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    Mongabay, a leading resource for news and perspectives on environmental and conservation issues related to the tropics, has launched Tropical Conservation Science - a new, open access academic e-journal. It will cover a wide variety of scientific and social studies on tropical ecosystems, their biodiversity and the threats posed to them. Tropical Conservation Science - March 8, 2008.

    At the 148th Meeting of the OPEC Conference, the oil exporting cartel decided to leave its production level unchanged, sending crude prices spiralling to new records (above $104). OPEC "observed that the market is well-supplied, with current commercial oil stocks standing above their five-year average. The Conference further noted, with concern, that the current price environment does not reflect market fundamentals, as crude oil prices are being strongly influenced by the weakness in the US dollar, rising inflation and significant flow of funds into the commodities market." OPEC - March 5, 2008.

    Kyushu University (Japan) is establishing what it says will be the world’s first graduate program in hydrogen energy technologies. The new master’s program for hydrogen engineering is to be offered at the university’s new Ito campus in Fukuoka Prefecture. Lectures will cover such topics as hydrogen energy and developing the fuel cells needed to convert hydrogen into heat or electricity. Of all the renewable pathways to produce hydrogen, bio-hydrogen based on the gasification of biomass is by far both the most efficient, cost-effective and cleanest. Fuel Cell Works - March 3, 2008.

    An entrepreneur in Ivory Coast has developed a project to establish a network of Miscanthus giganteus farms aimed at producing biomass for use in power generation. In a first phase, the goal is to grow the crop on 200 hectares, after which expansion will start. The project is in an advanced stage, but the entrepreneur still seeks partners and investors. The plantation is to be located in an agro-ecological zone qualified as highly suitable for the grass species. Contact us - March 3, 2008.

    A 7.1MW biomass power plant to be built on the Haiwaiian island of Kaua‘i has received approval from the local Planning Commission. The plant, owned and operated by Green Energy Hawaii, will use albizia trees, a hardy species that grows in poor soil on rainfall alone. The renewable power plant will meet 10 percent of the island's energy needs. Kauai World - February 27, 2008.

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Saturday, September 20, 2008

Austrian study: heating with biomass remains two-thirds cheaper than heating oil - households save €1800 per year, sector creates thousands of jobs

Heating buildings in a green, renewable way, is one of the most difficult challenges but also one of the most important ones needed to tackle climate change, because heating takes a large share of the energy used in modern societies. The least efficient, costliest and least climate-friendly way to heat buildings is by using electricity, which is why most households and commercial buildings use either heating oil or natural gas.

Of the renewables, a clear winner is now emerging, capable of taking over the fossil fuel based heating sector: biomass. From Austria come new data showing the fuel remains a whopping two-thirds less costly than heating with fossil fuels at today's prices. Biomass heat is now touted in Europe as a way for families to beat inflation caused by high energy bills, while simultaneously contributing in a practical way to fight climate change. For governments, it has become a strategy to tackle growing energy poverty in a cost-effective manner.

Last year we received some data from Austria, where heating with biomass pellets has seen a massive growth - a phenomenon witnessed throughout Europe. In September 2007 heating with heating oil on average cost 7.06 eurocent per kWh, whereas heating with pellets cost only 3.81 eurocent per kWh (previous post). This big difference has spurred further growth, with thousands of households switching to the green fuel. Increased demand pushed up prices for biomass pellets. So how do things look today, one year later?

According to a new study on the economics of biomass heating and the results of the European Biomass Action plan in Austria, the cost difference has grown further, because new wood pellet production plants have come online to meet increased demand. Biomass pellet trade too has grown strongly in Europe. According to the study, commissioned by industry association proPellets Austria, the average cost to heat a home with biomass is now around €1200 per year, whereas the cheapest alternative, heating oil, will set back families €3000 per year, based on projections for this year. (Graph: prices until the first quarter of 2008 - click to enlarge).

The data are based on a typical yearly consumption of 3000 liters of heating oil per household, with a heating oil price of €1/liter. Wood pellet prices were estimated to average €200 per ton. With these realistic numbers, individual households can save €1,800 per year by switching to renewable heat. The switch would also save 8,000 kilograms of CO2 per household.
The strong growth in biomass fueled heating systems amongst households and industry proves to be one of the most efficient and cleanest ways to fight inflation resulting from high energy prices. Biomass heating is having a tangible effect that helps counter the downward trend in the economy. Simultaneously renewable heat offers a cost-effective strategy to reduce CO2 emissions in a significant way. - Dr Christian Rakos
Energy poverty and inflation resulting from high heating bills does not have to be taken for granted, it has become a real social and economic problem that has governments throughout the EU worried. On the level of Austria as a whole, the implementation of the Biomass Action plan, of which the renewable heating component is the most important one, has been very beneficial in this regard.

The Biomass Action plan projects that by 2020 around 400,000 households in Austria will have made the switch to biomass-fueled boilers to heat their homes. This goal can be achieved by relying on locally and sustainably sourced biomass. The implementation of the plan will bring 11,000 new jobs in the country's heating sector - today's trend shows this projection is realistic. The switch would save Austria some €800 million euros per year by 2020:
:: :: :: :: :: :: :: :: :: :: :: ::

This summer Austria's Homeowners & Homebuilders Hotline - which informs citizens about renewables, conservation and efficiency in domestic buildings - has received twice as many applications for information about heating with biomass than in the summer of 2007, which was already a record year. Apparently, the relatively high acquisition and installation costs of a biomass heating unit doesn't deter Austrians to make the switch to renewable heating:

The price ticket for a new biomass heating installation for an average home is between 13,000 and 17,000 euros. Because the fuel is renewable and climate neutral, and thus helps the country achieve its Kyoto and EU goals, the state government contributes in paying 10% of this cost, whereas the federal government adds another 10%. This brings down costs to anywhere between 9,200 and 13,200 euros for a new boiler. For companies and industries, the incentive covers 30% of the costs.

At current heating oil prices, this investment is won back after 5 years. Modern biomass heating units at this price are fully automated and yield heat on-demand. They have a useful life of several decades.

Heating with biomass strongly reduces greenhouse gas emissions, which allows the government to win back the cash it spent on subsidizing the sector. According to the study, heating with electricity generates around 681kg per CO2eq / MWh; with heating oil 342 kg, with natural gas 228 kg and with pellets only 68kg / MWh (graph, click to enlarge). If the targets of the Biomass Action plan are met in Austria, the country will reduce its emissions by some 2 million tons per year. The accumulated amount will be 100 million tons in 2040.

The government wins back its subsidies by avoiding the purchase of carbon credits on the market. The scenario used in the study is based on a realistic carbon price of €17 per ton (today's price was €24.65 - September 20, 2008).

Biomass can be used for a myriad of products and services, from heat and power to bioproducts like plastics or building materials, to liquid fuels and hydrogen. But using it in the oldest, most simple way, - to heat your home - remains the more efficient option.

Most of the pellets used in Europe are wood pellets, but interest is growing in making them out of dedicated energy crops like miscanthus or fast growing trees like poplar.

