(this is one of many FAQ files found at Terry)

What are genetically modified organisms (GMOs)?

GMOs are plants and animals which have been genetically altered under laboratory conditions by the insertion of genes from other organisms into their natural genetic makeup.

Why should I be concerned about GMOs?

To understand the debate surrounding GMOs, we must first understand the problems associated with the world’s food supply. According to the United Nations (UN), the number of hungry people in the world rose to an astounding 852 million in 2002, an increase of 18 million since the mid-1990s. The harmful effects of chemical fertilizers and pesticides are another problem, with the World Health Organization (WHO) estimating that chemical pesticides cause 20,000 deaths a year and millions of cases of poisoning, the majority of which occur in developing countries. The continual reduction in the world’s biodiversity is a further cause for concern. Biodiversity is vital for proper nutrition, the development of new medicines, and adaptation to harsh environments and resistance to harmful pests. According to the Food and Agriculture Organisation (FAO), the genetic diversity of agricultural crops has been reduced by three-quarters over the last century. Just a dozen species of animals provide 90% of the animal protein consumed globally. Half of plant-based calories in the human diet are provided by just four crop species. This makes the world’s food supply more vulnerable to viruses, diseases and pests. The reduction in biodiversity is therefore regarded as a serious threat to both food security and sustainable agriculture.

What is the debate surrounding GMOs?

Right now the vast majority of GM crops (approximately two-thirds) are designed to tolerate herbicides. The company Monsanto dominates this technology, having introduced the first major GMO product, “Roundup Ready” soybeans, in 1996. The “Roundup Ready” soybeans are designed to withstand the company’s own Roundup herbicide. The next most common crop is Bt corn, which is inserted with a gene from the Bacillus thuringiensis, or Bt, and gives the plants a toxic protein that kills the corn borer pests.

The debate surrounding GMOs is about whether or not genetically engineered foods can help improve the situation for the world’s hungry by providing people with nutritional foods in a manner that is sustainable and has the least possible impact on the environment and on health. To assess this fundamental question, scientists, policy makers and the public alike have to ask themselves whether or not GM foods are safe to eat and whether or not biotechnology can increase food yields and biodiversity in a sustainable manner. Equally important is whether or not GMOs reduce pesticide use, what their overall costs and benefits are to farmers, whether viable alternative exist in their place, and whether there could be potential for disastrous environmental effects.

What are some potential benefits of GMOs?

Those promoting GMO use generally agree that technology has helped improve food production. For evidence, they point to the “green revolution” when agriculture became industrialized and large-scale fertilizer and pesticide use became common practice. GMO advocates believe that GMOs will continue this tradition of technology advancing food security for the growing human population. Critics argue that the indicators used to determine these improvements have not properly measured the long-term environmental effects of pesticides and fertilizers. GMO proponents believe that GMOs have the potential of reducing pesticide and herbicide use, providing better nutrition by increasing the nutritional content of crops, improving crop yields to feed a rapidly growing world population, promoting market competitiveness, and overcoming environmental conditions such as drought and heat.

What are some potential risks of GMOs?

Critics argue that GMOs can reproduce and interbreed with natural organisms, thereby spreading in uncontrollable and unpredictable ways. It is difficult to maintain a separation between GMO crops and non-GMO crops due to uncontrollable cross-pollination. Although GMO supporters believe biotechnology can overcome these problems with more advanced products, critics of GMOs argue that the long term effects of this contamination are unknown and potentially disastrous for biodiversity, food security and health. Scientists argue that GMO genetic material is very much unlike ordinary genetic materials. The gene-constructs are said to be designed to invade genomes and to overcome the natural species barriers, thus making the cross over of bacterial, herbicide, and pesticide resistance a much more common occurrence than in non-GM foods. The creation of “super-bugs” that could affect humans and crops is said to be a very real threat by some scientists who warn of the heightened potential for this type of gene transfer. This view contrasts with that of GMO supporters, who maintain that genetic engineering is simply an improvement on the slow and imprecise agricultural methods used for decades, such as selection, hybridization, wide crosses and use of radiation.

Critics argue that the introduction of GMOs into the environment will have adverse effects on beneficial insects, plants and ecosystems. The interaction of the introduced genes with the original genes of the organism may have the potential to cause previously unknown allergens and toxins. GMO critics argue that the introduction of genes is still a new science with too many uncertainties to be safe for widespread agricultural use and consumption. They contrast this to conventional foods which have been part of the human food chain for thousands of years and evolved over billions of years. GMO critics call for more extensive testing of GM goods, more transparency and independence in the research process, and more regulatory oversight before the release of the foods to the public. Until then, many critics call for a complete ban on GMOs, along with increased funding to sustainable agriculture techniques which have proved successful in the past.

Why is an Arts/Science perspective important in addressing GMOs?

Many now agree that science and technology are never neutral or value-free but always embedded in a social and political context. Scientists and the Sciences have been criticized for adopting an overly reductionist perspective in addressing pervasive global problems. Although scientists’ perspectives work brilliantly in addressing specific problems in closed systems, they have their limitations in the complex systems in which humans live. The so-called genetic determinism perspective, whereby genes are seen to lead directly to certain physical characteristics and behaviours has long been discredited. We now know that organisms, however minute, are constantly interacting with their environments and this, along with their particular genetic compositions, determines their traits. Despite idealistic visions, scientists are now realizing the limitations of trying to change the world’s most devastating problems, such as world hunger, with the addition or alteration of single genes in GM foods.

Furthermore, scientists, and molecular biologists in particular, have been criticized for having their research and its applications driven by profit rather than public good, and for the technological research being heavily directed toward the priorities of the developed world. This, they say, is as a result of many in the field of genetics having vested interests through partnerships with or shares in the biotechnology industry. Scientists such a Miguel Altieri and the well-known Vandana Shiva argue that agricultural research is often oriented towards agricultural industry research rather than research that supports the needs of poor farmers. Research that makes use of indigenous practices and human resources rather than biotechnology, they argue, can provide an affordable and sustainable means for poor farmers to improve their condition without endangering the environment. They further reason that “first world” farming practices and scientific research cannot simply be imported over to the “third world” where the physical, economical and social environments are drastically different. These scientists argue that GMO technologies are created for giant, American super-farms rather than the small-scale agriculture characterizing the majority of the developing world. Other important considerations for scientists and the public are the ethical and legal implications of patents on seeds, GMO products, and even naturally occurring genes.

