

Each year, in the northern hemisphere growing season, the CO2 levels drop as plants grow and soak up the atmospheric carbon.

Inexorable pattern

Later in the year, as leaves fall, crops are harvested and consumed, and soil is freshly tilled, most of that CO2 gets back into the atmosphere. It’s an inexorable pattern that follows the seasons.

Systematic measurements of CO2 levels began in 1958, and they show that swings within each year from high to low, and back again, have increased in amplitude by 50%, and go on increasing by 0.3% every year.

Two groups of researchers report that they concentrated on the northern hemisphere because that’s the part of the globe where most of the continental landmass, most of the vegetation and the greatest part of the human population is concentrated.

And both groups identified the cause of the widening CO2 swing as being as mix of steadily higher temperatures and the Green Revolution – the dramatic advance in agricultural productivity that fuelled the trebling of the human burden of the planet in less than a human lifetime.

“Changes in the way we manage the land can literally alter the breathing of the biosphere”

Josh Gray, research assistant professor in the Department of Earth and Environment at Boston University, US, reports with colleagues in Nature journal that they have gone one better by identifying the crop that makes the biggest difference: maize, or corn.

Together, the world harvest of maize, wheat, rice and soybean grew by 240% between 1961 and 2008, increasing the uptake of carbon during that time by 330 million tonnes.

Maize, grown ever-more intensively in the mid-western US and in China, is responsible for two-thirds of this change, the researchers calculate. Dr Gray calls the super-productive croplands “ecosystems on steroids”.

Carbon cycle

Ning Zeng, professor in the Department of Atmospheric and Oceanic Science at the University of Maryland, US, and lead author of the other Nature paper, reports that he and colleagues devised a new model of the terrestrial carbon cycle to explore the increase in seasonal CO2 swings, and the role of the Green Revolution in these swings.

There are several reasons for the increasing swings: average temperatures have started to rise; there is the natural “fertilization” effect of carbon dioxide, as some plants respond well to higher levels; and as the Arctic regions have thawed, more growing land is available − and vegetation has been marching north.

But a fourth reason is that farmers are now producing more yield from the same land, and the same crops. Between 1961 and 2010, the area of land planted with the world’s great crops grew by 20%, but – with improved strains, better fertilizers, and more irrigation − yield grew threefold. So more CO2 was taken up each year, and more released.

“What we are seeing is the effect of the Green Revolution on Earth’s metabolism,” said Professor Zeng. “Changes in the way we manage the land can literally alter the breathing of the biosphere.” – Climate News Network

Share This:

Saving forests not enough to stop carbon imbalance

Saving forests not enough to stop carbon imbalance

Creeping expansion of croplands into areas not previously covered with trees could undermine attempts by forest conservation schemes to address the problem of “carbon leakage” into the atmosphere.

LONDON, 21 November, 2014 − Foresters may be guardians of the planet, but they may need to think about more than just the forests to reduce the threats from climate change.

New research suggests that a policy that protects the planet’s forests from fire and the chainsaw must also deliver new ways of stopping the spread of agriculture into other habitats.

The trick − according to a report by Alexander Popp, a senior researcher at the Potsdam Institute for Climate Impact Research, Germany, and colleagues − is to be sure to reduce carbon emissions, rather than just displace them.

The researchers argue in the journal Nature Climate Change that while forest protection schemes could, by 2100, prevent 77 billion tonnes of carbon dioxide from escaping into the atmosphere, the same policies could trigger cropland expansion into areas that were not forested.

This, in turn, could release 96 billion tonnes of CO2 over the same timescale. The researchers call this “carbon leakage”.

Changes in land use

That is because around a tenth of emissions of greenhouse gases (GHGs) arise from changes in land use, and the worst of these changes − in terms of GHG releases − is from tropical forest to agricultural cropland.

So any forest policy focusing on saving emissions must also embrace strategies for using existing farmland more efficiently and productively.

Greenhouse gas emissions from fossil fuel combustion provide the chief cause for alarm about climate change, and a switch to renewable sources such as wind, hydro and solar power remains an important part of potential strategies to reduce the hazards of global warming.

