Carbon Copy

urban farm resources

I'm always on the lookout for urban applications of low-impact technologies. City Farmer in Vancouver has a lot of information related to urban agriculture, with a detailed discussion of their compost toilet and information on irrigation using grey water and rain water. Their composting toilet page also has a link to the Biolytix Waste Treatment System that is available in South Africa, New Zealand and Australia. Biolytix uses an aerobic method to break down toilet waste so that the liquids can be used for irrigation, unlike septic tanks where pathogens thrive.

urban climate

It's been known for some time that urban areas create a heat island as the hard surfaces store more solar radiation than the vegetation they replace. Adding to the effect is the heat generated from within buildings, and changes in air circulation. Studies have suggested that the result is significant enough to change the growth cycles of plants in some cities by altering the growing season.

Now scientists studying climate in areas of rapid urbanisation in China are finding changes in rainfall linked to urban sprawl. They speculate that an observed decrease in rainfall may be related to loss of vegetation, and the fast rate at which water runs off city streets, reducing the transfer of water to the atmosphere.

A lot can be done to mitigate urban energy waste, heat buildup and water runoff: from the layout of urban areas and the incorporation of vegetation, to the design of buildings and their heating and cooling systems. Strategies should include not only consideration of the way buildings are designed, built and operated, but also new approaches in disciplines like transport planning, traffic engineering, urban design and wastewater management. Some short-lived guidelines started to address these issues during the oil crisis of the 1970s, but only in recent years have planning guidelines started to incorporate energy considerations again. There are examples in Australia and the US.

I have no doubt that Dongtan Eco-city and its offspring will establish new standards for the planning of low-carbon cities, but until these initiatives become common practice, we'll have to rely on the examples set by individual buildings and small districts within cities. Here's a list (with pictures) of ten tall buildings that incorporate strategies to reduce carbon emissions and other environmental impacts.

second life presentation on drivers of change

If you're a designer, architect, engineer or planner; if you're interested in the things that are driving change in our world; and if you're at all curious about the virtual world of Second Life* - then here's something you may be interested in.

This Thursday, 14 June at 17h00 GMT, Chris Luebkeman will be presenting some of the work being done by his team at Arup on Drivers of Change. The presentation will be live from Autodesk Island in Second Life. Titled "Future Challenges: Global Creative Contexts", the promotional blurb says:

Population shifts, increasing scarcity, and the wanton consumption of arable land and natural (renewable and nonrenewable) resources amount to what could prove to be a significant global dilemma - a dilemma of disastrous proportion. Yet trends in design and an ever-increasing focus on conservation and environmental issues suggest that we are headed for a collective change. This program considers the impact of global drivers of change on sustainable creative contexts, explores potential implications, and provides attendees with examples of design work that is already responding to the challenges.

Let's hope there isn't another flood during the presentation. In April this year, the virtual world was partially flooded to highlight the risks of global warming.

*Never heard of Second Life? It's a 3D world built and imagined entirely by its residents - some 7 million users. Although it's a virtual world, it has a real economy. You can join for free, but real-world transactions worth millions of dollars take place every week based on interactions within Second Life. If you are not already a member, but want to join the presentation on Thursday, go to Autodesk and register.

thinking outside the closet

Millions of people still don't have clean drinking water, yet in modern cities we flush literally gallons of it down the toilet every time we go for a pee. This should be a crime.

There are lots of examples of low water toilets, dual-flush toilets, composting toilets, and waterless urinals. There are even incinerating toilets for those who dare. Here and there, these end-user technologies are adopted voluntarily or with incentive subsidies, but they are not being used in sufficient numbers to offset growth in demand for water. We seem to be stuck in the pilot project stage, meaning "Hey, I wonder if this thing works?". Of course it bloody works. Just do it. We don't have to go completely waterless, but there is no reason for any toilet to use more than six litres a flush.

But we should be beyond that by now, and here's why.

food labels: environmental impact

Food labeling has increased in complexity as the nature of the ingredients has become more difficult to understand, and many people fear that we are losing control over what we are ingesting. When we could no longer pronounce the names of ingredients, we started insisting that all ingredients should be labeled; when we realized that some food can make us fat, we asked for calorie and protein content; when cereals stopped including anything nutritious, we needed to see added vitamins and minerals; when we were told that some fat was good and some was bad, we asked for labelling of transfats; when we found that a lot of our staples were genetically modified, we wanted to know which ones; as we became more aware of allergies, we asked for labeling of known allergens.

These things are all relatively easy to identify and label - although there is plenty of resistance in some quarters - but when it comes to environmental impact, a minefield has opened up as supermarkets start labeling the carbon impact of foods. If the carbon footprint of a grocery item could be definitively quantified as a broad indicator of potential environmental damage (mainly from energy consumed in its production and transportation) then it would help improve consumers' ability to manage their own carbon footprints. Increased awareness should help weed out high-carbon products and encourage consumption of locally produced goods. I'm just not sure how carbon footprints will be standardised in a way that fairly compares different goods from different countries, and is clear enough for the average consumer to understand.

But it gets even more complicated. Carbon is not the only measure of environmental impact. Another hidden impact is the embodied water in foods. Water is exported and imported in the sense that food grown in one country requires water for its growth, so the producing country is selling virtual water to the importing country. One of the big problems with this is that many food producing countries don't have water to spare, and many food importing countries are saving their own water at the expense of others.