A recent study by Dutch and Canadian researchers has shown that using this biomass as a solid fuel for heating purposes is 570% more efficient in reducing greenhouse gas emissions than using the resource for the production of liquid transportation fuels. Biomass pellets from miscanthus reduce GHG emissions by 7,600 to 13,100 kg CO2e per hectare. By comparison, soybean biodiesel and corn ethanol were found to reduce GHGs by a mere 900 and 1,500 kg CO2e per hectare respectively.

Rakos, Christian, "Heizungstausch senkt Kosten für private Haushalte" [Making the switch strongly reduces costs for households], Study commission by proPellets Austria, September 2008.

Österreichischen Rundfunks: "Heizen mit Biomasse deutlich günstiger" [Heating with biomass clearly less costly] - September 18, 2008.

Biopact: Study: solid biofuels 570% more efficient than corn ethanol in reducing GHG emissions - September 10, 2008

Biopact: Biomass pellets revolution in Austria: 46% less costly than heating oil; most efficient way for households to reduce carbon footprint - October 06, 2007

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Friday, September 19, 2008

Genetics proves agriculture emerged much earlier and slower than thought

Researchers led by Dr Robin Allaby of the University of Warwick’s plant research arm Warwick HRI have found evidence that genetics supports the idea that the emergence of agriculture in prehistory took much longer than originally thought.

Until recently researchers thought the story of the origin of agriculture was one of a relatively sudden appearance of plant cultivation in the Near East around 10,000 years ago spreading quickly into Europe and dovetailing conveniently with ideas about how quickly language and population genes spread from the Near East to Europe. Initially, genetics appeared to support this idea but now cracks are beginning to appear in the evidence underpinning that model.

The team led by Dr Robin Allaby developed a new mathematical model that shows how plant agriculture actually began much earlier than first thought, well before the Younger Dryas (the last “big freeze” with glacial conditions in the higher latitudes of the Northern Hemisphere). It also shows that useful gene types could have actually taken thousands of years to become stable.

Up till now researchers believed in a rapid establishment of efficient agriculture which came about as artificial selection was easily able to dominate natural plant selection, and, crucially, as a consequence they thought most crops came from a single location and single domestication event.

However recent archaeological evidence has already begun to undermine this model pushing back the date of the first appearance of plant agriculture. The best example of this being the archaeological site Ohalo II in Syria (picture) where more than 90,000 plant fragments from 23,000 years ago show that wild cereals were being gathered over 10,000 years earlier than previously thought, and before the last glacial maximum (18,000-15,000 years ago).

The field of archaeobotany is also producing further evidence to undermine the quick development model. The tough rachis mutant is caused by a single recessive allele (one gene on a pair or group of genes), and this mutant is easily identifiable in the archaeological specimens as a jagged scar on the chaff of the plant noting an abscission (shedding of a body part) as opposed to the smooth abscission scar associated with the wild type brittle rachis.

Simply counting the proportion of chaff types in a sample gives a direct measure of frequency of the two different gene types in this plant. That study has shown that the tough rachis mutant appeared some 9,250 years ago and had not reached fixation over 3,000 years later even after the spread of agriculture into Europe was well underway. Studies like these have shown that the rise of the domestication syndrome was a slow process and that plant traits appeared in slow sequence, not together over a short period of time.

Genome wide surveys of crops such as einkorn and barley that in the past have suggested a single origin from a narrow geographical range, supporting the rapid establishment view, have long been in conflict with other gene studies. The most notable conflict is in the case of barley for which there is a large body of evidence that suggests more than one common ancestor was used in its development.

These challenges to the fast model of agricultural development need a new model to explain how and why the development was so slow and demonstrate why artificial selection of just one plant type does not have the expected quick result. This computer model has now been provided by the University of Warwick, the Institute of Archaeology, University College London, and Manchester Interdisciplinary Biocentre has outlined the new mathematical model in a paper published in Proceedings of the National Academy of Sciences and in a summary article in the Biologist:
:: :: :: :: :: :: :: :: :: ::

Their paper entitled "The genetic expectations of a protracted model for the origins of domesticated crops" used computer simulations that showed that over time a cultivated population will become monophyletic (settle into one stable species) at a rate proportional to its population size as compared various gene variations in the wild populations. They found this rate of change matched closely the 3000 years it took the tough rachis mutant to become established:

Ironically, this process is actually accelerated if there is more than one
wild source population (in other words if attempts at domestication happen more than once) because any resulting hybrid between those domesticated populations then has a heightened differentiation compared with either one of the wild populations of the two parent plants.

This mathematical model also more supportive of a longer complex origin of plants through cross breeding of a number of attempts at domestication rather than a single plant type being selectively bred and from a single useful mutation that is selectively grown quickly out paces the benefits natural selection.

The lead researcher puts the findings into perspective:
This picture of protracted development of crops has major implications for the understanding of the biology of the domestication process and these strike chords with other areas of evolutionary biology.

This lengthy development should favour the close linkage of domestication syndrome trait genes which may become much more important because linked genes will not be broken up by gene flow – and this makes trait selection and retention easier. Interestingly, as more crop genomes become mapped, the close linkage of two or more domestication syndrome genes has been reported on several occasions.

This process has similarities to the evolution of ‘supergenes’ in which many genes cluster around a single locus to contribute to one overall purpose.

We now need to move this research area to a new level. Domestication was a complex process and can now be viewed more legitimately as the paragon of evolutionary process that Darwin originally recognized. There are many interacting factors involved that we know about operating on a wide range of levels from the gene to the farmer and climate – the challenge is to integrate them into a single story. - Dr Robyn Allaby

Picture: Excavations at Ohalo II, the 23,000 year old fishing camp on the Sea of Galilee, revealing a broad variety of semi-domesticated plant seeds. Credit: University of Haifa.


Robin G. Allaby, Dorian Q. Fuller, Terence A. Brown, "The genetic expectations of a protracted model for the origins of domesticated crops", PNAS, September 16, 2008, vol.105, no.37, 13982-13986, doi: 10.1073/pnas.0803780105

Allaby, R.G., "The rise of plant domestication: life in the slow lane", Biologist, 2008, vol. 55, no. 2, pages 94-99

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Thursday, September 18, 2008

Plants in forest emit aspirin-like chemical to signal stress; discovery could aid farmers as early warning system

Scientists have discovered that trees respond to stress by producing significant amounts of a chemical form of aspirin. The finding, by scientists at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, opens up new avenues of research into the behavior of plants and their impacts on air quality, and also has the potential to give farmers an early warning signal about crops that are failing. Detecting chemical signals in the atmosphere would allow farmers to intervene faster, with fewer costly inputs, and prevent crop losses. Currently, farmers rely on visual inspection of crops to detect stresses and often they only see the problem when it is already too late.

