Urban Metabolism
It was reported that the concept of ‘urban metabolism’ has existed for decades and views large cities as living entities that consume energy, food, water, and other raw materials, and release wastes. These releases include carbon dioxide, the main greenhouse gas; air pollutants, sewage and other water pollutants; and even excess heat that collects in vast expanses of concrete pavement and stone buildings. Humans directly produce a significant share of this waste, but emissions from industrial, power generation and transportation systems emit the largest quantities of greenhouse gases and other air pollutants. Other urban metabolisers include sewage systems, landfills, domestic pets and pests like rats, which in some cities outnumber people.
During the last five years, this body of knowledge has drawn into sharper focus the hazards of poor air quality in mega cities, not just on the large local populations but also on population centres, agricultural activities and natural ecosystems located downwind from these sprawling areas. Researchers now acknowledge that carbon dioxide and other pollutants in mega cities make them immense drivers of climate change. They impact climate on both a regional and global level because these long-lived greenhouse gases are dispersed around the world.” More than half the world’s population today lives in cities, and the world’s largest urban areas are growing rapidly. The number of mega cities — metropolitan areas with populations exceeding 10 million — has grown from just three in 1975 to about 20 today.

The Culprits
The most highly polluted mega cities are in developing countries. They include Dhaka, Bangladesh; Cairo, Egypt; and Karachi, Pakistan. Some mega cities in less developed regions have recently mounted air quality management campaigns that have resulted in lower levels of pollution; they include Mexico City, Mexico; Beijing, China; Sao Paulo, Brazil; and Buenos Aires, Argentina. Even the cleanest mega cities like Tokyo/Osaka in Japan and New York City and Los Angeles in the United States — all in the developed world — still have serious problems.
The hot weather and frequent atmospheric inversions in southern California, for instance, foster Los Angeles’ legendary smog problem. Mexico City’s high altitude/low latitude location produces high levels of solar ultraviolet radiation that drive photochemical smog production, and the even higher surrounding mountains trap the resulting pollutants in and over the city on most days.
That causes a very serious situation for residents of Mexico City. There are very unhealthy levels of ozone and fine particle pollutants that produce large numbers of premature deaths each year. Studies show that for each increase of 10 micrograms per cubic metre of these particles, you get roughly a 10 percent increase in premature deaths, producing a decrease in average life expectancy of about 0.8 years. Hospital visits, including bronchitis and asthma cases, also rise.

Controlling urban growth key to improving global air quality
Scientists believe that controlling urban growth in the developing world is key to improving the world’s air quality. Urban pollutant levels in poor countries will remain high, with increased emissions expected as the city populations and economic activities increase. Until mega cities are rich enough to devote significant funds to reduce their emissions, two factors will invariably increase the stresses on their environment — increasing vehicular traffic and industrial growth.

California and Mexico reversing the trend
An example of attempts at reversing this trend can be seen in Southern California, which has taken successful action to modify its urban metabolism, pioneering efforts to reduce motor vehicle emissions. Mexico City — unlike most mega cities in less-developed countries — has also taken successful steps to partially address poor air quality. In the past two decades, the Mexican Government has introduced policies to improve air quality, including requiring pollution control devices like catalytic converters on newer vehicles, reducing sulphur levels in petrol and diesel fuel and relocating some large industrial emitters outside the Valley of Mexico. However, in other parts of the world for example the Mega cities in Asia and Africa urgently need to modify their urban metabolism in similar ways with a few fundamental changes such as getting rid of lead in their gasoline. In the developed world, we can institute emissions controls on diesel vehicles, which create hazardous fine particles, and we can also reduce pollution by using more rail-based mass transport or setting up specialized bus routes.”
The urban metabolism model can reveal how developed-world mega cities, such as Tokyo, New York and Los Angeles, have improved their air quality despite a rise in population. The study also assesses how developing-world mega cities are seriously grappling with the problem.

Adapted from materials provided by American Chemical Society.
American Chemical Society (2009, August 18). How Cities Mimic Life:
Mega cities Breathe, Consume Energy, Excrete Wastes And Pollute.

This unprecedented study has been conducted into how much food is wasted by UK households, but I very much doubt that any other developed country wherever it is in the world is any different. The results are staggering. This article should appall everyone who reads it and perhaps we should all reflect on the fact that while we are arguing about how we can feed the starving millions, we should look to ourselves for the answer.

