Dear Participants of the Botanik-Tagung 2022 in Bonn,

It is a great pleasure to welcome you all to the Botanik-Tagung 2022 in Bonn. Due to the Covid-19 pandemics, we could not hold our scheduled meeting in 2021. We are very happy that we can now meet in presence here in Bonn. On behalf of all members of the Deutsche Botanische Gesellschaft, I extend my sincere thanks to the organizers at Bonn, in particular to Professor Andreas Meyer and his team for making this conference possible.

The conference is held under the topic “Plant Sciences for a Sustainable Future”. Indeed, the plant sciences can make many meaningful contributions to achieving the 17 sustainable development goals (SDGs) put forward by the United Nations. Beyond the SDGs, anthropogenic climate change represents the grand challenge of our century. Solving climate change will also solve many of the SDGs. Since the beginning of the industrial revolution in the early 1800s, we have released more than 300 giga tons (Gt) of carbon into the atmosphere, mostly through thermal conversion of fossil resources. As a consequence, the atmospheric CO₂ concentration has risen from 280 ppm to more than 410 ppm in less than 150 years, causing an average global increase in temperature of 1.3 Kelvin since 1850 already. Clearly, to halt further warming and avoid the reaching of tipping points, such as thawing of permafrost soils, we must stop emissions and reach carbon neutrality as soon as possible. However, achieving net zero emissions will not be enough. Without active removal of carbon from the atmosphere and carbon long-term sequestration, CO₂ concentrations and hence increased global average temperatures will stay high for centuries to come. Hence we have to become carbon negative.

Removing 300 Gt of carbon from the atmosphere is a momentous task that will require energy input in the order of 5 to 10 EWh (1018 Wh). For comparison, global primary energy consumption in 2019 was 0.16 EWh. That is, the energy demand for atmospheric carbon removal is roughly equivalent to 50 years of global primary energy consumption at 2019 levels. Clearly, this is not achievable by technical processes that are fueled by renewable energy sources – there simply is not enough disposable carbon-neutral energy available.

There is hope, though. Every hour, the planet receives 0.173 EWh of solar energy. Plants are able to efficiently capture this solar energy and use it for carbon capture and sequestration into plant biomass. With plants – self-replicating solar-powered carbon capture devices – it will be feasible to sequester a sufficiently large amount of atmospheric carbon into biomass that can serve as a long-term carbon deposit. Every year, the 5 major crop plants alone assimilate 10 Gt of carbon into biomass. 20 years of crop production would suffice to reduce the atmospheric CO₂ concentration to 320 parts per million, which would be a sustainable level.

Of course, we must achieve carbon sequestration without compromising food security, increasing land use, increasing input of other resources or and increased loss of biodiversity. And this defines some of the major challenges for the plant sciences for the coming years. How do we align crop production with the needs for carbon farming? How do we increase the energy contents of plant biomass per unit mass and which plant-made products are sufficiently recalcitrant to rapid degradation? How can we use the plant root system to deposit carbon into deep soil?

The challenges are too many to list, and addressing these will require interdisciplinary research, bringing in expertise from engineering, material sciences, soil science, ecology and many more. So let’s set out and build interdisciplinary consortia that define the scientific questions that we need to solve for a sustainable future. Please use the conference for networking, for discussing ideas along these lines and making the motto of the conference, “Plant Sciences for a Sustainable Future”, a reality. I now wish you all a pleasant and productive time in Bonn!

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Professor Dr. Andreas Weber, 29^th August 2022, Bonn University, Germany

President of the German Society for Plant Sciences (Deutsche Botanische Gesellschaft, DBG), Heinrich-Heine-Universität Düsseldorf