C 2.4.2 Global filter

As the environmental risks that we wish to screen are closely tied to the people-environment interface, the global filter can be causally connected to the core problems of global change that have already been identified by the Council (WBGU, 1997a). These core problems characterize critical constellations in people-environment interactions that can be the source of global environmental risks. As they have global relevance per definitionem, it should be possi-ble to derive from them a globally relevant probabil-ity of hazard. The global filter thus first screens the relation of risks to the core problems of global change. Here it is asked whether an environmental risk is caused directly or is amplified significantly by the core problems. In addition to an effect upon the incidence of hazardous constellations, an increase in vulnerability plays a particularly important role here (Section E 2). It can be equated in this context with the damage potential.

Climate change, soil degradation, the loss of biodi-versity, scarcity of freshwater resources, overex-ploitation of the oceans, increasing incidence of (hu-man-induced) natural disasters, population growth, increasing mass migration (environmental refugees), urbanization dynamics, threats to global food securi-ty and to human health and the growing wealth gra-dient between industrialized and developing coun-tries are the prime negative manifestations of global change (Box C 2.4-1). They are modifying worldwide the vulnerability to consequences of disaster and thus also the evaluation of environmental risks with regard to their global relevance.

A further consequence of this nexus is that ade-quate environmental management of those global environmental risks that are connected, in the man-ner set out above, to the core problems of global change requires supranational cooperation (Section F).

Core problems of global change thus have two central attributes: they are transnational in character and can only be resolved through supranational ef-forts. Environmental risks directly connected to the core problems of global change will therefore always have global relevance.

The global filter must further take into considera-tion types of risk that have no direct connecconsidera-tion to the core problems of global change. This is the case, for instance, for certain genetic engineering applica-tions which, while having no such connection, do have the potential to pose a global risk.The global fil-ter therefore needs to be extended to include further screening criteria that refer, inter alia, to the threat or

management potential associated with a risk. Pro-ceeding from the above considerations, three ques-tions are formulated as filter criteria.

Criteria of the global filter

1. Is there a connection between the risk and the core problems of global change?

2. Does the potential threat presented by the risk have global or at least international relevance?

3. Is management at the global level required to master the risk?

C 2.4.3

Environmental filter

The purpose of the environmental filter is to ensure that only such risks are included in the analysis whose pathway can be expected to include significant environmental damage. This filter screens out all risks that do not relate to a people-environment or environment-environment interaction. In accor-dance with the mandate of the Council, people-peo-ple interactions such as ethnic conflicts (although in-dubitably of global relevance) are excluded from ex-amination.

Here we must also consider complex interrela-tions among various sorts of damage. Damage, be it isolated or widespread, can trigger a chain of further damage that may well develop a considerably wider scope of effects than the initial damage. The environ-mental filter must assess these consequential effects and integrate them in the evaluation.

The simplest constellations may be termed ‘two-link chains’. These include:

• Environment-environment interactions.

El Niño leads to the flooding of valuable natural areas.

• Environment-people interactions.

Earthquakes lead to considerable material dam-age.

• People-environment interactions.

Sulfur and nitrogen oxide emissions lead to glob-ally relevant forest damage.

The following ‘three-link chains’ are also still rela-tively distinct:

• Environment-environment-people interactions:

El Niño leads to flooding, this then hampering the supply of the population.

• Environment-people-environment interactions:

Earthquakes lead to the destruction of human set-tlements, resettlement then appropriates natural areas.

• People-environment-environment interactions:

Dams cause changes in river flow regimes, this leading to the loss of mangrove forests in distant

50 C Risk: Concepts and implications

coastal regions.

• People-environment-people interactions.

Inappropriate feeding practices lead to BSE in cattle, the consumption of beef then damages hu-man health.

As the syndromes of global change identified by the Council illustrate, complex people-environment in-teractions can have far more than three links in the

chain (WBGU, 1995a, 1998a). The chain can close in on itself. This creates feedback loops (‘vicious cir-cles’) of global change. If the chain does not close, or if there are indications of several sub-chains for a risk, then the question arises of the still tolerable number of secondary risks. In some cases the number of links in the chain can be ascertained exactly, in oth-er sphoth-eres of risk thoth-ere is inadequate knowledge to Box C 2.4-1

Core Problems of Global Change Ecosphere

• Climate change. By enriching the atmosphere with long-lived greenhouse gases, humankind is inducing a signifi-cant level of climate change that can already be distin-guished from natural climate variability ‘noise’. There is growing anxiety that anthropogenic global warming is having feedbacks on oceanic circulation and the dynam-ics of the polar ice caps. Extensive uncertainty still pre-vails as to the precise impacts that the predicted shift of the climate belts (and thus vegetation cover and cultiva-tion zones), rising sea level and increasingly frequent weather extremes will have on human societies and na-ture, both regional and globally.