Interestingly, the findings indicate that plants may communicate on an ecosystem-wide scale, by sending out chemical signals via the atmosphere.
Unlike humans, who are advised to take aspirin as a fever suppressant, plants have the ability to produce their own mix of aspirin-like chemicals, triggering the formation of proteins that boost their biochemical defenses and reduce injury. Our measurements show that significant amounts of the chemical can be detected in the atmosphere as plants respond to drought, unseasonable temperatures, or other stresses. - Thomas Karl, NCAR scientist, lead author
For years, scientists have known that plants in a laboratory may produce methyl salicylate, which is a chemical form of acetylsalicylic acid, or aspirin. But researchers had never before detected methyl salicylate in an ecosystem or verified that plants emit the chemical in significant quantities into the atmosphere.

The team of scientists reported its findings [*.pdf] last week in the open access journal Biogeosciences. The research was funded by the National Science Foundation (NSF), NCAR's sponsor.
Biosphere-atmosphere interactions are important to the understanding of the Earth system. This fortuitous discovery of methyl salicyclate in quantities not anticipated adds to an already important study. - Cliff Jacobs, program director in NSF's Division of Atmospheric Sciences
The discovery
Researchers had not previously thought to look for methyl salicylate in a forest, and the NCAR team found the chemical by accident. They set up specialized instruments last year in a walnut grove near Davis, California, to monitor plant emissions of certain volatile organic compounds (VOCs).

These hydrocarbon compounds are important because they can combine with industrial emissions to affect pollution, and they can also influence local climate.

When the NCAR scientists reviewed their measurements, they found to their surprise that the emissions of VOCs included methyl salicylate.

The levels of methyl salicylate emissions increased dramatically when the plants, which were already stressed by a local drought, experienced unseasonably cool nighttime temperatures followed by large daytime temperature increases.

Instruments mounted on towers about 100 feet above the ground measured up to 0.025 milligrams of methyl salicylate rising from each square foot of forest per hour.

Karl and his colleagues speculate that the methyl salicylate has two functions. One of these is to stimulate plants to begin a process known as systemic acquired resistance, which is analogous to an immune response in an animal:
:: :: :: :: :: :: :: :: :: :: :: ::

This helps a plant to both resist and recover from disease. The methyl salicylate also may be a mechanism whereby a stressed plant communicates to neighboring plants, warning them of the threat. Researchers in laboratories have demonstrated that a plant may build up its defenses if it is linked in some way to another plant that is emitting the chemical.

Now that the NCAR team has demonstrated that methyl salicylate can build up in the atmosphere above a stressed forest, scientists are speculating that plants may use the chemical to activate an ecosystem-wide immune response.
These findings show tangible proof that plant-to-plant communication occurs on the ecosystem level. It appears that plants have the ability to communicate through the atmosphere. - Alex Guenther, NCAR scientist, co-author
Implications for farmers
The discovery raises the possibility that farmers, forest managers, and others may eventually be able to start monitoring plants for early signs of a disease, an insect infestation, or other types of stress. At present, they often do not know if an ecosystem is unhealthy until there are visible indicators, such as dead leaves.
A chemical signal is a very sensitive way to detect plant stress, and it can be an order of magnitude more effective than using visual inspections. If you have a sensitive warning signal that you can measure in the air, you can take action much sooner, such as applying pesticides. The earlier you detect that something's going on, the more you can benefit in terms of using less pesticides and managing crops better. - Thomas Karl
The discovery also can help scientists resolve a central mystery about VOCs. For years, atmospheric chemists have speculated that there are more VOCs in the atmosphere than they have been able to find. Now it appears that some fraction of the missing VOCs may be methyl salicylate and other plant hormones.

This finding can help scientists better track the impact of VOCs on the behavior of clouds and the development of ground-level ozone, an important pollutant.

: NCAR researcher Alex Guenther studies a chemical form of aspirin produced by walnut trees in California. Credit: Carlye Calvin, UCAR.

T. Karl, A. Guenther, A. Turnipseed, E. G. Patton, and K. Jardine, "Chemical sensing of plant stress at the ecosystem scale", Biogeosciences, 5, 1287-1294, 2008

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Plants soak up less CO2 as planet warms - reforestation or conservation to combat climate change may not work

Plants are unlikely to soak up more carbon dioxide from the air as the planet warms, new research suggests. A large team of scientists found that grassland took up less CO2 than usual for two years following temperatures that are now unusually hot, but may become common. The conclusion parallels a real-world finding from Europe's 2003 heatwave, when the continent's plant life, including forests, became a net producer, not absorber, of CO2. This latest study is published as the cover story of the current issue of Nature.

The findings make the case for the creation or maintenance of 'carbon sinks' through reforestation or conservation efforts problematic. A lot of faith is being placed in some circles in this capacity of plants to maintain absorption of CO2 as concentrations of the gas rise, or even to use the extra CO2 to grow faster and absorb more of it. It is one of the reasons behind the recent upsurge of interest in having western governments pay to protect tropical forests.

But the new research is one of a growing number of pieces of evidence (here, here, here, here and here) suggesting this will not always work. Some ecosystems might continue to absorb carbon dioxide, and perhaps increase the rate of absorption; others may react to warming by releasing the greenhouse gas and become part of the problem, not the solution. Careful studies will be needed to see whether it makes sense to use land to grow trees or grasses on it as a carbon sequestration technique.

Researchers extracted four intact segments of grassland, about 3 sq m in area and weighing about 12 tonnes each, from the prairies of Oklahoma, and placed them in special chambers at the Desert Research Institute (DRI) in Reno, Nevada. Conditions in the chambers, such as temperature, moisture and sunlight, could be precisely controlled.

Two of the four chambers were given a set of conditions mimicking what actually happens, on average, on the wild prairies. Temperatures rose and fell with days and nights and seasons, and "rainfall" was injected in a realistic pattern. The other two chambers received the same prescription with the exception that for a whole year, temperatures were always 4°C higher.

The warmer plots saw a shortfall in carbon dioxide uptake of about 30% during the warm year and the one following.
In the warm year, the temperature goes up and causes more evapotranspiration from the plants. But plants have evolved to 'know' that when it gets dry they should curb their water loss, so they reduce the apertures of their stomata [pores] to conserve water, and that constrains the amount of CO2 they can take up [by photosynthesis]. - Professor Jay Arnone, Desert Research Institute, lead author
This response has been understood for some time. But what happened in the following year, when temperatures returned to 'normal', was not so familiar. Even during the warm year with its meagre amount of photosynthesis, plants had put carbon in the soil. So during the normal year following, soil microbes had extra carbon to process, which they did, emitting more carbon dioxide into the air.

Same story in Europe

By complete coincidence, the study mimicked fairly closely events on the other side of the Atlantic. As DRI researchers were turning up the heat in 2003 in their experimental plots, in Europe it was happening for real, with temperatures in some places reaching 6°C above normal.

An analysis led by French researchers, published in 2005, showed that as the continent became hotter, Europe's plants changed from being net overall absorbers of CO2 to net producers:
:: :: :: :: :: :: :: :: :: :: ::

The consequences of these findings are wide-ranging, and particularly worrying for those who see a future in mitigating climate change by creating and conserving forests or grasslands. As the planet warms, these ecosystems may become part of the problem instead of a solution.