“A central challenge is the avoidance of international carbon leakage if forest conservation is not implemented globally”

But, in a whole range of ways, agriculture is responsible for about 25% of all emissions, and in a world certain to reach a population of nine billion this century – and possibly 11 billion − the demands and the impacts of agriculture are likely to increase.

The Potsdam scientists warn: “A central challenge is the avoidance of international carbon leakage if forest conservation is not implemented globally.”

But, they add, even global forest conservation schemes will fail to contain such leakage if croplands expand into areas that may not be forested, and are not protected from development in some way.

Overall, in recent decades, the planet’s lands have soaked up more carbon than they have released. Plants take up CO2 from the atmosphere, and although some of them are harvested, and others are burned or decomposed, a proportion of this sequestered carbon stays in the soil.

Woodland, heath, marsh, savannah and even mature meadow and grazing lands have reached some sort of equilibrium: they remain as carbon sinks.

Disturbed equilibrium

But change, in the form of a farmer’s plough, disturbs this equilibrium. Between 1990 and 2010, say the researchers, 12% of all emissions came from changes in land use and changes in the vegetation that covered the land.

So the Potsdam researchers took a hard look at a UN-proposed strategy called REDD –Reduced Emissions from Deforestation and Degradation – which is likely to remain an important part of all future climate treaty negotiations. The conclusion: it is not enough just to preserve forests alone; nations have to look at the bigger picture too.

“The results show that the largest benefits for climate change mitigation could be achieved by a full participation of all countries in a forest conservation scheme and the inclusion of other land types with high carbon content, such as wet savannahs,” Dr Popp says.

“While protecting forests to abate climate change is definitely worthwhile, our results illustrate for the first time that forest protection policies alone will not be enough.” – Climate News Network

Share This:

Obama pledge gets dollars flowing into climate fund

Obama pledge gets dollars flowing into climate fund 

Many developing countries are already suffering the impacts of climate change, but a special fund to help them adapt to a warming world has been bolstered by promises of billions of dollars from wealthier nations.

LONDON, 20 November, 2014 − It’s been quite a week for those waiting for some action on climate change.

After US President Obama and China’s President Xi Jinping announced radical plans to cut back on greenhouse gas emissions, Obama then called on nations at the G20 summit in Brisbane, Australia, to agree to a new deal on climate.

And when he backed that up by pledging US$3 billion to the Green Climate Fund (GCF), set up in 2010 to promote low emissions and climate-resilient projects in the developing world, other countries quickly reached for their cheque books.

Paying their dues

Japan says it will be giving $1.5 billion to the GCF. Britain indicated it will be pledging a similar amount.  France and Germany have already announced they will be giving the $1 billion each. Sweden is pledging more than $500 million. And other countries in the developed world are lining up to pay their dues.

The GCF, which operates under the auspices of the United Nations Framework Convention on Climate Change, is holding a special High-Level Pledging Conference in Berlin today.

“This week’s announcements will be a legacy of US President Obama,” said Hela Cheikhrouhou, GCF’s executive director. “It will be seen by generations to come as the game‐changing moment that started a scaling‐up of global action on climate change.”

Obama said money paid into the GCF would help developing countries leapfrog some of the dirty industries that fuelled growth in the industrialised world, and will allow them to build clean-energy economies.

“Along with the other nations that have pledged support, this gives us the opportunity to help vulnerable communities with an early warning system, with stronger defences against storm surge, climate resilient infrastructure, to help farmers plant more durable crops,” Obama said.

In the past, calls for cash to support the Fund’s activities in the developing world have been largely unsuccessful. Now the mood seems to have changed.

“It will be seen by generations to come as the game‐changing moment that started a scaling‐up of global action on climate change”

In the US, the Republicans – who now control both houses of Congress – are for the most part firmly opposed to Obama’s new-found zeal for action on the climate.

The White House feels that public attitudes on climate change issues are changing, both within the US and around the globe, but a brave new, fossil fuel-free world is still a long way off.

There are big questions about how the emissions reductions announced in the US-China agreement are to be achieved.

