"It is going to get warmer without doubt, the question is when and by how much."
[Peter Usher, Meteorologist at the United Nations, 1986]
Basic Course 4: How Can We Protect the Climate?
Unfortunately we have a variety of environmental problems, which, in addition, are very closely intertwined. By far the most important problem is climate change according to a survey of experts in 2000. For this reason we will be covering the climate change in the following using examples.
The Day After Tomorrow - just a Horror Vision?
|In his film "The Day After Tomorrow" the producer and director Roland Emmerich relates the story of a climate researcher, who - like the rest of the world - is surprised by the onset of an abrupt change in the climate. Massive storms break out, Los Angeles is razed to the ground by a tornado, New York sinks beneath a giant flood wave, and an ice age breaks out across the whole northern hemisphere. In the film, the fall out of the Gulf Stream causes the sudden occurrence of an ice-age in Europe and the USA.
Our weather is a reflection of the state of the atmosphere around us, which is marked by changes in temperature, air-pressure, humidity, wind, cloud formation and precipitation within short periods of time (hours, day).
The medium-term course and frequency of extreme weather conditions over long periods of time (years, centuries, millennia) is to be understand under the term climate.
Could our future look like this?
|As a typical Hollywood production, the film presents the events in an exaggerated way and "for reasons of drama" in slow-motion. However, the main emphasis of the film presents the truth. We are certainly heading for a climate catastrophe. This will however - according to the opinion of most scientists - not occur in the next few decades and will not be as drastic as presented in the film. The researchers assume that we can slow down global warming and thus hinder catastrophes.
A good example
During the production of The Day After Tomorrow effort was made to produce as little carbon dioxide emissions as possible. Charges were paid voluntarily for unavoidable emissions in order to finance measures for carbon dioxide reductions elsewhere.
Our climate is changing
|During the course of the earth's history, the climate has continually and also dramatically changed partially. There has been change from warm to ice ages. However, the climate over the last 10,000 years has been particularly stable. The civilization of mankind has developed during this time. In the last 100 years - since the beginning of industrialisation - the global mean temperature has risen by approx. 0.6 °C, faster that ever before in the last 1000 years. The figure above from IPCC (Intergovernmental Panel on Climate Change) clarifies this development.
The focus of the climate change, which in the meantime no one doubts anymore, is the warming up of the earth, the rise in the global surface temperature of the earth. This automatically results in the other changes in the global climate system observed: Mountain glaciers and polar ice-masses melt down, the sea level rises, the water circulation is amplified, precipitation becomes more extreme and so-called natural catastrophes become more frequent.
Taken from an IPCC Report (2001)
The 1990's constituted the warmest decade and 1998 the warmest year in the last century.
New analyses of trunk rings, ice cores, coral and historical records have shown that the process of warming up in the last century has been the highest in the last 1000 years.
The rise in the sea-level globally in the last century equated to approx. 10-20 cm.
The snow covering in central and northern longitudes has melted since the end of the 1960's by some 10%, and the fall back in mountain glaciers is widely distributed at the same time.
What are the Consequences of the Earth Warming?