A complete understanding of the impact of GMOs requires us to understand not only the science and the technology behind GMOs, but the social, political, and economic implications of these products.

What is the political climate surrounding GMOs?

Europe and the U.S. are engaged in a giant struggle over agricultural market domination. Some similarities exist between the strategies used by the two powers. For example, both maintain enormous subsidies for their agricultural sectors, which lower international prices for many agricultural commodities, thus reducing the competitiveness of products grown in the developing world. However, there are differences between European and American subsidy programs. The subsidies from the EU have a significant environmental component, while the U.S. subsidies prioritize supporting the largest actors. The U.S. does not consider organic agriculture while the EU values it highly, and the EU takes a cautious approach to GMOs, while the U.S. is a leading advocate of GMO products.

The forum for this agricultural battle between the U.S. and the E.U. soon became the World Trade Organization (WTO). This happened when the U.S. claimed the E.U.’s cautious approach to GM foods represented a barrier to trade. In 2004 the E.U. lifted its ban on new GMOs. The U.S. would not lift its challenge and pursued further charges over Europe’s regulations on labelling GMO products and Europe’s rigorous system of verification and tracing of GMO foodstuffs.

Many see developing countries as the greatest victims of the GM food battle. Foreign aid sent to developing countries has been criticized as an underhanded way of imposing GM foods on the developing countries without their knowledge or consent.

Are there any international agreements to regulate GMO use?

The Biosafety Protocol is the first international agreement to regulate the international trade of GMOs. It is unique in that it advocates sustainability, prioritizes consideration of human health, and adopts the “precautionary approach.” The “precautionary approach” is from the Rio Declaration on Environment and Development, which states that “[w]here there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.” In the case of biotechnology, the risks are to biodiversity and human health. The Protocol simply requires countries to label shipments of seeds and organisms when they are meant to be released into the environment, and to include information about the genetic alteration made. According to the Protocol countries are permitted to reject GM imports if they have scientific reasons to doubt their safety. They are also permitted to consider socioeconomic factors in their decisions. The Biosafety Protocol came into force in September 2003 and stems from the UN Convention on Biological Diversity (CBD), signed by over 150 governments at the Rio “Earth Summit” in 1992. Countries such as the U.S., Argentina and Canada which produce 90% of GM crops world-wide have not ratified the Biosafety Protocol.

(artwork by Jane Wang)

(this is one of many FAQ files found at Terry)

You hear sustainability mentioned everywhere these days, but what does it actually mean?

In 1983 Norwegian Prime-Minister Gro Harlem Brundtland was commissioned by the United Nations to undertake a study into “sustainable development”. The study entitled “Our Common Future” was published in 1987. It has been referred to more popularly as “The Brundtland Report”. It is in this report that the most agreed upon definition of sustainability can be found.

“Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” (World Commission on Environment and Development – Brundtland Commission, 1987)

Although this definition is vague, it is the seed for changes in both thought and action. This definition has allowed various conventions and meetings such as the Earth Summits to have a starting point in dialogue. It is important to realize that the definition presented here is vague by necessity. As sustainability involves understanding the relationship between the environment, economics and society (1) any one definition must be able to be employed generally.

Is the need for sustainability a recent phenomenon?

We are not the first of societies to be caught in the downfall of our own economic and ecological spending. When the first foreigners reached the shores of Easter Island, the locals were engaged in great battles over the control of the last of the natural resources. Deforestation of the land had led to soil erosion and poor agriculture. It was their belief that construction of the iconic and famous large statues would appease the Gods and correct the situation. However, this practice inevitably used more resources and worsened the situation. Moreover, the fate of these threatened people was sealed upon the arrival of foreign ships.

Although the struggle between man and his environment is not a new one, our struggle today is of a different scale: global, rather than local and is a result of the ideals we associate with Western civilization, such as industrial growth and globalization. Over the last few decades we have started to identify some of the challenges that face us, such as greenhouse gases and population growth. But even, so the issue is of such merit that even new perspectives outside that of Western civilization are required to approach these challenges. It is imperative to not be complacent, to not follow a similar fate of those on Easter Island and other great civilizations which have failed by blindly following harmful courses of action.

What is the relationship between sustainability and environmentalism?

There are many ways to look at this. The human race has always had great impact on the environment and ecosystems. For example, long ago, the lands of North America, Asia, Australia and Europe were home to some of the most magnificently large animals, known as megafauna. The dates of their extinction around the world closely follow the path of humans, the skilled hunters, colonizing the land. Another example, is when humans moved into Australia, about 50 000 years ago. Here, colonization had a major impact on the ecosyste, including things as nuanced as the extinction of the Volkswagen beetle bug sized wombat. Furthermore, humans are have also molded the ecology of Australian land through the use of fires (2) To be blunt, the world has now inherited an Australia with an ecology that has in part become dependant on fire for survival.

Stephen Jay Gould, in his 1993 book “Eight Little Piggies; Reflections in Natural History,” points out that along with the megafauna, a proposed 99% of all animals ever in existence are now dead. Although, extinction is an accepted fate for all species, should man feel guilty about driving a few more animals to extinction? Perhaps. However, accepting extinction as a part and parcel of life on earth does not negate our desire to protect the planet at this point in time. Furthermore, as extinction and recovery from it, is on large geological scales, some suggest that our attempt to produce a sustainable lifestyle on our planet now is (above all) for our own comfort and that of our offspring.

Two common ideological flaws of popular environmentalism, as pointed out by Gould, are the ideas that our planet is fragile and that it is up to us to “act as stewards”. He argues that these are two ideas which are born of western ideology that “humans are separate from and above the rest of creation” (4). The paradigm in which we consider environmental causes is shifting as we realize that our planet isn’t so much bothered whether our species survives the next several hundred years nor is she bothered by whether she can recover from whatever we inflict on her. In some respects, this viewpoint suggests that we don’t so much need to care for her, but learn how to care for ourselves and those that surround us.

What is the difference between sustainability and environmentalism?

Many see sustainability from an environmental perspective, and it certainly does involve many environmental problems (most of which are akin to alarm clocks screaming to get us up). From oil spills, deforestation of the Amazon and the loss of biodiversity, to events like Chernobyl, the impact we have on the environment is non argumentative. Although there is academic debate over the cause of global warming, these arguments are splitting hairs. The point is that the world is becoming a much less comfortable place to be. Change needs to happen and has even been whispered at since the late 1960’s. Nowadays, this change is being realized as an entire shift in paradigm, that utlizes and heeds the entire framework of ideas and beliefs of the western culture. Essentially, many feel that as the world currently turns according to economic rules, the changes required at this stage involve practices in production, consumption and governance (5). The changes required will need to make sustainable practices an economically sound solution (1).