Different types of ecosystems will react differently to warming and elevated atmospheric CO2 levels, which is why they need targeted scrutiny.
We conducted this study under current ambient levels of CO2 so we don't know for sure what'll happen in the future. But we don't anticipate a huge effect of [elevated] CO2 on these systems. As high temperatures become more commonplace, you might expect a persistent reduction in the uptake of CO2 by natural ecosystems, and that may mean that the net rate of CO2 elevation may increase. - Professor Arnone
There is growing evidence that Northern forests are far less effective carbon sinks than tropical forests (previous post), even though some studies have suggested even tropical rainforests may become carbon emitters under warming conditions. But at least, this effect is offset by the fact that these humid forests generate clouds, which have a high albedo, reflecting sunlight back into space, and thus cooling the planet.

For grasslands, the findings have been less consistent, which is why the current study is so important: it is the first analysis showing the CO2 cycle response of grass to a warmer environment.

The large collaborative study involved scientists from the DRI; University of Nevada, Reno; University of Oklahoma in Norman, Okla.; University of New Hampshire; the National Center for Atmospheric Research in Boulder, Colo., and Rice University in Houston, Texas. The study was funded by the U.S. National Science Foundation's Division of Environmental Biology under the program, "Integrated Research Challenges in Environmental Biology".

: The grassland plots were grown in DRI's EcoCELL facility. Credit: DRI.

John A. Arnone III, et al. "Prolonged suppression of ecosystem carbon dioxide uptake after an anomalously warm year", Nature 455, 383-386 (18 September 2008) | doi:10.1038/nature07296

Biopact: Northern forests less effective carbon sinks than tropical forests - June 22, 2007

Biopact: Plant a tree and save the planet? Let's think again. - December 13, 2006

Eurekalert: Experiment suggests limitations to carbon dioxide 'tree banking' - August 7, 2007.

Eurekalert: Trees to offset the carbon footprint? - April 9, 2007.

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Greening Africa: how to bring the agrarian revolution to the continent?

The Green Revolution that has led to food being far more abundant now than forty years ago in South America and Asia has all-but bypassed Sub-Saharan Africa as that region's population trebled over that time period. Now, writing in the International Journal of Technology and Globalisation leading agronomists point to possible causes for this disparity and offer hope of reversing the trend based on a technological approach.

Agricultural production expert professor Prem Bindraban, plant breeder professor Huub Loeffler, and ecologist professor Rudy Rabbinge of Wageningen University and Research Centre in The Netherlands, highlight the disparity between growing food availability across the globe compared with Sub-Saharan Africa (SSA). Food has increased by almost one third per person over the last forty years globally, but in SSA it has decreased by 12%. (An example of this growing gap, the average maize yield per hectare for different regions, is shown in figure 1).

Currently 90% of the SSA population lives in rural areas and 70% of the labour force works in the agricultural sector. This figure is higher for some countries, including Burundi. As such, agriculture is an important economic sector that generates 30-60% of Gross Domestic Product. Nevertheless, the population has increased from 200 million in 1960 to 600 million today and finds 180 million people malnourished in SSA.

With most poor people living in rural regions and employed in agriculture, they explain that there is new interest in how farming and food production might drive overall development. Bindraban and colleagues emphasise how agricultural development has served as a "stepping stone for overall economic development in developed nations and in newly developing economies in Asia":
:: :: :: :: :: :: :: :: :: :: :: :: ::

While there have been a few isolated successes in development, modern agricultural technology, including genetically modified crops, modern pesticides, fertilisers and irrigation methods, mono-cropping for bulk production, has not spread widely to benefit the entire continent.

"For agriculture to develop, proper market and institutional conditions should catalyse the process that is initiated by technologies, as has been found for the green revolution," the researchers explain.

The researchers look into land (i.e., yield) and labour productivity, the relation between technology use and yield stability and, the environmental implications of input use. Ways and means are discussed as to what innovative technologies could close the gap, taking complex mixed farming systems as an entry point that account for 90% of Africa's agriculture.


P.S. Bindraban, H. Loffler, R. Rabbinge, "How to close the ever widening gap of Africa's agriculture", Int. J. Technology and Globalisation, 2008, 4, 276-295

Biopact: Feeding 40 billion people and the Green Revolution in Africa - March 02, 2008

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Wednesday, September 17, 2008

Scientists: take away global dimming, and global warming will be much worse - "formidable challenges ahead"

The case for carbon-negative bioenergy - capable of actively taking CO2 out of the atmosphere - has become stronger once again, because of a new report showing the need for drastic carbon emissions cuts to counter-balance the disappearance of a phenomenon known as "global dimming", which keeps the planet relatively cool. If the cooling blanket of air pollution - resulting from burning carbon rich fuels - is taken away, then global warming will be more strongly felt and bring greater environmental damage than was previously thought. Therefor, far more ambitious GHG emission reduction targets are needed than the ones currently on the table.

In the new study titled "On avoiding dangerous anthropogenic interference with the climate system: Formidable challenges ahead" the scientists say the earth will warm about 2.4° C (4.3° F) above pre-industrial levels even under extremely conservative greenhouse gas emission scenarios and under the assumption that efforts to clean up particulate pollution continue to be successful. The study, by professor V. Ramanathan from Scripps Atmospheric and Climate Sciences, and co-author Yan Feng, a Scripps postdoctoral research fellow, is published in the online edition of the Proceedings of the National Academy of Sciences.

That amount of warming reported in the new analysis falls within what the world's leading climate change authority recently set as the threshold range of temperature increase that would lead to widespread loss of biodiversity, deglaciation and other adverse consequences in nature. The researchers argue that coping with these circumstances will require "transformational research for guiding the path of future energy consumption."

Ramanathan and Feng assumed a highly optimistic scenario that greenhouse gas concentrations would remain constant at 2005 levels for the next century. For the concentrations to remain at 2005 levels, the emissions of greenhouse gases such as carbon dioxide must decrease drastically within the next decade.

Economic expansion, however, is expected to see emissions increase. The researchers then analyzed expected future warming by assuming that the cooling effect of man-made aerosol pollution will be eliminated during the 21st Century. Currently, particulate air pollution caused by fossil fuel combustion, forest fires and smoke from cooking and agricultural waste burning serves to mask global warming caused by greenhouse gases. The smog does so chiefly by creating a dimming effect at Earth's surface.

But mitigation of this type of pollution has been increasingly successful by countries around the world. Because soot and similar particles remain airborne only for a matter of weeks, it is expected that clean-up efforts produce relatively immediate results. Therefore, the authors based their projections of temperature increase assuming the absence of these pollutants in the atmosphere. By contrast, greenhouse gases can remain in the atmosphere for decades or, in the case of carbon dioxide, more than a century.

