Assessing change over the past five decades, the report provides a comprehensive understanding on the relationship between economic development pathways and its impacts on nature. The report then offers a range of possible scenarios for the coming decades with the most dire scenarios forecasting the loss of approximately one million animal and plant species, many within decades.
- Some of the findings on species from the report include:
- The current total estimated number of plant and animal species is 8 million (which includes the 5.5 million insect species).
- Three-quarters of the land-based environment and nearly two-thirds of the marine environment have been “severely altered” by human actions.
- More than 85 percent of wetlands present in 1700 were lost by 2000, and wetland loss is currently three times faster, in percentage terms, than forest loss.
- In 2015, 33 percent of marine fish stocks were being harvested at unsustainable levels; 60 percent were maximally sustainably fished, with just 7 percent harvested at levels lower than what can be sustainably fished.
- The average abundance of native species in most major land-based habitats has fallen by at least 20 percent, mostly since 1900.
- The numbers of invasive alien species per country have risen by about 70 percent since 1970, across the 21 countries with detailed records.
- More than 40 percent of amphibian species are threatened with extinction.
- Twenty-five percent (average proportion) of species are threatened with extinction across terrestrial, freshwater, and marine vertebrate, invertebrate, and plant groups (that have been studied in sufficient detail).
- There has been a 30 percent reduction in global terrestrial habitat integrity caused by habitat loss and deterioration.
To increase the policy relevance of the report, the report ranks the five direct drivers of changes with the largest relative global impacts so far: (1) changes in land and sea use, (2) direct exploitation of organisms, (3) climate change, (4) pollution, and (5) invasive alien species. Noting that, since 1980, greenhouse gas emissions have doubled, raising average global temperatures by at least 0.7 degrees Celsius, the negative impacts from climate change are expected to increase over the coming decades, in some cases surpassing the impact of land and sea use change and other drivers.
Gains from societal and policy responses have not stopped massive losses and the report warns the impacts will continue to 2050 and beyond. Yet, the report provides a glimmer of hope that if every level, from local to global, starts transformative change now, nature can be conserved, restored, and used sustainably. The report presents a wide range of illustrative actions for sustainability and pathways for achieving them across and between sectors.
The Summary for Policymakers of the Global Assessment Report is available at bit.ly/IPBESReport. The full report, expected to exceed 1,500 pages, will be published later this year.