The industrial revolution left us with an economy based on extraction from environment, production, consumption and inevitable waste – a very linear “cradle to grave” system. New ideas about economy and business, such as those promoted by world renowned architect William McDonough, suggests business as a circular cycle, a so called “cradle to cradle” system. Here, it is clear that the concepts underlying sustainability go far beyond the reaches of the environmental mantra of the three R’s; reduce, reuse and recycle. Although these are still fundamental concepts, sustainability goes many steps further, by emphasizing the notion that production and economic growth need not be limited. An example would be one textile factory in Switzerland, Rohner Textile, which was facing bankruptcy due to the cost of biohazardous waste removal and water treatment. Working with a chemistry company they identified safe dyes and chemicals for the production of their fabrics, leading to not just the reduction of harmful constituents but the removal of them. Now the end cuttings of the fabric, which were once considered biohazardous waste, are not just recycled but are actually composted, and returned to the earth. Factories still have a place in the future – they will just have to be cleaner than any regulation requires now (6).

More to the point, in order to allow for the changes at an economic level, there is a need to alter our own governance. Legislative changes at local, provincial, federal and international levels must allow for the growth of a sustainable business sector.

Is sustainable only available to developed nations?

Although it is due to both industrialization and globalization, that so much drastic environmental change has occured, it is also the wealth afforded by these same processes that allow us the economic freedom to start protecting our natural resources. In poor nations, however, little thought to natural resources is allowed when making economic decisions. Would you destroy natural resources when pressed with the need to feed, shelter, and clothe your children? However, even though third world countries simply do not have the same luxuries to model their development after Western society, it is also important that they are not led down the same path of destruction. Therefore, there is the challenge to implement the same responsible restrictions to countries as they develop, so that development is not stunted per se, and so that they are encouraged to foster their natural resources, knowing it to be an important part of their future livelihood (7). Bottom line is that development will concern the environment, as well as other urban considerations such as health care and status of women, like it has never been done before.

What will the future look like?

The future, for good or bad, is a metropolis. The United Nations estimates that in the year 2025 2/3 of the worlds population will live in cities and the urban areas surrounding them. Whether these cities will be home to disease, poverty and crime or peaceful sustainable societies will be decided over the next several years. The fate of our cultures rests in the ability of the city to adapt and change. People involved in all aspects of life are excited to discuss the future of their cities. For example, China is one of the fastest growing nations. Over the next decade 400 million people will need a roof over their head. The Chinese are now realizing how taxing this is to current systems of infrastructure, and are already looking at alternative methods of systems as diverse as water sanitation or alternative building materials (8).

In Vancouver, British Columbia, the Centre for Interactive Research on Sustainability (CIRS) produces visualizations tools for examining sustainability. As a cooperative effort between four post secondary institutions in BC (University of British Columbia, Simon Fraser University, British Columbia Institute of Technology, Emily Carr Institute of Art and Design) the CIRS is being given a home. It will be a new breed of building which will double as an experiment itself. New ideas in construction, waste management, water supply, air supply, energy usage and even transport of employees to and from work will be able to play out. To demonstrate the role of local government, the City of Vancouver has agreed to work with the development team to look at ameliorating the cities by-laws to allow the construction and servicing of a sustainable building.

What can I do now?

The most important change a person can make now, is to turn thought and concern into action. From being a knowledgeable consumer to being a responsible producer and becoming involved in local, provincial and national government to both push and allow for changes. It’s pretty much time to turn off that ringing alarm clock.

* * *

References:

1. Heal, Geoffrey “Valuing the Future” Columbia University Press, USA, 1998.

2. Miller et al. “Ecosystem Collapse in Pleistocene Australia and a Human Role in Megafaunal Extinction”. Science, 309 ( 5732). 287-290. 2005

3. Gould, Stephan J. “Eight Little Piggies; Reflections in Natural History” W.W. Norton & Company, Inc.USA.1993

4. Martin, Thomas. “Greening the past; towards a social-ecological analysis of history”International Scholars Publications, USA. 1998

5. http://sdgateway.net/introsd/default.htm, Sept 24, 2005

6. “The Next Industrial Revolution” Earthcome, 2001

7. Toakley, A. R. “Globalization, Sustainable Development and Universities”. Higher Education Policy. 17, 311-324. 2004)

8. Underwood, Anne. “Designing the Future”. Newsweek. May16, 2005.

(artwork by Jane Wang)

(this is one of many FAQ files found at Terry)

1. CLIMATE CHANGE? HUH?

Climate Change is the measured long-term shift or change in the climate of a certain location, region, and on a larger scale…the whole planet. These changes are seen in weather, temperature, rainfall, humidity and various other ecological features of our biosphere and are caused by both natural and human factors. In addition, the study of climate change engages atmospheric science and meteorology, but the subject is so complex that it involves many other areas of the earth sciences, as well as different disciplines, such as physics, chemistry, and even biology. This complexity makes climate science both fascinating and controversial. It also undergoes rapid change as new facts and analyses emerge.

2. SO WHAT CAUSES CLIMATE CHANGE?

Climate change occurs whenever something alters the total amount of the sun’s energy absorbed by the earth’s atmosphere and surface, or changes the amount of heat energy from the earth’s surface and atmosphere that escapes to space over a period of time. Significant alterations in climate can be caused both by natural events and processes and by human influences. Climate change does occur naturally – the ice age is an example. The earth’s natural climate has always been, and still is, constantly changing. Natural processes like volcanic eruptions, changes in the sun’s intensity, or very slow changes in ocean circulation or land surfaces that occur on time scales of decades, centuries or longer are factors in influencing climate change. Key natural factors include changes in the intensity of sunlight reaching the earth and in the concentration of volcanic dust. Both of these factors alter the amount of sunlight that is absorbed by the earth. Humans can also cause climates to change by releasing greenhouse gases and aerosols into the atmosphere, by changing land surfaces, and by depleting the stratospheric ozone layer. Greenhouse gases are especially critical in this discussion of human factors leading to climate change, because an increase in greenhouse gases enhances the natural greenhouse effect which in turn can lead to an increase in the earth’s average surface temperature.

