All posts by Marco Janssen

Collapse in Ancient America

The American Scientist and the Scientific American both have an article in their July edition on collapse of ancient societies in America. The Scientific American article is called Simulating Ancient Societies and is written by Tim Kohler, George Gumerman and Bob Reynolds (pp. 76-84). They report on a number of studies using agent-based models to explain the disappearance of a number of Anasazi cites in the South West of the USA. They conclude that it can not just have been a drought that led to the collapse, also cultural factors need to be included to explain the observations. The article in the American Scientist is by Larry Peterson and Gerald Haug (Climate and the Collapse of Maya Civilization, pp. 322-329). They report on detailed climate recordings from analyzing titanium concentrations in a lake in Venezuela, which is a strong indicator for the weather patterns in the Maya sites, more north in Mexico, Guatamala and Belize. They find a strong correlation between periods of regional collapse and droughts. The spatial pattern of collapse can be affected by the local conditions since people in northern Yucatan had a natural storage of water in caves, which led to a delay of the collapse.

Both cases show that both climate and social factors play an important role to understand collapse of the diverse ancient societies in America.

The cost of memory

It would be wonderful if we can remember all our experiences as individuals and communities, in order to improve our decisions in complex dynamic environments. But memory is costly, like the many years of education needed to transfer information, imperfectly, from one generation to the next. An interesting study with fruit flies show the cost of memory on the individual level:
“If you are forever forgetting people’s names or family birthdays, take heart. Forming permanent memories is so physiologically expensive it can result in early death – at least for fruit flies. When fruit flies form lasting memories, their neurons must make new proteins. Now Frederic Mery and Tadeusz Kawecki at the University of Fribourg in Switzerland have shown that this extra work takes its toll on the flies’ ability to survive. They trained one group of flies to associate a jolt with a bad-smelling mixture of two alcohols, while other flies were subjected either to jolts only or to jolts and odours, but not at the same time. When the flies were subsequently deprived of food and water, the group that had learned the link died an average of 4 hours, or 20 per cent, earlier than the others (Science, vol 308, p 1148).
The study suggests that there is a cost to memory and learning, raising the question of whether humans lost other qualities when they evolved superior intelligence. “We have such an extraordinary memory and learning capacity, we must have paid for it,” says Kawecki.”

From issue 2501 of New Scientist magazine, 28 May 2005, page 16

Environmental Tipping Points

Gerry Marten and his collaborators propose the concept of environmental tipping points. They define an “environmental tipping point” is a point in a linked eco-social system where a small action can catalyze major changes in the system’s health. The concept is illustrated by a few dozen examples on their website. A lot more work need to be done to make the concept more precise and systematic than just interesting stories, but I find it an interesting idea to pursue.

Governing the Resilience of Venice

Venice lies in the shallow waters of a coastal lagoon connected to the northern tip of the Adriatic sea. It is occupied for more than 1500 years, and in the 14th century it became a major martime power. However, human activities have reduced the resilience of Venice which is increasingly experiencing floodings. The buffering capacity of the lagoon has been reduced by pollution (affecting sea weed vegetation which keep sand together), fishery (clam fishing by mechanical equipment that damage the lagoon bed), groundwater withdrawn and sealevel rise (climatic change). Venice in Peril is a committee that coordinates research to save Venice. A nice book came out on this subject “The Science of Saving Venice” which can be ordered from this website.
A flooded St Mark's Piazzetta

Framing the Future

In the April edition of the Scientific American, Steven Popper, Robert Lempert and Steven Bankes discuss a computational approach to assess the impact of crucial uncertainties of future developments on the decisions one has to make to meet desired targets, Scientific American: Shaping the Future.

People have the tendancy to make decisions with a short time horizon. Many developments in social-ecological systems have uncertain long term developments. Popper et al. explicitly focus on the possible consequences of uncertainties and visualize the result of many simulations in to a useful figure of how robust future scenarios are for meeting policy targets.

The Environmental Limits to Globalization

In a new paper of David Ehrenfeld (Conservation Biology 19(2): 318 -326) the environmental consequences of globalization are discussed. Ehrenfeld argues that

Criticisms of globalization have been largely based on its socioeconomic effects, but the environmental impacts of globalization are equally important. These include acceleration of climate change; drawdown of global stocks of cheap energy; substantial increases in air, water, and soil pollution; decreases in biodiversity, including a massive loss of crop and livestock varieties; depletion of ocean fisheries; and a significant increase in invasions of exotic species, including plant, animal, and human pathogens. Because of negative feedback from these changes, the future of globalization itself is bleak. The environmental and social problems inherent in globalization are completely interrelatedany attempt to treat them as separate entities is unlikely to succeed in easing the transition to a postglobalized world.

The interesting perspective is proposed that globalization is a non-resilient temporary process but still rapid and effective enough to disrupt various social and ecological processes and states.

Resilience of social memory

Two recent publications provide some interesting ideas how knowledge can be maintained over a long period. John Cisne developed a population ecology model of medieval manuscripts. Manuscripts are copied manually, and more popular books have more chance to be copied. Cisne used concepts from population ecology to understand the paleodemography of the manuscripts and conclude that the leading technical titles who circulated in Latin probably survived. See also the commentary of Gilman and Glaze in the same Science edition.
We write only once a sentence that maybe read many times. Changizi and Shimojo analyzed the complexity and redundancy of characters of more than 100 languages. They conclude that the characters are constructed on average by 3 strokes, and that this is 50% redundant. The explanation for this is that characters are still correctly classified (by reading) when errors are made (by writing).

Paper competition on “Novel approaches of integrative science for the future”

The journal Ecology and Society invites submissions for in a manuscript competition on novel ways of performing integrative science and policy research. The annual ‘Ralf Yorque Memorial Prize’ of 5,000 Euro will be awarded to the most novel paper that integrates different streams of science to assess fundamental questions in the ecological, political, and social foundations for sustainable social-ecological systems.

Transdisciplinary science is often promoted in words and not in practice. Young scholars derive many incentives to specialize in certain disciplines, and experience few incentives to be creative in combining insights from various scientific disciplines and performing science in nontraditional ways. This paper competitions is meant to be an incentive in the effort to stimulate novelty and creativity of new ways of performing science.