Prof. Dr. Josef Settele
Prof. Dr. Josef Settele heads the Department of Conservation Biology and Social-Ecological Systems at the Helmholtz Centre for Environmental Research in Halle, Germany. In his role as co-chair, he co-authored the UN World Biodiversity Council IPBES 2019 Global State of Biodiversity Report. In 2020, he published “Die Triple-Krise. Artensterben, Klimawandel, Pandemien – Warum wir dringend handeln müssen” (“The Triple Crisis. Species Extinction, Climate Change, Pandemics – Why We Urgently Need to Act”). He has been a member of the German government's Advisory Council on the Environment (SRU) since 2020.
In your book “Die Triple-Krise” (“The Triple Crisis”), you describe how the uncontrolled exploitation of nature, species extinction and pandemics such as Covid-19 fuel each other in disastrous a way. How can this be explained?
"Biodiversity, or species diversity, plays a crucial regulatory role. Whenever humans open up new areas for themselves, there is a loss of species. The more animal and plant habitats we destroy, the more we allow our cities and their catchment areas to sprawl uncontrollably into the landscape, the higher the risk of new pandemics. Because wherever we humans spread out, a homogenized landscape emerges in which only a few dominant species survive.
"In addition, where there are masses of members of the same species, pathogens of these same species get plenty of opportunity to spread and modify themselves. This dominance of a few species – coupled with close contact with humans – increases the risk of such pathogens jumping over. With almost 8 billion people on Earth, the Covid-19 virus is thus given ample experimental space, as we have already seen in the emergence of various mutations."
If habitat destruction is one of the main reasons for the triple crisis, is it high time for a new approach to our forests and how humans use them?
"The biomass of the world's vegetation has been halved over the course of human history, and forests today extend over only about two-thirds of their pre-industrial extent. This is what we found in the Global Report of the World Biodiversity Council.8 Although forest loss has slowed globally since the 1980s, it is still proceeding very rapidly in many tropical regions. And the increasing thinning of forests in temperate and boreal1 vegetation zones goes hand in hand with increasing fragmentation and is accompanied by changes in function – e.g., carbon storage."
Planting trees for climate protection, because they bind carbon in their wood, is currently very popular with companies and consumers alike. Is this a promising approach?
"From a scientific point of view, we have to take a very close look here, because this question cannot be answered with a simple yes or no. Climate protection measures that aim to increase the carbon storage capacity of ecosystems can have significant additional consequences for the climate system. This applies, for example, to the planting of large areas of forest or the extensive cultivation of bioenergy crops. It is therefore important to consider all climate impacts when evaluating these climate protection measures – both the short-term impacts and the long-term ones."
The wood and paper industry is increasingly focusing on sustainable forest management. Could this change things for the better?
"As we elaborated in the joint report5 of the Intergovernmental Panel on Biological Diversity (IPBES2) and the Intergovernmental Panel on Climate Change (IPCC3), reduced forest clearing or degradation by avoiding uncontrolled logging could help to reduce annual anthropogenic4 greenhouse gas emissions. Maintaining and enhancing carbon storage could result in potential emissions reductions of 0.4 to 2.1 gigatons of CO2 equivalent per year."
What do you recommend to the forestry industry?
"Implementation needs to be very well planned and considered. In this context, it is also important to point out that the need to manage uncertainty suggests approaches to climate adaptation that place a strong emphasis on risk management and strategies that can evolve.
"For example, the projections for the water stress of trees are subject to large uncertainties in many places. This is due to other uncertainties, such as precipitation forecasts, carbon dioxide-driven evapotranspiration6 and other factors. Promoting mixed forests offers more flexibility than planting monocultures of drought-resistant tree species. Climate adaptation strategies too often focus on actions that lack flexibility when climate predictions or projected system responses to climate change turn out to be mistaken."
What are these, for example?
"Potential climate impacts include effects resulting from changes in emissions of greenhouse gases other than CO2, changes in the reflectivity of surfaces7, changes in evapotranspiration6, and changes in aerosol concentrations in the atmosphere. However, indirect changes in land use resulting from the expansion of large areas of forest or bioenergy crops may also be causal factors. Depending on the measures taken, their geographic location, their implementation, and their timing, these effects can either mitigate climate change or drive it."
So the interrelationships are complex. Can you summarize?
"Actions focused solely on climate change mitigation, as well as climate adaptation, can have direct and indirect negative impacts on nature and its benefits to humans."
How can our individual readers do their part to slow the triple crisis?
"Three things immediately come to mind that could make a significant contribution to addressing the biodiversity crisis, limiting climate change, and adapting. These are changes in individual consumption patterns, a shift in dietary habits, and a commitment to progress in the sustainable use of natural resources. Demand-driven actions like these will free up land and marine areas that can be used for biodiversity conservation – e.g., reforestation, coastal habitat restoration, protected areas – or for climate mitigation – e.g., afforestation, reforestation, and wind farms."
These sound like changes with consequences that will affect everyone on the planet.
"Major benefits to the environment and human well-being will result if the dietary transition is designed to bring about global equity in health by changing consumption in ways that reduce problems of malnutrition and wasteful consumption, as well as obesity worldwide."
Globally significant – locally implemented. What is particularly important in this implementation and should not be forgotten under any circumstances?
"We have to find the right path between massive emission reductions, biodiversity protection, and the corresponding land protection. Of course it makes sense to invest in strengthening nature, restoring ecosystems, and renaturating forests and increasing their CO2 storage capacity. But if corresponding initiatives lead to companies not further reducing or avoiding activities that cause CO2 emissions, we will miss our climate targets.
"Companies must first reduce their emissions and, on the other hand, invest in the future by providing funds to restore ecosystems to ensure long-term climate protection. It is important to remember that implementing oversimplified approaches and prescriptions for large-scale nature-based solutions such as tree planting can have negative impacts on biodiversity and human livelihoods if the local context is not properly taken into consideration. So ultimately, this is about the well-informed behavior of all of us in the details, but also about advocating for policy changes towards sustainability and quality of life for all people."
1 in the northern hemisphere
2 IPBES stands for Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, also known as the World Biodiversity Council. It is an intergovernmental body providing scientific policy advice on biodiversity. Website: https://ipbes.net
3 IPCC stands for Intergovernmental Panel on Climate Change. On its behalf, experts worldwide regularly compile the current state of knowledge on climate change and evaluate it from a scientific perspective. The IPCC provides a basis for science-based political decisions by identifying different options for action and their implications. It does not, however, propose concrete solutions or make recommendations for action.
4 Anthropogenic is the technical term for that which is influenced, created, produced, or caused by humans.
5 Joint report of IPBES and IPCC (key statements in German): www.ufz.de/index.php?de=44469
6 Evapotranspiration is total evaporation from a naturally vegetated soil surface. It is composed of evaporation and transpiration.
7 This back radiation is expressed in albedo, a measure of the brightness of a body. The brighter the body, the greater the albedo. An important implication is that more the incoming solar radiation is reflected, the brighter the body.
8 Global Report of the World Biodiversity Council (German-language abridged version): www.ufz.de/export/data/2/228053_IPBES-Factsheet_2-Auflage.pdf
Linked online: Interview: If nature is to stabilize the climate in the long term, it needs help. Prof. Hans-Otto Pörtner and Prof. Josef Settele: www.ufz.de/index.php?de=48298