Biodiversity loss

Biodiversity loss happens when various species disappear completely from Earth (extinction) or when there is a decrease or disappearance of species in a specific area. This in turn leads to a reduction in biological diversity in that area. The decrease can be temporary or permanent. It is temporary if the damage that has led to the loss is reversible in time, for example through ecological restoration. If this is not possible then the decrease is permanent. This ongoing global extinction (also called the holocene extinction or sixth mass extinction) is a biodiversity crisis. The cause for most of the biodiversity loss are those human activities that push the planetary boundaries too far.

The causes for current biodiversity loss are habitat loss, fragmentation and degradation; land use intensification (and ensuing land loss/habitat loss), often for commercial and agricultural uses (specifically monoculture farming). Further causes include nutrient pollution and other forms of pollution (air and water pollution), over-exploitation and unsustainable use (related to human overpopulation), invasive species and climate change.

Many scientists, along with the Global Assessment Report on Biodiversity and Ecosystem Services, say that the main reasons for biodiversity loss are the growing human population and excessive consumption. However other scientists have criticized this, saying that loss of habitat is caused mainly by "the growth of commodities for export". They also state that population has very little to do with overall consumption due to country wealth disparities.

Climate change is another threat to global biodiversity. For example, coral reefs – which are biodiversity hotspots – will be lost within the century if global warming continues at the current rate. However, habitat destruction (often for the expansion of agriculture), is currently the more significant driver of biodiversity loss, not climate change. Invasive species and other disturbances have become more common in forests in the last several decades. These tend to be directly or indirectly connected to climate change and have negative consequences for forest ecosystems.

Groups that care about the environment have been working for many years to stop the decrease in biodiversity. Now, preventing biodiversity loss is often included in global policies. It can be part of the response to the triple planetary crisis. For example, the UN Convention on Biological Diversity aims to prevent biodiversity loss and to conserve wilderness areas. However, a report of the United Nations Environment Programme in 2020 found that most of these efforts had failed to meet their international goals. For example, of the 20 biodiversity goals laid out by the Aichi Biodiversity Targets in 2010, only six were "partially achieved" by the deadline of 2020.