10/09/2019

A Globalised Solar-Powered Future Is Wholly Unrealistic – And Our Economy Is The Reason Why

The Conversation - Alf Hornborg, Professor of Human Ecology, Lund University

Valentin Valkov/Shutterstock.com
Over the past two centuries, millions of dedicated people – revolutionaries, activists, politicians, and theorists – have been unable to curb the disastrous and increasingly globalised trajectory of economic polarisation and ecological degradation. This is perhaps because we are utterly trapped in flawed ways of thinking about technology and economy – as the current discourse on climate change shows.
Rising greenhouse gas emissions are not just generating climate change. They are giving more and more of us climate anxiety. Doomsday scenarios are capturing the headlines at an accelerating rate. Scientists from all over the world tell us that emissions in ten years must be half of what they were ten years ago, or we face apocalypse. School children like Greta Thunberg and activist movements like Extinction Rebellion are demanding that we panic. And rightly so. But what should we do to avoid disaster?
Most scientists, politicians, and business leaders tend to put their hope in technological progress. Regardless of ideology, there is a widespread expectation that new technologies will replace fossil fuels by harnessing renewable energy such as solar and wind. Many also trust that there will be technologies for removing carbon dioxide from the atmosphere and for “geoengineering” the Earth’s climate. The common denominator in these visions is the faith that we can save modern civilisation if we shift to new technologies. But “technology” is not a magic wand. It requires a lot of money, which means claims on labour and resources from other areas. We tend to forget this crucial fact.
I would argue that the way we take conventional “all-purpose” money for granted is the main reason why we have not understood how advanced technologies are dependent on the appropriation of labour and resources from elsewhere. In making it possible to exchange almost anything – human time, gadgets, ecosystems, whatever – for anything else on the market, people are constantly looking for the best deals, which ultimately means promoting the lowest wages and the cheapest resources in the global South.
It is the logic of money that has created the utterly unsustainable and growth-hungry global society that exists today. To get our globalised economy to respect natural limits, we must set limits to what can be exchanged. Unfortunately, it seems increasingly probable that we shall have to experience something closer to disaster – such as a semi-global harvest failure – before we are prepared to seriously question how money and markets are currently designed.

Green growth?
Take the ultimate issue we are facing: whether our modern, global, and growing economy can be powered by renewable energy. Among most champions of sustainability, such as advocates of a Green New Deal, there is an unshakeable conviction that the problem of climate change can be solved by engineers.
What generally divides ideological positions is not the faith in technology as such, but which technical solutions to choose, and whether they will require major political change. Those who remain sceptical to the promises of technology – such as advocates of radical downshifting or degrowth – tend to be marginalised from politics and the media. So far, any politician who seriously advocates degrowth is not likely to have a future in politics.
Mainstream optimism about technology is often referred to as ecomodernism. The Ecomodernist Manifesto, a concise statement of this approach published in 2015, asks us to embrace technological progress, which will give us “a good, or even great, Anthropocene”. It argues that the progress of technology has “decoupled” us from the natural world and should be allowed to continue to do so in order to allow the “rewilding” of nature. The growth of cities, industrial agriculture, and nuclear power, it claims, illustrate such decoupling. As if these phenomena did not have ecological footprints beyond their own boundaries.
Meanwhile, calls for a Green New Deal have been voiced for more than a decade, but in February 2019 it took the form of a resolution to the American House of Representatives. Central to its vision is a large-scale shift to renewable energy sources and massive investments in new infrastructure. This would enable further growth of the economy, it is argued.
What will it take for us to seriously consider the roots of our problems? PicsEKa/Shutterstock