Here are just a few of the results taken from the study in the UK:

• Between us we throw away around 6.7 million tonnes of food every year.
• For every three bags of groceries that we take home from the supermarket, we throw one in the bin before opening it.
• People in the UK pay for, but do not eat, £10 billion of food every year. Pounds Sterling – not dollars!
• That’s an average of £420 per household.
• For families with children it’s more – an average of £610 a year.
• It costs another £1 billion annually for local authorities to collect and send most of it to landfill.

Can you imagine the cost of all this to the consumer, the local authorities and the wider economy? Can you imagine what £10 billion looks like or what we could do with it? And that is just in one country. As I mentioned above, I have no reason to believe that it is any different in the other developed nations.

The figures are truly horrifying and when you think that 70,000 children die of starvation each year throughout the world it really puts the whole thing into perspective.

More Examples from the study:
Every day in the UK, for example, we throw away:

• 7 million slices of bread (worth £140 million a year);
• 5.1 million whole potatoes (worth £140 million a year); and 4.4 million whole apples (worth £300 million a year).

Other staple items that don’t quite make the top 10 include:

• 660,000 whole eggs (worth £50 million a year);
• 260,000 unopened packs of cheese (worth £40 million a year); and 1 million slices of ham (worth £30 million a year).

Whole fruit and vegetables are wasted in large quantities. As well as the potatoes and apples that make the top 10, every day in the UK we throw away:

• 2.8 million tomatoes (worth £80 million a year);
• 1.6 million bananas (worth £90 million a year);
• 1.4 million mushrooms (worth £30 million a year);
• 13.2 million grapes (worth £40 million a year); and 1 million plums (worth £70 million a year).

Processed and ‘convenience’ food also gets wasted routinely – every day
in the UK we throw away:

• 1.2 million whole sausages (worth £60 million a year);
• 550,000 rashers of bacon (worth £50 million a year);
• 330,000 unopened processed meat-based meals(worth £60 million a year); and 330,000 chicken portions (worth £70 million a year).

But it’s not only staple foods that are wasted. Surprisingly we also waste treats
and luxury items, for example:

• 82,000 whole dessert cakes and gateaux every day (worth £20 million a year);
• 300,000 unopened packets of crisps (worth £20 million a year);
• 700,000 unopened packets of chocolate and sweets (worth £40 million a year); and 2,900 unopened cans or bottles of lager a day (worth just less than £10 million a year).

And every year, 20,000 tonnes, or £66 million worth, of breakfast cereals are
thrown away – a story that will be familiar to families across the country, who
rush to get to work or school and leave their breakfast unfinished.
Some of the food we throw away is still in date – at least 340,000 tonnes of it –
with long shelf-life products featuring strongly including drinks, condiments,
dried foods and confectionery.

The imperative is clear: our food habits, of which this summary is but a snapshot, are costing us and the environment dear. The energy expended by business and industry to produce, process, transport –often refrigerated – and sell the food we then waste is immense. Coupled with the energy we expend travelling to stores, transporting our purchases back home and then storing and refrigerating them, this is a story of inefficiency and wastefulness of huge proportions.

This information can be put into context if we remember that according to Lester R. Brown writing on the Earth Policy Institute web site (see http://earthpolicy.org/Updates/2008/Update69.htm for the full article), the World Bank reports that for each 1 percent rise in food prices, caloric intake among the poor drops 0.5 percent. Millions of those living on the lower rungs of the global economic ladder, people who are barely hanging on, will lose their grip and begin to fall off.

Projections by Professors C. Ford Runge and Benjamin Senauer of the University of Minnesota four years ago showed the number of hungry and malnourished people decreasing from over 800 million to 625 million by 2025. But in early 2007 their update of these projections, taking into account the biofuel effect on world food prices, showed the number of hungry people climbing to 1.2 billion by 2025. That climb is already under way.

Since the budgets of international food aid agencies are set well in advance, a rise in food prices shrinks food assistance. The U.N. World Food Programme (WFP), which is now supplying emergency food aid to 37 countries, is cutting shipments as prices soar. The WFP reports that 18,000 children are dying each day from hunger and related illnesses.
This above is a short set of highlights from a comprehensive research study more details of which are available on a more comprehensive version of the report which you can download. Please click here to see the report.

Editors note:
WRAP’s 3 primary targets are:

• SENDING LESS TO LANDFILL
WRAP will stop 8 million tonnes of waste materials from the household, industrial and commercial waste streams going to landfill.

• REDUCING CARBON EMISSIONS
WRAP’s programmes will save 5 million tonnes of CO2 equivalent emissions.

• INCREASING ECONOMIC IMPACTS
WRAP will deliver around £1.1 billion of positive economic impacts for business, local authorities and consumers