Extinction footprints

It is a sad result of human civilisation that we are driving other species into extinction. A new study highlights the main driving forces – rich countries’ consumption.

Humans have always affected their environment. Environmental history  is littered with stories of modifications of the environment to enhance  the growth of fruit-bearing plants and the impact of our hunting. In the  Americas, the late arrival of humans resulted in an extinction of most  large game – and their predidators, a story repeated quite impressively  and even more rapidly by the Polynesians who settled in New Zealand. The  scale of our impact on nature, however, has never been larger. And  while climate change looms as an important threat to species, it is  other mechanisms with which we are currently endangering biodiversity.  According to the Millenium Ecosystem Assessment,  the most important causes for ecosystem impacts are habitat change  (land use change, river change etc), the overfertilization of ecosystems  with phosphorus and nitrogen, invasive species, and unsustainable  fishing and hunting practices.

A new analysis by Manfred Lenzen and his team at the University of Sydney,  published in the prestigious journal NATURE, provides us with new  insight into the human causes of extinctions, in this case specifically  animal extinctions. The analysis is based on the information on causes  of individual species threats and extinctions of animals listed in Red  Lists of threatened species. These listings provide a specific  assessment of the threat, like hunting, poaching, specific types of  agriculture etc. The analysis connects these causes to economic  activities and traces these activities through the world economy. What  we learn from the analysis is that about 30% of all species threats are  caused by products that are traded internationally. The main products  are agricultural products, including coffee, tea and tabacco, but  forestry products also feature prominently. This is in fact an amazingly  large number, given that most of the food consumed is still grown  locally. The cause behind this high number is that it is high value  products that are traded internationally, and these appear to cause a  high impact.

The pattern that further emerges from the analysis is that rich  country’s consumption causes species threats in poor countries. This is a  pattern familiar also from the carbon footprint of nations, and it is  the same countries that are the main perpetrators, but it is different  countries where the species go extinct from where the coal is fired:  countries like Papua New Guinea, Madagaskar, and the large Pacific  Island nations of Southeast Asia feature prominently.

In a snazzy web tool,  the Sydney team displays the results of their analysis on a country  level. Here you can find out that Norway threatens 35 species on Red  Lists through domestic economic activity, mostly through fishing and  forestrly, that its imports cause 31 species threats in other countries,  and that of the 35 species threats, 14 are connected to exports. This  means that Norway is a net importer, and that its consumption causes 52  species threats, and that is quite a lot for such a small country.

I have had the honor to comment this paper in NATURE.  In my comment, I point to the need to better understand the mechanism  of these extinctions. I also question whether the extinctions can really  be effectively reduced by more benign production methods helped through  product labelling, or whether it is the overall scale of the human  enterprise that requires the land use and thus endangeres a lost of life  forms on Earth.