Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

For biofuels and climate, location matters

12.05.2015

Dedicating more land to biofuel production can lead to increased greenhouse gas emissions, which take decades to make up for. A new study shows that geography is a key factor determining how big that impact is.

A new study published in the journal Nature Climate Change shows that, when looking at the production site alone, growing biofuel crops can have a significant impact on climate depending on location and crop type. The study is the first geographically explicit life cycle assessment to consider the full range of greenhouse gases emissions from vegetation and soil carbon stock to nitrogen fertilizer emissions in all locations in the world.


Greenhouse gas payback times for corn-based bioethanol in intensively farmed crop locations, (where fertilizers and irrigation are used).

Elshout et al, 2015. Nature Climate Change


Greenhouse gas payback times for corn-based bioethanol, in extensively farmed crop location, (where fertilizers and irrigation are not used).

Elshout et al, 2015. Nature Climate Change

In the last couple of years, research has begun to raise questions about the sustainability of biofuels. Life cycle assessments—a method that calculates the environmental impact of a product through its entire production and use cycle—have returned uncertain results on biofuels, and new research has also begun to consider carbon emissions caused by land use change.

“When you convert wetlands or forests for biofuel production you lose a major carbon sink, so even if you are saving emissions by reducing fossil fuel use, in the short term you are increasing total emissions,” says IIASA Ecosystems Services and Management Program Director Michael Obersteiner, who co-authored the study along with researchers from IIASA, Radboud University in the Netherlands, and other partners.

In the long term, natural ecosystems such as forests and grasslands sequester carbon from the atmosphere and store it in vegetation and soils. While crops also absorb carbon from the atmosphere, they do not build carbon storage, and unsustainable agricultural practices can also lead to erosion and run-off that further degrades the carbon storage capability of soils.

The new study provides a method of accounting and evaluating biofuels based on a field-level high resolution greenhouse gas accounting. It calculates the time it would take, on a specific piece of land, for biofuel production to make up for the emissions it generates by converting from what was there prior to biofuel production. The researchers call this measure “greenhouse gas payback time.”

The study was led by Radboud University PhD candidate Pieter Elshout. He says, “Our model is the first that offers a global, spatially-explicit overview of biogenic gas emission resulting from crops used to produce biofuels. In developing this model, our calculations of the durations of payback times took account of the entire production chain for fossil fuels and biofuels with the accompanying greenhouse emissions.”

They find that the payback time varies widely around the world depending on the current land use of the specific location, crop type, and cultivation method. The most important factor was the location, according to the study, accounting for 90% of the variation on payback time.

“This study shows that geography is really the number one factor influencing the direct climate impact of biofuel production. We need to have more precise measurements of what is currently happening on a piece of land when evaluating the direct effects on biogenic carbon emissions of biofuels to be grown there,” says Obersteiner.

The researchers found that current land use and crop type played a big role in the payback time. When grown with no input (such as irrigation or fertilizer), rapeseed is found to have the lowest direct impact, with an average payback time around 20 years, and sugarcane the longest, with a global median of 60 years. When it comes to intensive agriculture, however, payback times systematically decrease for all crop types. The most efficient feedstocks appear to be cereals, such as winter wheat and corn, with payback times lower than 10 years.

While this study unearthed the value of high resolution information for the assessment of biofuels impacts, a broader sustainability perspective on agricultural products emissions remains indispensable, say the researchers. Previous IIASA research has shown that sustainability criteria limited to biofuels could prove inefficient by ignoring other agricultural uses and consumption changes in other parts of the world. [http://www.iiasa.ac.at/publication/more_XJ-13-089.php]

In addition, indirect land use change impacts can change the overall emission balance of biofuels, by displacing other crop production, through trade and demand responses.

IIASA is preparing a complementary study [http://www.iiasa.ac.at/web/home/research/researchPrograms/EcosystemsServicesandM...] on this matter, expected to be published this summer. It looks at a large range of crop-based but also advanced biofuels, using cereal straw or short rotation coppice.

“Today’s paper confirms that standard life cycle assessment approaches, by ignoring geography, have overly simplified biofuel greenhouse gas assessment. Bringing in the full agricultural system responses with indirect land use change could lead to even more nuanced insights on the final environmental merit of the different biofuel feedstocks,” says Hugo Valin, one of the lead authors of the ongoing study.

Reference
Elshout PMF, et. al. 2015. Greenhouse-gas payback times for crop-based biofuels. Nature Climate Change. doi:10.1038/NCLIMATE2642

Contacts
Pieter Elshout
+31 (0)24 365 2060
p.elshout@science.ru.nl

Michael Obersteiner
Program Director
Ecosystems Services and Management
+43(0) 2236 807 460
oberstei@iiasa.ac.at

Katherine Leitzell | idw - Informationsdienst Wissenschaft
Further information:
http://www.iiasa.ac.at

More articles from Earth Sciences:

nachricht GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center

nachricht Cyclic change within magma reservoirs significantly affects the explosivity of volcanic eruptions
30.11.2016 | Johannes Gutenberg-Universität Mainz

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>