And the pledges to the GCF look impressive, but leaders of the wealthier nations have a tendency for making grand monetary gestures at international gatherings –then not following through with the cash.

Despite this, climate change has been put firmly among the top items on the international agenda. Momentum has also been built towards achieving a new global deal at the UN Climate Change Conference in Paris late next year.

Clear message

The past week’s events have also sent a clear message to the fossil fuel industry, and to investors in the sector: many of the most powerful countries in the world now agree that greenhouse gas emissions have to be cut.

The message has not gone down well with Tony Abbott, the Australian prime minister, and host of the G20 summit.

Although Australia is considered by scientists to be one of the countries most vulnerable to global warming, the Abbott government has made known its scepticism on the issue and has rolled back various measures aimed at combating changes in climate.

It has also strongly backed the development of several large-scale coal mining operations on the east coast, adjacent to the waters of the Great Barrier Reef. – Climate News Network

Share This:

Fall of ancient civilization offers climate warning

Fall of ancient civilization offers climate warning

Prolonged drought – a familiar climate-related issue in the modern world – is believed by scholars to have been a key factor in the implosion of the powerful Assyrian empire 2,700 years ago.

LONDON, 19 November, 2014 − Two scholars have a new explanation for the collapse of one of the great Bronze Age civilizations. The Assyrian empire of the 7th century BC – based in Nineveh, in what is now northern Iraq – may have collapsed at least in part because of a population explosion and climate change in the form of sustained drought.

And, they point out, there are lessons in ancient history for the modern world as well.

Adam Schneider, an anthropologist at the University of California, San Diego, and Selim Adali, of the Research Centre for Anatolian Civilizations at Koç University in Istanbul, Turkey, put forward their proposal in the journal Climatic Change.

They say that demographic and climatic factors played an indirect but significant role in the collapse of a civilization chronicled not just in clay tablets and archaeological marvels but in the Hebrew scriptures and the Christian Old Testament.

Historic links

The climate change theory of history is now well established. In the last two years, researchers have linked both the dissolution of the Minoan empire in the ancient Mediterranean and the collapse of Levantine civilizations of the near East and the Harappan civilization of the Indus Valley to sustained drought.

Others have identified seasons of plentiful rainfall as the impetus for the conquest of Russia, China and Persia by the Mongol horsemen of Genghis Khan.

The connections with modern conflict, too, have been made before. In 21 studies of upheaval and conflict in modern societies, researchers have found clear links with rises in temperatures.

And just days after the Assyrian study was published in Climatic Change, research in the Proceedings of the National Academy of Sciences identified a link between temperature and rainfall anomalies in sub-Saharan Africa and violence in the region during the last 30 years.

“Hindsight . . . allows us to piece together from the past what can go wrong if we choose not to enact policies that promote longer-term sustainability”

Schneider and Adali looked through what climate scientists call “proxy evidence” of rainfall patterns in the Tigris Valley of northern Iraq more than two and a half millennia ago.

They considered the evidence of lake sediments and confirmed that many parts of the region experienced a “short but widespread dry phase” during the mid-to-late 7th century BC.

They also unearthed written evidence from 666 BC that welcomed “copious rains, huge floods, a fine rate of exchange…” to mark a new accession to the throne. But by 657 BC, another letter stated that “this year’s rains were diminished and no harvest was reaped”.

In fact, Assyrian engineers had established an impressive series of canals, waterways, cisterns and reservoirs to conserve water, and archaeological finds reveal that the imperial farmers grew barley and wheat, grapes, cucumbers, pomegranates, flax and cotton among many other crops.

But demand, too, was on the increase. The empire of built by Sennacherib, a king identified in biblical chronicles, had ambitions for the local populations. In at least 20 known acts of mass deportation, half a million people were resettled in the heartland.

Nineveh grew fivefold in area, and the population growth, the scientists think, placed significant strains on the immediate supplies of food in the region.

Conflict and insurrection

Within five years of the 657 BC drought, the Assyrian economy was struggling, and conflict and insurrection had broken out. By 609 BC, a remarkable civilization had been destroyed.