Rethinking technology
So the general consensus seems to be that the problem of climate change is just a question of replacing one energy technology with another. But a historical view reveals that the very idea of technology is inextricably intertwined with capital accumulation, unequal exchange and the idea of all-purpose money. And as such, it is not as easy to redesign as we like to think. Shifting the main energy technology is not just a matter of replacing infrastructure – it means transforming the economic world order.
In the 19th century, the industrial revolution gave us the notion that technological progress is simply human ingenuity applied to nature, and that it has nothing to do with the structure of world society. This is the mirror image of the economists’ illusion, that growth has nothing to do with nature and so does not need to reckon with natural limits. Rather than seeing that both technology and economy span the nature-society divide, engineering is thought of as dealing only with nature and economics as dealing only with society.
The steam engine, for instance, is simply considered an ingenious invention for harnessing the chemical energy of coal. I am not denying that this is the case, but steam technology in early industrial Britain was also contingent on capital accumulated on global markets. The steam-driven factories in Manchester would never have been built without the triangular Atlantic trade in slaves, raw cotton, and cotton textiles. Steam technology was not just a matter of ingenious engineering applied to nature – like all complex technology, it was also crucially dependent on global relations of exchange.
Sketch showing a steam engine designed by Boulton & Watt, England, 1784. Wikimedia Commons
This dependence of technology on global social relations is not just a matter of money. In quite a physical sense, the viability of the steam engine relied on the flows of human labour energy and other resources that had been invested in cotton fibre from South Carolina, in the US, coal from Wales and iron from Sweden. Modern technology, then, is a product of the metabolism of world society, not simply the result of uncovering “facts” of nature.The illusion that we have suffered from since the industrial revolution is that technological change is simply a matter of engineering knowledge, regardless of the patterns of global material flows. This is particularly problematic in that it makes us blind to how such flows tend to be highly uneven.
This is not just true of the days of the British Empire. To this day, technologically advanced areas of the world are net importers of the resources that have been used as inputs in producing their technologies and other commodities, such as land, labour, materials, and energy. Technological progress and capital accumulation are two sides of the same coin. But the material asymmetries in world trade are invisible to mainstream economists, who focus exclusively on flows of money.
Ironically, this understanding of technology is not even recognised in Marxist theory, although it claims to be both materialist and committed to social justice. Marxist theory and politics tend toward what opponents refer to as a Promethean faith in technological progress. Its concern with justice focuses on the emancipation of the industrial worker, rather than on the global flows of resources that are embodied in the industrial machine.
This Marxist faith in the magic of technology occasionally takes extreme forms, as in the case of the biologist David Schwartzman, who does not hesitate to predict future human colonisation of the galaxy and Aaron Bastani, who anticipates mining asteroids. In his remarkable book Fully Automated Luxury Communism: A Manifesto, Bastani repeats a widespread claim about the cheapness of solar power that shows how deluded most of us are by the idea of technology.



Nature, he writes, “provides us with virtually free, limitless energy”. This was a frequently voiced conviction already in 1964, when the chemist Farrington Daniels proclaimed that the “most plentiful and cheapest energy is ours for the taking”. More than 50 years later, the dream persists.

