Reasons for climate change
Man influences the greenhouse gases’ concentration in the atmosphere with increasing industrialization but since the 19th century at the latest. Human activities significantly increased the amount of climate-efficient gases, especially carbon dioxide, and thus contribute to global warming. Especially the burning of fossil energy sources like carbon, oil and gas and a change in land use, e.g. by forests clearing, have led to a dramatic increase of atmospheric CO2 concentration. Moreover, increasingly larger quantities of the greenhouse gases methane and nitrous oxide are released by intensified farming and ranching.
Natural and anthropogenic greenhouse effect
The natural greenhouse effect
There would be no life on earth without the greenhouse effect: the sun radiates through the atmosphere, is converted into thermal radiation at the earth’s surface and is emitted back from earth. Greenhouse gases in the atmosphere prevent a part of this thermal radiation from fading into space. If this “shield” weren’t there the earth would be literally frozen at -18°C. The natural greenhouse effect provides for a global average temperature of about 15°C and this that life can develop.
Overheated: the human-caused greenhouse effect
Today, there is human influence to this natural “greenhouse”: Especially by burning fossil energy sources (carbon, oil and gas) and by a changed land use (e.g. by clearing of forests) man has increased the greenhouse gases’ concentration in the atmosphere during the last 150 years. The global atmospheric concentration of carbon dioxide, the most important greenhouse gas, increased from around 280 ppm (parts per million i.e. 280 CO2 molecules to one million air molecules) in pre-industrial time to 384 ppm in 2008. The concentration of the greenhouse gas methane arisen by intense farming and ranching has more than doubled.
Today’s greenhouse gases’ concentration in the atmosphere is so high already that too much warmth is stored - with considerable consequences for the world climate. Between 1906 and 2005 there had already been a global increase of temperature by around 0.74°C. The eleven years between 1995 and 2006 belonged to the warmest since the beginning of measuring and calculating the global average temperature. The IPPC concludes in their latest report that the biggest part of the observed global warming of the last decades is very probably (that is with over 90 percent probability) due to human-caused greenhouse gas emissions.
The consequences of the human-caused climate changes are visible today already and will increase in the decades to come. Until 2100, an increase of temperature between 1.1°C and 6.4°C is awaited. Effects are threatening which can hardly be handled by human society and eco-systems.
What are greenhouse gases and CO2 equivalents?
Greenhouse gases are present in the atmosphere and absorb heat radiation, which they radiate back towards the earth's surface. The most important man-made greenhouse gas is carbon dioxide (CO2). It is caused by the burning of fossil fuels and changes in land use, such as deforestation. It is responsible for more than half of the anthropogenic greenhouse effect. In addition to CO2, the following greenhouse gases also contribute to climate change:
- Methane (CH4): Caused mainly by livestock farming and rice cultivation, and to a lesser extent by industrial sources such as the extraction and transport of fossil fuels.
- Nitrous oxide (N2O): Mainly produced in the agricultural sector.
- Chlorofluorocarbons (CFCs): A refrigerant whose manufacture and use is banned internationally today, but which is still released to a considerable extent due to the improper disposal of old refrigerators, among other things.
- Partially halogenated and perfluorinated hydrocarbons (PFC and HFC): Are caused by technical applications such as air conditioning systems.
- Sulphur hexafluoride (SF6): Occurs as a result of technical applications such as the use as insulating gas.
The gases contribute to the greenhouse effect to varying degrees. For this reason, CO2 equivalents are usually used to better compare their effect on the climate.
In addition to the most important man-made greenhouse gas, carbon dioxide (CO2), there are other greenhouse gases such as methane or nitrous oxide. The various gases do not contribute to the greenhouse effect to the same extent and remain in the atmosphere for different periods of time. Methane has a 25 times greater climate impact than CO2, but remains in the atmosphere for less time. In order to make their effect comparable, the United Nations Intergovernmental Panel on Climate Change (IPCC) has defined the so-called "Global Warming Potential" (GWP). This index expresses the warming effect of a certain amount of a greenhouse gas over a fixed period of time (usually 100 years) compared to that of CO2. Greenhouse gas emissions can thus be converted into "CO2 equivalents" and summarised. CO2 equivalents are referred to by the abbreviation "CO2e".
When calculating emissions, Klima-Kollekte always includes the most important other greenhouse gases and therefore calculates with CO2 equivalents. Since CO2 is the more familiar abbreviation, it is usually used - for example in the designation of the emission calculator as a "CO2 calculator" - in the not quite concrete, but commonly understood sense.
Germany: CO2 emissions above all
In Germany, we produce greenhouse gases primarily by consuming energy: around 80 percent of all greenhouse gas emissions round here are energy-induced, which means they are created from the production of heat and energy or from the burning of (mostly fossil) fuels in traffic. The remaining 20 percent almost exclusively result from industrial processes (around eleven percent), for example in the chemical industry and in farming (almost seven percent). The emission of carbon dioxide represents with around 87 percent the biggest part of the greenhouse gases emitted in Germany. In 2014, around 912 million tons of CO2 were emitted by industry, trade, households, government, farming and energy industry – 40 million less than the previous year but the wintertime was significantly milder. Not included in this balance are emissions generated during the production of goods which are made overseas and imported to Germany. Emissions of international air traffic are not included. This corresponds to the international regulations for calculating the greenhouse gas emission of a country but suppresses emissions of considerable quantity.
CO2 emissions per capita
According to the German Environment Agency, German CO2 emissions per capita amounted to around 11 tonnes in 2016. This is 2.5 tonnes more than the European average and more than double the global average of around 4.4 tonnes of CO2. Per capita CO2 emissions are much lower in many developing countries. If global warming is to be limited to well below 2°C - the international community has set itself this goal at the Paris declaration in 2015- global emissions must fall sharply. Since current and past emissions are so unevenly distributed, countries must make different efforts. German emissions should therefore be reduced by 40 percent by 2020 compared to 1990 levels and by 80 to 95 percent by 2050.
That is ambitious, but perhaps feasible if we all contribute to it. What is needed are political steps for example towards energy production from 100 percent renewable energy sources. But each and every one of us can do a lot, because many of our activities can be made more climate-friendly. Whether it's an organization, a private individual or a church, everyone should consider how and where greenhouse gas emissions can be avoided and reduced. And what about the remainder that is not avoidable? Klima-Kollekte can help you to offset your still existing CO2 emissions through its projects.