3. POTENTIAL IMPACTS OF CLIMATE CHANGE

All of the projections, postulations, and research into climate change indicate that the upcoming changes will be quite significant. Climate models indicate that warming will be greater in Arctic regions than in equatorial regions, and that continents will warm more than oceans. However, and perhaps due to the vastness of the subject, it is difficult for scientists to predict the exact consequences of continued increases in greenhouse gas or its impact on various regions. Even if developed nations deal well with the impact of climate change, there are other regions – particularly in the developing world that may not be as adaptable to these changes – thereby still impacting developed nations in terms of security issues and foreign aid. Throughout the world, climate change may threaten the world’s natural resources including forests (an increased fire risk because of the drying climate); water (needs may outstrip supply); cause severe water loss due to changes in evaporation and precipitation patterns; cause flood damage to low-lying countries and island states, including loss of coastal land to rising sea levels; intensify the movement of tropical diseases such as malaria to regions where populations have little or no immunity; and affect international trade patterns. Higher air temperatures and removal of the insulating vegetative cover could lead to a melting of permafrost in the Arctic regions and glaciers could also retreat more quickly.

4. CAN THIS BE STOPPED!?

Most scientists indicate that the current warming trend cannot be stopped or reversed and climate change may already be unavoidable. One explanation for this grim prediction is that there is a lot of inertia in the climate system (mainly because of the slow response of oceans), and hence the temperatures have only partially responded to the increased concentrations of greenhouse gases already in the atmosphere. Even if all emissions stopped today, further residual warming would take place for a number of decades before the climate reaches a new equilibrium conditions. However, immediate actions can slow down and eventually stop this increase.

5. WHAT DO THE SCIENTISTS KNOW?

In addition to the consistency of evidence for warming obtained from both the instrumental air temperature records and other temperature data, there are many other indicators of a warming world. These include warming of the upper layers of the world’s oceans, melting mountain glaciers, retreating sea ice and snow cover, rising sea levels, and shifts in distribution of many species of plants and animals. In addition, the instrumental records of surface atmospheric temperatures collected over the past 120 years agrees well with other indicators of climate, such as data from tree ring, ice cores, corals and ground temperatures. All show substantial warming over the past century.

6. BUT WHAT ABOUT THE GREENHOUSE EFFECT?

Greenhouse gases – primarily water vapour, carbon dioxide, methane, and nitrous oxide – trap the heat of the sun, preventing radiation from dissipating into space. Without the effect of these naturally occurring gases, the average temperature on the Earth would be -18° C, instead of the current average of 15°. Life as we know it would be impossible.
The greenhouse effect describes the role of the atmosphere in insulating the planet from heat loss. The small concentrations of greenhouse gases within the atmosphere that cause this effect allow most of the sunlight to pass through the atmosphere to heat the planet. However, these gases absorb much of the outgoing heat energy radiated by the earth itself, and return much of this energy back towards the surface. This keeps the surface much warmer than if they were absent. This is called the greenhouse effect because it resembles the role of glass in a greenhouse. Over the past 10,000 years, the amount of these greenhouse gases in our atmosphere has been relatively stable. But a few centuries ago, concentrations began to increase due to the demand for (i) energy caused by industrialization and rising populations, and (ii) to changing land use and human settlement patterns.

7. WHICH HUMAN ACTIVITIES CONTRIBUTE THE MOST TO GREENHOUSE GASES IN THE ATMOSPHERE?

Carbon dioxide is the main culprit here as far as human activities are concerned. Fossil fuel use and consumption currently accounts for between 70 and 90% of all human emissions of carbon dioxide. Fossil fuels are used for transportation, manufacturing, heating, cooling, electricity generation, as well as many other applications. The remainder of the carbon dioxide emissions comes from human land use activities – ranching, agriculture and the clearing and degradation of forests. For other greenhouse gases, primary sources include the production and transport of fossil fuels, agricultural activities, waste management and industrial processes. Methane (the second most significant greenhouse gas, next to carbon dioxide) emissions occur both naturally and as a result of human activities. Rice cultivation, cattle and sheep ranching, and decaying material in landfills all release methane, as do coal mining, oil drilling operations, and leaky gas pipes. Nitrous oxide comes from both natural sources and human activities. Fossil fuel combustion, industrial practices, and agricultural practices including the use of chemical fertilizers all increase atmospheric nitrous oxide. The industrial production of chlorofluorocarbons (CFCs) and other halocarbons – used in refrigeration, air conditioning, and as solvents – have added other greenhouse gas, but many of these sources are gradually being eliminated under existing international agreements because they deplete the stratospheric ozone layer. Ozone in the troposphere (the lower part of the atmosphere) is another important greenhouse gas resulting from industrial activities. It is created naturally, but is also produced by atmospheric reactions caused by smog precursors such as nitrogen oxide from motor vehicles and power plants.

8. WHAT ABOUT WHEN WE BREATHE?

The carbon dioxide that humans exhale is part of an active natural carbon cycle involving intake of carbon from food we eat and the release of carbon through breathing and human wastes. Unlike ruminant animals, which have different digestive systems, gases erupting from humans through flatulence or belching contain very little methane and do not contribute significantly to increased methane concentrations.

9. WHAT OTHER HUMAN ACTIVITIES AFFECT THE CLIMATE?

Although a lesser evil than greenhouse gases, ozone depletion in the stratosphere can also lend to climate change. Ozone depletion allows more ultraviolet radiation to reach the lower atmosphere but also reduces the greenhouse effect of the ozone involved. Deforestation, desertification, soil erosion, farming practices, and urbanization are some of the processes that affect the surface albedo of our planet (‘Surface Albedo’ refers to the amount of sunlight reflected by the earth’s surface back to space).

10. AND WHAT OF CLIMATE MODELS?

Complex climate models are developed using physics, computer science and mathematics. These models are tested against witnessed climates and climates of the past to ensure they can simulate real climates. Data is then used to project future climates for scenarios of future greenhouse gas emissions. While these tests show significant disagreements with observed and past climate data at regional scales, models of today replicate the global pattern and trends very well. Researchers are confident that they provide useful indications of how the climate will respond to human interference with the climate system.

11. WITH SO MUCH UNCERTAINTY ABOUT WHAT WE KNOW ABOUT CLIMATE CHANGE, MODELING, AND OTHER RESEARCH TECHNIQUES, IS IT NOT BETTER TO WAIT BEFORE ENACTING ANY MEASURES OR STEPS TO PREVENT CLIMATE CHANGE?

