Respecting Planetary Boundaries - Life in the Anthropocene

Before diving into specific sustainability issues, we'll get an overview of some of the key "planetary boundaries," as outlined by Carl Folke In Chapter 2 ofIs Sustainability Still Possible? As you'll see, we'll go over some of these in more detail in this lesson. One important term that Folke does not define, but is important to understand, is ecosystem services. The National Wildlife Federation defines an ecosystem service as:

"any positive benefit that wildlife or ecosystems provide to people."

Examples include plants that convert carbon dioxide into oxygen, fisheries that naturally replenish themselves and feed humans, wetlands that filter toxins and mitigate storm impacts, soil organisms that foster plant growth, and bees that pollinate food crops and other plants. We could cite innumerable examples, but without ecosystem services, life on earth would not be possible. Further, much of what we depend on for survival is offered for free by nature. Most ecosystem services are performed by the biosphere, which "includes all living organisms on earth, together with the dead organic matter produced by them." (Credit: Encyclopedia of Earth).

The following is a summary of some key points from the readings:

• Folke starts out with a brief discussion of the biosphere, which is "the living part" of the area on and near the earth's surface.
• He points out that humans have become "a dominant force in the operation of the biosphere."

The time that we find ourselves in now is what he terms the "Anthropocene," which he defines as "the age in which human actions are a powerful planetary force shaping the biosphere."

• Note that the term "Anthropocene" is well-known in scientific circles - Folke is nowhere near alone in using it! Regardless, the unprecedented success of the human species during this time has "to a large extent...been enabled by the human ability to draw on the functioning of the biosphere." He notes that ecosystem services (e.g., "fertile soils, storm protection, and sinks for greenhouse gases and other wastes") have played an essential role in humanity's success.
• He points out that there have been many positive benefits to people, but that we are overburdening the biosphere and risk "undermin(ing) the capacity of life-supporting ecosystems to...provide the essential ecosystem services that human well-being ultimately depends on."
• If we humans are to continue the success that we have realized in the past few thousand years, he believes that we need to work on reducing our ecological impact to the point that ecosystems can continue to thrive and provide essential services. In order to do this, he points to the need to measure our impact in "critical biophysical processes in the Earth's system." These are termed the "nine planetary boundaries."
• The nine planetary boundaries provide metrics that can be analyzed to determine if humans are overusing ecological capacity. They are called "boundaries" because they represent indicators of when we have crossed into dangerous territory. He is careful to point out that there is some uncertainty with some of the boundaries, but that they provide the best scientific analysis of whether or not humanity is operating within safe ecological limits. 

Figure 3.1. The Nine Planetary Boundaries. The green areas indicate sectors where humans are operating within safe margins, the yellow indicate uncertain but "increasing risk," and the red indicates "beyond the zone of uncertainty."

Credit: Azote for Stockholm Resilience Centre, Stockholm University. Based on Richardson et al. 2023, Steffen et al. 2015, and Rockström et al. 2009, CC BY-NC-ND 3.0

The Great Acceleration

By now you should have a sense that humans are using resources at an unsustainable rate. As we have seen previously, it is important to look at specific metrics when possible. The International Geosphere-Bioshpere Programme (IGBP) did just that when they looked at what they consider key socio-economic and earth system trends. What they found is frequently referred to as the Great Acceleration. (See the full original report here, if you are interested.)

Here is how they described what they found (emphasis added in bold): "The second half of the 20th Century is unique in the history of human existence. Many human activities reached take-off points sometime in the 20th Century and sharply accelerated towards the end of the century...The last 60 years have without doubt seen the most profound transformation of the human relationship with the natural world in the history of humankind." (Source: International Geosphere-Biosphere Programme)

The charts below provide a stark illustration of the Great Acceleration. Every indicator - world population, real GDP, foreign direct investment, urban population, primary energy use, fertilizer consumption, large dams, water use, paper production, transportation, telecommunications, international tourism, carbon dioxide, nitrous oxide, methane, stratospheric ozone, surface temperature, ocean acidification, marine fish capture, shrimp aquaculture, coastal nitrogen, tropical forest loss, domesticated land, and terrestrial biosphere degradation - took a sharp upward (upward is bad) turn sometime around the mid-20th century. Because of this, some scientists point to the mid-20th century as the beginning of the Anthropocene.

For more detailed information, see IGBP. If you have trouble seeing the image, click on itfor a resizable version. You can also see each one up close in the slideshow below the image.

Great Acceleration 2015 from International Geosphere-Biosphere Programme

Figure 3.2. The Great Acceleration. 

Credit: IGBP