Estimating and reducing our carbon footprints

There has been a substantial rise in greenhouse gas emissions since the pre-industrial era, driven mainly by increased use of fossil fuels as a result of economic and population growth. This has led to atmospheric concentrations of carbon dioxide, methane and nitrous oxide that are unprecedented in the last 800,000 years.

These emissions are very likely to have been the dominant cause of current global warming, which is itself a major cause of more extreme weather events, flooding, a rise in sea levels, and ocean acidification, amongst other changes across the world. Climate change is already making the poorest poorer in developing countries, from the effects of droughts and heat waves. People on low incomes will suffer the brunt of extreme weather events, in the UK as well as elsewhere. See here for a 5-minute film with Bill Nye from the Climate Reality Project explaining the basic science behind climate change.  And see Winchester Action on Climate Change for more information.

We can all reduce emissions of carbon dioxide (CO2) and methane through changes in our lifestyle. These changes will often also save us money. Some of them (e.g. walking short journeys rather than driving, or eating less meat) will improve our health too.

Domestic energy use (heating, lighting, appliances) accounts for roughly a quarter of CO2 emissions. The actual amount varies widely depending on the type of house (from flats to large detached houses) and lifestyle and habits. The average annual CO2 emission for a 3 bed semi-detached house is 4.5 tonnes for the household.

Estimating CO2 emissions from energy consumption

You can convert the consumption of energy given on your fuel bills or annual statements to tonnes of CO2 by multiplying by the following factors:

Type of fuel (unit of measurement) Multiplication factor to calculate CO2e emissions (kilos)
Gas (kWh) 0.18
Electricity (kWh) 0.19
Heating oil (litres) 3.18
Bulk LPG (litres) 1.56
Bulk Propane gas (m3) 5.77
Propane (kg) – red bottle 3.00
Butane (kg) – blue bottle 3.03
Coal (kg) 2.88
Estimating your total carbon footprint – and taking action to reduce it

Many carbon footprint “calculators” are available on the internet. The following table gives an overview of average CO2 emissions and the type of action you could take to lower them, whilst saving money and perhaps improving your health. You could use the table to add your own ideas and targets.

Winchester Action on Climate Change offer a number of “top tips” to follow.

Average carbon emissions per person: UK 11 tonnes, USA 19 tonnes, China 3 tonnes

Source of carbon emissions – and average emissions per person Ideas for reducing emissions
Home energy – 2 tonnes

Average gas 16,000 kwh/year

Average electric 3000 kwh/year

Consider purchasing 100% green electricity

See money-saving tips – using less fuel saves money and reduces carbon emissions

Food – 2 tonnes

Includes eating meat daily

e.g. eating less meat, meat-free days
Land transport – 2 tonnes

1 car, 8000 miles/year

Minimal use of public transport

e.g. walking and cycling short journeys, using train and bus whenever possible
Goods and services – 3 tonnes

Buying all new goods, no second-hand purchases

Frequent shopper/high turnover of goods

e.g. buying fewer goods;  buying second-hand goods
Flying – 2 tonnes

Europe 1 tonne, New York 4, West coast USA 6, India 10, New Zealand 13 tonnes

e.g. holidaying in the UK, travelling by train or coach in Europe