Much of the uncertainty is related to the consequences of climate change. Scientists are in general confident that the basis for concern about climate change is scientifically sound and that the risks of danger are real and significant. Such risks make it important that precautionary steps are taken now. With regards to climate change, early action is more beneficial and likely less costly and disruptive than delayed action. The scientific community has recommended precautionary actions that will at least reduce the risks by slowing down the potential rate of climate change.

12. ARE THERE ANY ALTERNATIVE VIEWS TO CLIMATE CHANGE THEORY?

Although evidence does heavily indicate on-going climate change, it is important to look at all sides of the climate change issue in order to make an informed decision. Scientists presenting alternate views on climate change argue that the human influence on climate is not yet apparent, and that the results of climate modeling are exaggerated. However, most generally agree with the fundamental science underlying the concern about climate change.

13. ARE THERE ANY BENEFITS FOR HUMANS IN RELATION TO CLIMATE CHANGE?

For cold countries (such as Canada), climate change can provide some significant benefits, like reduced heating costs and longer, warmer growing seasons. This would potentially offset some or all of the harmful effects caused by climate change (if the rate and magnitude of climate change is minimal modest). However, even if these countries escaped somewhat unscathed, major negative impacts are projected for many of the developing countries of the world, even for modest changes in climate. These off shore impacts can also have indirect yet significant negative consequences for countries like Canada. Climate change may also present other benefits (environmental technology and services, increase exports, and create jobs). However, other consequences of climate change are expected to be very harmful. These include: the combined effects of sea level rise and ocean storm surges, enhanced drought conditions that threaten large populations with starvation in some regions of the world, increased intensity of summer rainfall and related heavy flooding and erosion, and increased frequency of high temperature extremes are related stresses on ecosystems and human populations.

14. ANY DEBATES OVER TEMPERATURE AND CLIMATE CHANGE MODELING?

The subject of climate change leans heavily on observations of temperature. Researchers are inundated with data, much of which does not add appreciably to the discussion; on the other hand, they lack crucial information about the past that may never be recovered. The large discrepancy between model results and observations of temperature trends (whether from satellites or from the surface) also demands an explanation. The models developed around the world by expert groups differ among themselves by large factors. Computer models forecast rapidly rising global temperatures, but data from weather satellites and balloon instruments show no warming whatsoever.

15. SO WHAT CONCLUSONS CAN WE DRAW FROM THE OTHER SIDE OF THE DEBATE? WHAT’RE THEY SAYING?

Government officials have declared repeatedly that climate science is sound and compelling. The clear implication is that we know enough to act; any further research findings would be perhaps redundant and not important to the international deliberations of the parties to the climate treaty. The ‘other side’ holds that the observational evidence touted by proponents of climate change suggest that any warming from the growth of greenhouse gases is likely to be minor, difficult to detect above the natural fluctuations of the climate, and therefore inconsequential. It is also a popular belief among skeptics that the impacts of warming and of higher CO₂ levels are likely to be beneficial for human beings.

(artwork by Stephanie Cheung)

Nancy started this…

Essentially, it was her idea to get David and Allen together to work on a project that used and focused on interdisciplinary thought – connections between the sciences and the humanities, directed specifically towards the undergraduate community. Fortunately, and over coffee, David and Allen hit it off pretty quick and started to think a little (and then a lot) about such a grand educational initiative.

The first thing they realized, of course, was that neither was at all comfortable talking about the sciences and the humanities. Allen, after all, specializes in international security, and David dabbles in molecular genetics, worthy disciplines on their own, but obviously nowhere near representative of the enormous breath behind the two largest faculties on campus. What to do? What to do?

What they did, was write a grant. And this grant essentially said something like the following:

We would like to offer a “Global Citizenship Seminar Series” as a joint initiative of the University of British Columbia’s Faculties of Arts and Science (as well as many others including those from groups as diverse as UBC Student Development and UBC Community Affairs). Its primary mission is to educate members of the UBC community (notably undergraduate students) on the pressing global issues of our time. This will encompass a website, design of a future interdisciplinary course addressing global issues, and delivery of the aforementioned speaker’s series showcasing high profile (and engaging) academics, cognoscenti, and proactive members of our global community. By creating a synergistic forum that addresses topics such as climate change, sustainability, GMOs and AIDS, we hope to stress the importance of multi-disciplinary learning, thus inspiring students to actively pursue university educations that will assist them in developing and promoting just, civil, and sustainable societies throughout the world.

Nice, right? Without the more eloquent grant speak, it simply queried: “We’ve got this great idea for an interdiciplinary course, but need to do some homework first ,before we’re comfortable delivering it. To focus a bit, let’s concentrate on pressing global issues, maybe start a website to collect information, and bring out great people who we can learn from – get pumped up, you know. Grant reviewer people, can you help us?”

Happily, they did, and this website is one small but important part of that ideal. This website aims to act as a voice, a textbook of sorts, and a place to present information, opinions, creations, reviews and really anything that tackles some aspect of the many topics and subjects that fall under the global issues of concern.

Of course, there is always the fear that a project of such considerable intent will crash and burn. But we hope to be resilient, and are optimistic that there are many like us who want to help make it work. Funny, but in some respects, these are attributes not unlike the needs and hopes of our own troubled planet.

Alright. Game on.

(also read our Seminar FAQ, and see next semester’s roster of speakers)

I am an avid reader of The Onion. For those of you who don’t know what I’m talking about please be rest assured that I’m not some sort of weirdo who looks for messages in tea leaves and the like. Perhaps the name of a vegetable is a rather unusual choice for a satirical periodical, although I would have to disagree with anyone who felt that any prior publications of this genre had set lasting precedents. The more absurd the name is the better, and as we all know, absurdity is inherent to human existence. To clarify this thought I will kindly refer you to Scientologist actors with the surname of Cruise and to pop stars who don’t know when to call it a day with the plastic surgery. Thankfully, such selfless individuals provide us with an abundance of high quality entertainment. If we feel like having a good laugh at their expense, might as well do so while reading an oddly named, hilarious publication. The Onion it is.

