Mikko Heino is a researcher in the IIASA Evolution and Ecology Program who over the past 18 years has worked on the problem of fisheries-induced evolution, showing that selective harvesting of bigger fish can lead to evolutionary changes towards smaller and faster-maturing fish populations. A new review by Heino and colleagues explores the accumulated evidence on the topic, and future directions for new research.
What is fisheries-induced evolution?
In agriculture we are used to thinking about selective breeding: farmers select the best animals or plants to breed, in order to improve their fitness or select for certain traits in the next generation. They are intentionally trying to improve the stock used for breeding. In fisheries, the opposite happens: fishermen usually try to catch the fish that are more valuable—bigger and heavier. Consequently, those valuable kinds of fish are less likely to reproduce and contribute to the next generations.
It’s not intentional, and maybe because we don’t see the fish that are left behind, people are not used to thinking of this as selective breeding—and they may not realize that in the long term it could harm the productivity of the whole fishery.
Atlantic cod are among the best-studied and most important fisheries worldwide (Credit: © davidyoung11111 | Dollar Photo Club)
What kinds of evolutionary changes do your research show that you would see from fisheries?
Most of our data comes from fisheries institutions. We have a lot of data on maturation—the age at which fish start to reproduce. Studies show that heavily harvested fish populations may mature faster and start reproducing earlier. There’s also some data on growth, showing that fisheries pressures can lead to slower growth rates, with fish staying smaller.
In recent years, experimental studies have shown that fishing is also selective with respect to behavioral traits. Some fish are bolder than others and those bolder fish may be more likely to be captured by gillnets or traps, because bold fish are more explorative, they like to investigate things, and by doing so they may end up in a trap. But at the same time, they may be better in escaping fishing gear like a trawl.
Why is it important that we understand what’s happening with fisheries-induced evolution?
At one level it’s important because changes in these kind of traits will affect the productivity of fish stocks—and based on our current knowledge, these changes are often negative, leading to lower productivity. However, some parts of these changes may be positive in the short term, because they may enable fish stocks to tolerate higher levels of fishing without collapsing. Yet in the long term, we would expect fisheries-induced evolution to lead to reduced productivity, and lower yields. And that’s quite worrying, because fish are an important part of the human diet, especially in many coastal developing countries.
What are the major questions remaining in this research?
One big question arises from the fact that evolution of course implies genetic change. In fisheries, we are observing this evolution at the level of phenotypes—visible, directly measurable characteristics. To be sure that we really observe evolutionary change, we also need to understand the genetic basis for these kinds of changes.
How can you do that?
There are ongoing projects trying to look at it the genetics of fisheries-induced evolution. But it’s a lot more difficult than it sounds because life-history traits and behavioral traits are affected by many genes. It’s not like there’s one gene for early maturation. There are probably tens if not hundreds of genes that have some influence on maturation. And that means that at the level of a single gene we may not see very much change at all. And trying to identify those changes and separate those from random drift, and from changes caused by other factors, is actually quite difficult.
Sequencing genomes is easy nowadays, but finding a signal in the resultant large amounts of data is not simple. If you have more data, you also get more false positives. Basically, either you need to sequence a lot of individuals, so you can separate the different signatures. The other possibility is to try to analyze data from selection experiments, because in an experiment you can try to exaggerate the changes. That’s maybe the most fruitful avenue in the short term.
Evidence for fisheries-induced evolution: research shows fisheries-induced evolution in many fish populations, including marine and freshwater species. (Credit: Heino & Dieckmann, 2015)
What can fisheries managers do to avoid unintended evolutionary changes?
We’re currently exploring that question. We more or less know that it’s not possible to avoid all types of evolutionary responses. But we can still try to minimize harmful changes, by fishing in a way that does not cause much negative change in productivity.
Of course, fisheries-induced evolution will not be the only thing we care about when managing fish stocks. It has to be seen together with other objectives. Yet the simplest way of reducing unwanted evolutionary changes is to keep fishing pressure at moderate levels. That’s the single easiest and most certain way of reducing unwanted evolution, and that’s in agreement with what scientists recommend from other perspectives too.
What are the dangers of failing to account for fisheries-induced evolution?