This means that if the cooling effect of the air pollution is taken away, the temperature increases resulting from the build up of greenhouse gases are no longer counter-balanced. The warming will persist and be felt more strongly.
This paper demonstrates the major challenges society will have to face in dealing with a problem that now seems unavoidable. We hope that governments will not be forced to consider trade-offs between air pollution abatement and mitigation of greenhouse gas emissions. - Professor V. Ramanathan
Ramanathan and Feng estimated that the increase in greenhouse gases from pre-industrial era levels has already committed Earth to a warming range of 1.4° C to 4.3° C (2.5° F to 7.7° F). About 90 percent of that warming will most likely be experienced in the 21st Century. In 2007, the Intergovernmental Panel on Climate Change identified a temperature increase range between 1° C and 3°C (1.8° F and 5.4°F) as the threshold at which society commits the planet to biodiversity loss and deglaciation in areas such as Greenland and the Himalayas.

The pace at which the world approaches the threshold depends in part on national and international air pollution reduction policies. Despite the masking effects of atmospheric aerosols, the authors note that their removal is still an important objective because of the deleterious human health, agricultural and water supply effects of smog. The authors point out that the real problem is not the reduction of air pollution, but it is the lack of comparable reductions in emissions of CO2 and other greenhouse gases to offset the reductions in the surface cooling effect of the polluting fog:
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Given that a potentially large warming is already in our rear-view mirror, scientists and engineers must mount a massive effort and develop solutions for adapting to climate change and for mitigating it. - Professor V. Ramanathan
The study implies that most current climate policies - which often take a comfortable target of limiting atmospheric carbon dioxide levels to 450 parts per million (ppm) - are not ambitious enough. Current levels stand at 384ppm. Some climate scientists, like NASA's Dr James Hansen, urge us to aim for a reduction of CO2 levels to 350ppm, to keep the planet liveable (previous post). This goal calls for the large-scale introduction of carbon-negative bioenergy, which is the only way to generate both energy to run societies, while at the same time actively removing carbon dioxide from the atmosphere.

Such radical concepts are needed if we want to counter the effect of taking away the blanket of pollution that keeps us relatively cool.

Scientists like Paul Crutzen have suggested that geo-engineering techniques aimed at creating an artificial 'cooling blanket' - he proposed filling the upper atmosphere with sulphur particles - could counter global warming, if its effects proved to be worse than thought. But then we would be switching from one form of 'cooling' pollution (soot and aerosol particles) to another, far more dangerous one. The potential environmental damages resulting from an idea like Crutzen's have been studied in-depth, and were found to be dramatic. This particular geo-engineering proposal has therefor been quickly dismissed as being too risky (previous post).

Professor V. Ramanathan and Dr Yan Feng's study demonstrates that a deep cut in carbon emissions is the only rational response to the disappearance of the global dimming effect. Carbon-negative bioenergy will play an important role in reducing GHG levels, because it is the most radical of all clean energy technologies. Contrary to ordinary renewables, which are 'merely' carbon-neutral, carbon-negative bioenergy goes beyond zero emissions, by actively removing CO2 from the atmosphere.

The Scripps Institution of Oceanography, at UC San Diego, is one of the oldest, largest and most important centers for global science research and education in the world. The National Research Council has ranked Scripps first in faculty quality among oceanography programs in the U.S. Now in its second century of discovery, the scientific scope of the institution has grown to include biological, physical, chemical, geological, geophysical and atmospheric studies of the earth as a system.

Hundreds of research programs covering a wide range of scientific areas are under way today in 65 countries. The institution has a staff of about 1,300, and annual expenditures of approximately $155 million from federal, state and private sources. Scripps operates one of the largest U.S. academic fleets with four oceanographic research ships and one research platform for worldwide exploration.

Eastern China. Dozens of fires burning on the surface (red dots) and a thick pall of smoke and haze (greyish pixels) filling the skies overhead. This pollution contributes to 'global dimming', which keeps the planet relatively cool. Photo taken by MODIS aboard NASA's Aqua satellite. Credit: Wikimedia.


V. Ramanathan and Y. Feng, "On avoiding dangerous anthropogenic interference with the climate system: Formidable challenges ahead", PNAS published ahead of print, September 17, 2008, doi:10.1073/pnas.0803838105

Biopact: Carbon-negative bioenergy making headway, at last - June 06, 2008

Biopact: Climate change and geoengineering: emulating volcanic eruption too risky - August 15, 2007

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Researchers develop graphene-based ultracapacitators, promise doubling of storage capacity

Engineers and scientists at The University of Texas at Austin have achieved a breakthrough in the use of a one-atom thick structure called "graphene" as a new carbon-based material for storing electrical charge in ultracapacitor devices, perhaps paving the way for the massive installation of renewable energies such as wind and solar power.

The researchers, led by professor Rod Ruoff, who holds the Cockrell Family Regents Chair in Engineering, believe their breakthrough shows promise that graphene (a form of carbon) could eventually double the capacity of existing ultracapacitors, which are manufactured using this entirely different form of carbon. The team's findings will be published in the Oct. 8 edition of Nano Letters. The article was posted on the journal's web site this week.
Through such a device, electrical charge can be rapidly stored on the graphene sheets, and released from them as well for the delivery of electrical current and, thus, electrical power. There are reasons to think that the ability to store electrical charge can be about double that of current commercially used materials. We are working to see if that prediction will be borne out in the laboratory. - Rod Ruoff, professor of mechanical engineering and physical chemist
Two main methods exist to store electrical energy: in rechargeable batteries and in ultracapacitors which are becoming increasingly commercialized but are not yet as popularly known. An ultracapacitor can be used in a wide range of energy capture and storage applications and are used either by themselves as the primary power source or in combination with batteries or fuel cells. Some advantages of ultracapacitors over more traditional energy storage devices (such as batteries) include: higher power capability, longer life, a wider thermal operating range, lighter, more flexible packaging and lower maintenance.

Ruoff and his team prepared chemically modified graphene material and, using several types of common electrolytes, have constructed and electrically tested graphene-based ultracapacitor cells. The amount of electrical charge stored per weight (called "specific capacitance") of the graphene material has already rivaled the values available in existing ultracapacitors, and modeling suggests the possibility of doubling the capacity:
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Our interest derives from the exceptional properties of these atom-thick and electrically conductive graphene sheets, because in principle all of the surface of this new carbon material can be in contact with the electrolyte. Graphene's surface area of 2630 m2/gram (almost the area of a football field in about 1/500th of a pound of material) means that a greater number of positive or negative ions in the electrolyte can form a layer on the graphene sheets resulting in exceptional levels of stored charge. - Professor Ruoff
The U.S. Department of Energy has said that an improved method for storage of electrical energy is one of the main challenges preventing the substantial installation of renewable energies such as wind and solar power. Storage is vital for times when the wind doesn't blow or the sun doesn't shine. During those times, the stored electrical energy can be delivered through the electrical grid as needed.

Ruoff's team includes graduate student Meryl Stoller and postdoctoral fellows Sungjin Park, Yanwu Zhu and Jinho An, all from the Mechanical Engineering Department and the Texas Materials Institute at the university.

This technology, Stoller says, has the promise of significantly improving the efficiency and performance of electric and hybrid cars, buses, trains and trams. Even everyday devices such as office copiers and cell phones benefit from the improved power delivery and long lifetimes of ultracapacitors.

Ruoff says significant implementation of wind farms for generation of electricity is occurring throughout the world and the United States, with Texas and California first and second in the generation of wind power.