Because I read The Onion so frequently and with such enthusiasm, I can quote many of the memorable phrases with some degree of accuracy…maybe not with the same familiarity the Republican Supreme Court Justices display with the Ten Commandments, but then again, that would be a difficult task indeed. My obsession with The Onion rather alarms my mother who wishes I paid similar attention to the Bible of her Mennonite heritage. Unfortunately, another lifelong love of mine, the Simpsons, has ruined any hope of me ever rising before noon on Sundays. Sorry Mom. You see, humour isn’t necessarily appreciated in all church settings (recall that Mennonites don’t drink or dance), and I happen to find Our Saviour’s name humorous. Yes, blame it on Homer. Some of you may recall the episode where he is sent away by the Good Reverend Lovejoy to do missionary work (which he botches horribly I might add). As he flies away on a plane (to avoid the wrath of the fabulous PBS tag team of Big Bird and the Teletubbies) Homer repeatedly shouts out, “Save me Jebus!” Apparently he really was dreaming of dancing bears during the sermons. Anyways, enough about cartoons, religion, and my lame excuse for not going to church – let’s get back to the story. Like any other newspaper, The Onion has headlines, feature articles, editorials, and yes, even horoscopes for those who require extra assistance. When I was asked to write a piece on climate change, I immediately thought, “Ha!” (not “Eureka!” as will be explained later). I’m sure you will be very surprised to hear that a headline from the May 30, 2002 Onion issue popped into my head. Atop of a photograph of a large floating sheet of ice was the headline, “Ross Ice Shelf Embarks on World Tour.” The first time I read this I was confounded (‘real confused like’ for those Republicans). Rising global temperatures, melting glaciers, inanimate objects giving concerts…I didn’t quite know how to feel. Should I be depressed or doubled-over?

Before deciding on an answer, I thought a little research might be in order. First off, I needed to determine what an ice shelf was. A little Google action quickly took care of that problem. According to our good friends at Wikipedia, an ice shelf is a “thick floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto an ocean’s surface.” The key message I took from this definition was that an ice shelf is a floater; even before parts of it begin to circumnavigate the globe. With this in mind, a number of seemingly legitimate questions came to mind. Why are ice shelves breaking up? What are the consequences of melting ice shelves? Who will open for U2 if the Ross Ice Shelf melts? In response to the first of these queries, you will be relieved to know that ice shelves are continually undergoing calving, a process that causes them to release icebergs into the ocean [1]. Calving allows an ice shelf to achieve a sort of mass equilibrium that is necessitated by continual snow build-up and subsequent ice formation. I think we can be fairly certain that the headline in The Onion is referring to the fact that rising global temperatures are speeding up calving, and that the overall mass of the Ross Ice Shelf is slowing being degraded as a result. Thankfully, only a small fraction of the Ross Ice Shelf is on tour for the time being.

One of the major fears of the seers of drastic climate change is that melting glaciers will cause ocean levels to rise dramatically; up to 69 meters by some accounts [Houghton et al., 2001]. To tackle the second question posed in the previous paragraph, what we really need to do is determine the effect, if any, of a melting ice shelf on sea level. For a thorough analysis of this situation, let’s do the logical thing and go back to ancient Greece.

In 275 BC, a military leader seized control of the independent city-state of Syracuse; no doubt inspiring future US foreign policy in Latin America. To commemorate his proclamation as king ten years later, Hiero II paid a prominent Syracusan craftsman to fashion an ornate crown out of a quantity of gold. Sometime after receiving the finished product, Hiero became suspicious of the craftsman’s integrity. Fearing that he may have been tricked, Hiero asked a scholarly relative by the name of Archimedes to determine if the crown was indeed constructed entirely of gold. In his account some two hundred years later, the Roman architect (part-time historian?) Vitruvius noted that Archimedes figured out the problem while bathing himself in a tub one day. He observed that a greater volume of bath water was displaced when he submerged a larger fraction of his body. By this same logic, Archimedes reasoned that if identical masses of silver and gold were submerged in water, the silver would displace more water because it has a larger volume (i.e. lower density). By comparing the amount of water displaced by the crown and by an equivalent mass of gold, the king would be able to determine if the craftsman had replaced some of the gold with a cheaper metal! Vitruvius goes on to state that Archimedes jumped out of the tub excitedly shouting “Eureka!” and ran home naked. No word on whether he was arrested for public exposure.

So why have I included a Greek history lesson in an article that claims to deal with climate change? Well, Archimedes is the father of hydrostatics: an “interesting” scientific field that discusses floating objects, submerged objects, and buoyant forces. As hydrostatics can be used to explain the effects of melting icebergs on sea levels, it is rather relevant to our discussion of climate change. To start off with, let’s state the obvious: frozen water floats in liquid water. If you don’t believe me, refer to my all-time most hated movie: Titanic. The problem with icebergs is that unless you are a sea-dwelling creature or a submarine, you can’t really see a whole lot of them. As has been repeatedly rediscovered over the years by lousy nautical pilots, floating ice is almost entirely submerged (89.5% to be exact).

Like any floating object, ice displaces a quantity of the liquid it is immersed in. To verify this idea of ‘displacement’ please perform the following experiment: put your Speedos on, place a dry towel by the edge of a full pool, and cannonball away! If everything goes according to plan you will have a damp towel, indicating that you ‘displaced’ water from the pool onto the pool deck. The question of the day is: How much? From earlier discussion we know that a fully submerged object will cause an equal volume of water to be displaced. This is a seemingly trivial result. Where the object is located, the water cannot be. Thus, 500 cubic centimeters of sunken pirate treasure (or a Syracusan crown for that matter) will displace exactly 500 cubic centimeters of water. The same is not true for floating objects as they displace a weight of fluid equal to their own weight. To fully understand this statement, let’s start with a few basics. Pretend you’ve just stepped onto a bathroom scale and the scale spits back some politically correct number in politically correct units (kilograms NOT pounds). One might be tempted to say, “Keep me away from that chocolate cake. I weigh too much.” In reality, you do not ‘weigh’ 60 kilograms. You have a MASS of 60 kilograms. If you know any physics nerds, engineers will do, please mention this conundrum to them and they will be more than happy to explain (if you happen to meet one at a party, it can also be a good way to avoid any potential Star Trek conversation). As I happen to have studied some physics, I will briefly discuss weight and hydrostatics – and yes, I promise not to write it in Klingon. However, if you find yourself reading this next passage and saying, “Turn down the suck,” please appreciate that while science can be very entertaining, Fubar (which you’ve probably seen far too many times by the way) has set the bar pretty high. Anyways, here we go…

