April's Questions and Answers

How to calculate carbon footprint?

It would be very complicated to offer a manual calculator due to the huge variations in regional areas, carbon emissions from varying types of cars and each source saying varying amounts sometimes with a huge range.

If you still wish to go with the manual calculation here are some of the multiple factors for the calculator from sources I have looked at in the past.

Electricity - 0.43kg of Co2 / kWh (Defra 2005), if from renewables, then 0.00kg/kWh

Natural Gas - 0.19kg of Co2 / kWh

LPG - 1.49kg of Co2 / litre

Oil - 2.69kg of Co2 / litre

Coal - 2.55kg of Co2 / litre

Car Milage - You can find Co2 data for all car types at
VCA Car Fuel Data it might be best to offer 3 to 5 different types of car in varying engine ranges.

Bus - 0.073kg / mile (Department of Transport, Canada)
Train - 0.027kg / mile (Virgin Trains)
Underground - 0.070kg / mile (kingston.ac.uk)

Flights - This is not hugely accurate however you can break this down to; Short-haul (within US) 600kg of Co2, Medium-haul (transatlantic / east coast to west coast) 1300kg of Co2 or Long-haul (world wide) 3700 kg of Co2. If you want to work this on miles rather than types a factor of 0.15kg of Co2/km (Defra 2005)


You should also include a secondary carbon footprint as follows (these are UK figures);

Food and Drink - 585kg
Clothes and Shoes - 486kg
Car Manufacture - 715kg
Buildings, Furniture and Appliances - 982kg
Recreation and Services - 1,546kg
Finance and other services - 361kg
Share of Public Services - 1,276kg

Total Secondary Footprint - 5,950kg

What is the amount of water Singapore consumes in a year currently?

Using figures from the Ministy of the Environment and Water Resources, the daily requirement of water in Singapore is 1.36 billion litres per day, of which 0.72 billion litres are for domestic use. Over a year this equates to 496 billion litres total use and overall domestic use of 263 billion litres.

50% of this consumption is supplied by rainfall, with the remainder originating from imports from neighbouring Malaysia. Two contracts for water importation from Malaysia are due to end in 2011 and 2061, the two countries are engaged in a price dispute over the charges which has lead the government to implement measures to become self-sufficient in its water supply. These include conservation, building additional reservoirs and the worlds largest desalination plant.

What are some ways to make my house more eco friendly and save money?

A few ways you can save money around the home are;

Installing CFLs in your home can reduce your annual electricity bill by 14% and last 6 to 8 times longer than incandescent bulbs. They are now widely available in many styles and designs for as low as $1.50 a bulb.

Insulation, you could consider installing cavity wall insulation or roof insulation. 25 - 40% of heat is lost through the walls and 25% through the roof. Installing both will signifigantly reduce your annual heating bills and you should beable to recoup the cost within 2 to 3 years. This will save about 2-3 tonnes of Co2 per year. The cost is about $750, but grants are available.

Purchase local produce and use tap water not bottled, not only does this support the local economy it also reduces the carbon emissions from food transport, which accounts for about 19% of all emissions.

The average household wastes $76 in stand-by a year, turn your appliances off when not in use.

Reduce your heating thermostat by 1 degree can reduce your heating bills by 10% per year. Reduce your hot water tank thermostat to 50 degrees, each 5.5 degree reduces you hot water heating cost by 13%. Put a thick insulation jacket on your hot water tank (about $20), this prevents heat loss from your tank and can save about $20 a year in hot water costs.

Also check out these free energy saving tips.

Considering the mercury content of fluorescent bulbs will the disposal of these bulbs cause a bigger environmental problem than the energy consumption posed by the more common bulbs used now?

Whilst the amount of mercury used in production a CFL bulb is at most 6mg, the average mercury content is 4mg. The total emissions of mercury created by a CFL bulb from electricity consumption over its lifetime is about 2.4mg of mercury. In comparison the emissions from an incandescent light bulb is about 10mg. Therefore overall CFLs result in a slightly less amount of mercury emitted over the lifetime of a CFL bulb. The real gain is the reduction of 38kg of Co2 per CFL per year and an overall saving of 14% on your electricity bill.

To ensure the safe disposal of CFL bulbs you should return them to the retailer or to an appropriate recycling facility. Once collected the bulbs are crushed in a machine that uses negative pressure ventilation and a mercury absorbing filter allowing the mercury to be reclaimed.

In countries where recycling facilities do not exist, you should contact the manufacture who should have details of how you can safely dispose of the CFLs.


Note: It is assumed the emissions from electricity consumption is from standard electricity supply. Should renewables be used then the emissions of mercury would be 0mg (not including the production of the renewable source), however for the use of incandescent bulbs to be effective we would need to be using a high proportion of renewable energy.

PS ... you can now get CFLs with ultra-low mercury levels.

Regarding the total road humps in the UK (a) how much have they cost (b) how many tonnes CO2 have they caused?

Road / Speed humps are extremely popular the world over as an effective traffic calming measure. However there are many negatives to them;

In 2003, the chairman of the London Ambulance Service, Sigurd Reinton was reported as claiming that delay due to speed bumps was responsible for up to 500 avoidable deaths from cardiac arrest each year, however, he later denied the statement.

Research in the USA from Boulder, Colorado suggests that for every life saved by traffic calming, as many as 85 people may die because emergency vehicles are delayed.

Each speed hump slows the average fire engine by 3-4 seconds and an ambulance by 10 seconds.

The Association of British Drivers is critical of speed humps claiming Drivers are distracted by the bumps, therefore ignoring other hazards such as children.

(a) On average a road / speed hump cost from £500 to £4 850, the upper range being for the latest "smart hump" which reduce or eliminate negative effects of speed bumps such as increased noise and pollution, uneven traffic speed, and impeding emergency vehicles. Traffic tables can cost upto £10 000.

I have been unable to find a figure for the total number of speed humps, however statistics from Edinburgh Council Meeting Questions & Answers state there are 794 in Edinburgh, which has a population of 448 624, or about 1.77 per 1 000 residents. This is a lower figure as it does not include private developments. Taking the Edinburgh figure and muliplying it by the UK population of 60 609 153 this would equate to 107 269 speed humps in the UK (however this is a very unstatistical analysis of the total).

(b) Speed humps cause atmospheric pollution from the speeding up and slowing down of traffic between the humps. For example, TRL reports a 59% increase in CO, about 50% increase in HC and about 25% in CO2 from petrol catalyst vehicles averaged over all types of traffic calming measures, with even higher numbers over more "severe" measures such as speed bumps. In addition the use of bumps and cushions seems to encourage the use of larger vehicles which are more polluting.

Why should I recycle, when the government can always build a new landfill? Recycling just takes too long?

The main reason you should recycle is that it does actually save alot of energy. That in turn actually saves you money. If packaging companies have to continually use new raw materials that will mean that the price they pay for packaging will be higher than purchasing recycled material.

For example by recycling aluminium cans, it takes only 4% of the energy to recycle them than to produce them from raw materials. Saving 64,300 kWhs per tonne. Taking the US average kWh price across all states at 8.14c per kWh, this equates to a saving of $5234 per tonne of aluminium in energy costs and emissions of about 29 tonnes of Co2.

Any additional landfills that are provided by the government will increase your taxes through land purchase, construction and legal & consultancy fees.

So as you can see recycling is financially beneficial as well as environmentally friendly.



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