La lune

Manicore

Documentation > Greenhouse effect > Greenhouse gases and us > How much greenhouse gases in our wastebin?

How much greenhouse gases in our wastebin ?

september 2003

website of the author : www.manicore.com - contact the author : jean-marc@manicore.com

 

We europeans throw away a little more domestic waste every day (and this "a little more", after a while, quickly turns into "a lot more" : in France we have increased domestic waste by 33% in 10 years only, which is considerable !) :

Evolution of the domestic waste in a selection of european countries
Country

Domestic waste (thousand tonnes)

Domestic waste per inhabitant (kg)

1980

1990

1980

1990
France

15.570

20.320

290

360

Germany

21.417

21.172

348

333

United Kingdom

15.500

20.000

312

348

Italy

14.040

20.033

252

348

Spain

10.100

18.540

270

322

Data from rapport Miquel du Sénat on the recycling of domestic waste

 

This domestic waste certainly includes potato scraps, but also a lot of manufactured products :

Breakdown of french domestic waste by nature

Type of waste

% of total

kg/hab/year
Fermentescible (organic waste)

28,8%

125

Paper

16,2%

70

Cardboard

9,1%

39

Plastics

11,1%

48

Glass

13,1%

57

Metals

4,1%

18

Various non combustible

6,8%

30

Misc. combustible

3,2%

14

Textiles

2,6%

11

Sanitary textiles

3,1%

13

Complex (packagings made of several materials)

1,4%

6

Special waste

0,5%

2

TOTAL (1997 or 1998)

100%

434

From : ADEME, Déchets municipaux, les chiffres clefs - février 1998

It is easy to see that organic waste is a little minority of everything we throw away !

Well the production and the processing of all these materials that we will eventually throw away has required energy and led to greenhouse gases emissions . For example, to obtain a steel product from iron ore, it is necessary to perform all the following acts, each of them inducing greenhouse gases emissions :

extract the ore,

transport it,

reduce it with coal (this operation, conducted in a blast furnace, generates the largest part of the emissions),

purify the cast iron (with oxygen for example),

laminate or draw the steel,

transport the steel to the factory where it will be transformed (in cans or car doors),

transform it,

and at last transport the manufactured product to the store.

Emissions - more or less well identified - can be associated to each stage. The main methodological problem arises when a same operation yields several products or services at the same time. For example, if a boat transports at the same time washing machines and bath towels, we must decide of a rule to allocate the emissions of the boat to the various goods transported (depending on their volume ? their weight ?) and it is not always obvious.

This being said, here are some rough figures for the emissions (all greenhouse gases) linked to the production of a tonne of various basic materials :

Matériau

kg carbon equivalent per tonne produced (european value)
Steel from iron ore

850

Steel from steel scraps

300

Aluminium from bauxite

3.000

Aluminium from aluminium scraps

600

Flat glass

400

Bottle glass

120

Basic plastics (polyethylene, polystyrene, PVC, PET)

500 to 1,600

Paper - cardboard

500

Cement

250

Data from Jancovici/ADEME, 2003

Hence, when we buy a kg of packaging steel, made from iron ore, that will end in the bin, we will be responsible, at best, of 300 grammes carbon equivalent of greenhouse gases emissions if this steel is recycled (we therefore can see that recycling does mean zero impact), and, at worst, of 850 grammes grammes carbon equivalent, if this steel came from ore and is not recycled.

But waste can generate other emissions :

fermentescible waste (that is organic waste, paper and cardbord for the most part), when dumped in a yard, lead to emissions of methane while decaying, and methane is a greenhouse gas.

combustible waste (that is plastic, paper, cardboard) lead to CO2 emissions when burnt ; and for plastic, made out of oil, this CO2 is "fossil".

Still it is possible to save "something" through various valorization processes :

it is possible to recycle some materials (most metals, paper, some plastics...), but this recycling nevertheless requires various processes that consume energy and emit greenhouse gases (for paper and cardboard, the overall balance for greenhouse gases is about the same when starting from old paper than when starting from wood !),

it is possible to valorize the combustion heat to produce electricity of urban heating,

it is possible to collect the methane from decaying organic waste to convert it into heat then electricity.

Nevertheless a valorization, just as in the case of steel recycling, never makes throwing away a neutral act : it is by far preferable not to throw, hence to buy products with the least packaging possible.

If we take into account the proportions of the various waste management methods (dumpyard, incineration, with or without valorization), and if we take mean values for the emissions associated to the manufacturing of the materials thrown away, here is the amount of greenhouse gases that we will find in the wastebien of an average French person :

Type of waste

kg/hab/year

kg carbon equivalent per kg thrown (*)

kg carbon equivalent
Déchets putrescibles

125

0,17

21

Papier - carton

110

0,58

64

Plastiques

48

0,9

43

Verre

57

0,28

16

Métaux

18

0,6

11

Autres

76

0,5

38

TOTAL

434

-

193

(*) this value includes production emissions and end of life emissions (linked to fermentation or incineration).

Hence our wastebin "contains" 200 kg carbon equivalent per person and per year, that is a little 10% of the average emissions for a French person. Significantly decreasing the quantity of waste that we generate - and as a consequence the amount of packaging that we buy - represents an action possibility which, even though not sufficient, is not totally ridiculous in the total.

 

Back to climate change index
Back to the top