Biodiversity, crucial to human and planetary health, is declining faster than at any time in human history. Agriculture is driving this trend, making food system reform an urgent priority.
Humanity relies on the earth’s natural systems to regulate the environment and maintain a habitable planet. The diversity of life – biodiversity – in any given region creates ecosystems of interacting individual organisms, across many species, that collectively contribute to and support key planetary processes. For example, terrestrial and marine ecosystems remove more than half (60 per cent) of carbon emissions from the atmosphere every year, and thus play a crucial role in regulating the earth’s surface temperature. Ecosystems help buffer the impacts of adverse weather and provide resilience to climate change. The earth’s naturally occurring ecological processes sustain the quality of the air, water and soils that humanity depends on. In addition to providing basic life-enabling conditions, ecosystems are a source of many products vital for survival, including food, fuel, fibre, medicines and shelter. Together, the above processes and goods are known as ‘ecosystem services’ or ‘nature’s contributions to people’.
Food production systems require a diverse range of plants, animals, bacteria and fungi, both for the direct supply of food and to sustain the underlying ecosystem processes that make agriculture possible – from water supply to soil fertility enhancement, pollination and natural pest control.
Beyond food, humanity benefits in a myriad of ways from biodiversity in the environment. While the value is difficult to quantify in monetary terms, biodiversity has clear positive impacts on quality of life through both physical and psychological experiences – via nature as an aid to exercise and discovery, for example, or as a source of education and inspiration. Exposure to natural spaces and access to the richness of animal and plant species around us are associated with positive outcomes for well-being and mental health, even in urban settings. One study estimated the annual monetary value of protected areas, in terms of their positive impact on the mental health of visitors to them, to be much greater than the value of protected-area tourism, and far in excess of the combined budgets of global protected-area management agencies. The ‘planetary health’ concept underlines the intrinsic links between humanity’s well-being and the health of the global ecosystem, and the need to ensure the vitality of ecosystems essential for our survival.
1.1 Trends in biodiversity loss
Despite increasing recognition of the crucial role of biodiversity in maintaining human and planetary health, biodiversity is declining faster than at any time in human history, and perhaps as fast as during any mass extinction. Especially over the past 50 years, biodiversity has been severely compromised and altered at an unprecedented rate. The global rate of species extinction is at least tens and possibly hundreds of times higher than the average rate over the past 10 million years. Around a quarter of species in most animal and plant groups are already under threat from extinction, and around 1 million more species face extinction within decades. In total, the extent and condition of natural ecosystems have declined on average by around 50 per cent relative to their earliest estimated states. Since 1970, the population sizes of mammals, birds, fish, amphibians and reptiles have declined by an estimated average of 68 per cent. Despite the increasingly urgent need to reduce biodiversity loss, recent attempts to arrest the decline have been unsuccessful.
Biodiversity loss applies within agriculture as well as to wildlife: many domesticated plant and animal species that have historically been food sources are becoming less widely consumed. This loss of genetic diversity makes food systems (defined in Box 1, below) less resilient to threats, including pests, pathogens, extreme weather and climate change, thereby threatening global food security.
