"The ecological footprint must incorporate all climate factors"

Emissions of the greenhouse gas CO2 are responsible for most of global warming. However, land and oceans currently absorb only about half of these emissions. So-called CO2 removal measures such as renaturation of peatlands, coal phase-out, energy-efficient building refurbishment and climate-friendly mobility are intended to counteract global warming. But are these measures really enough to rebalance carbon sources and sinks? No - says Nadine Mengis.

Climate-friendly cement from mining sludge

It's a question of perspective: Up to now, many companies have regarded mining sludge and mine water as pollutant-containing waste because they contain cadmium and arsenic, for example. But a research team from the TU Bergakademie Freiberg sees things differently. In a pilot project, the experts have developed a process that removes the pollutants from sludge and water, extracts valuable substances and uses the rest as raw material for a more climate-friendly production of cement and concrete alternatives.

Recycled fertilizer from manure and leaves

Too much nitrate is still entering soils, groundwater and bodies of water as a result of improper fertilization. In agricultural regions in particular, groundwater is therefore often overly contaminated with nitrate. This is because if more fertilizer is applied than plants and soils can absorb, excess nitrate leaches into water reservoirs. According to the German Federal Environment Agency, agriculture is responsible for around 75% of nitrate inputs. But this is set to change.

Food system: Only growth is not enough

How can our food system become more sustainable? This question is currently occupying many researchers. Eating less meat and more vegetables is just one way of protecting the environment and climate, as well as making agriculture more sustainable. Like other sectors of the economy, however, agriculture is geared to constant growth. For a long time, there have been voices arguing for an economy without growth, because this development is harmful to the environment. Researchers have now taken a closer look at these so-called "degrowth" approaches.

Solvents are to become greener

Solvents are central chemicals in many manufacturing processes in the chemical industry. They are used to dissolve starting materials at the beginning of a production process, but also to isolate and condition the desired compound from the reaction mixture at the end. However, most solvents have been based on petroleum. The international DECADES research project funded by the European Commission is therefore now looking for bio-based alternatives.

Mobilize sustainable biomass for gas production

Whether for electricity and heat production, for use in gas-powered household appliances or as a fuel, biogas is firmly established in everyday life. There are around 9,000 biogas plants nationwide, producing 94 terawatt hours (TWh) of biogas. Biogas production currently accounts for about 9% of total natural gas consumption in Germany. About half of the natural gas was imported from Russia in 2021. However, with the attack on Ukraine and a looming gas embargo by Russia, gas supply has become more uncertain.

With agri-voltaics to sustainable fruit cultivation

Energy crops such as rapeseed and corn are grown on more than one-fifth of the arable land in Germany. This means that they compete with food production for valuable agricultural land. Agri-photovoltaics (Agri-PV) promises a resource-efficient dual use of arable land. The simultaneous use of fields for the cultivation of food crops and for the generation of electricity also opens up new sources of income for farmers.