Green chemistry part 3 carbon footprints

1 of 9 © Boardworks Ltd 2009


What are carbon footprints?

Carbon footprint is a measure of the impact of a person’s activities on the environment, in terms of

how much CO2 is produced by each activity.

What do you think are the units of carbon footprint?

Country Average carbon footprint

USA

Australia

UK

China

India

20

17

10

3

1

(tonnes of CO2 per person per year)


Carbon footprints


Reducing your carbon footprint


What is carbon neutral?

Carbon neutral describes any activity that produces no overall emissions of CO2.

There are two ways of working towards carbon neutrality:

reducing carbon emissions

carbon offsetting.

Carbon offsetting is the practice of balancing activities that emit CO2 with activities that absorb it; for example,

planting trees that take in CO2 as they grow.

Carbon offsetting is controversial because the act of planting trees in large numbers uses energy and emits CO2 even if the trees themselves absorb it.


What is carbon neutral?

In 2003, the Rolling Stones went on the first carbon neutral tour. They calculated the amount of CO2 that would be produced by transporting the band, by fans travelling to the gigs and by energy use at the venues.

Radiohead toured in the summer of 2008 using only reduction of emissions, not carbon offsetting. Do you think both of these methods are equally good?

To make up for the CO2 produced, they organized the planting of two new forests in Scotland with trees that would absorb the same amount of CO2.


Are biofuels carbon neutral?


Advantages of biofuels


Is hydrogen carbon neutral?

When hydrogen is burned as a fuel, the only product is water.

Do you think hydrogen is a carbon neutral fuel?

The hydrogen fuel is generated by the electrolysis of water.

2H2 + O2 2H2O

Fuel cells that use this method of energy production can be incorporated into engines, as shown on the right.

Technology

Green chemistry part 3 carbon footprints