William F. Ruddiman pose an interesting hypothesis by arguing that humans have had a measurable impact on the climate system for 8000 years. In his book “Plow, Plagues and Petroleum”, the emeritus environmental science professor shows interesting anomalies in the trends of atmospheric CO2 concentration (since 8000 years) ago when Europeans start cutting down forest in Middle and Eastern Europe for agriculture, and CH4 concentration (since 5000 years) when irrigated rice farming started at large scale. This has led to an temperature increase of 0.8 degrees Celsius before the industrial revolution started which led to a similar amount of emissions, but in a much shorter period. Ruddiman argues that instead of heading to a cooler climate, as was expected from traditional climatology (due to regular orbital changes) increased human-induced emissions avoided this cooling down, and may lead to a brief warming period (on geological scale). There is also an interesting chapter where brief declines of CO2 concentrations are related to major pandamics (like black plague), which led to a temporarely regrowth of forests. If Ruddiman’s thesis is true humans have unconsiously entended the K-phase of preferable climate before a dramatic reorganization phase (in the coming years?) occur.
Author Archive for Marco Janssen
Henry Petroski wrote a wonderful book ‘Success through failure’ on the importance of failures in the design of successful projects, buildings, policies etc. Petroski is a professor in civil engineering and history at Duke university. The book stress the importance of failures in designing successes. Building only on successes might actually lead to severe failures. Petroski discuss designs of various objects like presentations (from the cave to powerpoint), bridges, sky crapers, etc. A lot of these designs are improvements of earlier designs. Due to thinkering with previous designs, previous failures are avoided, but new ones may occur. By being open to learn from failures, robust designed objects may evolve.
An interesting observation is the regularity of major failures in the design of bridges. Every generation of engineers, a major failure occurs. Probably with a new generation, lessons from previous failures get ignored or forgotten, and less emphasis is made on double checking and testing the designs.
A nice interactive game on solving dilemmas between different stakeholders can be found at http://www.alwayssunny.com/lab/lindissima/. The game is a simple-minded and optimistic story which is used as an excercise for people to learn the basics about scenario simulation, dynamical adaptive systems, sustainability attributes, multicriteria analysis, among others. In the first act, slash and burn maize farmers are compelled by the government to leave a biodiversity reserve zone and to intensify maize production in a smaller area using urea. The user plays the role of the farmer, explores scenarios and decides if he can sustain his family economy under the government´s proposal.
In act 2, rural families that depend on ecotourism in a clear lake downhill feel their income threatened by water murkiness caused by nitrogen coming into the lake from the maize farmer´s fields. As part of negotiation with uphill farmers, the user (now in the role of the lake-side dweller) needs to know how much N they can accept to run into the lake before it becomes murky. A number of simulations helps the user find out the limits (which of course depend on initial conditions in the bi-stable regime). Time series coupled with parameter-sensitive cup and marble models that run as real time animations allow the user to better understand the cusp catastrophe involved
In act 3 farmers try to comply with such restriction imposed by the interests of the lake side people. The farmer, together with the lakesier and the government, first consider if its possible to do so under a maize moncrop system and later under a maize-leguminous shrub system. A simple agroforestry model is behind the curtains and the user currently has access only to a small set of its parameters.
Each act provides: the story with illustrations, a scenario simulator based on minimalist dynamical models, a number of excercises that must be solved before going further and a graphical tutorial.
New Scientist of January 12, report on an initiative of the Norwegian government to create a large concrete room, hewn out of a mountain on a freezing-cold island just 1000 kilometres from the North Pole, to hold around 2 million seeds, representing all known varieties of the world’s crops.
It is being built to safeguard the world’s food supply against nuclear war, climate change, terrorism, rising sea levels, earthquakes and the ensuing collapse of electricity supplies. “If the worst came to the worst, this would allow the world to reconstruct agriculture on this planet,” says Cary Fowler, director of the Global Crop Diversity Trust, an independent international organisation promoting the project.
This initiative shows a practical implementation of principles to enhance resilience: redundancy and diversity.
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.
Earth and Sky radio asked 50 prominent scientists on their opinion what it means to be human in the 21th century?
Increasingly ecological and social processes are connected at different levels of temporal and spatial scales. This has consequences on the role of humans on earth and being human. The variety of opinions of the scientists are listed on the website of Earth and Sky radio.
New Scientist has an interview with Paul van Vlissingen who is the largest private parks operator in Africa. Interesting is his focus on the importance of integrating the people and the park:
No park will survive in the long run unless it is supported by the people living in and around it. They need to know there is something better to do with a zebra than eat it, that they can benefit from protecting it.
Our management philosophy is completely different from anything that has been there before. We say that the villagers in and around our parks should see the park rangers as people who will help them, not as policemen who go round beating up anybody they think is poaching. Our rangers visit the villages and ask if there is anything they can do. There is a lot of physical suffering there: hunger, malaria, AIDS, people being mauled by lions. Our rangers have radio equipment, so they can get doctors or medicine. We offer security, too. In Liuwa, our park in Zambia, there were 60 or 80 murders a year before we went there. In the first year that we were there, that number went down to 26, the next year to two.
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The National History Museum of Los Angeles County has an exposition Collapse? running until January 17, 2006, inspired by the book Collapse: How Societies Choose to Fail or Survive by Jared Diamond. See also the post Partha Dasgupta vs. Jared Diamond |
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In the July 8 edition of Science an interesting study is presented by Miller et al. (2005) and commented by Johnson (2005) on the impact of human activities. Around 45,000 years ago, the human started to occupy Australia, and like similar puzzles in the Americas, the questions is the impact of human activities on the extinction of many large herbivores. Miller et al. (2005) provide “the best evidence to date that human arrival, rather than climate, played the leading role in the extinctions of many large herbivores in Australia. They look especially to the diets of the emu and of the largest flightless but now extinct bird Genyornis.
Figure compares Genyornis & Emu.
Continue reading ‘Why the emu’s survived the human occupation’
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.
