What is biodiversity and why does it matter?

Last updated: 04/03/2022

Biodiversity is the diversity of life on Earth: within species, between species and between ecosystems. Within species it refers to the variation of genetic traits between individuals or populations of that species, which is critical for its capacity to adapt to changing conditions. Between species it refers to the Earth's estimated (depending on methodologies used) 8.7 million to 1 trillion species of plants, animals and microorganisms, of which about 1.75 million have been recorded. Between ecosystems it refers to the variety of forest, desert & dryland, mountain, wetland, marine, river & lake, and agricultural habitats that house these species, defining their interaction with the soil, water and air. Finally, biodiversity goes beyond the taxonomic (pertaining to types and numbers of component genes, species or ecosystems): between species there is also phylogenetic diversity (diversity of species' evolutionary lineages) and functional diversity (the range of species traits that influence ecosystem functioning). When evaluating a region's species diversity one should therefore consider not only the numbers and populations of species present (taxonomic diversity) but also how far apart these species lie on the evolutionary tree (phylogenetic diversity), as well as the range of ecological functions they serve (functional diversity).

This combination of life forms, functions and interactions is the result of billions of years of evolution shaped by natural processes, making our planet uniquely habitable for human beings. And yet, human intervention is fundamentally – and to a significant extent, irreversibly – destroying the Earth's biodiversity at a pace never observed before.

Biodiversity and ecosystems sustain our lives via a range of essential services that can be classified into 3 types:

• Provisioning: providing food, water, fuel, shelter, genetic resources, medicine
• Regulation & Maintenance: pollination, decomposition, water purification, erosion and flood control, disease control, carbon storage, adaption to climate and other changes, lifecycle maintenance, soil regulation
• Cultural: enhancing cultural identity & heritage, creative inspiration, recreation.

Why is global biodiversity governance important?

Unprecedented global economic growth (global economic activity increased more than 13-fold in 70 years) has had an equally unprecedented impact on nature. The anthropogenic drivers of biodiversity loss are either steady or increasing in intensity. The main direct drivers are changes in land- and sea-use, direct exploitation of organisms, climate change, pollution, and invasion of alien species. Underlying these five direct drivers are the indirect drivers relating to production and consumption patterns, human population dynamics, trade, technology and governance. The costs of damaging nature are not reflected in market prices, and give rise to "externalities." They need to be factored into economic analyses and decision-making. From 1997 to 2011, the world lost an estimated €9-39 trillion per year in ecosystem services owing to land-cover change and land degradation. These costs and benefits are unequally distributed. In particular, poor and indigenous communities that have benefited least from economic growth often inhabit high-biodiversity areas, are more dependent on natural capital for daily sustenance, and more vulnerable to biodiversity loss.

As a result of human intervention, the Earth may already have entered a new epoch, the Anthropocene, functionally distinct from the Holocene. This is borne out by studies of biogeochemical signatures and of "planetary boundaries," the quantitative boundaries within which nine critical biophysical earth-system processes operate, and beyond which irreversible environmental change is likely. Of the nine, "biosphere integrity" has gone farthest in transgressing its boundary, while two closely related processes (land-use change and climate change) are also in the danger zone. Changes in biodiversity were more rapid in the past 50 years than at any time in human history, and are projected to continue or accelerate. The planet lost 50% of its wetlands, 40% of its forests and 35% of its mangroves during the last century. Species extinction rates, currently estimated at 100 to 1000 times higher than over the past tens of millions of years, are continuing to rise. But biodiversity cannot be measured via species or ecosystem abundance alone. Its multiple levels (genes, species, ecosystems) and attributes (taxonomic, phylogenetic, functional) require a plethora of indicators. This fact also motivated a revision of the biosphere integrity measure in the planetary boundary framework. For governance purposes, biodiversity loss is defined as “the long-term or permanent qualitative or quantitative reduction in components of biodiversity and their potential to provide goods and services.”

Nature does not recognise national borders. Moreover, given our increasingly globalised economy, neither does the main underlying driver of biodiversity loss: unsustainable economic growth. For instance, consumer demand in high-income countries entrains biodiversity loss in low-income ones where local communities are most dependent on natural capital. Globally coordinated biodiversity governance is thus crucial for reversing biodiversity loss and restoring ecosystems while ensuring the wellbeing of all, especially the most vulnerable. The overall benefit-to-cost ratio of an effective global programme for nature conservation has been estimated to be at least 100 to 1.

It is now widely accepted that reversing biodiversity loss will entail global transformative change: fundamental system-wide reorganisation across technological, economic and social factors, including paradigms, goals and values. The drivers of biodiversity loss need to be disrupted, as well as the underpinning societal values and behaviours. This in turn requires transformative governance, whose requisites include ensuring coherence and integration of ecological concerns in different sectors, participation of local and marginalised communities, democratic institutions, continuous adaptation to complex environmental change, and recognition of multiple legitimate perspectives on biodiversity.