Systemic Environmental Risks

Un article de U-Sphere - Michael Vaillant.
Jump to: navigation, search

The first version of this article was published during the year 2005. The interdisciplinary field called "Earth System Science" was only introduced on Wikipedia starting in 2009.

Biological stress factors, environmental risks

At the international scale, establishing programs to set up indicators, map, and monitor all systemic risks weighing on the planetary environment will increasingly appear as a major priority.

It is interesting to observe that, over the years, these risks have been progressively taken into account, especially where long-term societal and economic stakes are being considered (World Forum, UN).

Direct measures of biodiversity

Biodiversity responds to the pressure the environment exerts on living beings.
Measuring biodiversity indirectly makes it possible to measure biological stress.

Given the current state of knowledge and measurement capabilities, it seems difficult to assess biodiversity at the scale of entire regions: it can only realistically be done locally. A few methods exist for this:

  • Abundance–Biomass Comparison (ABC) method: computation of disturbance level (Clarke & Warwick, 2001a)
  • Shannon or Shannon–Wiener diversity index (H') (Pohle et al., 2001)
  • Species abundance curve
  • Average Taxonomic Distinctness (AvTD) and Variation in Taxonomic Distinctness (VarTD) (after Clarke & Warwick, 2001b): their mean values are independent of sampling effort; the response to increasing environmental stress is monotonic (i.e., it decreases or increases with the level of disturbance)

Biodiversity responds to the environment and to the pressure it exerts; therefore, since in the context of this study we are specifically interested in what disturbs biodiversity, it is not necessarily useful to measure it directly, but rather to focus on the pressures the environment exerts.

This can be assessed by inventorying sources of biological stress.

Biological stress

It expresses itself through aggressions against the environment; it promotes the development of certain species to the detriment of many others. A "stressed" ecosystem will respond with a reduction in the absolute number of species, in favor of a few that will occupy the most affected—or even vanished—ecological niches.

Mean ranked abundance (or dominance) curves of species (a) and mean ranked cumulative abundance curves (k-dominance curves) (b), for samples from disturbed stations located near (dashed line) an oil drilling operation and from relatively little-affected stations (solid line), representing populations undergoing different types of biological stress (after Clarke & Warwick, 2001a).
Abundance–biomass comparison method (h6b585ku) (ABC) to compute the disturbance level, based on comparing the (species) biomass and abundance (k-dominance) curves, showing the relative positions of the curves at different degrees of pollution (after Clarke & Warwick, 2001a).

"abundance": % of individuals of species i
"biomass" : % of biomass represented by species i

Environmental Vulnerability Index (EVI)

Listing vulnerabilities is a task that should increasingly concern future generations, all the more so as they will be confronted more and more with global climate change.

For example, the Environmental Vulnerability Index (EVI) is a measure designed by the South Pacific Applied Geoscience Commission (SOPAC) and the United Nations Environment Programme to characterize the relative severity of various types of environmental problems experienced. EVI results are used to focus on planned solutions to negative pressures on the environment, while promoting sustainability.

These vulnerabilities are structured according to a 3-level logic (see next chapter):

  • Environmental source system(s)
    • Natural or artificial disturbing factors (stressors)
      • measurable indicators

See Environmental Vulnerability Index on Wikipedia.

Examples of stress factors

  • Climatic phenomena,
  • Precipitation,
  • Droughts,
  • Amount of heat,
  • Storms,
  • Frost,
  • Pollution,
  • Fires,
  • Biological phenomena,
    • Nutrient content in food,
  • Geological phenomena,
    • Volcanic eruptions,
    • Avalanches,
    • Landslides, ...

Examples of measured variables

In all cases, starting from these environmental factors, the goal is to find measurable indicators and identify the most important factors. These must be measured over sufficiently long durations to be considered "relevant/critical". For example:

  • Change in pH,
  • Sulfate concentration (SO4/SO2),
  • Phosphorus / phosphate concentration (P/PO4),
  • Nitrogen concentration (N/NO3),
  • Vertical and horizontal ozone concentration (O3),
  • Photosynthetically active radiation,
  • Air temperature at the ocean surface (satellite),
  • Chlorophyll concentration measurements,
  • Atmospheric dust concentrations,
  • CO2 level, ...

Classification of environmental systems

We can classify environmental risks according to their original environmental sphere. On U-Sphere, the following breakdown was used:

  • The Heliosphere, the Magnetosphere,
  • The Atmosphere,
  • The Lithosphere,
  • The Hydrosphere, Cryosphere,
  • The "Cosmosphere",
  • The Anthroposphere

Cosmosphere

Generally, dust or volcanic explosions produce a cooling of Earth’s atmosphere by reflecting part of solar energy back into space and cooling the Earth. However, very energetic cosmic rays interact little; but when they do, they break molecules in the upper atmosphere, typically CO2. This counteracts the greenhouse effect, and moreover the broken molecules will recombine to form water-vapor clouds that modify the planet’s albedo and trigger imbalances.