The danger is that it’s much easier to cause these changes than to reverse them—on practical time scales, these changes are more or less irreversible. So whatever changes we cause, will be around for many generations to come. That’s a reason to be precautionary. We don’t have absolute certainty that this is happening, but there’s a large body of research showing that it is quite likely to happen, and since if it’s happening it’s more or less irreversible, then we should avoiding it even before we have full scientific certainty.
There is quite a similarity between climate change and fisheries-induced evolution. Both processes happen on long timescales—at the level of a few years, the change is not much. But it is a change that will accumulate, and if you let that happen for longer periods, you end up having very significant changes. So it’s easy and attractive to ignore it in the short term, but that’s a dangerous position in the long term.
Heino M, Pauli BD, Dieckmann U (2015). Fisheries-induced evolution. Annual Reviews in Ecological Systems. 46:461-480. doi: 10.1146/annurev-ecolsys-112414-054339
Note: This article gives the views of the interviewee, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.
Within the next few decades, the world will need to increase food production to support a growing population also striving for higher shares of animal protein in their nutrition. But food production always affects the environment: Nitrogen runoff from fertilizer has led to major pollution of waterways around the world, while deforestation to extend cropping areas and methane emissions from livestock increase the amount of greenhouse gases in the atmosphere, adding to the problem of climate change. In order to increase food production, without further increasing nitrogen pollution and greenhouse gas emissions, agricultural systems will need to innovate.
In a recent study, IIASA researcher Wilfried Winiwarter explored the range of solutions for future agriculture, researching current literature for ideas and innovations, and examining their feasibility and potential.
“I call this a science fiction paper,” says Winiwarter. “It’s not about what exists and can be implemented immediately, but about the possible innovations that could conceivably be developed in the long-term.”
The study focused on innovations ranging from seemingly simple behavioral changes to radical technological fixes as discussed in more detail below. It reviewed existing scientific literature, mostly peer-reviewed, including design studies that quantified potential environmental effects of such innovations.
Precision farming refers to technological solutions to improve yields and reduce waste in farming. On the one hand, precision farming can refer to the mechanization of agriculture that may not be environmentally benign, but on the other side, to optimized processes that reduce losses and impacts on the environment.
“Much is already happening,” says Winiwarter. For example, milk production in Europe now occurs mainly in large sheds, with indoor cows, not with free-ranging cows in idyllic meadows. While this industrial approach to agriculture makes food cheaper and more abundant, it also raises questions about animal welfare, and the massive scale of such operations can lead to increased greenhouse gas emissions.
Precision farming can also be used to reduce the amounts of fertilizers or irrigation used, for example, using soil sensors or other high-tech infrastructure to detect exactly what is needed and apply no more than necessary.
Genetic modification (GM) of crops allows scientists to equip organisms with certain traits in a much more directed way than traditional breeding. It presents the potential to increase yields, provide drought or pest resistance, or introduce additional nutrients to foods that lack them. GM is already widely used in some crops (mostly to increase pesticide resistance and thus also pesticide application), but in Europe the subject is controversial and GM foods are viewed negatively
Winiwarter notes that the side effects of genetic modification are in general not well understood, and thus possible impacts are quite unpredictable.
The study looked into the growing popularity of urban gardening, the “green” trend to grow food in individual gardens inside cities. While urban gardening is generally considered environmentally benign due to small-scale, low transport needs and high personal motivation, Winiwarter notes that it doesn’t have the potential to produce staple food required to feed large populations. One key background study calculated that urban gardens had the potential to produce 10% or less of the food needed in a given city.
“You need space to produce food,” says Winiwarter.
As people move to cities and land becomes scarcer, one logical concept is to construct skyscraper “farms” with multiple levels of vegetables growing in hydroponic or aeroponic tanks – like giant, multistory greenhouses. “Compared to an open field, you could produce 200 times as much food on the same space,” explains Winiwarter. “In a city like Vienna, you could conceivably produce all the food for the city within city limits.”
Another advantage of vertical farming is that it could be organized to avoid waste: whereas fertilizer in a field runs off or percolates through the soil into the water table, a vertical farm would employ nutrient solutions that could be contained and recycled.
However, the sunlight needed for photosynthesis could not so easily be multiplied. Instead, the process would require artificial light, which means enormous amounts of energy – even if efficient LED lighting could be employed. “The question is where you would get that energy,” he says.
Cultured meat can now be grown in laboratories – but will it ever make sense on a large scale?
