Can geoengineering save the world?
It sounds like science fiction, but it is science. Researchers are trying to artificially influence the climate with technical measures. The ideas range from sunshades and mirrors in space to huge CO2 filter machines. The problem with this is the massive intervention in natural processes and the fact that the consequences have not yet been researched.
Keep away from sunlight
There are two different geoengineering approaches to reduce anthropogenic greenhouse gas emissions. The first group of methods - Solar Radiation Management SRM - attempts to block sunlight from the Earth in order to reduce global warming. This would be attempted, for example, by means of enormous sunshades and mirrors in space, the cost and effort of which are incalculably high. The Intergovernmental Panel on Climate Change advises against such measures.
It would also be possible to imitate a natural volcanic eruption such as that of Mount Pinatubo in the Philippines in 1991, which led to a short-term global cooling of the climate by half a degree. To do this, sulphur particles would have to be released into the stratosphere by airplanes. However, such an intervention would have considerable side effects: The sulphur particles could damage the ozone layer and the temperature difference between the tropics and the poles would be reduced - with unforeseen consequences.
Researchers also assume that the summer monsoon in India and China will be affected, jeopardizing the water balance and thus also the agriculture of the countries concerned. Scientists and climate activists consider these experiments to be so dangerous that they stopped a field trial in Sweden in 2021.
The effort that would be required (7,000 flights per day) and the achievable effect plus unplannable side effects make this type of geoengineering uninteresting because it is too dangerous and itself harmful to the climate.
Cleaning our air
The second approach to geoengineering uses technical measures to remove carbon dioxide from the air - this is also known as Carbon Dioxide Removal (CDR) or Negative Emissions Technologies (NET) .
According to calculations by the Intergovernmental Panel on Climate Change, we will probably only be able to achieve the 2-degree target with "negative emissions". The idea behind this: CO2 should be filtered out of the air and stored using technical or near-natural methods.
There are already plants that filter carbon out of the air, for example in Iceland. This must then be safely stored somewhere underground or under the seabed. It is problematic if leaks occur. These would have massive negative effects.
Another problem is the enormous energy requirement of these systems, which means that they can only be operated sensibly with renewable energy.
Natural methods: Reforestation
One idea for storing Co2 in a natural way is large-scale reforestation with trees and/or other Co2-storing plants such as elephant grass. However, such large areas would have to be reforested - some researchers speak of an area 50 times the size of Germany, others of a third of all agricultural land worldwide - that this seems very unrealistic. Reforesting desert or savannah regions could lead to warming, because light, highly reflective areas would become darker areas. Furthermore, it is not clear what effect such gigantic afforestation would have on the entire ecosystem and the water cycle.
Promising success? The principle of weathering
In combination with water, some types of rock can remove CO2 from the atmosphere and bind it permanently. In the future, we could scatter rocks on fields and in oceans to reduce CO2, according to studies by the DFG research project "Climate Engineering - Risks, Challenge, Opportunities?", led by climate researcher Andreas Oschlies from the GEOMAR Helmholtz Center for Ocean Research Kiel.
The problem is the immense impact on our ecosystem with unforeseen consequences (e.g. pollution with heavy metals) and the enormous amount we would need to have a real effect on the climate - namely the equivalent of a mountain's worth of rock per year.
There are many ethical and legal concerns about geoengineering, as we are massively interfering with ecosystems. Furthermore, we should work on effective measures to reduce CO instead of using geoengineering. Our active intervention in the global climate is also very questionable and serious in legal terms, as it transcends national borders, as the video from the Max Planck Institute explains well.
Our pro.earth.conclusionMany things are possible for us humans today. However, the question of meaningfulness, the relationship between effort and result and the effects, which are unpredictable especially with such immense interventions in natural cycles, always remains.
Geoengineering is being researched and driven forward by scientists, but we as civil society (like many other areas of research) must examine its ethical, social, legal, ecological and economic meaningfulness.
