Tree planting projects help tackle the climate crisis, but they can also impact water suppliesCostfoto/NurPhotoThe major environmental, social and economic crises facing the world today involving biodiversity, climate change, health, food and water are inextricably interlinked, and tackling them together has many benefits. Focusing on one issue alone, however, can make the other crises worse.That is the conclusion of a major report put together by 165 researchers from 57 countries over the past three years, and approved by the governments of 147 countries. AdvertisementThe UN conventions on issues such as biodiversity and climate focus on these problems individually. So what hasnt been done before that we now do in this report is to join all of that together and show looking at these crises individually not only is inefficient but actually has a real danger, says Paula Harrison at the UK Centre for Ecology & Hydrology, who co-chaired the assessment process for the report. Action is urgent, but if we dont act in a way that takes account of these interdependences, it will cause new problems or make existing problems worse.Harrison says the scientific studies assessed for the report provide strong evidence that there are many actions that can be taken that have beneficial effects in all five areas simultaneously. These include conserving and restoring mangrove forests, boosting soil health and carbon content, creating early warning systems for all kinds of hazards, reducing the risk of diseases spreading from animals to humans, universal healthcare and international cooperation on technologies related to these issues.There are trade-offs: the actions with wide-ranging benefits arent the same as the actions that are the most optimal solution to any one problem, she says. Unmissable news about our planet delivered straight to your inbox every month.Sign up to newsletterWhat you cant do is get the highest possible value all at the same time, says Harrison. You cant optimise food production and not have negative impacts on everything else, but you can have a balanced approach across them all that benefits them all.Harrison gives the example of planting trees to remove carbon dioxide from the atmosphere. If the focus is solely on climate, the trees chosen may be fast-growing exotic species that dont support any wildlife and impact water supplies by taking up too much water. But if projects take a more holistic approach, they would choose native tree species that use less water and boost biodiversity. They might not sequester quite as much carbon, but they will provide a lot of value for other aspects of the system, says Harrison.There are also economic benefits to an integrated approach that helps preserve biodiversity as well as achieving other goals. The Nexus report, as it is officially known, says that more than half of global gross domestic product $50 trillion is moderately to highly dependent on nature.It is estimated that the unaccounted-for costs of current approaches to economic activity reflecting impacts on biodiversity, water, health and climate change, including from food production are at least $10 to 25 trillion per year, Pamela McElwee of Rutgers University in New Jersey, the other co-chair, said in a statement.Theres a lot of evidence now if we carry on the way that we are, there are very strong and increasing biophysical risks to economic prosperity and financial stability, says Harrison.The Nexus report was put together by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), which is a non-UN body but works in a similar way to the Intergovernmental Panel on Climate Change. The report was officially approved on 16 December by representatives of the 147 member states of IPBES, meeting in Namibia.The report is very ambitious, says Anne Larigauderie, the executive secretary of IPBES. The aim is to provide the science and evidence needed to support the achievement of other international treaties, she says, including the UN Sustainable Development Goals, the Kunming-Montreal Global Biodiversity Framework and the Paris Agreement on climate change.Topics: