We Are in the Midst of the Sixth Mass Extinction. What Is It? What Is Causing It? How Can We Slow It Down?

March 28, 2021 by John Pullman

What is it?

Biodiversity–a metric that accounts for the number of distinct species of flora and fauna on Earth–is greater now than ever before.[1] However, scientists expect that to change. Historically, there have been five mass extinction events, and many scientists now predict the planet is entering a sixth.[2] A mass extinction event occurs when there is a greater than anticipated natural extinction rate over a relatively short time period. In previous mass extinction events, 75-90 percent of all species went extinct in just a few million years.[3] Alarmingly, over the past few decades, extinction rates have been hundreds to thousands of times greater than those in the tens of millions of years prior.[4] For instance, over 400 vertebrate species have gone extinct in the past 100 years; normally, that should have taken about 10,000 years.[5]

The species going extinct often have significant roles in proper ecosystem function.[6] Moreover, the extinction of just one major species can substantially affect other species in the same ecosystem. Since species in our ecosystems typically rely on one another for food and population control of predators, losing a major species can decimate the entire ecosystem. Finally, people need healthy levels of biodiversity, which helps maintain clean air, provides food resources, and aids medicine development.[7] This all underscores the importance of pinpointing the causes of the increased extinction rate and determining how to slow it down. Although biodiversity may eventually recover as it has in the past, that recovery could take millions of years.[8]

What is causing it?

Human activity appears to be the source of increasing extinction rates.[9] Of the 8,688 species listed as threatened or near-threatened, “72% (6,241) are being overexploited for commerce, recreation or subsistence.”[10] Under the Endangered Species Act (ESA), a species is threatened when they are likely to become endangered within the foreseeable future.[11] “Near-threatened” is a term that the IUCN created to describe species that are likely to be classified as “threatened” in the near future.[12] In this study, the researchers concluded the major causes of the increased extinction rate were overexploitation of wildlife and changing agricultural practices.[13]

Overexploitation accounts for human practices like logging, hunting, fishing and plant gathering.[14] Of these activities, logging is the greatest contributor to the destruction of biodiversity.[15] Logging refers generally to the practice of cutting down trees and using them for timber or pulp production.[16] This leads directly to deforestation, and therefore, rampant habitat destruction.[17] Out of the 8,688 species in the aforementioned study, 4,049 species were affected by logging, making this practice by far the biggest culprit in population decline.[18]

A different study published recently in the Nature Sustainability Journal analyzed models that, based on historical trends, predicted growth in agricultural land use. Out of 19,859 vertebrate species that preferred the habitats analyzed, 87% were predicted to lose at least part of their habitats to agricultural expansion by 2050.[19] This study supports the idea that agricultural practices are another big factor for which models must account to effectively slow the extinction rate.

What can we do to prevent it?

One thing we can do to mitigate the damage is take action against illegal logging. Illegal logging accounts for a large amount of deforestation, especially in tropical areas where there is a large concentration of biodiversity.[20] To cut down the amount of illegal logging that takes place, it will be important to work with local governments and authorities at sites where a large amount of illegal logging occurs.[21] The International Union for the Conservation of Nature (IUCN) determined illegal logging is profitable for many communities that need the money, and because of this, many are willing to overlook the lack of long-term negative impact on sustainability.[22] However, in 2014, Omar Vidal and colleagues conducted a twelve-year study that examined the efficacy of conservation action in a forest in Mexico.[23] The researchers found that illegal logging affected a larger percentage of the land than any other human activity between 2001 and 2009.[24] Then, after years of engagement in Vidal’s study area, the World Wildlife Fund (WWF) convinced local authorities that stopping the destruction of forests would be economically beneficial in the long run.[25] The WWF was able to convince this community in part by providing economic support and alternatives for employment in the logging industry.[26] The Mexican government also made sure to contribute by providing enforcement through their own state and federal authorities.[27] Thereafter, the effects from large scale logging in the area decreased significantly each year until it was gone entirely in 2012.[28]

Jones et al. conducted a ten-year study to see how improved access to healthcare and education affected illegal logging and deforestation in rural Borneo in Malaysia.[29] This research started from the premise that poverty and a lack of access to essential resources were a major factor incentivizing illegal logging and deforestation.[30] To fix this problem, researchers wanted to see if providing communities with access to healthcare and periodic education could reduce deforestation in those communities.[31]Researchers partnered with a non-profit organization and were able to set up clinics with discounts to “offset costs that would historically be met with illegal logging.”[32] Over the course of the study, 28,462 unique patients were treated at the clinics.[33] In the end, illegal logging decreased the most in areas that were closest to the villages      with the most participation.[34] Surveys also found that over 97% people living in the participating villages thought the efforts were successful in reducing illegal logging and deforestation.[35]

Both of the above studies suggest that illegal logging is incentivized because communities near forest ecosystems lack access to important resources and economic support. Based on the results, to curb illegal logging and deforestation, we need to provide more economic stability to the communities that benefit the most in the short term from illegal logging. These studies suggest that if these communities are more economically secure, they will have less of incentive to participate in illegal logging. If there is less illegal logging, there will be less deforestation and a preservation of biodiversity.[36] This can be accomplished by working with local governments and authorities to provide more of these essential resources as well as education on the long term effects of deforestation.[37]

Illegal logging is the largest contributor to biodiversity loss, but other activities we can focus on more generally are agricultural and hunting practices.[38] Many current agricultural practices destroy habitats unnecessarily and therefore decrease biodiversity.[39] One action people can take to prevent this is to make more of an effort to ensure that pesticides do not spill over onto any land where they are not necessary.[40] People can also reduce the need to spray pesticides by creating and deploying disease resistant strains of crops.[41] Bushmeat hunting is the hunting of wildlife for human consumption and it is an unsustainable practice that is contributing greatly to mass extinction.[42] This problem can be assuaged through more clear legal regulation as well as an increase in education about the dangers of over hunting.[43]

