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You don’t need to know everything by heart, you just have to know where to find it! Here we give short and easy explanations about important terms and concepts we use in our blog.

Albedo effect

Albedo is the percentage of incoming radiation reflected of a surface. An albedo of 1 means that 100% of incoming radiation is reflected and no radiation is absorbed. An albedo of 0 means that 0% of incoming radiation (“heat”)  is reflected and all radiation is absorbed. Light surfaces (e.g. ice sheets) reflect more radiation. Dark surfaces absorb it (you can feel this if you are wearing a black shirt in summer!). Water absorbs as well quite a lot.

The Albedo effect is why melting ice sheets caused by global warming is like a vicious cycle. The ice normally reflects a lot of radiation and so helps to cool the planet. If the ice cover decreases, less radiation gets reflected and more absorbed by the water! This leads to a continuous heating of our planet.

Check out more about the albedo effect in this short video:

Atmosphere

The Atmosphere is the gas layer surrounding the earth and that makes life comfortable here: It allows us to breath, balances temperatures and protects us from radiation. When we are talking about air, we actually mean the atmosphere. Main components are nitrogen, oxygen – and with a huge gap – Argon and Water vapor. Other trace gases include the greenhouse gases or more inert gases. The atmosphere consists of five layers that are varying in air content and pressure: Troposphere, Stratosphere, Mesosphere, Thermosphere and Exosphere.

What we see if we are looking into the sky is basically the troposphere, the lowest layer of the atmosphere. It is the air we breathe and where our weather occurs. It contains the major amount of the whole atmosphere mass, since the gases are dense and so the pressure high. Next is the stratosphere, which includes the Ozone layer. The Ozone layer is important as it protects us from ultraviolet radiation coming from the sun. The coldest parts of our atmosphere are located in the Mesosphere that can reach temperatures of –90°C on average. The mesosphere is also the layer where most meteors burn up upon atmospheric entrance. In the fourth layer from Earth’s surface, the thermosphere, where the air is already very thin. That means fewer air molecules are quite far apart and the pressure is very low. The thermosphere can get temperatures up to 1,500°C. However, due to the very low pressure, you wouldn’t feel hot there but also you wouldn’t be able to breath and your body would swell massively. No chance to live there. The Exosphere is the upper layer of atmosphere, where the air is so thin that atoms and molecules escape into space.

You want to know more? Then check this documentary; it’s easy to watch and really worth the 50 minutes!

Bioaccumulation

The conversion of energy from food into biomass is incredibly inefficient. On average only 1/10 of what is consumed is transformed into biomass, the rest is lost in maintenance. This also means that an animal needs to consume 10 times its body mass in order to maintain itself. While from this large amount that is consumed, only 1/10 is kept in biomass, the toxins, like for example mercury, are kept from all 10/10. As a consequence these toxins tend to accumulate in larger and larger amount as we move up the food chain, each level having 10 times the amount of toxins, if its prey had carried the toxin. This bioaccumulation is a good argument for eating species comparatively low on the food chains, with plants, as primary producers not having accumulated as much toxin as a carnivorous fish like tuna would have.

bioaccumulation
Very crude own illustration: A certain type of algae might be contaminated with a toxin. Small fish now need to consume ten of these algae to survive. A larger fish needs in turn, ten of these small fish to survive – he now has 100 times the amount of the toxin that was in the original algae within its body.

Biodiversity

Biodiversity is the variety of life on earth. It is a complex term and includes variations on genetic level, species level as well on ecosystem level.Thereby a species is a group of organisms that can interbreed (for instance dolphins, dogs, sunflowers…). But it is not only about the total number of different species on the planet or in a certain region, it is also about constellations, the relation between species and about species communities. In the end, it is the interaction of lifeforms that shapes life.

Biodiversity is extremely important for life. We all rely on it because it provides us food (e.g. via pollination) or medication (e.g. herbs, drugs), it regulates climate (e.g. tropical forests) and nutrient cycles; and on genetic level it prevents diseases and drives adaptation. All life on Earth is interlinked and depends on each other. If one species get losts, it impacts many more. For instance, we are dependent on crops, crops are dependent on bees and other on pollinators – and if the bees get extinct, we lack food. This is why Biodiversity is important.