The realities
Electricity globally represents about 19% of total energy use – the other major energy drains being transports and industry. In 2017, only 0.7% of global energy use derived from solar power and 1.9% from wind, while 85% relied on fossil fuels. As much as 90% of world energy use derives from fossil sources, and this share is actually increasing. So why is the long-anticipated transition to renewable energy not materialising?
One highly contested issue is the land requirements for harnessing renewable energy. Energy experts like David MacKay and Vaclav Smil have estimated that the “power density” – the watts of energy that can be harnessed per unit of land area – of renewable energy sources is so much lower than that of fossil fuels that to replace fossil with renewable energy would require vastly greater land areas for capturing energy.
In part because of this issue, visions of large-scale solar power projects have long referred to the good use to which they could put unproductive areas like the Sahara desert. But doubts about profitability have discouraged investments. A decade ago, for example, there was much talk about Desertec, a €400 billion project that crumbled as the major investors pulled out, one by one.
Today the world’s largest solar energy project is Ouarzazate Solar Power Station in Morocco. It covers about 25 square kilometres and has cost around US$9 billion to build. It is designed to provide around a million people with electricity, which means that another 35 such projects – that is, US$315 billion of investments – would be required merely to cater to the population of Morocco. We tend not to see that the enormous investments of capital needed for such massive infrastructural projects represent claims on resources elsewhere – they have huge footprints beyond our field of vision.
Ouarzazate Solar Power Station (OSPS), one of the largest solar plants in the world. EPA/STR
Also, we must consider whether solar is really carbon free. As Smil has shown for wind turbines and Storm van Leeuwen for nuclear power, the production, installation, and maintenance of any technological infrastructure remains critically dependent on fossil energy. Of course, it is easy to retort that until the transition has been made, solar panels are going to have to be produced by burning fossil fuels. But even if 100% of our electricity were renewable, it would not be able to propel global transports or cover the production of steel and cement for urban-industrial infrastructure.
And given the fact that the cheapening of solar panels in recent years to a significant extent is the result of shifting manufacture to Asia, we must ask ourselves whether European and American efforts to become sustainable should really be based on the global exploitation of low-wage labour, scarce resources and abused landscapes elsewhere.
Workers in a factory of a Chinese solar panel maker in Hangzhou. EPA/STR
Collecting carbon
Solar power is not displacing fossil energy, only adding to it. And the pace of expansion of renewable energy capacity has stalled – it was about the same in 2018 as in 2017. Meanwhile, our global combustion of fossil fuels continues to rise, as do our carbon emissions. Because this trend seems unstoppable, many hope to see extensive use of technologies for capturing and removing the carbon from the emissions of power plants and factories.
Carbon Capture and Storage (CCS) remains an essential component of the 2016 Paris Agreement on climate change. But to envisage such technologies as economically accessible at a global scale is clearly unrealistic.
To collect the atoms of carbon dispersed by the global combustion of fossil fuels would be as energy-demanding and economically unfeasible as it would be to try to collect the molecules of rubber from car tires that are continuously being dispersed in the atmosphere by road friction.
The late economist Nicholas Georgescu-Roegen used this example to show that economic processes inevitably lead to entropy – that is, an increase in physical disorder and loss of productive potential. In not grasping the implications of this fact, we continue to imagine some miraculous new technology that will reverse the Law of Entropy.
Economic “value” is a cultural idea. An implication of the Law of Entropy is that productive potential in nature – the force of energy or the quality of materials – is systematically lost as value is being produced. This perspective turns our economic worldview upside down. Value is measured in money, and money shapes the way we think about value. Economists are right in that value should be defined in terms of human preferences, rather than inputs of labour or resources, but the result is that the more value we produce, the more inexpensive labour, energy and other resources are required. To curb the relentless growth of value – at the expense of the biosphere and the global poor – we must create an economy that can restrain itself.

