Heat, drought, melting polar ice caps and unpredictable weather: climate change is here to stay. People like to preach how much the individual can do – but what is possible on a large scale? There are many ideas in research on how to combat climate change. How exactly is this supposed to work? An overview.
The persistent summer drought in Europe represents one of the greatest threats of our time. It is expected to be particularly dangerous for the Alps, Spain and the Mediterranean region in the future. Regions in Germany such as Brandenburg or Saxony are also fighting increasingly worse forest fires in summer. The glacier rupture in northern Italy recently showed that climate change is causing more and more deaths.
The main reason for the warming of the planet is the so-called greenhouse effect, which is driven by the excessive emission of gases such as carbon dioxide (CO2). There is no doubt that each and every one of us can contribute to CO2 savings. But in the end, buying plastic-free products, for example, makes very little difference. According to “Statista”, the biggest sources of emissions are industry, agriculture and transport. Innovative technologies in these areas have the potential to promote global reductions in harmful emissions.
Compensation starts small. This is shown by genetically modified bacteria, which actually have the ability to absorb and utilize CO2 – for example in oxygen. As the research team reported in “Nature Biology”, the so-called “Clostridium autoethanogenum” bacteria utilize various organic molecules that contain carbon atoms. According to “Spektrum”, the researchers have genetically modified the bacteria in such a way that they can also produce chemicals such as acetone, formerly contained in nail polish remover.
What is special about these optimized bacterial cultures, however, is that they bind more carbon than they release. This in turn means that they can not only convert CO2 into other substances, but also help prevent more carbon from entering our atmosphere.
The disadvantage: In order to achieve any noticeable savings in greenhouse gases, almost the entire chemical industry would have to switch to manufacturing processes with these bacteria. American chemists calculated for the journal “Nature Biotechnology” that a maximum of two percent of global CO2 emissions would be saved in such a case.
Your organic shop for fruit, vegetables and natural foods
One of the simplest solutions could also be one of the most effective: Trees have great potential as natural CO2 stores because they bind large amounts of greenhouse gases and convert them into oxygen. All they need is sunlight and water.
According to a study at ETH Zurich, almost three million hectares of forest can be reforested in Germany alone. That could convert 18 million tons of CO2. The recent serious forest fires in Brandenburg show that climate change is not leaving its mark on German forests, which have suffered massively from the heat in recent years. This in turn could massively endanger the permanent storage of CO2.
The downside: Many of the trees planted are felled again within decades – such as pines, which are important in furniture production. This not only eliminates the effort involved in reforestation, but when the wood weathers or burns, the stored CO2 is released back into the atmosphere. Another problem is the absorption of heat: the earth also absorbs more sun rays through forests and can still warm up, because this is only partially compensated for by the forests.
Bogs make up some of the largest CO2 reservoirs that exist in nature. Nevertheless, bogs have been drained again and again in the last century – for arable land. This makes perfect sense from an agricultural point of view, but rewetting the peatlands has great potential to help in the fight against climate change. According to the State Institute for the Environment in Baden-Württemberg, moors store roughly 700 tons of carbon per hectare.
Today, according to the federal government, there are only 75,000 hectares of semi-natural moors that store CO2 out of the original 1.5 million hectares. At the same time, nitrous oxide, which is much more harmful to the atmosphere, escapes from drained moors. We can therefore avoid the fact that almost 45 million tons of CO2 escape from our drained moors every year by rewetting them.
The disadvantage: Farmers in particular have little use for this solution, as they would have to give up valuable farmland. As a result, the farmers would also lose income. After all, they cannot lucratively cultivate maize or sugar beets on rewetted moors.
Ground rock reacts with carbon dioxide and can remove it from the atmosphere – this has been shown by a study by the University of Augsburg. The carbon is then stored in the soil layers. If the rock is eroded, for example by rain, it is removed and stored in rivers or the sea. This stops the release into the atmosphere and thus its warming.
We humans can also accelerate this weathering process with certain types of rock. The international research team from the University of Augsburg has demonstrated that basalt is considered a particularly promising candidate because it can also be used on infertile farmland: when it weathers, basalt releases nutrients such as phosphorus, which is also used as a fertilizer.
To do this, ground basalt has to be scattered on fields, for example, and can thus stimulate weathering and thus the binding of carbon even without rock formations. It is estimated that basalt stores around 1.2 gigatonnes of CO2 worldwide. Currently, the cost of this is about $150 per tonne of CO2 removed. With the expansion of basalt mining, however, these would drop significantly.
The downside: It takes about 50 years for weathering to complete. A bigger problem, however, is the area required for the maximum effect: Among other things, pilots would have to dust 55 million square kilometers with basalt by plane – that’s larger than the Asian continent. In addition, there are the hitherto unknown consequences of large-scale basalt mining, especially for nature.
The tiny species of algae can convert huge amounts of carbon into oxygen. According to the University of Bremen, phytoplankton obtain food and energy by converting carbon, for example, with sunlight. The use of iron sulphate particles can also stimulate their proliferation – a kind of “fertilizer” for algae.
When the small creatures die, they sink to the sea floor and bind the digested CO2 there. A correspondingly large population of phytoplankton is theoretically not only able to convert large amounts of CO2 into oxygen, but can also prevent it from re-entering the atmosphere later on.
The disadvantage: The use of phytoplankton has not yet been 100% clear. In addition, there are the possible effects on ecosystems in the ocean: the more CO2 the bacteria absorb, the greater the risk that the water will become more acidic when they sink to the sea floor. They could also deprive other living beings of oxygen. An application must therefore be carried out with great care.