For more information check this article or watch this short video:

Carbondioxid (CO2)

CO2 is a greenhouse gas playing a major role in global warming. It has the lowest global warming potential but it just stays in the atmosphere. Also, CO2 emissions are much higher compared to other gases and its relative contribution to total emissions is over 50%. The rising CO2 concentrations in the atmosphere are almost entirely based on the burning of fossil fuels, which has been increasing since industrialization. However, deforestation and other land use changes also play an important role. Current atmospheric concentrations – around 390 ppmv (parts per million by volume) are about 20% higher than preindustrial concentrations. There is currently and increasing at a rate of around 0.5% per year.

Ecosystem Services

Ecosystem Services are produced by, who would have guessed, ecosystems! As ecosystems do what ecosystems do, i.e. plants grow, get eaten by animals who get eaten by animals, a lot of things happen that are beneficial to us, the humans. The most obvious of this is plants, with the help of insects, producing fruit for seed dispersal – fruit that we happen to like to eat. This is an example of a so-called provisioning service, one of four categories that ecosystem services are most frequently divided into. Other provisioning services are the provision of fresh water, or wood for construction and fuel. But it doesn’t stop there. Ecosystems provide other services that are directly beneficial to us, even though we do not ‘consume’ them. These are regulating services, like flood control, provided for example as vegetated areas take up water, or mangroves form buffer zones along the shore. A third category, the most human-specific one is formed by the cultural services: we often find relaxation and solace by going into nature, we might also have spiritual or religious attachment to it. The last, but most definitely not least, group of services is one that we humans do not really experience directly. It is formed by the processes that run in the background, kind of like all those things that take up memory on your computer even though you aren’t actively doing anything with them. These supporting services include such things as nutrient cycling, which are absolutely essential to all of the other services.

Check this website for more examples of ecosystem services, or the crash course ecology video below for an explanation of ecosystem services and the human impacts on them!

Millenium Ecosystem Assessment classification of Ecosystem Services, taken from the Synthesis Report:

Ecosystems

Ecosystems are a collection of species – plants, animals, fungi, bacteria etc. embedded within the nonliving environment. The ecosystem functions include all interactions within this environment, both between species, within species and between species and the nonliving components, starting from the take up of nitrogen by plants, over the consumption of the herbivores by the carnivores, up to the release of CO2 as the animals breathe and the decomposition of dead material by decomposers (detritivores).

Ecosystems differ in terms of the species present, which again depends on the environmental conditions like temperature, water availability, nutrient availability etc. Examples of ecosystems include lakes, streams, mangroves, forests, grasslands… but you could also call the planter box on your balcony an ecosystem.

Ecosystems are not isolated from one another. Usually there is no point at which you can say that you have now moved from one ecosystem to another. An ecosystem has no concrete boundary, rather, ecosystems slowly transition from one to the other, without ever losing all connection to the next one. A lake ecosystem might seem to have a quite clear geographic boundary: the shore of the lake. However, ecologically the inhabitants of the lake interact with the surrounding ecosystem. Lake inhabiting decomposers might be decomposing the leaves dropped by nearby trees. Similarly the animals inhabiting the surrounding ecosystem might come to the lake to drink. Amphibians might move between the lake ecosystem and the surroundings in the course of their life.

This as always high-speed crash course ecology video can bring you up to date on further aspects of ecosystems and their ecology.

Global Warming Potential

The global warming potential is the warming potential of 1 kg gas relative to that of CO2. The higher the GWP the more the gas contributes to global warming. However: keep in mind that the time the gas stays in the Atmosphere also plays a role! For example CO2 has the lowest global warming potential (let’s just set it to 1); however, the problem is: it stays in the atmosphere unchanged even after 500 years.

The table below shows the GWP of the most important GHG and its approximate decay within 500 years (Data based on IPCC).