Between illegal logging, agricultural practices, and bushmeat hunting, humans are contributing significantly to the sixth mass extinction event. However, there is a lot we can do to mitigate the damage. It is important that we work with the communities that participate the most in these practices and educate as many people as possible regarding the potential consequences of a mass extinction event such as the loss of food, medicine and a reduction in air quality.[44]


[1] M. J. Benton, Diversification and Extinction in the History of Life, 268 Science 52, 58 (Apr. 7, 1995), https://science.sciencemag.org/content/268/5207/52?ijkey=aa3ce814e4891b1c361a7af316f36e6369b82095&keytype2=tf_ipsecsha, [https://perma.cc/HMG5-4YPB].

[2] Gerardo Ceballos et al., Vertebrates on the Brink as Indicators of Biological Annihilation and the Sixth Mass Extinction, 117 Proceedings of the National Academy of Sciences 13596, 13602 (June 1, 2020), https://www.pnas.org/content/117/24/13596#ref-2, [https://perma.cc/XY9F-YYME].

[3] Id.

[4] Id. (comparing the larger, contemporary rate of extinction compared to that of lower, historical rates).

[5] Id. at 13,596–97.

[6] Id. (Explaining that the extinctions will have an effect on the ecosystems in which species formerly belonged).

[7] See generally Patrick ten Brink et al., The Health and Social Benefits of Nature and Biodiversity Protection, Inst. for Eur. Envtl. Pol’y (Apr. 28, 2016), https://ec.europa.eu/environment/nature/biodiversity/intro/docs/Health%20and%20Social%20Benefits%20of%20Nature%20-%20Final%20Report%20Main%20sent.pdf, [https://perma.cc/XD8Q-4ZDL].

[8] Ceballos et al., supra note 2.

[9] Maxwell et al., Biodiversity: The Ravages of Guns, Nets and Bulldozers, 536 Nature 143, 145 (Aug. 11, 2016), https://www.nature.com/news/biodiversity-the-ravages-of-guns-nets-and-bulldozers-1.20381, [https://perma.cc/B5H8-C5FN].

[10] Id.

[11] 16 U.S.C.  § 1532.

[12] Maxwell et al. supra note 9.

[13] Id.

[14] Id. (describing human practices that have contributed most to elevated extinction rates).

[15] Id.

[16] Id. (explaining what the practice of logging is and how it leads to deforestation).

[17] Id.

[18] Id.

[19] David Williams, Proactive Conservation to Prevent Habitat Losses to Agricultural Expansion, Nature (Dec. 21, 2020), https://www.nature.com/articles/s41893-020-00656-5, [https://perma.cc/4ST4-QNUH]

[20] See generally Hironori Toyama et al., Effects of Logging and Recruitment on Community Phylogenetic Structure in 32 Permanent Forest Plots of Kampong Thom, Cambodia, 370 The Royal Society Publishing 1, 13  (Feb. 19, 2015), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4290422/#RSTB20140008C1, [https://perma.cc/2YEC-2G36].

[21] Id.

[22] Jones et al., Improving Rural Healthcare Reduces Illegal Logging and Conserves Carbon in a Tropical Forest, 117 Proceedings of the National Academy of Sciences 28,515, 28,515 (Oct. 26, 2020), https://www.pnas.org/content/pnas/117/45/28515.full.pdf, [https://perma.cc/B9EB-6NB2].

[23] Omar Vidal et al., Trends in Deforestation and Forest Degradation after a Decade of Monitoring in the Monarch Butterfly Biosphere Reserve in Mexico, 28 Conservation Biology 177, 186  (Sept. 3, 2013), https://conbio.onlinelibrary.wiley.com/doi/epdf/10.1111/cobi.12138, [https://perma.cc/HB9K-ERLL].

[24] Id. at 180–82.

[25] Id. at 183–84 (explaining how the researchers convinced the local communities that it was economically beneficial to stop illegally logging).

[26] Id..

[27] Id.

[28] Id. (exhibiting the how the study results showed a steep decline in illegal logging).

[29] Jones et al., supra note 22 at 28,515.

[30] Id.

[31]  Id.  (explaining how a lack of access to healthcare can lead to poverty, which can then drive families to rely on resources like illegal logging).

[32] Jones et al., supra note 22 at 28,516.

[33] Jones et al., supra note 22 at 28,517.

[34] Jones et al., supra note 22 at 28,515 (explaining the clear correlation between participation in the clinics and decreases in illegal logging; this implies that providing communities with healthcare helped disincentivize illegal logging).

[35] Jones et al., supra note 22 at 28,520.

[36] See generally Jones et al., supra note 22.

[37] See generally Jones et al., supra note 22.

[38] Maxwell et al., supra note 9 at 145.

[39] Raven and Wagner, Agricultural Intensification and Climate Change are Rapidly Decreasing Insect Biodiversity, 118 Proceedings of the National Academy of Sciences, 1, 1-2 (Aug. 24, 2020), https://www.pnas.org/content/pnas/118/2/e2002548117.full.pdf, [https://perma.cc/B25T-KW79].

[40] Id. at 5.

[41] Id. at 5.

[42] Ripple et al., Bushmeat Hunting and Extinction Risk to the World’s Mammals, Royal Society Open Science 1, 2 (Sept. 20, 2016), https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.160498, [https://perma.cc/MCJ3-ZASB].

[43] Id. at 10-12.

[44] Patrick ten Brink et al., supra note 7.