A multi-year drought, the researchers argue, “would have placed serious stress on the agricultural economy of the Assyrian state and, by extension, upon the imperial political system”.

They see parallels with today, as the fate of the Assyrian empire offers lessons for modern society about the hazards of valuing short-term economic growth over long-term security and sustainability.

“The Assyrians can be ‘excused’ to some extent,” they conclude, “for focusing on short-term economic or political goals that increased their risk of being negatively impacted by climate change, given their technological capacity and their level of scientific understanding about how the natural world works.

“We, however, have no such excuses, and we also possess the additional benefit of hindsight, which allows us to piece together from the past what can go wrong if we choose not to enact policies that promote longer-term sustainability.” – Climate News Network

Share This:

Murders turn spotlight on Peru’s forest policies

Murders turn spotlight on Peru’s forest policies

The killing of tribal leaders trying to defend their Amazon rainforest lands from illegal logging has put Peru’s president under pressure ahead of next month’s UN climate conference.

LONDON, 18 November, 2014 − Preserving forests is a vital step in preventing climate change, but people who defend them against illegal logging and land grabs are being murdered in increasing numbers.

And one of the worst recent examples is in Peru, the country hosting the United Nations climate change conference that opens in the capital, Lima, on December 1.

Four indigenous leaders from the Ashéninka people from the Peruvian Amazon − including Edwin Chota, a prominent anti-logging campaigner − were killed attempting to defend their lands in the Ucayali region in September.

The killings were highlighted yesterday in a report, titled Peru’s Deadly Environment, by the independent environmental investigation agency, Global Witness. The report calls into question “the commitments of Peru to protect its carbon-rich forests and the people who live in them, in light of unfettered illegal logging, disregard for indigenous land claims, and new laws that favour industrial exploitation over environmental protection”.

Tragic reminders

Patrick Alley, co-founder of Global Witness, said: “The murders of Edwin Chota and his colleagues are tragic reminders of a paradox at work in the climate negotiations. While Peru’s government chairs negotiations on how to solve our climate crisis, it is failing to protect the people on the frontline of environmental protection.

“Environmental defenders embody the resolve we need to halt global warming. The message is clear: if you want to save the environment, then stop people killing environmental defenders.”

The report follows a wider Global Witness investigation of the escalating number of people killed trying to defend the environment. Between 2002 and 2013, it says, 908 campaigners were killed in 35 countries. Brazil was the worst offender, with 448 killings, Honduras second with 109, and the Philippines with 67.

“Peru’s credibility as a forest protector hinges upon providing land and resource rights to  indigenous and rural populations”

The recent killings in Peru makes it the fourth most dangerous place to be a defender of the environment, with 57 people killed − 60% of them in the last four years. This is mostly in disputes over land rights, mining and logging. Over 20 million hectares of land claims of indigenous communities have not been processed.

Edwin Chota had received numerous death threats for his resistance to the loggers who were gutting his community’s forests, but his appeals to the authorities were ignored. There was speculation that there was collusion between the loggers and the authorities. Before he died, Chota sent local police photographs of the illegal loggers and the sites they were exploiting. It is these loggers who have now charged with his murder.

In an attempt to make it worthwhile for Peru to leave the country’s forests standing, Norway and Germany have offered a $300 million partnership deal to support Peru’s efforts at reducing greenhouse gas emissions from deforestation and forest degradation in the country’s Amazon region.

Ironically, the deal was announced in September − the same time as the four activists were murdered.

The money was to cover the period up to 2020, and Peru would get the cash from Norway if it recognised indigenous people’s land claims, and so preserved the forest. At the same time, Germany would continue its extensive support for Peru on climate and forest issues.

At the time of the deal, the President of the Peru, Ollanta Humala, said: “There is growing evidence that economic growth and environmental protection can be combined. The Letter of Intent with Norway is a major step forward in realising the vision of deforestation-free development, and we are firmly committed to implement its provisions faithfully. We do this because it is in the self-interest of Peru.

