Global Lake Health

Lakes, when healthy, provide many ecosystem services that are essential for human well-being, ranging from providing drinking water and food to supporting biodiversity and recreation. Not all lakes around the world are, however, healthy. Here, we assess the current status of global lake health by reviewing common visible and invisible lake health problems around the world. Our review shows that the majority of the world’s 1.4 million lakes ≥ 10 ha suffer from one or more health problems. Although widespread, the kind of lake health problems and their direct threats to human health show large geographical differences. Most critical is the health of lakes that are located in densely populated low-income countries. We regard approximately 115,000 lakes on Earth as being critically degraded, which poses not only a severe direct threat to the health of more than 153 million people who live around them but also to all those who are dependent on their ecosystem services. Because lake health problems show distinct differences between continents, countries and also on smaller scales, preventative, treatment and rehabilitation strategies are needed across all scales, from local to global. On the global scale, priority should be given to mitigate climate change and to regulate the rapid release of anthropogenic chemicals into the hydro-, bio- and atmosphere, as the health risks of all the ongoing uncontrolled chemical reactions are largely unknown. We recommend coordinated multidisciplinary and multisectorial preventative, treatment and rehabilitation strategies, based on improved environmental regulations, timely policy reviews, and extensive stakeholder and citizen engagement. If those are not implemented in the near future, threats to the health of millions of people will become increasingly severe.