The most effective solutions to the world’s many challenges requires us to work across disciplines and across sectors

The world is facing multiple challenges. We are in the midst of climate and nature emergencies, with freshwater security, food security and human health and wellbeing also threatened, yet as scientists, we are trained to focus on narrow disciplines. This is also reflected in the way we address problems globally, often focusing on one issue at a time, and having separate UN bodies, e.g. IPCC, IPBES and FAO, to suggest solutions. Recent efforts globally have begun to work across disciplines to try to find solutions that can help address multiple problems at the same time.

Many options exist to tackle various global challenges, and many can co-deliver to multiple challenges. “One-size-fits-all” solutions are not normally possible. Interventions need to be locally tailored according to circumstances, and that they will be most effectively delivered when co-designed with a range of relevant stakeholders, including indigenous peoples and local communities.  Where potential trade-offs exist, these need to be managed carefully, but taking a nexus approach allows these trade-offs to be foreseen, and approaches to be planned to minimise trade-offs.

For many potential interventions, they can lead to either positive or negative impacts on one or more nexus elements depending upon how they are implemented. Take tree planting as an example. If a mix of native tree species is planted in an area that can support woodland on suitable soils with minimal soil disturbance, can provide benefits for climate change mitigation and adaptation, for nature, for water, for health and wellbeing and potentially even for food (edible fungi). If, however, a single-age tree monoculture of non-native species is planted on unsuitable soils or in areas which would not normally support woodland, far fewer benefits, and often trade-offs across multiple nexus elements can occur.

For most interventions, practical barriers to implementation exist. Factors such as institutional inertia, resource constraints, and the misalignment of planning horizons across sectors are key barriers to practical implementation, as are factors prevalent in the broader political economy, such as power asymmetries, vested interests, and governance fragmentation. Improved cross-sectoral governance can help to overcome such barriers. Key platforms to address simultaneous global challenges include the G20, the IMF, and the World Bank, so implementation could be enhanced by these platforms.

Some interventions act as enablers for others, so bundling and/or sequencing these interventions would yield the greatest benefits. Take for example dietary change toward more plant-based diets in overconsuming countries. This demand-side option not only significantly reduces greenhouse gas emissions, contributing positively to climate change mitigation, it also reduces pressure on land, freeing land for conservation and more environmentally friendly farming practices so is good for biodiversity, as well as improving dietary health. So, implementing policies to encourage a reduction in animal product consumption acts as an enabler for many other actions, improving their efficacy.

There are many examples of options to tackle various global challenges that have been implemented in ways that only consider the impact on the challenge they are meant to address. Because of this narrow way of thinking, we are missing out on potential synergies that would help us to deliver to multiple challenges simultaneously. Designing options from the outset to co-deliver to multiple challenges would improve efficiency and reduce total cost. It is vital that we progress beyond narrow ways of thinking, and to adopt a “nexus” approach to tackling global challenges.