“Our indigenous peoples’ groups have traditionally been the best guardians of our forests. By embarking on this path of deforestation-free development, we hope also to reach out to our indigenous peoples and move together towards a more harmonious future.”

Weak government

All three countries accepted that there were serious problems in implementing the agreement because of weak government and pressure from miners, loggers and small farmers. There are 68 million hectares of forest, with 350,000 indigenous people living in it − including several uncontacted tribes.

Despite the president’s words, Peru had already invoked a new law in July 2014 that grants extended land use rights to investors for the expansion of large-scale agriculture, mining, logging and infrastructure projects.

At an award ceremony in New York yesterday, the four dead activists were honoured as Diana Rios Rengifo, daughter of one of the murdered men, Jorge Rios, accepted an environmental award from the Alexander Soros Foundation on behalf of her father and their Ashéninka community.

“They may have killed my father and his friends, but I am still here,” she said. “And I will continue to fight for the rights to our territories and for the rights of the other indigenous peoples of Peru.”

David Salisbury, associate professor of geography at the University of Richmond in the US, has spent time with Edwin Chota’s community. He says: “Peru’s credibility as a forest protector hinges upon providing land and resource rights to the country’s indigenous and rural populations.

“The government should recognise there are people in the forests, and give them rights to them. How can you maintain standing forest, and mitigate climate change, if the defenders of the forest are being assassinated?” – Climate News Network

Share This:

Climate threatens striking change to US weather

Climate threatens striking change to US weather

Global warming is expected to have an explosive effect across America as scientists predict that there could be a 50% increase this century in the frequency of lightning strikes.

LONDON, 17 November, 2014 − Climate scientists foresee a brighter future for America − but no one will thank them for it, as global warming is expected to increase the total number of lightning strikes across the US this century by 50%.

David Romps, assistant professor in the Department of Earth and Planetary Science at the University of California, Berkeley, and colleagues report in Science journal that they looked at predictions of rainfall, snow, hail and cloud buoyancy in 11 different climate models. They concluded that the outcome could only be more atmospheric electrical action.

Right now, the continental US is hit about 25 million times a year by lightning.

But Dr Romps said: “With warming, thunderstorms become more explosive. This has to do with water vapour, which is the fuel for explosive deep convection in the atmosphere. Warming causes there to be more water vapour in the atmosphere, and if you have more fuel lying around, when you get ignition, it can go big time.”

More evaporation

Warmer weather means more evaporation. But higher temperatures also mean that the atmosphere’s capacity to hold water vapour increases as well, with a potential for more clouds, more flow of air, and more precipitation.

The volume of water hitting the ground – as hail, snow, sleet or rain – offers a measure of the convection properties of the atmosphere, and convection generates lightning.

Hundreds of people are struck by lightning each year, and scores are killed, but these remain a very small proportion of accidental deaths in any year. The real hazard might lie far from populated areas: half of all wildfires are caused by lightning strikes.

Lightning also generates more nitrous oxides in the atmosphere, which could also affect atmospheric chemistry. So it makes sense to know what to expect as the planet warms.

“We already know that . . . the more precipitation,
the more lightning”

The scientists examined US Weather Service data for 2011, and the counts from the National Lightning Detection Network, to see if they could confirm a link between cloud buoyancy and precipitation as a predictor of lightning. They also looked at data from balloon-borne instruments released every day in the US to measure the rate at which clouds rise.

As a result, they calculate that 77% of the variation in lightning strikes could be predicted from knowledge of the two conditions.

“Lightning is caused by charge separation within clouds, and to maximise charge separation you have to loft more water vapour and heavy ice particles into the atmosphere,” Dr Romps said. “We already know that the faster the updrafts, the more lightning, and the more precipitation, the more lightning.”

Potential energy

Their climate models predicted, on average, an 11% increase in convective available potential energy for every extra degree Celsius rise in average temperatures. They calculated that if average planetary temperatures were to rise by 4°C, the potential for lightning strikes would go up by 50%.

Their calculations are limited to the US mainland and may not apply equally to other parts of the planet. Overall conditions, and therefore the potential for thunderstorms, tend to vary widely.