Another radical idea for food production is to take meat production off the farm, and instead culture animal cells in petri dishes to grow artificial meat in a laboratory in a nutrient solution. Indeed, the first hamburger from cultured meat was produced in 2013. But Winiwarter notes that meat from the laboratory may not be less resource-intensive than the real thing, since it would need energy, heat, light, and nutrients, which all would make the process extremely expensive, even under ideal conditions. He says, “Upscaling such a process may come with a number of negative surprises – from sanitary issues to pollution as a side-effect of tackling potential health threats. Little is known on the potential environmental effects in a life cycle.”
“In general, meat has a higher environmental footprint than a vegetarian diet,” says Winiwarter. “It takes more area to produce feedstock for an animal than it would to produce vegetarian food for humans.”
Europe in particular has a high level of meat consumption, Winiwarter explains, so cutting meat consumption in the region has a large potential. In much of the highly populated areas of Asia, people consume a mostly vegetarian diet. As these countries become richer, increased consumption of meat and milk production is observed when people tend to copy European lifestyle. If Europeans were able to cut down on meat consumption and treat themselves with a more healthy diet, positive environmental effects may even spread to world regions where European food patterns may serve as an example.
Agriculture, like a high-tech industry, will continue to develop dynamically in the future. Many paths of development can be imagined, and have been described in scientific or other literature. “There is no ‘silver bullet’ to resolve the environmental damage of agriculture”, Winiwarter says. Instead, future innovations will need to be carefully monitored and evaluated for potential environmental effects, in order to minimize damage of nitrogen pollution and maintain livelihood on earth.
Winiwarter W, Leip A, Tuomisto HL, Haastrup P. 2014. A European perspective of innovations towards mitigation of nitrogen-related greenhouse gases. Current Opinion in Environmental Sustainability. http://www.sciencedirect.com/science/article/pii/S1877343514000396
By Katherine Leitzell, IIASA Science Writer
By Robbert Biesbroek, Wageningen University and Research Centre, the Netherlands
Over the past years, a series of reports by the World Economic Forum have identified “failure to adapt to climate change” as being of highest concern to society. But in practice, what does adaptation to climate change mean? What makes adaptation particularly challenging for those policymakers, consultants, businesses and other practitioners working on adaptation in practice? An often heard answer is, “Because there are barriers to adaptation.”
The storm surge barrier Oosterschelde nearby Neeltje Jans in The Netherlands. With its low elevation and long coastline, the Netherlands is particularly sensitive to sea level rise, and has taken an early start to climate adaptation planning (Photo: Shutterstock)
In a recent study, we identified numerous examples of barriers to adaptation encountered by practitioners across the globe. These barriers to adaptation emerge from all angles and direction; they can be institutional (e.g. “rigid rules and norms”) resources (e.g. “lack of money”, “uncertain knowledge”) social (e.g. “no shared problem understanding”), cognitive (e.g. “ignorance”, “apathy”).
As scholars, we have proven to be very good in making lists of barriers to adaptation, but rather poor in understanding where these barriers come from, what the concept of “barriers” means to practitioners, why barriers are mentioned at all, or how barriers can be dealt with in an meaningful way. In a follow-up study, colleagues and I argued that listing barriers in isolation from their decision-making context is an interesting first step, but has hardly provided insights in the openings needed to adequately deal with them. In fact, they often lead to a linear argumentative logic – “Not enough money? Then we need more money or we need to spend the money we do have more wisely!” Such superficial advice is not particularly useful to practice.
By delving deeper in the questions of why adaptation is challenging, we found that what practitioners mention as barriers are mere simplifications of what really happened. Barriers become metaphors that capture people’s lived experience and evaluation of the process into easy to communicate messages – e.g. “no money.” We can argue about whether this is truly a barrier, because their interpretation stems from a complex and dynamic chain of events that only makes sense to those that were actively involved. By putting labels on these events, they automatically become static, therefore lacking the necessary insights in the dynamics that caused the process to become challenging and provide the necessary openings to intervene. We concluded that using barriers as units of analysis to explain why adaptation is challenging is therefore flawed: the analytical challenge is to go beyond barriers in search of the explanatory causal processes, or so-called causal mechanisms.