According to the American Wind Energy Association, in 2007 wind power installation grew 45 percent in this country. Ruoff says if the energy production from wind turbine technology grew at 45 percent annually for the next 20 years, the total energy production (from wind alone) would almost equal the entire energy production of the world from all sources in 2007.
While it is unlikely that such explosive installation and use of wind can continue at this growth rate for 20 years, one can see the possibilities, and also ponder the issues of scale. Electrical energy storage becomes a critical component when very large quantities of renewable electrical energy are being generated. - Professor Ruoff
Funding and support was provided by the Texas Nanotechnology Research Superiority Initiative, The University of Texas at Austin and a Korea Research Foundation Grant for fellowship support for Dr. Park.


Meryl D. Stoller, Sungjin Park, Yanwu Zhu, Jinho An, and Rodney S. Ruoff, "Graphene-Based Ultracapacitors", Nano Letters, ASAP Article, Web Release Date: September 13, 2008, DOI: 10.1021/nl802558y

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Tuesday, September 16, 2008

CIFOR report: conservationists' call for ban on bushmeat would 'starve Africans'

A blanket ban on bushmeat hunting in Central Africa, as called for by some conservationists and animal welfare activists from the wealthy West, would endanger both humans and animals, says a new report by the leading Centre for International Forestry Research (CIFOR). If current hunting levels persist, many species will be extinct in less than 50 years. But bushmeat provides up to 80% of protein and fat needed in rural diets. Giving local people the rights and incentives to hunt sustainably would protect their livelihoods and save forest mammals from extinction, claims CIFOR. Criminalising their current way of life is counter-productive, the researchers say.

The report titled Conservation and Use of Wildlife-based Resources: The Bushmeat Crisis [*.pdf] was produced for the Secretariat of the Convention on Biological Diversity. It will be discussed at the forthcoming IUCN World Conservation Congress, in Barcelona, on 5 October. A summary can be found here: New Report Says Blanket Ban on Bushmeat Trade in Central Africa Could Have Dire Consequences for the Region’s Poor.

The CIFOR study on the busmeat trade in Central Africa offers a very interesting case-study of how short-sighted calls for moratoria on certain land use and hunting practises may result in far greater damages over the longer run.
The bushmeat crisis is not only a crisis of extinction, it is is also a crisis of livelihoods and food security. Criminalising the whole issue of bushmeat simply drives it underground. We need to decriminalise parts of this hunting and trade and give local communities the rights and incentives to manage these resources sustainably for their own benefit. - Frances Seymour, director general of CIFOR
CIFOR estimates that the annual harvest of bushmeat in Central Africa amounts to more than one million tonnes — the equivalent of four million heads of cattle. According to the report, large mammal species are particularly vulnerable.

Many of these - elephants, gorillas and other primate species - have already become locally extinct. But CIFOR warns that existing policies designed to 'crackdown' on hunting are often counter-productive, as they 'effectively outlaw' the hunting of rodents and other fast-breeding species that are not under threat of extinction.

Overall, international trade in wild animal products has an estimated value of US$3.9 billion. For West and Central Africa alone, the estimates range from $42m to $205m a year. Yet, these statistics are still largely ignored in official trade and national policies regulating forest policy, claims the CIFOR report:
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The authors of the study call on policymakers in the region to develop policies protecting endangered species, while allowing sustainable hunting of 'common' game, since there is no clear substitute available if common wild meat sources were to be depleted. They cite successful models in Peru and also in Sarawak, Malaysia, where a ban on trading in bushmeat was complemented with recognition of the hunting rights of indigenous peoples.
If local people are guaranteed the benefits of sustainable land-use and hunting practices, they will be willing to invest in sound management and negotiate selective hunting regimes. Sustainable management of bushmeat resources requires bringing the sector out into the open, removing the stigma of illegality, and including wild meat consumption in national statistics and planning. Reframing the bushmeat problem from one of international animal welfare to one of sustainable livelihoods might be a good place to start. - Frances Seymour
The study highlights the role of the timber industry in sustainable wildlife management, as around half of the remaining forest in Africa now falls within timber concessions. The authors also note that European consumers are 'partly responsible' for the bushmeat crisis. Apart from the direct demand for bushmeat products from expat communities, European demand for African timber exports helps to drive this local timber extraction - both legal and illegal.

The report recommends that the local and international timber industry work with NGOs, local communities, and governments to develop forest policies and management plans that incorporate wildlife concerns.
Unless bushmeat hunting is legalised - obviously within an adequately enforced regulatory framework - it will remain largely unregulated and increasingly unsustainable. But as well as empowering local people and creating mechanisms for community management of bushmeat, which includes working out what level of hunting is sustainable, we need to direct funds, such as those from payments for ecosystem services or carbon, to communities so that they have incentives to do this. - Dr Noelle Kumpel, programme manager, Central, East and Southern Africa Programme, Zoological Society of London
The logic held by the authors of the CIFOR report resembles a line of thought often maintained by Biopact, when it comes to tackling complex issues like tropical deforestation or biodiversity loss resulting from agriculture. For example, a full ban on palm oil, rightly blamed for spurring deforestation, would destroy one of the few low-cost, high-profit economic opportunities for smallholders in the tropics (even when most of the acreage is controlled by large estates). If this opportunity is lost, they would fall back into poverty, and revert back to even more unsustainable agricultural techniques in order to survive. Fertility rates would spike, increasing pressures on ecosystems. The net result would be more, not less deforestation and biodiversity loss. Attempts to use the wealth generated by palm oil farming to make the industry more sustainable, are far more productive than the moratoria some conservation groups are calling for.

Alternative ways to fund a gradual phase-out of unsustainable agricultural production methods - such as funds for carbon or ecosystem services - would have to be competitive with the local, tangible benefits of land use practises we may think to be 'unsustainable' at first sight. What is more, discussions about alternatives have to go beyond mere local and immediate circumstances, and instead take into account the broad historical, social and economic context of the situation. All the key drivers of the problem must be taken into account, that is, local, regional, national and international factors.

Image 1: Skinned antelopes for sale, Guinea. Credit: Terry Sunderland.

Image 2: Local kids carry a monkey, Loa Loa village, Gabon. Credit: Meilinda Wan.

CIFOR: Conservation and Use of Wildlife-based Resources: The Bushmeat Crisis [*.pdf]- September 16, 2008.

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Building houses out of crops could help combat climate change - showcase at University of Bath

The world's tallest wooden residential building is being built in Murray Grove, in Hackney, London, by architects Waugh Thistleton. The nine-storey building will be built of cross-laminated timber panels - a material that the architects say will save 125 tonnes of carbon emissions compared to a concrete structure of similar size. Check the final stages of the construction, here.

Houses made of modern hemp, timber or straw composites could help combat climate change by reducing the carbon footprint of building construction, according to researchers at the University of Bath.

Currently the construction industry is a major contributor of environmental pollutants, with buildings and other build infrastructure contributing to around 19% of the UK’s eco-footprint.

