Ecological Management, General, Regime Shifts, Reorganization

The Greening of Sahel: Passive recovery or active adaptation?

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The drought years in the Sahel in the early 1970’s that resulted in a large-scale famine gave rise to scientific and policy discussions about land degradation and desertification. A popular belief was that the limited resource base in the Sahel, with vulnerable soils and highly variable and scarce rainfall could not sustain the growing population. The droughts was seen as a stress to a system which was already struggling with a rapidly decreasing resource base (e.g. deforestation of woodlands for agricultural expansion, shortening of fallow times, and soil nutrient depletion) and bad land management practices leading to increased poverty and out-migration.

Sahel Greening. Overall trends in vegetation greenness throughout the period 1982–2003 based on monthly AVHRR NDVI time series. Percentages express changes in average NDVI between 1982 and 2003. From Hermann et al 2005

New analysis of satellite data, by among others Olsson et al., illustrating a greening trend in the Sahel since 1983 thus comes as a surprise for many people. It has also triggered a scientific discussion of whether this greening is merely a recovery of vegetation due to increasing rainfall, or if this trend at least partially can be explained by widespread changes in land management by farmers in the region. Hutchins et al., in the introduction to a recent special issue of Journal of Arid Environments, suggests that there is increasing evidence that farmers have adapted to the changes during the droughts and made a transition from degrading land use trajectories to more sustainable and productive production systems, suggesting that the recovery in many places actually is an active adaptation by the farmers in the region.

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Design, General, Networks

Robustness of the Internet

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Router-level topology of Abilene. Each vertex represents a router, and each link represents a physical connection; however, each physical connection can support many virtual connections, giving the appearance of greater connectivity at higher layers of the IP stack. End-user networks are shown in white, peering networks are shown in blue, and high-degree routers can only be found at the network periphery (not shown).
John Doyle and his colleagues published a very interesting paper on the structure of the internet and its implications for robustness. It is a popular belief that the structure of the Internet follow a scale free distribution of the number of connections, which then results in being sensitive to target attacks at the hubs. Doyle et al. dig deeper in to the real structure of the internet and falsify this myth. Indeed the number of connections follow a scale free distribution, but there are various ways to derive such a distribution. Doyle et al. find that the components of the internet with the most connections are not the crucial hubs of the internet.

Doyle et al. define an alternative model to generate networks structures of the internet (an alternative to the preferential attachment models). This alternative model is based on the highly optimized tollerance (HOT) concept and includes specific technological (bandwidth) and economic (costs) constraints. The resulting model generates statistics more in line with the real internet, and an important finding is that this structure is robust to targeted attacks to highly connected nodes.

Reference
John C. Doyle, David L. Alderson, Lun Li, Steven Low, Matthew Roughan, Stanislav Shalunov, Reiko Tanaka, and Walter Willinger (2005) The “robust yet fragile” nature of the Internet, Proceedings of the National Academy of Sciences of the United States of America 102: 14497-14502

Regime Shifts

Is the Arctic Already Lost?

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Veg/Climate Feedbacks in Arctic

Is the home of polar bears, seals and Inuit communities already doomed? asks Jon Foley in Tipping Points in the Tundra a recent commentary Science. According to him, several recent sources of evidence show that feedback mechanisms seem to be kicking into high gear as the Arctic warms up. Temperature data illustrate, for example, that from the 1960’s to the 1980’s, the Arctic warmed by 0.15 degrees Celsius per decade, but since then the warming has been nearly 0.3 to 0.4 degrees per decade.

Recent evidence comes from Terry Chapin and his co-workers who have analyzed Arctic data on surface temperature, cloud cover, energy exchange, albedo, and changes in snow cover and vegetation. They concluded that the recent changes in the length of the snow-free season have triggered a set of interlinked feedbacks that will amplify future rates of summer warming. One of these feedbacks relate to that the snowmelt has advanced by around 2.5 days per decade which has lead to an increase in the amount of energy that is absorbed and transferred to the atmosphere. The resulting regional increase in temperature is estimated to be comparable (per unit area) to the global atmospheric heating that is projected from a doubling of CO2 levels in the atmosphere.

Chapin et al. also analyses the role of vegetation change for triggering positive feedbacks. Tall shrublands have increased rapidly in the surrounding region of the Arctic. Tree lines have also moved further north. Although the estimated contributions these have on warming were found to be small, the authors expect that they will continue to increase disproportionally in the future.

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Greenlash, Regime Shifts, Visualization

Tipping Points in the Earth System – an icon of climate change?