20 years 100 years 500 years
Carbon dioxid 1 1 1
Methane 72 25 7.6
Nitrous oxide 289  298 153
Chlorofluorocarbons
(e.g. CFC-11)
6730 4750 1620

Greenhouse Effect

The greenhouse effect is caused by the Earth’s atmosphere modifying the global energy balance. It is the process by which thermal radiation from the Earth’s surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation goes back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases. The greenhouse effect itself is not a bad thing. Without it (and without the atmosphere) temperature on earth would be -18 °C. Pretty cold!

For a more detailed explanation check this or have a look on Wikipedia which provides a nice overview as well! Or watch this short explanatory video:

Greenhouse gases

Greenhouse gases (GHG) are atmospheric gases that contribute to the greenhouse effect and hence to global warming. These gases are: Carbondioxid (CO2), Methan (CH4), Nitrous-oxide (N2O), Chlorofluorocarbons (CFCs), Watervapor (H2O), Ozone (O3). The Concentration of all GHG increased significantly due to industrialization. As a consequence temperature on earth is rising and therefore we need to reduce emissions. The gases differ in their contribution to global warming, which is dependent on three factors (1) the global warming potential (GWP) (2) The persistence of the gas in the atmosphere and (3) the amount of each gas present.

Carbondioxid (CO2): CO2 has the lowest global warming potential but it just stays in the atmosphere. Also COemissions are much higher compared to other gases and its relative contribution to total emissions is over 50%. The rising CO2 concentrations in the atmosphere are almost entirely based on the burning of fossil fuels, which has been increasing since industrialization. However, deforestation and other land use changes also play an important role. Current atmospheric concentrations – around 390 ppmv (parts per million by volume) are about 20% higher than pre-industrial concentrations. There is currently and increasing at a rate of around 0.5% per year.
Methan (CH4): It has a relatively short life time (approximately 12 years) because it reacts with OH-radicals in the atmosphere, but the global warming potential is much higher than this of CO2. Its current atmospheric concentration is 1.772 ppmv, which is more than two times higher than preindustrial concentrations and it is increasing at a rate of 0.9% per year
Nitrous Oxide (N2O): The warming potential is over 250 times higher than that of CO2. The Current atmospheric concentration is 310 ppbv (8% greater than pre-industrial) and it is increasing at a rate of 0.8 ppmv per year (0.25%). Major sources are agricultural practices and deforestation (in general denitrification processes in aerobic soils)
Chlorofluorocarbons (CFCs): These gases formerly used in refrigerators or as propellants are entirely man-made and absolutely evil. They have a global warming potential up to several thousand times higher than that of CO2 and they inert in the lower atmosphere and are stable over 100 years without reaction. In the higher atmosphere, where they are broken down by UV light, they further contribute to ozone depletion. Fortunately their use has gradually been decreased due the Montreal protocol, an international agreement made in 1986. However, due to its long life time they still play a role in global warming.

Urban Heat Island

urban_heat_klein
Bildquelle, angepasst

Der sogenannte Urban Heat Island Effekt bezeichnet das Phänomen, dass Städte im Allgemeinen wärmer sind als die ländliche Umgebung. Diese Städte sind dann Urban Heat Islands, also städtische Wärmeinseln. Dabei wurden Unterschiede zwischen 0,1 und 12°C gemessen, je nach Größe, Tageszeit und geografischer Lage der Stadt. Ein Grund dafür ist die große Menge an versiegelten Flächen und Gebäuden in Städten, die aus wärmespeichernden Materialien (z.B. Beton, Asphalt und Stein) bestehen, welche diese Wärme wieder abgeben, sobald die Luft abkühlt. Außerdem wird in den Städten durch den verstärkten Betrieb von Elektrogeräten und Heizungen zusätzliche Hitze erzeugt. Ein weiterer Faktor ist die vergleichsweise geringe Menge an Pflanzen, die durch Schatten und Evaporation von Wasser die Umgebungsluft kühlen.

Mehr Info gibt es z.B. hier

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