Is Climate Change Affecting Species Extinction? Is There Any Reason for Some Optimism on the Theme of Species Extinction?

Last week, a good friend of mine read my blog entry on hurricanes and how climate change is not making hurricanes more frequent or intense. He thought it was well-researched and agreed with the ultimate conclusion. Part of his reply was that hurricanes are only a part of the potential impact of climate change. He specifically asked about whether climate change is exacerbating the extinction of animals. He pointed me to an article from the Guardian that linked a report from the World Wide Fund for Nature. The WWF report found that the global animal population has declined 69 percent in the past 50 years (see below for regional breakdown). Four years ago, that figure was at 60 percent. 

I already feel some skepticism not simply because it is in my nature to be skeptical, but also because there historically has been alarmism from environmentalists. On the theme of climate change, climatologists like to use highly improbable, worst-case modeling to make their point. This is not to say that global temperatures are getting warmer or humanity has not contributed in any respect, but there have been environmentalist doomsday predictions about climate change for decades that never came to be. Thomas Malthus predicted mass starvation due to a growing population when he turned out to be wrong. Rachel Carson did not fare much better with Silent Spring. There were also the scares of acid rain and nuclear winter that did not pan out.

It is due to this historic alarmism that I want to see if species extinction is as bad as it sounds. First, I would like to point out that some species extinctions are bound to happen. The background rate of extinction, which is the pre-human rate that would occur naturally, is about 0.1-1 per 10,000 species per 100 years (Ceballos et al., 2015). Also, 99.9 percent of species have already gone extinct. There have been five extinction events, including the one that wiped out the dinosaurs in the Cretaceous era about 66 million years ago.

Pointing out that species extinction is naturally occurring is not to say that humans have not had an impact on the environment. As the Royal Society points out, human effects on global diversity date back 60,000 years. The year 1500 was when human-induced extinction kicked in and increased the extinction rates (see above), and that has only seems to have worsened since the Industrial Revolution. A study shows that some species would have survived an extra 800 to 10,000 years if it were not for human activity (Ceballos et al., 2015).

This conversation gets further blurred with the idea of speciation, which is the creation of new species. There might be more species in net due to human speciation, although this article from The Atlantic shows that it could come with a cost to biodiversity. The Royal Society discusses how speciation works along side of species extinction. 

The International Union for Conservation of Nature (IUCN) has a Red List with number of endangered species. The Red List has identified more than 41,000 species that are threatened with extinction, although that is likely an underestimation of the actual number. That sounds like a lot of species at first glance. However, we need to answer an even more important question: how many species are on the planet? It makes sense to answer this question to contextualize the species extinction. What is the answer to that question? 

As of 2019, we have identified 1.6 million species. One renowned study estimated that the total count was 8.3 million species (Mora et al., 2011). Scientists have estimated that the range could be from anywhere between 5 million and 1 trillion. This wide range of uncertainty makes it difficult to pinpoint the magnitude of the problem, although we have at least a low-bound estimate. Even if the number is low, it does not stretch the imagination as to how the extinction of certain species can have a ripple effect on various ecosystems. At the same time, multiple species have been wiped out of existence and the planet lives on. 

To play Devil's Advocate, here is an article from the Washington Post in which George Washington University biology professor R. Alexander Pyron argues how preserving biodiversity should not be an ends unto itself, in no small part because species extinction is inevitable. Pyron's solution is moderation:

While we should feel no remorse about altering out environment, there is no need to clear-cut forests for McMansions off 15-acre plots of crabgrass-blanketed land. We should save whatever species and habitats can be easily rescued, refrain from polluting waterways, limit consumption of fossil fuels, and rely more on low-impact renewable energy sources. 

So far, we discover that there is a naturally occurring extinction rate, human activity accelerates said rate, and the number of species on the planet is unknown. Given the political climate (pun intended), it seems convenient to blame anthropogenic climate change. However, the main driver is not climate change. According to a 2018 WWF report, "the main drivers of biodiversity decline continue to be the overexploitation of species, agriculture, and land conversion."

While there are some discouraging trends in terms of species extinction, there is also some reason for optimism on the theme of species extinction when looking to the future: 

• The Food and Agricultural Organization (FAO) shows that land use for agricultural purposes per capita is about half of what it was in 1961. This leaves room to use the land for other uses, such as forestation. Oxford also points out that we have already reached and passed peak agricultural land use.
• A study using NASA data shows that the Earth has gotten greener during the first 15 years of the 21st century (Chen et al., 2020). A greener earth will not only cool down global temperatures, but it will help with maintaining biodiversity and helping species to rebuild. 
• Since 2010, protected areas covering 21 million square kilometers (or the size of the Russian Federation) have been added to the global network of protected ares (Protected Planet).
• Dematerialization seems to be manifesting. As Co-Director of the MIT Initiative on the Digital Economy Andrew McAfee explained on a podcast, many developed nations are learning to reduce its usage of timber, metals, and fertilizer. This article from 2015 uses data to show how dematerialization takes place. Such dematerialization can take some pressure off of ecosystems.
• In his book Inheritors of the Earth, University of York conservation biologist Chris Thomas argues that humans have been enriching local diversity by "moving around and introducing species to areas where they were previously absent." 

We need to weigh the costs and benefits of keeping species alive, much like we do with any other policy. We also do not need to choose between the economy and the environment. As one optimistic paper in BioScience arguing about how we will regain conservationism this century, "the only sensible path for conservation is to continue its efforts to protect biodiversity while engaging in cities to build the foundations for a lasting recovery of nature (Sanderson et al, 2018)." Rather than give into despair, there is reason to be optimistic. A combination of technological development, urbanization, and economic advancement will likely result in the freeing up land for conservation and development of biodiversity, thereby evading most, if not all, the catastrophic predictions about species extinction.