The evils of capitalism
Much of the discussion on climate change suggests that we are on a battlefield, confronting evil people who want to obstruct our path to an ecological civilisation. But the concept of capitalism tends to mystify how we are all caught in a game defined by the logic of our own constructions – as if there was an abstract “system” and its morally despicable proponents to blame. Rather than see the very design of the money game as the real antagonist, our call to arms tends to be directed at the players who have had best luck with the dice.
I would instead argue that the ultimate obstruction is not a question of human morality but of our common faith in what Marx called “money fetishism”. We collectively delegate responsibility for our future to a mindless human invention – what Karl Polanyi called all-purpose money, the peculiar idea that anything can be exchanged for anything else. The aggregate logic of this relatively recent idea is precisely what is usually called “capitalism”. It defines the strategies of corporations, politicians, and citizens alike.
All want their money assets to grow. The logic of the global money game obviously does not provide enough incentives to invest in renewables. It generates greed, obscene and rising inequalities, violence, and environmental degradation, including climate change. But mainstream economics appears to have more faith in setting this logic free than ever. Given the way the economy is now organised, it does not see an alternative to obeying the logic of the globalised market.
It’s the rules which are the issue – not those who win. Theera Disayarat/Shutterstock.com
The only way to change the game is to redesign its most basic rules. To attribute climate change to an abstract system called capitalism – but without challenging the idea of all-purpose money – is to deny our own agency. The “system” is perpetuated every time we buy our groceries, regardless of whether we are radical activists or climate change deniers. It is difficult to identify culprits if we are all players in the same game. In agreeing to the rules, we have limited our potential collective agency. We have become the tools and servants of our own creation – all-purpose money.
Despite good intentions, it is not clear what Thunberg, Extinction Rebellion and the rest of the climate movement are demanding should be done. Like most of us, they want to stop the emissions of greenhouse gases, but seem to believe that such an energy transition is compatible with money, globalised markets, and modern civilisation.
Is our goal to overthrow “the capitalist mode of production”? If so, how do we go about doing that? Should we blame the politicians for not confronting capitalism and the inertia of all-purpose money? Or – which should follow automatically – should we blame the voters? Should we blame ourselves for not electing politicians that are sincere enough to advocate reducing our mobility and levels of consumption?
Many believe that with the right technologies we would not have to reduce our mobility or energy consumption – and that the global economy could still grow. But to me that is an illusion. It suggests that we have not yet grasped what “technology” is. Electric cars and many other “green” devices may seem reassuring but are often revealed to be insidious strategies for displacing work and environmental loads beyond our horizon – to unhealthy, low-wage labour in mines in Congo and Inner Mongolia. They look sustainable and fair to their affluent users but perpetuate a myopic worldview that goes back to the invention of the steam engine. I have called this delusion machine fetishism.
Not the guilt free option many assume them to be. Smile Fight/Shutterstock.com
Redesigning the global money game
So the first thing we should redesign are the economic ideas that brought fossil-fueled technology into existence and continue to perpetuate it. “Capitalism” ultimately refers to the artefact or idea of all-purpose money, which most of us take for granted as being something about which we do not have a choice. But we do, and this must be recognised.
Since the 19th century, all-purpose money has obscured the unequal resource flows of colonialism by making them seem reciprocal: money has served as a veil that mystifies exploitation by representing it as fair exchange. Economists today reproduce this 19th-century mystification, using a vocabulary that has proven useless in challenging global problems of justice and sustainability. The policies designed to protect the environment and promote global justice have not curbed the insidious logic of all-purpose money – which is to increase environmental degradation as well as economic inequalities.
In order to see that all-purpose money is indeed the fundamental problem, we need to see that there are alternative ways of designing money and markets. Like the rules in a board game, they are human constructions and can, in principle, be redesigned. In order to accomplish economic “degrowth” and curb the treadmill of capital accumulation, we must transform the systemic logic of money itself.
National authorities might establish a complementary currency, alongside regular money, that is distributed as a universal basic income but that can only be used to buy goods and services that are produced within a given radius from the point of purchase. This is not “local money” in the sense of LETS or the Bristol Pound – which in effect do nothing to impede the expansion of the global market – but a genuine spanner in the wheel of globalisation. With local money you can buy goods produced on the other side of the planet, as long as you buy it in a local store. What I am suggesting is special money that can only be used to buy goods produced locally.
Locally produced goods. Alison Hancock/Shutterstock.com
This would help decrease demand for global transports – a major source of greenhouse gas emissions – while increasing local diversity and resilience and encouraging community integration. It would no longer make low wages and lax environmental legislation competitive advantages in world trade, as is currently the case.
Immunising local communities and ecosystems from the logic of globalised capital flows may be the only feasible way of creating a truly “post-capitalist” society that respects planetary boundaries and does not generate deepening global injustices.
Re-localising the bulk of the economy in this way does not mean that communities won’t need electricity, for example, to run hospitals, computers and households. But it would dismantle most of the global, fossil-fuelled infrastructure for transporting people, groceries and other commodities around the planet.
This means decoupling human subsistence from fossil energy and re-embedding humans in their landscapes and communities. In completely changing market structures of demand, such a shift would not require anyone – corporations, politicians, or citizens – to choose between fossil and solar energy, as two comparable options with different profit margins.
To return to the example of Morocco, solar power will obviously have an important role to play in generating indispensable electricity, but to imagine that it will be able to provide anything near current levels of per capita energy use in the global North is wholly unrealistic. A transition to solar energy should not simply be about replacing fossil fuels, but about reorganising the global economy.
Solar power will no doubt be a vital component of humanity’s future, but not as long as we allow the logic of the world market to make it profitable to transport essential goods halfway around the world. The current blind faith in technology will not save us. For the planet to stand any chance, the global economy must be redesigned. The problem is more fundamental than capitalism or the emphasis on growth: it is money itself, and how money is related to technology.
Climate change and the other horrors of the Anthropocene don’t just tell us to stop using fossil fuels – they tell us that globalisation itself is unsustainable.

