Ecology: the biology of interaction. 6.01. The ecological crisis of modern times
Chapter 6. Human Ecology and Nature Conservation The components of the modern ecological crisis are as follows. The growth of the human population has caused shortages of food, energy, and fresh water. Overcoming these problems is aggravated by climate change, the destruction of natural ecosystems, the decreasing...
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5.27. (supplement) Pressure at depth: endurance and overcoming
D. Shabanov, M. Kravchenko. Ecology: the biology of interaction Chapter 6. Human ecology and nature conservation
D. Shabanov, M. Kravchenko. Ecology: Biology of Interaction Chapter 6. Human Ecology and Conservation
6.02. Demographic explosion
Chapter 6. Human ecology and nature conservation 6.01. Ecological crisis of modernity When you do not want to hear the worst, It will fall upon you silently… William Shakespeare We have all repeatedly heard that we are witnesses of a global ecological crisis. What does this concept mean? First of all, the notions of crisis, catastrophe and collapse must be distinguished. A crisis is a reversible state of a system, during which it may return to a normal condition or transition to another one. A catastrophe is associated with the destruction of regulatory mechanisms that maintained the previous state of the system and a transition to a different quality. Collapse is an irreversible change leading to the destruction of the existing system as such. Ecological collapse is linked to the environment shifting to a state that excludes the existence of organisms that previously inhabited it. Thus, crisis = dysfunction of the system, catastrophe = its restructuring, collapse = destruction. One must differentiate local, regional and global crises. Local crises are linked to problems of individual habitats and specific human populations, regional crises cover large areas, and global crises extend over the entire planet. Therefore, when we speak of an ecological crisis, we assert that the current biosphere is unstable and may shift to a new state markedly different from the one to which we and other inhabitants of our planet have adapted. From this perspective, the ecological crisis is an observed fact. Likely, the task before us is not to “defeat” the crisis, but to avoid the transition of an ecological catastrophe into a biospheric collapse. The biosphere has undergone crises and catastrophes long before humanity appeared. Mass extinction (in paleontology called a “crisis,” although in the sense above it is clearly a catastrophe) at the Cretaceous–Paleogene boundary became widely known. An even larger catastrophe occurred at the Permian–Triassic boundary. That the Paleozoic, Mesozoic and Cenozoic eras are divided precisely by these catastrophes is not surprising: each marked a transition of the biosphere to a new quality. However, when discussing these crises and catastrophes, it should be noted that their duration lasted tens to hundreds of thousands of years. The peculiarity of the current crisis is its rapidity (by biospheric history standards). Our species has also experienced numerous crises. For example, population‑genetic studies indicate that at some stage of our history (even before Homo sapiens dispersed beyond Africa) the total number of our species fell to a few dozen individuals. In population genetics such reductions are called “bottlenecks”; their consequence is a substantial loss of genetic diversity. Strangely, despite racial and national differences, members of our species are genetically far more homogeneous than, for instance, chimpanzees. It can be assumed that the odds of extinction for our species at that moment were quite high. In the era of fragmentation (before becoming global) humanity repeatedly went through local ecological crises and catastrophes (and perhaps collapses of individual ecosystems). These catastrophes were caused both by factors independent of human populations and by the consequences of human activity. The former include local ecological disasters triggered by locust swarms, or the collapse of medieval Norwegian settlements in Greenland caused by climatic cooling. However, the adverse effects of human activity were far more extensive. Our species was shaped by the lifestyle of a non‑specialized predator and gatherer of African savannas. As interaction mechanisms among group members and planning of actions improved, representatives of our species became the most efficient hunters in Earth’s history. As they spread across the planet, people began exploiting various populations of large ungulates. As their numbers grew, so did their capacity to reduce the numbers of their prey. A crisis erupted roughly 10–12 kyr ago, when the possibilities for maintaining such a way of life were exhausted. Increased human population, intensive hunting, and climate changes not driven by humans led to the complete extinction or sharp decline of large‑mammal fauna. This change affected Eurasia most strongly, but also impacted Africa, Australia and the