Researchers at the BRE Centre for Innovative Construction Materials are researching low carbon alternatives to building materials currently used by the construction industry. Their research is one of the projects being presented at the Sustainable Energy & the Environment showcase on Wednesday 17 September at the University of Bath.

Although timber is used as a building material in many parts of the world, historically it is used less in the UK than in other countries. Researchers at the centre are developing new ways of using timber and other crop-based materials such as hemp, natural fibre composites and straw bales. Their work using straw bales as a building material has already been featured on Channel 4’s Grand Designs series.
The environmental impact of the construction industry is huge. For example, it is estimated that worldwide the manufacture of cement contributes up to ten per cent of all industrial carbon dioxide emissions.

We are looking at a variety of low carbon building materials including crop-based materials, innovative uses of traditional materials and developing low carbon cements and concretes to reduce impact of new infrastructure. As well as reducing the environmental footprint, many low carbon building materials offer other benefits, including healthier living through higher levels of thermal insulation and regulation of humidity levels
. - Professor Peter Walker, Director of the BRE Centre for Innovative Construction MaterialsCentre

Straw bale houses are increasingly popular in Europe. Here an example from Switzerland, where prefab meets straw in a clean, modern aesthetic. The Strohaus, designed by Zurich-based architect Felix Jerusalem, makes use of compressed straw panels (click to enlarge).
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The exhibition will be opened by David Willetts MP, Shadow Secretary of State for Innovation, Universities & Skills, and will be attended by industrialists, research councils, local and national government representatives and other key stakeholders from across the South West.

The showcase coincides with the launch of the Institute for Sustainable Energy & the Environment (I-SEE) at the University of Bath, which will bring together experts from diverse fields of science, engineering, social policy and economics to tackle the problems of climate change.

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Oil palm plantations no substitute for tropical rainforests - study

The continued expansion of oil palm plantations will worsen the dual environmental crises of climate change and biodiversity loss, unless rainforests are better protected, warn scientists in a comprehensive review of the subject. Lead author Emily Fitzherbert from the Zoological Society of London and University of East Anglia says there has been much debate over the role of palm oil production in tropical deforestation and its impacts on biodiversity. The researchers wanted to put the discussion on a more scientific footing. They point to the potential threats of an unregulated expansion of palm oil plantations, but they also offer some strategies to reduce these pressures.

The authors did not take into account the socio-economic arguments often heard in countries where palm oil production is a major contributor to the economy. These arguments boil down to the idea that, without palm oil, it would be difficult progress economically, and that, in the long-run, stagnation is equally or even more damaging to the environment. In a country like Malaysia, timber and palm oil combined are the second biggest export earner, after petroleum and natural gas. Any analysis of the damaging impacts of the palm oil industry must be balanced against these immediate 'benefits', some argue. The environmental effects of economic regression must be projected and taken into account as well.

Some of these countries go so far as to say that rich nations in the West have been able to develop by deforesting most of their land over the past 200 years. Because of the wealth they have accumulated during this period, these countries now have the economic means to engage in reforestation efforts. If these wealthy countries want to prevent developing nations from following a similar pathway, they should at least compensate the poorer nations. Thus, it is argued, a more comprehensive approach of the palm oil debate is needed. One that takes into account not only the immediate effects of oil palm expansion, but the history of modernity as such and the complex socio-economic drivers of deforestation in the tropics.

Palm oil, used in food, cosmetics, biodiesel and other products, is now the world's leading vegetable oil. It is derived from the fruit of the oil palm, grown on more than 50,000-square miles of moist, tropical lowland areas, mostly in Malaysia and Indonesia. These areas, once covered in tropical rainforest, the globe's richest wildlife habitat on land, are also home to some of the most threatened species on earth.

The review, published today in the journal Trends in Ecology and Evolution, singles out deforestation associated with plantation development as by far the biggest ecological impact, but finds that the links between the two are often much more complex than portrayed in the popular press:
Most land-cover statistics do not allow us to distinguish where oil palm has actually driven forest clearance. Oil palm certainly has directly replaced tropical forest in some areas, but oil palm companies also often have close links with timber or paper pulp companies, giving additional motives for deforestation. - Matt Struebig, co-author, Queen Mary, University of London
Within countries, oil palm is usually grown in a few productive areas, but it looks set to spread further. Demand is increasing rapidly and 'its potential as a future agent of deforestation is enormous', the study says. Most of the suitable land left is within the last remaining large areas of tropical rainforest in Central Africa, Latin America and Southeast Asia. Where oil palm has replaced tropical forest the impact on wildlife depends on what species survive in the new oil palm habitat:
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The study confirmed that oil palm is a poor substitute habitat for the majority of tropical forest species, particularly forest specialists and those of conservation concern.
By compiling scientific studies of birds, bats, ants and other species, we were able to show that on average, fewer than one-sixth of the species recorded in primary forest were found in oil palm. Degraded forest, and even alternative crops such as rubber and cocoa, supported higher numbers of species than oil palm plantations. - Emily Fitzherbert, lead author, Zoological Society of London and University of East Anglia
Even this estimate is likely to be optimistic, because forest habitats are more difficult to survey and some species inhabit plantations briefly before going extinct.

There is little potential to help wildlife within plantations, so ensuring that new plantations do not replace forest and protecting what is left of native forest in and around plantations are the only real options for protecting the majority of species, the researchers say.

International policies demanding evidence of environmental responsibility, in particular that land of high conservation value is not converted to oil palm, can help.
There is enough non-forested land suitable for plantation development to allow large increases in production without further deforestation. - Ben Phalan, co-author, University of Cambridge
However, in identifying these areas, there needs to be a careful distinction between degraded land that is of low conservation value, such as imperata grasslands, and partially logged or degraded forest areas which can still harbour relatively high levels of biodiversity and bring greater wildlife and carbon storage benefits if restored.

Unless governments in producer countries show stronger leadership in controlling logging, protecting forests and ensuring that crops are planted only in appropriate areas, the impacts of oil palm expansion on biodiversity will be substantial, adds Phalan.

This study is released as pressure mounts on UK and EU officials to rethink targets for biofuel sales. The UK's Renewable Fuels Agency estimates that more than 80 per cent of UK biofuels were not meeting voluntary environmental standards and has urged the UK government to slow the introduction of biofuels until more is known about their negative impacts.

While increases in palm oil based biofuel use will almost certainly add to pressure on tropical forests, the study highlights how those pressures might be reduced.

A recent initiative, the Roundtable on Sustainable Palm Oil, has encouraged 40 per cent of the palm oil industry to commit to saving wildlife on and around plantations. The scientists hope that the Roundtable will continue to attract many of the remaining 60 per cent.

In Indonesia, some NGOs are using satellite technology and the internet to investigate illegal forest clearance by oil palm companies and to put public pressure on them to improve. These initiatives will help, but the study warns that unless they are scaled up and better supported by stronger government action against deforestation, damage to rainforests and their unique wildlife will continue.