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'Like Nothing We've Seen': Queensland Bushfires Tear Through Rainforest

The Guardian

Fires that swept though subtropical rainforest around the historic Binna Burra lodge are unprecedented, experts say
Heritage listed Binna Burra lodge in the Gold Coast Hinterland rainforest, before and after it was destroyed by fire Composite: Supplied/Seven News


Queensland’s former fire commissioner says an erratic bushfire front that climbed into the state’s subtropical rainforest and razed the 86-year-old Binna Burra Lodge is “like nothing we’ve ever seen before”.
“What we’re seeing, it’s just not within people’s imagination,” said Lee Johnson, who spent 12 years in charge of Queensland’s fire service.
“They just didn’t believe it could ever get so bad.”
Queensland remains in the grip of one of the worst bushfire threats in its history, fuelled by prolonged dry conditions and fierce gusting winds; an “omen” of a potentially devastating fire season ahead. There are still 52 fires burning across the state. Schools are closed and about 20 structures have been destroyed.
Early on Sunday morning, a fire front climbed into the Lamington national park and razed Binna Burra, a historic eco-tourism lodge built in the 1930s and surrounded by subtropical Gondwana rainforest.
The heritage-listed main lodge was built in 1933. It has never before been seriously threatened by bushfire, protected in part by lush and damp surroundings that typically suppress the progress of dangerous fires.
“There have certainly been fires in the area before,” said the lodge chairman, Steve Noakes. “Back in the traditional owners’ time there’s evidence of fires, but certainly in the period of European history in this part of Australia, this is the most catastrophic.
“There’s nothing left to burn at Binna Burra, it’s all gone.”
Heritage listed Binna Burra Lodge in the Gold Coast Hinterland before it was destroyed by fire. Photograph: Supplied
Last year, Queensland experienced “unprecedented” fire conditions in November – a combination of hot, dry and windy days in tropical and subtropical parts of the state.
A year later, and again conditions are being described in similar terms, the sort that can fuel catastrophic wildfires. Southeast Queensland has been particularly dry; the fire-threatened town of Stanthorpe is almost out of drinking water.
In Lamington National Park, the rainforest has had very little recent rain.
Johnson, who is now a director of the Bushfire and Natural Hazards Cooperative Research Centre, said in those sorts of extremely dry conditions the forest terrain became a potential tinderbox.
“We’ve had a very long history of concern about that area, but we definitely have not seen fire conditions like this,” Johnston said.
A koala rescued from the fires in the Gold Coast hinterland. Photograph: Jimboomba Police
“Their terrain is very similar to parts of southern New South Wales and Victoria where bushfires are the norm. In Queensland the potential is there. That country at Lamington National Park in particular, the topography is just cruel.
“The weather conditions they’re now facing are just unheard of. The thing about fire, the bush in those conditions, is you can’t actually fight it. The heat generated means you can’t put people or equipment in front of this fires, you just can’t do it.”
Part of the attraction of a place like Binna Burra is the isolation. There is one narrow access road. About 3am on Sunday morning, concern about the welfare of firefighters forced a retreat. All anyone could do was wait, while the fire front moved through.
“We can’t access the site, it will be cut off for some days because of the rock slides and the tree fall,” Noakes said. “A couple of the emergency services workers hiked in yesterday, they were very brave, but it’s basically a write-off.”
Noakes said the situation was “a signal to us that we need to take a more proactive approach to climate change.
“We need to know more about the impact of climate change on subtropical rainforests of Australia and what that means in terms of long term infrastructure. That’s why people come to Queensland, to experience these places.”
He said Binna Burra would be rebuilt in a way that took into account the likely impacts of climate change.
“Binna Burra is 86 years old. When we position and design and build and operate tourism infrastructure in these sorts of natural environments, we have to think about 50 or 100 years ahead and what changes climate impacts are going to have on the built infrastructure.
“Our responsibility now is to have a vision that is crafted of the knowledge and the understanding of the climate as it will impact on the tropical and subtropical rainforest.”

