Environmental Engineering Reference
In-Depth Information
all part of a biogeochemical cycle. People take in carbohydrates and breathe in oxygen.
They convert both substances into carbon dioxide, which they then breathe out again.
Plants in turn bond this carbon dioxide and provide our carbohydrates. Carbohydrates
are organic compounds consisting of carbon, hydrogen and oxygen and are produced in
plants through photosynthesis. For example, grains and noodles comprise 75% carbohy-
drates. It is even possible that the wheat in Italian spaghetti has converted the carbon
dioxide that we breathed out during our last Tuscan holiday into carbohydrates.
When a plant burns, rots or ends up as a carbohydrate supplier, it generates just as much
carbon dioxide as it previously extracted from the air. The natural cycles are therefore
CO
2
-neutral and do not lead to an increase in concentration. However, this does not
apply to the holiday trip to Italy and the transport of Italian spaghetti to other
countries.
Fossil energy use is the main cause of the increase in carbon dioxide concentration.
If we burn fossil energy sources, this is regarded as oxidation from a chemical point
of view. This reaction releases heat. We therefore use the effect of heat that results
when the carbon from oil, natural gas and coal is combined with the oxygen from
the air. The waste product we get in return is carbon dioxide - and we get it in
enormous quantities: currently over 25 billion tons. The average human produces
about 4000 kg per year. A corresponding amount of carbon dioxide would fi ll a cube
with sides 13 m long, or around two million one-litre bottles.
As with energy consumption, the emissions in individual countries can vary a great
deal (Table 2.1). For example, whereas someone from Mozambique would tip the
scales at less than 100 kg, thus one-tenth of a ton of CO
2
, per year, in China it is
almost 4 tons per head. In Germany it is 10 tons, and in the USA just short of 20
tons. If the carbon dioxide generated by Germans each year were dispersed over the
country's entire land area, every German would sink down into more than one metre
of CO
2.
In contrast, the carbon dioxide in Mozambique dispersed over the country
would not even form a layer one millimetre thick.
Table 2.1
The ten countries on earth with the highest energy-related carbon dioxide emissions.
Status: 2006. Data: IEA (International Energy Agency, 2008).
Country
Mil.
t CO
2
Mil.
inhab.
t CO
2
/
inhab.
Country
Mil.
t CO
2
Mil.
inhab.
t CO
2
/
inhab.
1. USA
5697
299
19.00
6. Germany
823
82
10.00
2. China
5606
1312
4.27
7. Canada
539
33
16.52
3. Russia
1587
143
11.14
8. Great Britain
536
61
8.86
4. India
1250
1110
1.13
9. South Korea
476
48
9.86
5. Japan
1213
128
9.49
10. Italy
448
59
7.61
World
28 003
6546
4.28
133. Mozambique
2
20
0.08