But the continental US – the predictions do not include Hawaii or Alaska − is flanked by two oceans and with a subtropical sea to its south. It is distinguished by a sharp temperature gradient and dramatic topography, and is already a forge for fierce and destructive tornadoes, and a target for frequent hurricanes.

So the barometer remains set for future storms, with added lightning. – Climate News Network

Share This:

Diet’s effects on emissions give food for thought

Diet's effects on emissions give food for thought

American researchers confirm that a shift to vegetarian, Mediterranean or fish-based diets would cut greenhouse gases, conserve forests and savannah, and have a big impact on obesity-linked health problems.

LONDON, 14 November, 2014 − The worldwide trend towards a Western-style diet rich in meat and dairy produce will lead to an 80% increase in greenhouse gas emissions (GHGs) from agriculture.

And since agriculture already accounts for 25% of all emissions, two US scientists argue in Nature journal that a shift away from the trend towards steak, sausage, fried potatoes and rich cream puddings offers tomorrow’s world three palpable rewards.

  • Greenhouse gas emissions would be reduced.
  • There would be less pressure to clear forests and savannah for farmland, so biodiversity would be conserved.
  • There would be lower rates of disease linked with obesity and cardiovascular hazard.

“The implementation of dietary solutions to the tightly-linked diet-environment-health trilemma is a global challenge, and opportunity, of great environmental and public health importance,” the report’s authors say.

For example, GHGs from beef or lamb per gram of protein are about 250 times those from a serving of peas or beans.

Rise in diabetes

And in China, the shift from traditional cuisine towards a Western-style diet rich in refined sugars, refined oils, meat and processed foods led to the incidence of type II diabetes rising from less than 1% in 1980 to 10% in 2008.

To put this greener, more sustainable world on the scientific menu, David Tilman, professor of ecology at the University of Minnesota, and Michael Clark, graduate science student at the Bren School of Environmental Science and Management, University of California Santa Barbara, simply looked at the already published evidence.

They identified 120 separate analyses of the GHGs from the entire life cycle of crop, livestock, fishery and aquaculture, all the way to the farm gate.

These analyses embraced a total of 550 studies, involving 82 types of food plant and animal products, and from all this they were able to calculate the diet-related emissions per gram of protein, per kilocalorie and per serving.

To confirm the connection between diet and health, they looked again at 18 studies based on eight long-term population studies that incorporated 10 million person-years of observation. They used 50 years of data about the dietary habits and trends in 100 of the world’s most populous nations to see the way food consumption patterns were changing.

“Dietary changes that can add about a decade to our lives can also prevent environmental damage”

And they confirmed something that nutritionists, health chiefs and medical advisers have been saying for decades: that a shift to vegetarian, traditional Mediterranean or fish-based diets could only be good.

“We showed that the same dietary changes that can add about a decade to our lives can also prevent massive environmental damage,” Professor Tilman said.

“In particular, if the world were to adopt variations on three common diets, health would be greatly increased at the same time global GHGs were reduced by an amount equal to the current GHGs of all cars, trucks, planes, trains and ships.

“In addition, this dietary shift would prevent the destruction of an area of tropical forests and savannahs of an area half as large as the United States.”

Such a shift away from the calorie-rich Western omnivore diet could reduce the incidence of type II diabetes – a condition notoriously linked to diet and obesity − by about 25%, cancer by about 10%, and death from heart disease by about 25%.

The close link between meat production and GHGs has been reported before.  Researchers have also stressed the environmental value of a diet rich in grains and legumes. rather than meat and dairy.

Not everybody will agree with the detail of their analysis. Other scientists have argued that − in the US, at least − healthy diet recommendations may not make a big difference to GHGs, or might even lead to an increase in them.

Acidic oceans

And because the authors specifically identify trawling for fish as wasteful, destructive and costly in emissions, and because ocean waters are becoming more acidic because of GHG emissions, a planetary switch to a pescatarian or fish and seafood diet is likely to be problematic.

But the two scientists nevertheless are clear on the main point. GHGs are, they say, “highly dependent on diet”.