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Are We Overestimating How Much Trees Will Help Fight Climate Change?

Grist - Jan Ellen Spiegel

Yulia-Images via Getty Images
Bob Marra navigated his way to the back of a dusty barn in Hamden, Connecticut, belonging to the state’s Agricultural Experiment Station. There, past piles of empty beehives, on a wall of metal shelves, were stacks of wooden disks — all that remains of 39 trees taken down in 2014 from Great Mountain Forest in the northwest corner of the state.
These cross-sections of tree trunks, known as stem disks — or more informally as cookies — are telling a potentially worrisome tale about the ability of forests to be critical hedges against accelerating climate change.
As anyone following the fires burning in the Amazon rainforest knows by now, trees play an important role in helping to offset global warming by storing carbon from atmospheric carbon dioxide — a major contributor to rising temperatures — in their wood, leaves, and roots. The worldwide level of CO2 is currently averaging more than 400 parts per million — the highest amount by far in the last 800,000 years.
But Marra, a forest pathologist at the Experiment Station with a PhD in plant pathology from Cornell University, has documented from studying his fallen trees that internal decay has the capacity to significantly reduce the amount of carbon stored within.
His research, published in Environmental Research Letters late last year and funded by the National Science Foundation, focused on a technique to see inside trees — a kind of scan known as tomography (the “T” in CAT scan).
This particular tomography was developed for use by arborists to detect decay in urban and suburban trees, mainly for safety purposes. Marra, however, may be the first to deploy it for measuring carbon content and loss associated with internal decay. Where there is decay there is less carbon, he explains, and where there is a cavity, there is no carbon at all.
“What we’re suggesting is that internal decay in trees has just not been properly accounted for,” says Marra.
This tree trunk section, or cookie, shows a large hollow in the center. Marra argues that traditional methods can miss such decay, and therefore overestimate how much forests will contribute to storing carbon. Jan Ellen Spiegel
While the first round of his research was a proof of concept that necessitated the destruction of 39 trees to show that tomography is accurate, his ultimate goal is a nondestructive technique to enable better assessments of carbon sequestration than those done annually by the U.S. Forest Service. Under the United Nations Framework Convention on Climate Change, ratified in 1994, governments are required to report annual estimates of carbon holdings in all their managed lands. The most recent Forest Service figures show that U.S. forests offset about 14 percent of the nation’s carbon emissions each year.
The Forest Service estimates that carbon makes up 48 to 50 percent of a tree’s biomass, so ones with decay will be less dense and therefore hold less carbon. But Marra contends that the visual signs monitored by the Forest Service, such as canopy and tree size, along with conspicuous problems such as lesions or cankers, don’t accurately reflect internal decay — a tree that looks healthy may have decay and one that appears problematic may be fine inside.
In addition, he says, foresters typically use a mallet to hammer a tree to register a sound that might indicate it’s hollow. “You know that there may be a hollow, but you don’t know how big the hollow is,” Marra says. As a result, he believes the government’s baseline data used to estimate carbon storage are not accurate.
“There are a lot of ways to improve our estimates of carbon being stored above ground in forests, and this decay component could certainly prove to be important,” says Andrew Reinmann, an ecologist and biogeochemist with the City University of New York’s Advanced Science Research Center. But, he added,
“We haven’t really had the technology to explore this before — it’s still a little bit of an unknown.”