[Figure: Hurricane Lilly, Liam Gumley, Space Science and Engineering Center, University of Wisconsin-Madison]
|Inland glaciers and polar ice melt.|
|The rise in the temperature of the oceans and sea-level (land is lost, the existence of small islands threatened)|
|The global circulation of water increases More water evaporates in the tropics than rains in northern latitudes; A changed pattern in precipitation|
|The salt content of the North Atlantic is becoming less;
the Gulf Stream and therefore the transportation of heat to Europe is becoming weaker and could stop altogether; Abrupt changes in the climate cannot be excluded|
|The cumulation of extreme weather conditions Cyclones, heavy rain, floods, drought|
|Expansion of deserts (area loss, environmental refugees)|
|Change in vegetation: massive forest areas can die out. Large quantities of carbon dioxide are released as a result that make the greenhouse effect even worse and could lead to the earth warming up more quickly ("galloping greenhouse effect")|
|Potential damage to the ozone layer: It is assumed that the earth warming up results in a cooling down of the stratosphere (parts of the atmosphere 15-25 km up), which accelerates the break down in the ozone layer at that height|
Why is the Earth Warming Up? - The greenhouse effect
The higher temperatures in a greenhouse result from the energy-rich sunlight shining in unhindered, whereas the warmth emanating from the earth is not let out. Our atmosphere acts in the same way. The gases that absorb infra-red here, which are known as greenhouse gases, function like a greenhouse (more information on greenhouse gases can be found on a
Water vapour and natural trace gases like carbon dioxide, nitrous oxide, methane and ozone contained in the atmosphere let the energy-rich short-wave rays of the sun hit the earth nearly completely unhindered, but absorb the long-wave heat rays given off by the earth. The greenhouse gases emit this energy into space and then reflect it back towards the surface of the earth. As a result the earth heats up to an average temperature of approx. 15°C (instead of approx. -18°C) and thus allows people to live on this planet. This is what one refers to as the natural greenhouse effect.
|Through human activity, the concentration of natural greenhouse gases and above all carbon dioxide has increased considerably in the atmosphere since the beginning of industrialisation. Besides this additional synthetic gases affecting the climate are released, in particular halogenated hydrocarbons. This amplifies the greenhouse effect and the global mean temperature rises. One speaks of the anthropogenic (caused by humans) greenhouse effect here.
What needs to be seen as well is that the environmental problems listed at the beginning are very closely intermeshed and can amplify one another. For instance the deforestation of rain forests leads among other things to them no longer being able to absorb carbon dioxide, which amplifies the greenhouse effect.
Why has mankind been releasing more greenhouse gases than ever before in the last 100 years?
Energy needs increase as a consequence of industrialisation and the increased growth in the world population resulting from this and the increase in traffic density. That leads to the increased combustion of fossil fuels. In addition the need for foodstuffs increases and the effort required to secure the increase in living standards. As a result agriculture is intensified and natural landscape increasingly transformed into cultural space. This trend has held until today.
A further example would be the interplay of the greenhouse effect and the break down of the ozone level: The atmosphere close to the earth warms up as a result of the greenhouse effect. The results in a reduction in temperature in the stratosphere, which favours the break down of the ozone level at that height. Ultraviolet radiation on earth increases. This is not only damaging for mankind, but also leads to sea plankton increasingly dying out. This leads to additional carbon dioxide being released, which again amplifies the greenhouse effect. The atmosphere close to the surface of the earth continues to warm up and the (vicious) circle closes.
How can a climate catastrophe be avoided?
The concentration of greenhouse gases in the atmosphere should not be allowed to increase any further. The can only be achieved by attaining a drastic reduction in emissions. The combustion of fossil fuels (oil, gas, coal) needs to be reduced considerably by:
|A reduction in energy consumption|
|converting the energy supply to renewable energies (sun, wind, water, biomass, heat from the earth)|
In addition carbon dioxide can be removed from the atmosphere, e.g. through afforestation. Large forest areas which function as depressions must be retained, i.e. the deforestation of large areas must be stopped.
However according to the IPCC report on climate change from 2001, even when an immediate halt in all emissions were to take place, the warming up of the atmosphere and the rise in sea-level would still continue for decades, or perhaps even centuries.
Further sections within the framework of Basic Course 4
|Greenhouse Gases: What chemicals are concerned, where do they come from and how are they formed... [... more]|
|Climate protection: Of decisive importance is that every individual needs to help do something against the climate change. What can I do to protect the climate... [... more]|
|Climate policy: What is politics doing on a global, national and regional level to reduce greenhouse gas emissions... [... more]|
|History: The milestones in international environmental policy in historical summary... [... more]|
|Gulf States: Can the Gulf Stream, The "warm-water heating system of Europe", come to a standstill and lead to a new ice-age, as shown in the film The Day After Tomorrow... [... more]|
[Author: Dipl.Biol. Marietta Enss, Edited by: Ragnar Müller]
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