Americas. Human numbers fell severalfold. Many ancient human populations likely perished. Nevertheless, humanity managed to emerge from the crisis by fundamentally altering its relationship with the environment. The solution was the transition to agriculture and animal husbandry, which sharply reduced hunting pressure on natural ecosystems. This turning point in human history is called the Neolithic crisis or Neolithic Revolution. The described transition unfolded differently in various parts of the world. Depending on the region where adapting human populations lived, they used different crops and began domesticating various animals. The most advanced agricultural civilizations arose in the Near East, while the indigenous Australian culture was the least transformed. Subsequent world history was significantly shaped by these circumstances. Interestingly, the set of crops cultivated today is a consequence of choices made by Neolithic humans. During our era “in culture (excluding oil‑seed, medicinal and ornamental plants) only sugar beet, hemp and the rubber tree (Hevea) were introduced” (N.N. Vorontsov, 1999). It is possible to supplement Vorontsov’s list with a few species (e.g., rapeseed—a technical crop), but this does not negate the exceptional dependence of modern agriculture on the outcomes of the Neolithic Revolution. Thus, humanity has “experience” of emerging from a global crisis accompanied by climatic changes. This emergence was accompanied by painful breaking of former norms and a change in the nature of human‑environment relations. Unfortunately, this emergence gave rise to new local crises. “The greatest ecological result of Neolithic livestock breeding was the formation of the Sahara desert. … Ten thousand years ago the Sahara was a savanna, inhabited by hippos, giraffes, African elephants, ostriches. Human overgrazing of cattle and sheep turned the savanna into a desert. Rivers and lakes dried up—hippos disappeared—savanna vanished—giraffes, ostriches, most antelope species disappeared. With the loss of North African savannas, the once abundant cattle also vanished” (N.N. Vorontsov, 1999). Likely many Asian deserts, such as the Karakum, have a similar origin. Modern humanity is undergoing a new crisis in its history. This is the first crisis our species has faced since becoming a global species. Because of the interconnection of different parts of humanity, it can be assumed that either humanity as a whole will pass through the current crisis (with greater or lesser losses), or it will undermine its own survival prospects in the course of a large‑scale ecological catastrophe or a collapse of the Earth’s habitat. The present nature of human‑environment relations, based on rapid consumption of fossil‑fuel reserves, cannot continue for long. Already within the 21st century, humanity’s way of life will have to change. How? We do not yet know. To some extent this depends on our actions. What causes the current crisis? The components of the modern ecological crisis are as follows. Population growth has caused food shortages, energy deficits, and freshwater scarcity. Overcoming these problems is aggravated by climate change, destruction of natural ecosystems, loss of biodiversity, pollution, and military threats. Each of these factors is highly complex. For example, pollution is a whole suite of environmental changes. Its partial components: — alteration of the gaseous composition and properties of the atmosphere (CO₂ and O₃ issues); — dispersion of fuel‑combustion products and their consequences—smog, acid rain; — poisoning of water, air and soil with toxic substances; — dispersion of foreign elements and xenobiotics; — contamination of air, water and soil with radionuclides; — pollution of natural media by pathogenic microorganisms from waste; — degradation of water bodies due to excess biogenic input, eutrophication from organic overload, siltation by washed‑in sediments; — thermal, acoustic, electromagnetic pollution; — local pollution of the immediate human habitat: food, indoor air, household items, etc. The main causes of the current crisis are linked to human activity. At the same time, external factors beyond our control can exacerbate it. For instance, one manifestation of the global crisis is global warming. International climate commissions have concluded that humans most likely influence this process. This conclusion is reinforced by NASA data (U.S. space agency), which recorded global warming on Mars. It is probable that both changes in solar activity and the consequences of industrial human activity are expressed in this phenomenon. We will examine the listed components of the crisis and then discuss possible ways out. Additional materials: Column: Mountain Road Column: Dies irae Air‑pollution data in Ukrainian cities 5.27. (supplement) Pressure at depth: endurance and overcoming
D. Shabanov, M. Kravchenko. Ecology: the biology of interaction Chapter 6. Human ecology and nature conservation
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6.02. Demographic explosion
6.02. Population Explosion