As predictions on the future will inevitably vary, and will rightly be argued over, any solid scientific assessment needs to base itself on analysis of data available today, not projected to any future date, as that requires extrapolation of data according to variables, that due to their nature of being variables, can’t as of yet be defined. Therefore, any assessment of species extinctions need to be based on analysis of data that is available to us today, from observations that come from the past leading up to the present. One useful resource to assess extinctions is the IUCN Red List of Threatened Species. In 2016, the journal Nature published an interesting infographic based on the 2016 IUCN Red List of Threatened Species. Here it is below:
From the infographic above, we can list the “big killers” of species, or the main reasons for extinctions in the order set below:
- Overexploitation (6,241 species)
- Agricultural Activity (5,407)
- Urban Development (3,014)
- Invasion and Disease (2,298)
- Pollution (1,523)
- System Modification (1,865)
- Climate Change (1,688)
- Human Disturbance (1,223)
- Transport (1,219)
- Energy Production (913)
With regards to using data from 2016, the authors write that this study takes into account data that make it relevant for at least a ten year period, therefore at least until 2026:
For Red List assessments, the impacts of future threats (including climate change) in reducing a species’ population size are projected across three generations or over a ten-year period — whichever is longer. Hence, unless the species being assessed is long-lived (with an expected lifespan of 30–50 years, say), projections cover a period during which the effects of climate change, in particular, will be relatively modest.
The authors of the article based on the Red List conclude:
Of all the plant, amphibian, reptile, bird and mammal species that have gone extinct since AD1500, 75% were harmed by overexploitation or agricultural activity or both (often in combination with the introduction of invasive alien species). Climate change will become an increasingly dominant problem in the biodiversity crisis. But human development and population growth mean that the impacts of overexploitation and agricultural expansion will also increase..we appeal to all concerned with the sustainability of life on Earth to take stock of the current balance of threats — and refocus their efforts on the enemies of old.
The analysis was performed by a four-person team under lead author Sean Maxwell, a PhD candidate in environmental management at the University of Queensland, where co-authors Richard Fuller and James Watson are both associate professors. Fourth author is Thomas Brooks, head of science at the International Union for Conservation of Nature (IUCN) – the organisation that maintains the global Red List of endangered species.