Weight is a measurement of force. The strength of Earth’s gravitational field is approximately 9.8m/s² at sea level. This means that a television thrown out of a 9th floor Gage tower window on the day of Arts County Fair will accelerate towards innocent bystanders in such a fashion that it’s vertical velocity increases by 9.8m/s during each second it is in flight (ignoring air resistance of course). I’m thinking that a direct hit from a large meteor might be a slightly more dignified way to go…although neither a TV nor a chunk of alien-encrusted space rock is likely to result in the awarding of a prestigious (and posthumous) Darwin award. Anyways, with our newfound understanding of gravity we are now in a position to quantify weight. By referring back to our 60 kg person we can determine that they exert a gravitational force of 588 Newtons (60 kg x 9.8 m/s²) on the ground. Another way of stating this same information is to say that the person has a weight of 588 N. Thus, if this person were of a floatable body composition, they would displace exactly 588 N of water if lying in a pool (face up is always preferable). Believe it or not, this seemingly trivial piece of information will allow us to determine the effect on sea level if an iceberg or ice shelf melts.

Let’s pretend we have a large tub of water, into which we drop a block of ice weighing 30 N. For simplicity, we will assume that the ice and the water are of the same elemental composition (pure H₂O with no chlorine, metal ions or other troublesome contaminants). For all of you budding thermodynamicists out there, understand that the ice will be liquefied as it has been placed into contact with heat reservoirs (i.e. air and water). Logic tells us that thermal energy will flow from the heat reservoirs to the ice, increasing both the temperature of the ice and the entropy of the universe in the process! Upon melting, the 30 N block of ice will become 30 N of water. As this water has the same volume as the water that was originally displaced, the level of the water in the tub will not change after the ice melts! In reality, the situation for ice shelves is slightly more complicated. Coleridge’s The Rime of the Ancient Mariner provides us with some valuable insight as to the composition of seawater: “Water, water, every where/ Nor any drop to drink.” As you are well aware and have no doubt guessed, the glittery-eyed Mariner is alluding to the fact that seawater contains salt, which makes it bad for drinking but good for curing Albatross. The Ross Ice Shelf, on the other hand, is comprised of pure water with little to no salt content (ice crystals like to arrange themselves in regular formations – any salt crystals present are gradually pushed out). So unlike the example previously discussed, ice shelves and the water in which they float have different compositions. This will require us to perform some additional analysis to determine if a change in sea level occurs when the floating ice melts.

If a 30 N block of ice floats in a tub of seawater, 30 N of seawater will be displaced. When the block melts, 30 N of freshwater (just over 3 litres) will be mixed in with the seawater, displacing an equivalent volume. The freshwater is essentially ‘replacing’ the seawater that was displaced by the ice. To determine whether or not the water level in the tub will rise or fall, all we need to do is compare the volume of 30 N of seawater with the volume of 30 N of freshwater (note that any weight of 30 N at the Earth’s surface corresponds to a mass of 3.06 kg). If the seawater has a larger volume, the water level in the tub will drop after the ice melts; the converse statement is also true. As seawater is denser than freshwater due to its salt content, 3.06 kg of seawater will occupy a smaller volume than 3.06 kg of freshwater. Thus, the water level in the tub will rise when the block of ice melts because the smaller volume of seawater is ‘replaced’ by a larger volume of freshwater! If we assume that the tub used in this example has a surface area of one square meter, the actual increase in the water level will only be a fraction of a millimeter. This leads us to the rather mundane conclusion that a floating block of ice such as an ice shelf or an iceberg won’t exactly cause a flood of Biblical proportion when it melts.

Let’s recap…I told you that there is enough water stored in all of the glaciers on Earth to raise the sea level by up to 69 meters if they were to melt. We then went on to prove that of this 69 meters, the maximum contribution of floating ice shelves and icebergs would be a few millimeters. With this in mind, a logical question might be, “Then what is causing the estimated sea level rise to be so large?” The answer is quite simple: land ice. Antarctica and Greenland are covered in massive ice sheets. If these glaciers were to melt, all of the runoff would directly increase the volume of water held in the world’s oceans, accounting for over 99% of the predicted increase [Houghton et al., 2001]. As the volume of ice held in mountainous glaciers and ice caps is so much smaller than that held in the ice sheets, the predicted rise due to their melting would account for the remainder (about 0.5 meters) [Houghton et al., 2001].

So what is the take-home message?

Even if all of the icebergs and ice shelves in the world were to melt, the direct impact on sea level would be an increase of a few millimeters at most. There are even some who believe that we would see a drop in sea level if this were to occur. Water is densest at 4oC and by liberating molecules of water from ice through the melting of floating glaciers, the total population of molecules at this temperature is bound to increase, leading to denser, more compact oceans. This might even be true, but by arguing about whether the sea will rise or fall by 5 or 6 millimeters, we are really missing the point. The fact of the matter is that while the slow destruction of the Ross Ice Shelf isn’t going to kill us, it is ultimately a sign of things to come. I ended up laughing at the ‘World Tour’ headline, but I probably shouldn’t have; climate change is happening around us and there is really nothing all that humorous about it. Today we are dealing with melting icebergs and ice shelves that aren’t causing significant changes in global ocean levels. But what about tomorrow? If we don’t act now to develop a more sustainable approach to life, the land-bound ice sheets in Greenland and Antarctica will eventually melt due to rising global temperatures and the consequences will be severe; nations will be flooded, disease will be spread, and countless lives will be claimed. At this time, we cannot afford to apathetically hide in the shadows like T.S. Eliot’s Hollow Men. We need action, and all of the global community would be wise to ratify and implement the Kyoto protocol immediately. Maybe it doesn’t contain all of the answers, and maybe it doesn’t go far enough, but it is a start that we can build on. Oh, and by the way, I still haven’t heard from Bono; it appears as though he is rather annoyed with Canadians at the moment.

References:

1. http://en.wikipedia.org/wiki/Ice_shelf

2. Houghton, J.T. et al. Intergovernmental Panel on Climate Change Report. Climate Change 2001: The Scientific Basis. Cambridge University Press, 2001.