An example: In our study, we identified 24 different barriers encountered by practitioners during the design and implementation of an innovative adaptation measure for temporal water storage in the city center of Rotterdam, the Netherlands. By going beyond this list, we uncovered three underlying mechanisms that explain why the first attempt to implement the so-called “water plaza” failed. One mechanisms, we called the risk-innovation mechanism—which is basically a miscommunication about risk that leads to public outcry.
An illustration of the proposed water plaza in the Netherlands. (Image: De Urbanisten)
In this case, the government took a technocratic stance in communicating the risks and benefits of the project. Meanwhile the citizens, as mutual bearers of the risks, wanted to negotiate about what levels of risk were acceptable. By taking such stance the government avoided a moral debate about the risk of the innovation (the innovation was “adaptation”), but the result was angry citizens who to rebelled against the project and the municipal government. This analysis provided openings to change communication strategies – an intervention the project team used successfully in next stages of the process.
Insights from this study have broader implications. It explains, for example, why existing guidelines to support practitioners to overcome barriers to adaptation have not worked well: As I explored more deeply in my thesis, these guidelines are simply not tailored to the real reasons why adaptation is challenging. We can continue to make endless lists of barriers, but to advance theoretically and conceptually, and to provide meaningful strategies to intervene in practice, we need to rethink how we use the concept of “barriers to adaptation” and start searching for underlying causal mechanisms.
Robbert Biesbroek completed his PhD in January 2014, supervised by IIASA Director General and CEO Prof. Dr. Pavel Kabat.
Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.
(1) Biesbroek, G. R., Klostermann, J. E. M., Termeer, C. J. A. M., & Kabat, P. (2013). On the nature of barriers to climate change adaptation. Regional Environmental Change, 13(5), 1119-1129.
(2) Biesbroek, G. R., Termeer, C. J. A. M., Klostermann, J. E. M., & Kabat, P. (2014). Rethinking barriers to adaptation: mechanism based explanation of impasses in the governance of an innovative adaptation measure. Global Environmental Change 26, (1) 108-118
(3) Biesbroek, G. R. (2014). Challenging barriers in the governance of climate change adaptation. Ph.D. thesis, Wageningen: Wageningen University.
Eric F. Wood is a hydrologist at Princeton University, well-known for his work in hydrology, climate, and meteorology. He worked as a research scholar in IIASA’s Water program from 1974 to 1976. On 30 April, 2014, he received the European Geophysical Union’s Alfred Wegener Medal in Vienna, Austria.
Eric F. Wood (Credit: Princeton University)
IIASA: How did you get interested in hydrology? What drew you to the field?
EW: I came to IIASA after I finished my doctorate at MIT. I worked in the areas of system analysis and statistics related to water resources. During my first sabbatical leave at the Institute of Hydrology in the UK (now the Center for Hydrology and Ecology), I started to collaborate with Keith Beven on hydrological modeling, which started my transition towards the physical side of the water cycle from the policy and systems analysis side.
A few years later, Robert Gurney, then at NASA and now at the University of Reading (UK), asked if I would be on the Science Advisory Committee for NASA’s Earth Observing System (EOS), which was just starting to be planned. This started my research activities in terrestrial remote sensing. Over the next 25 years these elements have played heavily in my research activities.
What have been the biggest changes in hydrology and earth science over your career – either in terms of new understandings, or in how the science is done?
I can name three huge changes, all inter-connected: One is the increase in computational resources. High performance computing—petabyte computing using 500,000+ cores—is now available that allows us to simulate the terrestrial water and energy budgets using physics resolving land surface models at 100m to 1km resolutions over continental scales, and soon at global scales. The second big change is the availability of remotely sensed observations. There are satellite missions that have lasted far beyond their planned lifetimes, such as the NASA EOS Terra mission, where we now have over 15 years of consistent observations. These observations have been reprocessed as algorithms have improved so we can now use the information to understand environmental change at regional to global scales. The third major shift has been computer storage. Large amounts are available at low prices. We have about 500 Terabytes of RAID storage, and can acquire 150TB for about $10,000 or less. This allows us to store model simulations, remote sensing data, and do analyses that were once impossible. Together, these three changes have transformed my field, and the field of climate change related to terrestrial hydrology. Going forward, we have the data, the projections and analytical tools to look at water security in the 21st Century under environmental change.
What insights has remote sensing brought to hydrology?