Wikipeida goes into more detail on the impacts of embodied water, particularly as related to global trade, noting also that this issue doesn't apply only to food. Those jeans you're wearing represent 10,850 litres of embodied water. Waterwise estimates that of all the water used by the average Briton, 65% is embedded in food, 30% in industrial goods. Out of 3400 litres used by each person every day, only 150 comes from the tap.

I am in favour of finding some way of identifying the impacts of the way food and other goods are produced and transported, but it's going to take some time to figure out how. Embodied water and carbon are the two most all-encompassing measures of environmental impact, but there are others. And what about labour practices and other social impacts? The list goes on.

shout it from the rooftops

There are many good reasons for developing green roofs:

[An] important environmental benefit of green roof systems is their potential to moderate the urban heat island effect... The climactic benefits of green roof systems are not limited to temperature moderation. Urban plantings have also been shown to improve urban air quality, by trapping and absorbing nitrous oxides, volatile organic compounds, and airborne particulate matter.

And another reason, less often mentioned, is the potential for local food production:

The average American meal travels 1500 miles from field to table (Norberg-Hodge et al 2000), using 10 times more energy than the caloric value of the food itself (TFPC 1999). This represents an incredible environmental cost in fossil fuel emissions, pollution associated with extraction, and loss and division of natural habitat by asphalt, to name a few of the more direct costs... Rooftop agriculture is one way in which urban areas could attempt to be more balanced and sustainable in their resource consumption. It is possible to produce a variety of fruit, grain, and vegetable crops on rooftops, either in containers or as field crops (TFPC 1999).

Some roofs growing food across Canada: in Montreal, Toronto, Peterborough, Calgary, and Vancouver.

My previous post on urban farming.

And for all those stormwater managers out there, in 2004 Earth Pledge was commissioned by the New York City Water Board to develop a stormwater simulation model to measure stormwater retention and detention on a specific building or area, specifically to evaluate the impact of green roofs. Micro Model is applied to specific buildings; Macro Model is applied to an area encompassing a network of green roofs. They are now developing Stormwater Model 2.0 based on updated data.

air, water and Roman ingenuity

A friend of mine from Chile told me a year ago about the use of nets for harvesting fog, and underground clay pots for irrigation where water is a very scarce resource. But I wasn't able to find a detailed description of these technologies - until now. UNEP has produced a Source Book of Alternative Technologies for Freshwater Augmentation in Latin America and the Caribbean, providing detailed descriptions of these and other water conservation systems and technologies.

I have been interested in drip irrigation for its higher level of efficiency and reduced waste in comparison with most other types of irrigation, but clay pot irrigation is even better for reduced wastage. It's best for home gardens or rural plots of up to a hectare. Subsistence farmers in the tropical, semi-arid parts of Brazil have are using this system, contributing to steady or even higher agricultural output owing to the highly efficient and economical use of water. A system of this kind was used centuries ago by the Romans, and initial experience in Brazil suggests that different varieties of plants can thrive in a range of soil types on small amounts of water using the clay pot technology. Chapters 4.2 and 5.7 of the UNEP sourcebook describe this system in detail, with illustrations.

The small coastal town of Paposo, Chile has a declining population of 300 residents, and so little water that it is trucked in periodically. Work on fog harvesting and other water systems is underway to try to reduce the town's reliance on external water supplies. Nonprofit groups like Water Aid and Arup Cause [see also page 24 of 2.4MB PDF file] are involved in projects to improve the sustainability of Paposo. FogQuest is involved in various countries - have a look at their pictures of fog harvesting.

SA has some way to go on water conservation

At a two-day National Water Conservation and Demand Management indaba in Midrand last week, international water expert Asit Biswan said despite recent reports that South Africa was losing billions of litres of water annually due to leaks and burst pipes, the country was rated among the top ten in the world on water conservation. Two countries that are doing well are Singapore and Cambodia, and South Africa was encouraged to look to them for ideas.

Hermanus Municipality in the Western Cape is one of South Africa's innovation leaders in water conservation, first addressing residential demand management and then using the country's Working for Water programme to clear alien vegetation that used a lot of groundwater. Despite considerable progress, there have been claims in the past that poor communities are adversely affected by the Hermanus initiative. This raises the important question of how demand management and cost recovery efforts can be applied equitably in a country where poverty is widespread.

what do you drink when there's nothing else?

Recycling greywater by individual households for irrigation and flushing toilets has generally only been adopted by hardcore greens, but the BBC reports that now the Queensland (Australia) government is looking at drinking recycled waste water. Drought is forcing the situation, but this should help increase awareness of the need for water conservation in the long term. According to the BBC News report, water is already recycled in places like Singapore and the UK, but the idea is still unpopular in Australia.

And another BBC report this week says Sydney faces the threat of severe droughts and other climate-related dangers.

water, water everywhere

The Cape Times reported on 1 December:

Between 38% and 53% of Cape Town's water is 'lost' every year somewhere between the supply dams and our taps... [the authorities] don't know where the missing water is going.

Considering current rates of use and government's targetted economic growth of at least 6%, water supply in the Western Cape will soon be a serious challenge. 95% of the rivers that feed into the water management regions of the province are in an ecologically critical condition. There are no more opportunities to build dams, so the only remaining supply options are desalination of seawater and tapping the Table Mountain aquifer (estimated to hold 66 billion cubic metres). Using the aquifer is cheaper than desalination, but recharge rates are unknown, so this may not be a sustainable solution.