Emily B. Fitzherbert, Matthew J. Struebig, Alexandra More, Finn Danielsen, Carsten A. Brüh, Paul F. Donald and Ben Phalan, "How will oil palm expansion affect biodiversity?", Trends in Ecology and Evolution, doi:10.1016/j.tree.2008.06.012

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Economic value of insect pollination worldwide estimated at 153 billion euros

Earlier we reported on how smartly designed bioenergy systems can help restore ecosystems and protect or enhance their services to humanity. We zoomed in on the current crisis afflicting bee colonies, which suffer under the devastating 'colony collapse disorder'. Bioenergy crop systems offer an opportunity to restore the plant diversity needed by honey bees and other pollinators (previous post). A new study now points out just how important the survival of pollinators really is. According to scientists from France and Germany, the global economic value of the pollination services provided by insects, was €153 billion in 2005, for the main crops that feed the world.

The scientists from France's INRA and CNRS, together with German colleagues from the Helmholtz Centre for Environmental Research (UFZ) found that the worldwide economic value amounted to 9.5% of the total value of the world's entire agricultural food production. The study also determined that pollinator disappearance would translate into a consumer surplus loss estimated between €190 to €310 billion. The results of this research on the economic valuation of the vulnerability of world agriculture confronted with pollinator decline are published in the journal Ecological Economics.

Among biodiversity concerns, the decline of pollinators has become a major issue, but its impact remains an open question. In particular, the economic value of the pollination service they provide had not been assessed on solid ground to date. Based upon the figures of the literature review published in 2007 on pollinator dependence of the main crops used for food, the new study used FAO and original data to calculate the value of the pollinator contribution to food production in the world.

Three main crop categories (following FAO terminology) were particularly concerned; fruits and vegetables were especially affected with a loss estimated at €50 billion each, followed by edible oilseed crops with €39 billion. The impact on stimulants (coffee, cocoa,...), nuts and spices was less, at least in economic terms.

The scientists also found that the average value of crops that depend on insect pollinators for their production was on average much higher than that of the crops not pollinated by insects, such as cereals or sugar cane (€760 and €150 per metric ton, respectively). The vulnerability ratio was defined as the ratio of the economic value of insect pollination divided by the total crop production value. This ratio varied considerably among crop categories with a maximum of 39% for stimulants (coffee and cocoa are insect-pollinated), 31% for nuts and 23% for fruits. There was a positive correlation between the value of a crop category per production unit and its ratio of vulnerability ; the higher the dependence on insect pollinators, the higher the price per metric ton:
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From the standpoint of the stability of world food production, the results indicate that for three crop categories – namely fruits, vegetables and stimulants – the situation would be considerably altered following the complete loss of insect pollinators because world production would no longer be enough to fulfil the needs at their current levels. Net importers, like the European Community, would especially be affected. This study is not a forecast, however, as the estimated values do not take into account all the strategic responses that producers and all segments of the food chain could use if faced with such a loss. Furthermore, these figures consider a total loss of pollinators rather than a gradual decline and, while a few studies that show a linear relationship between pollinator density and production, this must be confirmed.

The consequence of pollinator decline on the well being of consumers, taken here in its economic sense, was calculated based on different price elasticities of demand. The price elasticity represents the effects of price change on consumer purchase, that is, the percent drop in the amount purchased following a price increase of 1%. In their study, the scientists assumed that a realistic value for the price-elasticities would be between -0.8 and -1.5 (for a value of -0.8, the consumer would buy 0.8% less of the product when its price increases by 1%). Under these hypotheses, the loss of consumer surplus would be between €190 and €310 billion in 2005.

These results highlight that the complete loss of insect pollinators, particularly that of honey bees and wild bees which are the main crop pollinators, would not lead to the catastrophic disappearing of world agrioculture, but would nevertheless result in substantial economic losses even though the figures consider only the crops which are directly used for human food.

The adaptive strategies of economic actors – such as re-allocation of land among crops and use of substitutes in the food industry – would likely limit somewhat the consequences of pollinator loss. Yet the authors did not take into account the impact of pollination shortage onto seeds used for planting, which is very important for many vegetable crops as well as forage crops and thereby the whole cattle industry, non-food crops and, perhaps most importantly, the wild flowers and all the ecosystem services that the natural flora provides to agriculture and to society as a whole.

The authors of the study are part of an EU research project called ALARM (Assessing Large-Scale Risks for Biodiversity with Tested Methods), which is an integrated research agenda dealing with the relations between (sustainable) development, global change and ecosystems.

Nicola Gallai, Jean-Michel Salles, Josef Settele, Bernard E. Vaissière, "Economic valuation of the vulnerability of world agriculture confronted with pollinator decline", Ecological Economics (2008), doi:10.1016/j.ecolecon.2008.06.014.

Biopact: Could bioenergy save the bees? - August 18, 2008.

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Monday, September 15, 2008

Researchers design more efficient fluidized bed for biomass gasification

Scientists from the Carlos III University of Madrid (UC3M) have developed a new system that improves the efficiency of the conversion process of biomass to gas that will contribute to the production of renewable energy.

One of the challenges that chemical engineers face is placing solid materials in contact with gases to generate certain reactions. One of the options is to use a fluidized bed, consisting of a vertical cylinder with a perforated plate inside where solid particles are introduced using pressurised air.

This way, the solid particles are suspended, and behave much like boiling water. Solids behaving like a liquid depend on the speed of the air stream, making it key to achieving the desired behaviour. With insufficient air, the particles don’t move, but with too much the opposite happens, and they are carried away by the air stream.

Fluidized beds have important environmental applications because they allow the gasification of biomass to produce energy in an efficient manner. That is, producing fuel gas from crushed biomass which can then be used for energy production.

According Mercedes de Vega from the Energy System Engineering Group of the department of Thermal and Fluid Engineering of the UC3M, using fluidised beds as chemical reactors allows for a more efficient conversion by achieving high mixing degrees and high exchange rates of mass and heat.

According to the researchers, this renewable energy source has great potential, especially in processes of co-combustion, direct combustion, and gasification. The applications are mainly industrial, open to be used in motors for the production of electricity, in gas turbines, drying processes, as well as in the pharmaceutical industry for the treatment of powder.

Greater efficiency
The study analyses the behaviour of a new bed designed with a rotating base (illustration, click to enlarge). The base consists of a perforated plate where holes represent just 1% of its total area. The study evaluates the performance of this new design, considering the increase in pressure and the quality of the fluidisation:
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It also analyses the effect of the rotation speed of the perforated plate on the performance of the fluidised bed. This type of beds can usually present problems such as agglomeration of solid particles and points of high temperature.

But one of the most important conclusions determined that the rotating perforated plate reduces these problems by maintaining a very uniform fluidisation. The researchers now propose, for future investigations, to study different rotation speeds over a hundred revolutions per minute, and to alter the configuration of the holes in the plate.

Celia Sobrino, co-author of the study, states that the new rotating distribution plate produces smaller bubbles inside the fluidised bed and distributes them better, while improving the efficiency of the conversion in gasification applications.


C. Sobrino, J.A. Almendros-Ibañeza, D. Santana and M. de Vega, "Fluidization of Group B particles with a rotating distributor", Powder Technology, doi: 10.1016/j.powtec.2007.05.014

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