3. The story of Archimedes and the Golden Crown can be found at this website

(artwork by Arthur Kwan)

* * *

(REPRINTED FROM ISSUE TWO, JULY 25th, 2005)

Last weekend, Candace, Will and I visited my mother. And, while I was there, I realized I was very tired. Granted, I had not slept well the night before, but it suddenly occurred to me that I am often tired when I visit my mother. Then, on the way home, it also occurred to me that I often feel tired when Candace and I visit her father or mother. I brought this up to Candace. I asked her if she thought I had some kind of problem. “Have I developed a mental association with our parents…some self-imposed Pavlovian condition…is it my way of checking out around them?” Candace, defending me from myself, offered another perspective – “maybe you just relax when you visit our parents. You know, kind of like going back to your childhood home. You don’t have any obligations or chores like at home. You chill.”

Good, I thought. Then I realized that our eight month old son often seems tired. He certainly sleeps a lot – three solid naps a day and he snoozes through most of the night. He can barely keep his eyes open after two hours around us. Then I thought about all of the other parents that I know. And, you know what? Their babies sleep a lot, too. And when we get together with these parents all we talk about is how tired we are.

I am beginning to suspect that its not babies that make parents exhausted…its themselves. It is us.

If my supposition is true, parents are a sedative, even to themselves. We (or at least I) get sleepy around our parents, our children get sleepy around us, and we get sleepy around other parents. In fact, for the last eight months all I’ve talked about is how tired or not tired I am (usually the former). My daily condition is based on this. But, I’ve been eyeballing the wrong culprit. It is not Will. It is myself.

I wonder if babies were left to their own devices if they would stay up all day like a “normal” human being. Maybe that’s the way it should be. We let the babies hang-out and play with each other all day, while we parents hang-out with ourselves and breath in the sweet sedative that is us. Then we could all curl up on the floor, like in kindergarten (maybe they used to keep a stash of parents in the closet so we’d get tired at “nap-time”). It certainly would be nice to give into the red-eyed junky-demon that is exhaustion sometimes.

The more I think about it, the more this makes some kind of wicked sense. All of my older friends who suffer from insomnia either don’t have children or their children have grown up and moved on. Perhaps the sedative-effect only occurs while you are actually parenting.

You know, I could rent out parents to insomniacs. I could set up sleep clinics where those who suffer from sleep disorders are administered three or four parents a night until they can return to restful nights or sleep. Or I could even create a Parent Channel that features a line of parents jumping over a fence like sheep to help those who need a little assistance to drift off. Yeah, that’s it.

Besides, who likes warm milk anyway.

* * *

(REPRINTED FROM ISSUE ONE, APRIL 25th, 2005)

1. Claim CA005: Evolution promotes racism.

2. Claim CA010: Homosexuality is considered acceptable and even desirable by most evolutionists, who point out that homosexuality is common in many species.

3. Claim CA041: Students should be taught all sides of a controversial issue. Evolution should not be taught without teaching the controversy that surrounds it.

4. Claim CB301: The eye is too complex to have evolved.

5. Claim CE010: NASA scientists, using computers to track planetary motions, discovered that a day of time was missing, corresponding to biblical accounts of the sun’s standing still for Joshua for almost a day, plus the sun moving backwards forty minutes for Hezekiah.

6. Claim CF001: The second law of thermodynamics says that everything tends toward disorder, making evolutionary development impossible.

7. Claim CG001: Darwin renounced evolution on his deathbed.

8. Claim CH100: God’s word, the Bible, must be our ultimate authority. The Bible says it, I believe it, and that settles it.

9. Claim CI001: Intelligent design theory is science.

10. Claim CI001.1: Intelligent design (ID) is scientific, not religious.

1. Claim CA005: Evolution promotes racism.

2. Claim CA010: Homosexuality is considered acceptable and even desirable by most evolutionists, who point out that homosexuality is common in many species.

3. Claim CA041: Students should be taught all sides of a controversial issue. Evolution should not be taught without teaching the controversy that surrounds it.

4. Claim CB301: The eye is too complex to have evolved.

5. Claim CE010: NASA scientists, using computers to track planetary motions, discovered that a day of time was missing, corresponding to biblical accounts of the sun’s standing still for Joshua for almost a day, plus the sun moving backwards forty minutes for Hezekiah.

6. Claim CF001: The second law of thermodynamics says that everything tends toward disorder, making evolutionary development impossible.

7. Claim CG001: Darwin renounced evolution on his deathbed.

8. Claim CH100: God’s word, the Bible, must be our ultimate authority. The Bible says it, I believe it, and that settles it.

9. Claim CI001: Intelligent design theory is science.

10. Claim CI001.1: Intelligent design (ID) is scientific, not religious.

The Structure of Romantic and Sexual Relations at “Jefferson High School.” Each circle represents a student and lines connecting students represent romantic relations occuring within the 6 months preceding the interview. Numbers under the figure count the number of times that pattern was observed (i.e. we found 63 pairs unconnected to anyone else)

REFERENCE:
Chains of Affection: The Structure of Adolescent Romantic and Sexual Networks. (2004) Peter S. Bearman , James Moody, and Katherine Stovel , American Journal of Sociology 110: 44–91

ABSTRACT:
This article describes the structure of the adolescent romantic and sexual network in a population of over 800 adolescents residing in a midsized town in the midwestern United States. Precise images and measures of network structure are derived from reports of relationships that occurred over a period of 18 months between 1993 and 1995. The study offers a comparison of the structural characteristics of the observed network to simulate networks conditioned on the distribution of ties; the observed structure reveals networks characterized by longer contact chains and fewer cycles than expected. This article identifies the micromechanisms that generate networks with structural features similar to the observed network. Implications for disease transmission dynamics and social policy are explored.

The Structure of Romantic and Sexual Relations at “Jefferson High School.” Each circle represents a student and lines connecting students represent romantic relations occuring within the 6 months preceding the interview. Numbers under the figure count the number of times that pattern was observed (i.e. we found 63 pairs unconnected to anyone else)

REFERENCE:
Chains of Affection: The Structure of Adolescent Romantic and Sexual Networks. (2004) Peter S. Bearman , James Moody, and Katherine Stovel , American Journal of Sociology 110: 44–91

ABSTRACT:
This article describes the structure of the adolescent romantic and sexual network in a population of over 800 adolescents residing in a midsized town in the midwestern United States. Precise images and measures of network structure are derived from reports of relationships that occurred over a period of 18 months between 1993 and 1995. The study offers a comparison of the structural characteristics of the observed network to simulate networks conditioned on the distribution of ties; the observed structure reveals networks characterized by longer contact chains and fewer cycles than expected. This article identifies the micromechanisms that generate networks with structural features similar to the observed network. Implications for disease transmission dynamics and social policy are explored.