8.1.0 Information text: Guessing game
CO2 sources – CO2-stores
People are sources of CO2. Whether it’s what we eat or wear, whether we are driving to work or heating our houses – all these things use energy and, in doing so, they release CO2. Each person in Germany produces around 11.5 tonnes of CO2 per year (as of 2013), but this can vary depending on lifestyles. Alongside our personal behaviour the calculations also depend on factors over which we have no direct influence: for example, the public infrastructure.
By contrast forests, oceans and bogs store CO2. A quasi-natural bog can store around 1.2 tonnes of CO2 per hectare and year. But when bogs are dried out they are transformed into CO2 sources. A dried up bog used for farming purposes releases around 5 tonnes of CO2 per hectare and year. In addition laughing gas (N2O) has a significantly greater influence on the climate. If we include this factor a dried up bog releases around 50 tonnes of climate-changing emissions pro hectare and year.
"It may seem like a good idea to use peat as a fuel in order to save on wood, but a wood can regrow several times within a century, whereas a bog takes several centuries to be filled with peat."
Carl von Linné, Skånska Resa (1751)
8.2.1 Alternatives to peat
Gardening without peat
Every year in Germany around 8,000,000 m3 of peat are used. Much of this lands in private gardens and flower beds; the remainder in commercial horticulture. Even though peat is a renewable resource it does not grow nearly as quickly as it is dug out. The peat we use today in our gardens is up to 10,000 years old!
When we dig out peat we harm the climate and large areas of land are lost as habitats for unique species of flora and fauna.
Yet there have long been good alternatives: for example compost, bark humus, wood, coconut and hemp fibres. We might even consider using young peat mosses as a substitute for fully grown peat.
With a little effort we can produce compost from our own garden waste. Alternatively we can buy it from commercial compost sites. Here organic waste compost is particularly rich in nutrients and has a positive effect on the quality of the soil.
The Hanover Regional Waste Disposal Association (aha) also produces compost from green waste. Every customer can collect up to 1 cubic metre of compost free of charge at the recycling depots.
8.2.3 Bark humus
Bark humus consists of crushed and composted softwood bark. This contains many pores and ensures that the soil is well aerated. It also stores less water than peat. The nutrient content is less than in peat or compost, but this is often improved by adding substrates.
8.2.4 Wood fibres
Wood fibres usually come from sawmills. Similar to bark humus they contained large pores that ensure that the soil is well aerated. They are also very bad at storing water. They contain scarcely any nutrients and are therefore mostly enriched with fertilisers.
8.2.5 Coconut fibres
Coconut fibres are highly suitable for horticultural usages. Their fibres loosen up the soil and they can store water very well because of their swelling capacity. In addition they only decay very slowly and thus are able to improve the quality of the soil over a lengthy period of time.
8.2.6 Peat moss
The use of peat moss (Sphagnum) as a substitute for peat is still in its experimental stages. It can be traced back to paludiculture, whereby re-wetted bogs are used for agricultural purposes. In horticulture, peat moss plants have very similar characteristics to white peat. But where the extraction of white peat means that bog areas are destroyed, peat moss can be easily gathered on the surface. At the moment pilot projects are being used to test the economic feasibility of such a procedure.