Remote sensing offers a global consistency that is unavailable with in-situ observations, and offers observations over regions without ground data. This permits us to analyze hydrologic events such as droughts within a global context, and relate these hydrologic events to other drivers like ENSO (tropical Pacific sea surface temperature anomalies) that affect weather and seasonal climate patterns.
Wood’s work has focused in part on drought and climate change. Badwater, California, a huge salt flat drainage system for the Death Valley desert. Credit: Carolina Reyes (distributed via imaggeo.egu.eu)
What do you see as the key questions currently facing water resources?
The biggest question I see over the next decades is how water security will be affected by environmental change. By environmental change I mean climate change, global urbanization, increasing demand for food, land use and land cover change, pollution, etc. Water security is coupled to food and energy security, and water security is and it is intrinsically linked to the climate system and how that may be changing.
How did IIASA influence your research interests or career?
I made many friendships during my stay at IIASA and I was exposed to world-class research and researchers. This helped me in thinking about important research questions and the types of problems and research that will have impact.
What do you think is the role for IIASA in the worldwide research community?
There are many answers to this question. IIASA plays an important role in providing critical scientific information and analyses related to global issues that go beyond countries – transboundary analyses, and therefore that can provide the scientific basis for global policies. There is an urgent need for more global policies on environmental change and adaptation, food and water security, and environmental refugees, to name just a couple examples in my area.
IIASA has also developed scientific methods and data that can be applied by various groups. For example, IIASA’s world renowned integrated assessment models have been used in climate change modeling for the IPCC and Coupled Model intercomparison Project (CMIP).
Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.
By Linda See, Research Scholar, IIASA Ecosystems Services and Management Program
Researchers estimate we spend 3 billion hours a week on game playing. CC Image courtesy TheErin on Flickr
On a recent rush hour train ride in London I looked around to see just about everybody absorbed in their mobile phone or tablet. This in itself is not that unusual. But when I snooped over a few shoulders, what really surprised me was that most of those people were playing games. I hope this bodes well for our new game, Cropland Capture, introduced last week.
Cropland Capture is a game version of our citizen science project Geo-Wiki, which has a growing network of interested experts and volunteers who regularly help us in validating land cover through our competitions. By turning the idea into a game, we hope to reach a much wider audience.
Playing Cropland Capture is simple: look at a satellite image and tell us if you see any evidence of cropland. This will help us build a better map of where cropland is globally, something that is surprisingly uncertain at the moment. This sort of data is crucial for global food security, identifying where the big gaps in crop yields are, and monitoring crops affected by droughts, amongst many other applications.
Gamification and citizen science
The idea of Cropland Capture is not entirely unique. There are an astonishingly large number of games available for high tech gaming consoles, PCs and increasingly, mobile devices. While the majority of these games are pure entertainment, some are part of an emerging genre known as ”serious games” or ”games with a purpose.” These are games that either have an educational element or through the process of playing them, you can help scientists in doing their research. One of the most successful examples is the game FoldIt, where teams of players work together to decode protein structures. This is not an easy task for a computer to do, but some people are exceptionally talented at seeing these patterns. The result has even led to new scientific discoveries that have been published in high level journals such as Nature.
Jane McGonigal, in her book Reality is Broken (Why Games Make us Better and How They Can Change the World), estimates that we spend 3 billion hours a week alone on game playing, and that the average young person spends more time gaming by the end of their school career than they have actually spent in school. Although these figures may seem alarming, McGonigal argues that there are many positive benefits associated with gaming, including the development of problem-solving skills, the ability to cope better with problems such as depression or chronic pain, and even the possibility that we might live ten years longer if we played games. If people spent just a fraction of this time on “serious games” like FoldIt and Cropland Capture, imagine how much could be achieved.
Since the game started last Friday, 185 players have validated 119,777 square kilometers of land (more than twice the land area of Denmark).
Cropland Capture is easy to play – simply swipe the picture left or right to say whether there is cropland or not.
Get in the game
You can play Cropland Capture on a tablet (iPad or Android) or mobile phone (iPhone or Android). Download the game from the Apple’s App Store or the Google Play Store. For those who prefer an online version, you can also play the game at: http://www.geo-wiki.org/games/croplandcapture/. For more information about the game, check out our videos at: http://www.geo-wiki.org/games/instructions-videos/. During the next six months, we will be providing regular updates on Twitter (@CropCapture) and Facebook.
