Frequently asked Questions

The temperature of the earth has always fluctuated. Does current warming just reflect natural variability?

The temperature of the earth has indeed always fluctuated, for example, it was even warmer at the time of the dinosaurs than it is now or it was colder at the time of the ice ages. But these changes occured very, very slowly. The temerature changes that we have been observing in recent decades, have previously only occured within millennia. When temperature changes slowly within thousands of years, it is not a big problem, because then plants, animals and humans can slowly adapt. However, changes are now happening within such a short time period, that entire ecosystems are being lost, species become extinct at an increddible rate, people are losing their livelihoods, farmers cannot adjust their cultivation forms quickly enought, and they cannot easily relocate.
Temperature change since the last ice age and resulting sea level rise. Since the last ice age temperature increased by 3.5°C within 20 000 years. From 1750 to 2015 temperature increased by ca. 1°C (source: Prof. V. Quaschning; data: CDIAC, Marcott et al. 2013, Shakun et al. 2012, Fleming et al. 1998).

Why would climate change matter to me? An increase of a few degrees doesn’t sound dramatic

Global warming is not just about a slightly higher average temperature, but about the following: 1. The average temperature has risen by about 1 ° C, which means little has changed in some regions, and much more in others. In the Arctic, for example, heating has already reached 4 ° C. In the medium term, that causes flooding of many coastal cities. Hurricane Sandy and Katrina were a taste of increasing floodings during storms. 2. Low average warming also leads to imbalances in the atmosphere: the warming of the oceans leads to more evaporation and the warmer air over the oceans can absorb larger amounts of water. Over the landmasses, however, the soil is dried out by warming and the air over land masses gets warmed up much more than the air above the oceans. These imbalances are increasingly causing extreme weather events (droughts, forest fires, storms, etc.). The heatwave in Europe in 2003 alone caused 70 000 casualties. More details about this topic can be found here.

Do scientists agree that climate change is man-made?

Excluding ‘scientists’ paid by certaint stakeholders (industry), the vast majority of scientists does indeed agree that climate change is man-made and that it threatens our near future on this planet. A review summarising 12 000 articles from scientific journals revealed that doubts about man-made climate change were only raised in 0.7% of all articles. Please find more details about this in this article.

One hears often that there are doubts about man-made climate change, is that true?

This is not true. There is a strong lobby disseminating this information. A view at the sponsorship of the people providing such information and a review of their claims can help to see if these people are neutrally sharing information or not. More details about this issue can be found here.

When will climate change start?

Climate change has started since industrialization, but it is now accelerating, because on the one hand our emissions are rising more and more and on the other hand greenhouse gases that have already been emitted so far remain in the atmosphere. We have known for 70 years that the CO2 concentration in the air has risen due to the burning of fossil fuels and that consequently the temperature has risen too (details can be found here). The consequences of climate change have also been visible for years (see article on the costs of climate change).

Why do some people follow a vegan or vegetarian diet to save the climate?

The production of animal products (meat, cheese, milk, etc.) leads to a particularly high emission of greenhouse gases, especially methane. At the same time, the production of animal products requires much more arable land for the production than what is needed to produce the same amont of vegetable food (and hence, more greenhouse gases, especially N2O, are produced in conventional agriculture). For example, one serving of beef is 60 times more harmful to the climate than one serving of beans or other vegetable food. At the same time, for protein in the form of beef, an area about 18 times larger (for forage crops) is needed than for the same amount of protein from soybeans (Wikipedia). More information on this can be found here.

Humans and their livestock now represent 96% of all land living mammals (wild mammals compose only 4% of the biomasse of mammals, see this article). Of these 96% only 36% are humans and the rest (60%) represents livestock. This demonstrates why the meat and dairy industry has a significant effect on our greenhouse gas emissions and has several other ecological consequences (such as a loss of habitat, extiction of species, etc.).

What difference does it make when we do something against climate change, but the USA and China are not following?

First of all, it should be noted that China is massivly investing in renewable energy, while in other countries such as Germany investments have been reduced actively (see e.g. this article in Spektrum or talks by Prof. B. Burger or Prof. V. Quaschning; all in German). As a result, these countries have lost the leadership in renewable energies. Meanwhile, China and other Asian countries are market leaders in the production of solar cells and storage systems. China is also investing in wind energy (about twice as much as the US, for details see here).

Left: Installed wind power in 2017 in GW (data from Prof. V. Quaschning). Right: Installed solar power in GW in different countries (data from Prof. V. Quaschning).

Furthermore, we can achieve a lot in terms of redution of greenhouse gas emissions. Per capita, a German, Dutchman or Belgian causes about 10 tons of CO2 per year (that is equivalent to a cube of about 18 m edge length, i.e. the cube has the height of a 6-storey residential building). This amount is about twice as much as in France, Spain or Portugal, or five times as much as in India or 10-20 times as many as in many African countries (see overview at Wikipedia). Hence, it makes a big difference if we save greenhouse gases in Central Europe, the US or other similar countries.

What difference does it make if I do something for climate protection, I’m just one in billions?

First of all, we live in a so-called developed country. We produce a multiple of the emissions that people from the majority of countries produce, namely about 5 to 15 tonnes of CO2 per year (see previous question; 10 tonnes equals a cube from the height of a 6-story high-rise we produce every year). Therefore, we achieve a great deal if we reduce our emissions (which is not so difficult, see this article). In addition, we can raise interest in friends, parents, children, colleagues and acquaintances, to save a lot of CO2 emissions by only small adjustments, so that we can keep our standard of living in the future (which will not be the case if we continue business as usual for the next 10 years, as far as our emissions are concerned). The change of the electricity provider alone, or the increased use of the public transportation, or a swith to a slightly healthier diet can do a lot (see this article).

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