Marra used a two-stage system for his research: sonic tomography, which sends sound waves through the tree, followed by electrical resistance tomography, which transmits an electric current. Both processes are necessary to fine-tune each other’s readings.
The system, which costs about $25,000 and fits in a backpack, is cheap and small by scientific equipment standards. Each reading takes no more than a few minutes and computerized visual renderings of the results appear instantly.
Marra uses a kind of scan known as tomography to measure carbon storage and decay in trees. Jan Ellen Spiegel
Marra experimented with three northern hardwoods — sugar maple, yellow birch, and American beech — and included more than two dozen of each, along with some control trees with no decay.
The researchers analyzed the lower bole — the first two meters or so — of each tree, which is the oldest part and closest to the soil, where most decay-causing fungi would come from.
A dozen or so nails were tapped in a circle around the trunk and connected by cables to the tomograph; a sonic hammer then activated the system to get sound-wave measurements.
For the electric resistance tomography, a second set of nails was hammered between the first, and electrodes — plus and minus — were attached to each.
The various nail areas were painted in different colors to enable the computer renderings to be aligned later with photographs of the cookies after the trees were cut down.
The cookies, about 4 inches thick and which Marra called “the truth,” were only taken from where the measurements were made — the areas with the paint markings.
He analyzed 105 cookies from the 39 trees taken down. In the 11 cases where tomography found no decay, the cookies revealed only one small cavity. In the 32 cases where incipient, or early, decay was detected, the cookies showed one additional cavity.
The cookies confirmed the tomography results in 36 cases where active decay was found, though eight small cavities were also detected. Tomography correctly identified cavities in the remaining 26 cookies, meaning that it missed a total of 10 cavities among the 105 cookies.
“One thing to sort of mitigate against this failure, if you want to call it that — these were very small cavities,” Marra says of the ones the tomography missed. “So they would have very little impact on a carbon budget.”
Marra readies a tree for scanning with electrodes and a tomograph. Jan Ellen Spiegel
Then came the time-consuming process of measuring the actual amount of carbon in each tree. After air-drying the cookies for a year, the wood from 500 drilled holes was sent to a gas chromatography lab at the University of Massachusetts to determine the carbon levels.
The tomography and lab results were then combined to calculate how much carbon was stored in the lower boles and to contrast that with the levels if the trees had been solid wood. Those calculations took until 2017 to complete.
“You’re looking at anywhere from a 19 percent to a 34 percent carbon loss for an actively decaying tree among those studied," Marra says. “But any place there’s a cavity you’ve lost all of your carbon.”

The upshot of his five years of research, says Marra, is that accurate tomographic readings are possible in just a few minutes. “And what our tomography tells us is the carbon content,” he says.
At the same time, Marra is aware that tomography is not a practical substitute for the Forest Service’s carbon estimate system — which itself is a clunky and labor-intensive slog. But it could provide a valuable way to augment those estimates.
“Those are very, very impressive results,’’ says Kevin Griffin, a tree physiologist at Columbia University and its Lamont-Doherty Earth Observatory. “They obviously have obtained a lot of precision in the techniques.”
“The results are important,” he adds, “but whether internal tree decay is the single most burning question? Probably not. There’s probably bigger fish to fry before we get there.”
Among them, he says are forest growth rates and overall tree health and age, as well as the impact of harvesting and other kinds of losses, including disease.
A tree’s architecture and height could also play large roles in carbon sequestration, says Reinmann of the City University of New York’s Advanced Science Research Center, as could the makeup of the forest landscape. His own research, for instance, found trees grow faster and have more biomass at the edge of fragmented forest.
“I think they’re making a good point that we’re probably over-estimating” carbon storage levels, says Aaron Weiskittel, director of the University of Maine’s Center for Research on Sustainable Forests.
Even so, Weiskittel and others — including Marra — say the research needs to be scaled up to many more tree types and full forests. For his part, Marra would like to sample forests randomly with many more trees and controlling for factors including species, age, and soil characteristics.
The goal, he says, is to develop a methodology for generating data to provide better carbon estimates for more than three tree types in one small part of the country.
“We need to use tomography to refine models so we’re more accurately assessing the role that forests are playing as sequesterers or climate change mitigators,” Marra says. “We don’t want to be over-estimating the roles that they play.”

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