Between 2009 and 2050, the global population will increase by 36%. People will also become better off, and their appetites and demands will grow. “When combined with a projected increase in per capita emissions from income-dependent global dietary shifts,” they say, “the net effect is an estimated 80% increase in global greenhouse gas emissions from food production.”

This 80% would represent 1. 8 billion tonnes per year of carbon dioxide or its equivalent − which was the total emissions from all forms of global transport in 2010.

“In contrast,” they say, “there would be no net increase in food production emissions if, by 2050, the global diet had become the average of the Mediterranean, pescatarian and vegetarian diets.” – Climate News Network

Share This:

Iron’s mixed blessing for health of oceans

Iron’s mixed blessing for health of oceans

New research shows that iron fertilisation stimulates growth of the plankton that help transport carbon dioxide to the deep ocean – but swells the number of small creatures who feed on plankton and whose shells put CO2 back into the atmosphere.

LONDON, 16 November, 2014 − Technology’s answer to climate change in a world in which humans go on releasing carbon dioxide in the atmosphere has just had another setback. The idea of fertilising the planet’s oceans with iron filings to stimulate green growth and turn the oceans into a carbon sink isn’t so simple as hoped.

Two studies – both involving experiments at sea – have confirmed that trace elements such as iron affect plankton growth, and that more iron can mean more carbon dioxide exported to the sea bed in the form of dead and buried life forms. But new research in Nature Geoscience shows that the story is more complex.

Ian Salter, bioscience researcher at the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research, Germany, and colleagues report that they took a closer look at what happens around the Crozet Islands in the Southern Ocean − basaltic islands that deliver a steady natural supply of iron to the surrounding waters.

Carbon pumped

More iron meant more phytoplankton, which meant that more carbon was pumped into deeper waters. But more phytoplankton also meant more little creatures such as foraminifera, which graze on phytoplankton, and then make shells of calcium carbonate − a process that puts carbon dioxide back into the atmosphere.

Dr Salter and his colleagues estimate that the carbonate manufacture in waters naturally fertilised by iron reduced the overall amount of carbon transferred to the deep ocean by between 6% and 32%, whereas in waters not fertilised by iron, the reduction was 1% to 4%. So added iron might make the phytoplankton grow, but it also soups up the return of carbon dioxide to the atmosphere.

The finding is not conclusive. It doesn’t settle the question of whether the presence of trace iron ultimately assists the removal of more carbon from the atmosphere in the long term.

It also doesn’t answer questions about how things might work in warmer waters, and doesn’t offer a guide to the overall effect of iron deliberately added to waters where the phytoplankton don’t bloom in profusion.

“We are in the middle of an experiment we cannot reverse, but which we still don’t understand . . .”

But it does provide a snapshot of science in action, and is yet another reminder that the climate system – and especially the traffic in carbon between rock, water, air and living tissue – is immensely complex, and still puzzling.

And if that wasn’t already clear, new research in the Proceedings of the National Academy of Sciences confirms that there is a lot more to be learned about the role of oceans in climate science.

Researchers report that ocean temperatures have been far more variable over the last 7,000 years than anyone had realised.

Thomas Laepple, a climate scientist at the Alfred Wegener Institute, and Peter Huybers, Professor of Earth and Planetary Sciences at Harvard University, US, combed the climate archives, examined indirect evidence from sediment cores and corals and other sources, and reconstructed sea surface temperatures in a range of different locations over a period of thousands of years.

Then they picked 20 climate models and conducted more than 100 test runs to see if they could simulate the same pronounced fluctuations in ocean temperatures in the same places over the same timescale

Greater discrepancies

They could − but only for short periods. The longer the time sequence, the greater the discrepancies. Over timescales of a thousand years, the models underestimated the variations by a factor of 50.

“Fundamentally, there are only two explanations,” Dr Laepple says. “Either the climate archives do not provide reliable temperature data, or the climate models underestimate the variability of the climate. Or both may be true to some extent.”

Neither finding suggests that climate scientists don’t know what they are doing. In fact, quite the reverse: researchers are establishing just what they can be sure about, and what remains uncertain.