The game is being played for six months, where the top scorer each week will be crowned the weekly winner. The 25 weekly winners will then be entered into a draw at the end of the competition to win three big prizes: an Amazon Kindle, a smartphone, and a tablet. The game was launched only last week so there is plenty of time to get involved and help scientific research.
In a new commentary (subscription required) in Nature Geoscience, IIASA researchers Michael Obersteiner, Marijn van der Velde, and colleagues write about the problems facing the world’s food supply as we exhaust our supplies of phosphorus. Projections show that phosphorus supplies could run out in the next 40 to 400 years. In this interview, Obersteiner and van der Velde give more background on the “phosphorus trilemma.”
Fertilizers containing phosphorus are vital for crop production – but phosphorus is limited in availability and growing scarcer.
Why is phosphorus so important?
MV: Phosphorus is essential for life on Earth. It is a key component of DNA and cell membranes, and vital for cellular energy processes. Crops need phosphorus to grow. And to maintain crop production, and to make sure that soils remain productive, we have to add extra nitrogen and phosphorus as fertilizer. This is one of the food security issues in Africa where soils are suffering from nutrient depletion without replenishment.
Where do we get phosphorus and why is that supply in danger?
MO: Phosphorus is ubiquitous in the Earth’s crust. However, most of it is strongly bound in the soil , where plants cannot access it. Modern agriculture (which made human population explode) essentially began when we found ways to extract nitrogen from the air and phosphorus from minerals to make fertilizers for agricultural purposes.
The problem is that minable phosphorus is geographically concentrated in very few places. For example 75% of known reserves are located in Morocco and these reserves are limited. If, for example, political turmoil restricted access to the mines of Morocco, we would be in danger of short-term shortages that could lead to rising food prices or food insecurity in poor countries.
What problems do you expect as phosphorus becomes even more limited?
MO: The biggest problem we face is limited or no access to phosphorus fertilizers by the poor and food insecure.
MV: At the same time, rich countries apply excess fertilizers causing eutrophication to their lakes and rivers, while the poor cannot afford fertilizers.
What can be done about these problems?
MV: More efficient fertilizer application would make fertilizers cheaper to poor farmers, and at the same time help address the environmental problems. But in the long run we need to figure out how to produce food in a way that recycles nutrients at minimum loss rates. (This also includes losses from human excrement!)
To better solve the issues around long-term phosphorus availability and equitable use we also need better data on how much phosphate rock is remaining in the world and where it is located. Countries will need to be persuaded to collaborate on both these issues to ensure equity.
How does IIASA research inform this debate?
MV: In a paper we published earlier this year in PLOS ONE we showed the importance of soil phosphorus and the significant increases in yields that could be achieved in Africa with balanced micro-dosed applications of nitrogen and phosphorus. Available phosphorus in soils is generally low, especially in older weathered soils in the tropics where a lot of the phosphorus can be locked up in iron and aluminum complexes. We are currently investigating what application rates of nitrogen and phosphorus would be optimal for a range of soils and climates. This can then lead to better soil and nutrient management.
MO: In addition researchers in the Mitigation of Air Pollution and Greenhouse Gases program have been very active in finding solutions to the problem. For example: http://www.iiasa.ac.at/web/home/resources/multimedia/Podcasts/Our-Nutrient-World—Wilfried-Winiwarter-on-Reality-.en.html
What should people to know about this issue?
MO: Many things in nature that we like or depend on for our livelihood are substitutable. But phosphorus is in everything we eat and cannot be substituted by any element. If we continue business as usual we will squander this resource and thereby potentially compromising the wellbeing of our daughters and sons.
M. Obersteiner, J. Peñuelas, P. Ciais, M. van der Velde, and I.A. Janssens, 2013. The phosphorus trilemma. Nature Geoscience, 6, 897-898, doi:10.1038/ngeo1990 [COMMENTARY].
M. van der Velde, L. See, L. You, J. Balkovič, S. Fritz, N. Khabarov, M. Obersteiner and S. Wood, 2013.Affordable nutrient solutions for improved food security as evidenced by crop trials. PLoS ONE 8(4): e60075. doi:10.1371/journal.pone.0060075 [OPEN ACCESS].
Marijn van der Velde is a Research Scholar with IIASA’s Ecosystems Services and Management (ESM) Program
Michael Obersteiner is the leader of IIASA’s Ecosystems Services and Management (ESM) Program.