  • Meteors, Comets

The Solar System is crossed by objects of various sizes that can represent a major risk for Earth. Until recently, these risks were beyond any possibility of control; today, space agencies—and NASA in particular—are setting up monitoring programs.


Heliosphere, Magnetosphere

The Sun is the source of a large number of phenomena that can impact Earth’s environment

The variability of solar activity and the limited historical perspective we have still makes this risk largely underestimated.

Surface of the Sun

Solar plasma

Solar radiation

Interplanetary Magnetic Field (IMF) EM fields generated by solar plasma (/EUV ?)


Atmosphere

Essentially an interface for storing aerosols and particles and transforming them under the effect of temperature and solar radiation.

Beyond climatic phenomena, the atmosphere is a mediator for a set of phenomena linked to human activity.
  • The Greenhouse effect
    • Greenhouse gases: H2O, CO2, CH4, N2O, O3, Halocarbons
    • Infrared radiation
    • Risk.gif Anthropogenic production of greenhouse gases
      • CO2 (55%), CH4 (15%), Halocarbons (15%), O3 (15%), N2O (5%)
      • >> Increase in global temperatures
  • Stratospheric ozone layer (~25 km)
    • ozone production by absorption of UV radiation
  • Atmospheric pollutants
  • Tropical storms, cyclones
  • Air temperature


Hydrosphere, cryosphere

  • Droughts,
  • Floods,
  • Tsunamis,
  • Ice-melt rate,
  • Changes in rivers or bodies of water,
  • Dissolved oxygen and CO2 levels, ...


Biosphere

This concerns feedback effects linked to the activity of living species in relation to environmental changes and shifts in equilibria.

  • Eutrophication,
    • increase in algal biomass,
    • increase in gelatinous zooplankton biomass,
    • degradation of the organoleptic qualities of water (appearance, color, odor, taste),
    • development of toxic phytoplankton,
    • decrease in the biotic index,
    • decrease in dissolved oxygen concentration,
    • death of higher organisms (macrophytes, insects, cnidarians, crustaceans, mollusks, fish, etc.).
  • changes in ocean currents.

(These causes are not strictly linked to the hydrosphere, but rather to exogenous human and ecological factors.)

Related markers/variables

  • plankton biodiversity

it is essential to the biodiversity of the species that feed on it, but also to respond to spatial and temporal variations in environmental constraints. Thus, the quality of a marine ecosystem can be based on the quality of the "planktonic" spectrum (zooplankton and phytoplankton).

  • coral growth

these are markers of past climate and pollution levels.


Anthroposphere

This involves measuring the systemic footprint through human activities.

  • Decision and control zones (governments, command centers),
  • Pollution and contamination zones:
    • Nuclear,
    • Bacteriological,
    • Chemical and industrial,
  • Resource exploitation zones:
    • Natural resources (still) available,
    • Exploitation of natural/biological resources,
    • Contamination of the ecological environment,
    • Destruction of species and habitats,
  • Conflict zones


Lithosphere

  • Plate tectonics
    • Volcanism,
      • Dust and gases >> atmosphere
    • Earthquakes,
      • Tsunamis,
  • Tilt, Precession, Ecliptic

Coupling of risks and flows

File-vsd.gif biosphere-risques.vsd

Biosphere, coupling of environmental risks

Human attitude toward systemic risks

A strategic monitoring plan

The survival of the species and environmental balances depends upstream on monitoring the parameters listed above.

The environment acts on humans and in return humans act on the environment: factors of social evolution must therefore be taken into consideration.

Likewise, the evolution of scientific and technical means (Technosphere) will weigh on interactions between humans and their environment, and on their ability to modify the environment in which they live.

Here are additional parameters that should be taken into account:

Human development

  • Industrial,
  • Demographic,
  • Social,
  • Ideological,
  • Scientific,
  • Biological (species-level).

Societal reaction capacities

  • Psychosocial tendencies toward submission,
  • Psychosocial tendencies toward conserving attitudes,
  • Subordination of Technology.

We draw here a parallel between this monitoring and the monitoring that other intelligent species in the universe might carry out, with the objective of their survival and/or the understanding of ecological systems they may encounter.

Récupérée de « http://www.u-sphere.com/wiki//index.php?title=Systemic_Environmental_Risks&oldid=26477 »