Nor does either finding suggest that long-term alarm over the consequences of increasing levels of atmospheric carbon dioxide is based on uncertain science.

Dr Laepple says: “We are in the middle of an experiment we cannot reverse, but which we still don’t understand well enough to make clear statements at the regional level on longer timescales. Unfortunately, we will just have to continue with this uncertainty for some time.” – Climate News Network

Share This:

China and US deliver radical climate surprise

China and US deliver radical climate surprise

It’s been called an historic agreement − a game changer in the battle to combat climate change. But can China and the US fulfil the promises in their announcement of plans to cut carbon emissions?

LONDON, 13 November, 2014 − China went to considerable lengths to make sure that this week’s Asia Pacific Economic Co-operation summit in Beijing was a successful affair.

Factories were shut down, car traffic and even cremations were restricted, and schools and most government offices were closed. As a result, delegates experienced blue skies over the Chinese capital, rather than the city’s notorious smog.

But the most newsworthy and surprising event came on the summit sidelines, with President Xi Jinping and President Obama warmly shaking hands as they unveiled plans for radical cutbacks in emissions of CO2 − the most potent of the climate-changing greenhouse gases (GHGs).

Biggest emitters

China and the US are by far the world’s biggest emitters of CO2, with China accounting for more than 20% of total global CO2 emissions and the US 15%.

Under the plans announced in Beijing, the US says it will reduce CO2 emissions by between 26% and 28% from 2005 levels by 2025, and will achieve “economy-wide reductions in the order of 80% by 2050”.

Meanwhile, China for the first time announced a date when it says its CO2 emissions will peak − 2030 − and then taper downwards. It also said it would be ramping up its already ambitious renewables programme, with the potential of cutting back on CO2 emissions at an earlier date.

“These announcements send a clear signal to the private sector and the financial markets on where global policy is now heading”

In addition, Obama and Xi – despite their considerable differences on territorial, trade and other issues − announced plans to expand co-operation on various research and technology projects related to climate change.

“The United States of America and the People’s Republic of China have a critical role to play in combating global climate change, one of the greatest threats facing humanity,” said a White House statement.

“ The seriousness of the challenge calls upon the two sides to work constructively together for the common good.”

Christiana Figueres, the executive secretary of the United Nations Framework Convention on Climate Change, said the Beijing announcement was an important step towards a better and more secure future for human kind.

“Together, these announcements send a clear signal to the private sector and the financial markets on where global policy is now heading,” Figueres said.

Resilient world

“These announcements have the potential to unleash and accelerate the kinds of entrepreneurship and innovation needed to propel all economies towards ever greater levels of ambition – if not significantly exceeding their ambitions – en route to a low-carbon, resilient world over coming years and decades.”

However, amid the euphoria, some big questions remain:

  • Global CO2 emissions are still increasing, despite years of climate change negotiations and increased warnings from the scientific community about the dire consequences of a warming world. Experts say cutbacks have to be achieved much sooner than 2030 in order to halt runaway climate change.
  • Doubts persist about how realistic these cutbacks are. Under the plans, China will need to produce an extra 800 to 1,000 gigawatts of power from wind, solar and nuclear sources over the next 15 years − more power than its coal plants produce today. And experts point out that Beijing’s timeline for reducing emissions does not represent a binding target.
  • Obama is going to have a tough time pushing these plans through. Republicans, who now control both houses of Congress, have already denounced the measures, saying they will seriously damage the US economy.
  • Negotiations on tackling climate change and limiting emissions of GHGs have been held on a worldwide basis under UN auspices. Such bilateral agreements as the one announced by the US and China could undermine the global consensus and weaken UN processes.

But the news from Beijing has been generally welcomed in the scientific community.

Nicholas Stern, lead author of the 2006 Stern Review on the economics of climate change, says the US/China announcement will give momentum to a new global deal on climate due to be negotiated in Paris late next year.

“President Obama and President Xi should be congratulated for demonstrating real leadership with this historic announcement,” Stern told the Financial Times in London. – Climate News Network

Share This: