Much of the discussion around climate change and human impact on the environment focuses on factors such as ice caps and average global temperatures. However, a recently published survey examines a wider range of factors to illustrate how human civilization is heading into uncharted territory compared to previous millennia.
According to a recently published analysis based on extensive research, Earth has crossed six of the nine environmental boundaries that have sustained the conditions for the development of human civilization. The study attempts to take a broad look at how the Earth is changing in a way that modern society has never experienced.
Climate change - the most discussed aspect of human impact on ecology - is just one factor disrupting conditions that have persisted on Earth over the past 10,000 years or so. Other factors, such as biodiversity, forest cover, freshwater supplies and biogeochemical flows (the relationship between freshwater, oceans and soil), also far exceed the standards established during this period.
The term "Holocene" describes the relative stability of Earth's temperature and environment since the end of the last Ice Age about 10,000 years ago. The entire complex history of human civilization, including agriculture and urban construction, took place during this period. Scientists use nine "frontiers" to define the environment conducive to this development, and all of these borders have been in danger since the beginning of the Industrial Revolution.
In the image above, the green areas represent the environments modern humans are accustomed to, while the red areas represent boundaries that have been crossed. Dark red indicates which areas are most at risk. The two ends of the chart are blurry because researchers either don't have enough relevant information or don't know how abnormal the situation could become.
Biosphere integrity, involving biodiversity, is the area at greatest risk. Research shows that human land use caused species extinction rates to exceed Holocene normal levels in the late 19th century, and that the population explosion and food production that began in the 1960s worsened the problem. However, the analysis stresses that overpopulation is not the key problem. Theoretically, human civilization can feed a population of 10 billion through appropriate adjustments while maintaining environmental stability.
One area where the potential risks of human intervention remain largely unknown involves artificial substances such as microplastics, nuclear materials and various chemicals. While the possible adverse effects of these substances on human health and the environment have been widely discussed, whether they threaten Earth's habitability remains unclear. The long-term consequences of these man-made materials, their impact on ecology and their interactions with natural systems are all subjects of current research and interest.
Ozone levels are an example of humans successfully reversing conditions to Holocene standards. Since the ratification of the Montreal Protocol in 1987, ozone depletion rates have recovered and now exceed safe limits only in spring in Antarctica and high southern latitudes. Scientists say this and other factors prove it's not too late to act.