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tipping pts in the earth system

Martin Kemp writes in Nature – Science in culture: Inventing an icon

Any public campaign benefits from having an iconic image — something that captures the essence of the message and engraves it indelibly on our memories. But it is almost impossible to predict which images will actually stick, so creating one on demand is extraordinarily difficult. …

Even so, finding an iconic image was one of the goals of a meeting, Changing the Climate, held in Oxford, UK, on 11 and 12 September. Researchers and practitioners of the visual, literary, musical and performing arts came together to publicize the predicted perils of climate change, and there was much talk about a memorable image that would encapsulate the initiative…

The data must come from the best science available, but the presentation for maximum impact is a matter of invention in art and design. Of the images produced by the scientists, one in particular seemed to have the potential to combine iconicity with complexity. This is the ‘Tipping Points Map’ devised by Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research in Germany and research director of the Tyndall Centre for Climate Change Research at the University of East Anglia, UK. This global map, shown here, outlines what Schellnhuber has identified as regions where the balance of particular systems has reached the critical point at which potentially irreversible change is imminent, or actually occurring.
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Tools, Visualization

Mapping Humanity’s Global Footprint

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Navin Ramankutty, from the Center for Sustainability and the Global Environment at University of Wisconsin, has developed a Global Land Use Database that allows people to download global land datasets they have developed as either gridded maps or tabular data.

Global croplands

The data includes:

  • Population density: 1990, 1995
  • Potential natural vegetation
  • Cropland extent from 1700 to 1992
  • Grazing land extent in 1992
  • Built-up land extent in 1992
  • 18 major crops extent in 1992
  • Land suitability for cultivation
    • Ideas, Tools

    Principles of Biomimicry for Green Design

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    Jeremy Faludi’s article Biomimicry For Green Design (A How-To) on WorldChanging reviews principles designers can adopt from Nature to produce green products.

    It’s easy to talk about how exciting biomimicry is, and how we’ll see more of it in the future, but it’s another thing to actually design and built things that are biomimetic. Most designers, engineers, architects, and other people who build things just don’t know that much about biology and the natural world; and even when they do, there’s often a gap of capability in available materials, manufacturing methods, and economic systems. Some of these obstacles are out of the designer’s hands, and you just have to move on to things that are more feasible. (But don’t forget your ideas; maybe ten years from now the technology will be there.) Even with existing technology, however, an enormous realm of possibilities is feasible, it just requires the right approach. Here is my attempt to describe the biomimetic approach, with a comprehensive list of principles. It combines lessons from Janine Benyus, Kevin Kelly, Steven Vogel, D’Arcy Thompson, Buckminster Fuller, Julian Vincent, and my own limited experience. I also mention at the end where biomimicry will not help you, a subject often glossed over, as well as further resources (books and schools).

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    Gaming, Tools

    Regime Change Game: A Force More Powerful

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    screenshot from -A force more powerful

    Ethan Zuckerman writes about Ivan Marovic an important figure in the Otpor (Serbo-Croatian for resistance) Serbian democracy movement is working on a video game to help people learn to organize non-violent democracy movements.

    Zuckerman writes:

    The movement demonstrated their power in opposing Milosevic in the 2000 elections – by the time the election took place, it was quite obvious that Milosevic would lose to opposition leader Zoran Dindic. The real question was whether or not Milosevic would step down. (And, of course, he didn’t.) So the movement took the next step, and organized to actually remove Milosevic from power.
    …
    And hundreds of thousands of activists eventually organized a nonviolent takeover of Parliament, forcing Milosevic out of power and eventually into trial at The Hague.

    In some ways, this was just the beginning for Otpor – Kumara, a movement in Georgia that took down Shevrednadze, used the same symbolism and the same tactics as Otpor. And the Orange Revolution in Ukraine used many of the same tactics, and the movements were in close contact.

    Ivan is less interested in writing another book about non-violent organizing or making another video – instead, he’s helping build a game, called A Force More Powerful. It’s a simulation game developed with Breakaway Games. It looks a little like Sim City or Civilization, but is focused on teaching organizers the tactics of non-violent resistance.
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    Tools, Visualization

    Weather Visualization: Fast & Slow

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    sea surface temperatures surrounding hurricane Katrina

    NASA has done a wonderful visualization of the 2005 hurricane season showing the named storms from June 1 up until Oct 17 (missing Alpha and only getting the start of Wilma).

    It reveals how weather patterns (fast variables) are structured by ocean temperatures (a slower variable) along with the storm paths.

    Identifying changes in slow variables is an important part of managing for resilience. For a quick introduction to this idea see Lance Gunderson’s short 1999 article Resilient management: comments on “Ecological and social dynamics in simple models of ecosystem management”.

    Gaming, Tools

    Climate Change Games

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    graphic from Keep Cool

    In Playing Games with the Climate WorldChanging discusses several games sponsored by the European Climate Forum, including Keep Cool – a climate change policy board game co-developed by Gerhard Petschel Held from Potsdam Institute for Climate Impact Research (PIK).

    The game Keep Cool was a hit in Germany, where it sold out of stores.

    The game lets:

    each player takes a role within global climate politics. You have to put through economic interests, e.g. of the USA and its partners or of the Developing Countries. Yet you must not forget the strong lobby groups in your country like the oil industry or environmental groups as they also decide whether you win or loose. Within each round of the game you have to decide between measures for climate protection good for all and egoistic decisions just for your owns sake. The risk: catastrophes like droughts, floods or pandemics. The chance: welfare and a stable global climate. Whoever reaches his or her targets first wins, yet if you are not cooperative enough all players might loose due to a collapse of the world climate.

    Tragically, and unexpectedly, Gerhard died in the summer of 2005. Those of us who knew him lost of great friend, while the scientific community lost a great mind.

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