• Soil degradation. In many countries today the soils of the Earth display degradation ranging from medium to ex-treme severity, and the situation is worsening from year to year. Such degradation is caused by rapid growth of the world population and its economic activities, result-ing in overexploitation and transformation of plant cov-er, compaction and surface sealing of soils, as well as con-tamination by organic and inorganic compounds. Severe soil degradation means destruction of humanity’s life-support systems and can therefore trigger famine, migra-tion and military conflicts.

• Loss of biodiversity. Land-use changes spanning large areas of the globe (such as clearing of forests, conversion of pasture land to cultivated land, etc.) bring about a re-duction in the reservoir of potentially useful species and the natural products they provide, an impairment of the regulatory function of ecosystems and a decline in cultu-rally and esthetically valuable biotopes. Loss of plant va-rieties and domestic animal breeds leads to greater sus-ceptibility to pests and diseases, thus endangering the very food sources on which humanity is vitally depen-dent.

• Scarcity and pollution of freshwater resources. Freshwa-ter resources are being overexploited on a local and re-gional scale through irrigation farming, industrialization and urban growth. Many parts of the world face mount-ing scarcity and pollution of water supplies. The conse-quence is a rise in economic, social and political conflicts over declining water resources, which in turn may have global impacts.

• Overexploitation and pollution of the world ocean. The oceans perform important ecological (especially climat-ic) functions, are a major source of food and act as a sink for anthropogenic wastes. Coastal regions and marginal seas, in particular, are further polluted with contami-nants through immissions and direct discharges via riv-ers. Global impacts ensue, beyond the threats to fishing regions, due to the importance of fisheries for global food security.

• Increasing incidence of human-induced natural disasters.

There are many indications that natural disasters are in-creasing in frequency as a result of human interference with natural systems. Forest clearing in the Himalayas, for example, gives rise to floods in foothill regions, thus posing an existential threat to the population there.

Among other things, this induces migration pressure (en-vironmental refugees) and the concomitant impacts on large sections of the international community.

Anthroposphere

• Population growth and distribution. The world popula-tion continues to grow, primarily in the developing and newly industrializing countries. One of the root causes is inadequate education, which is bound up with high birth rates, weak social security systems and social marginal-ization of large parts of the population in these countries.

Other trends are rural-urban migration and intra- and international migration flows. The latter produce rapid urban growth, particularly in coastal regions; the urban infrastructure (energy, water, transport, social services, etc.) of many cities is unable to keep pace with this growth. The environmental degradation and poverty which then result, and the potential for social unrest this entails, are having global impacts.

• Environmental threats to global food security. Large sec-tions of humanity suffer from malnutrition and under-nourishment. Feeding these people is rendered increas-ingly difficult by soil degradation, water scarcity and population growth.This trend is frequently reinforced by misdirected economic and development policies.

• Environmental threats to health. Factors such as popula-tion growth, famine, war, contaminapopula-tion of drinking wa-ter and inadequate waste wawa-ter treatment lead to an in-creasing incidence of infectious diseases and epidemics in many countries of the world.As global mobility grows, so, too, does the risk of rapidly spreading epidemics. In industrialized countries, air pollution causes increased incidence and severity of certain illnesses among the population.

• Global disparities in development. The structural imbal-ances between industrialized and developing countries have not declined in recent decades – on the contrary.

The driving forces behind this development are economic, technical and social changes, above all the glo-balization of the world economy and the intensifying international division of labor. This process has helped some countries to achieve the desired economic devel-opment, though often at the expense of the natural envi-ronment. Nevertheless, most developing countries (par-ticularly in Africa) have remained very poor, and it is there that the loss of social security and related migra-tion processes are creating enormous problems. This ‘de-velopment dilemma’ is characteristic of global change and represents a growing risk.

identify all secondary risks. Section E discusses in depth the systemic interrelations among chains of damage.

The Council derives the following criterion for the environmental filter: the chain of effects of a risk must include at least an environment-environment, people-environment or environment-people interac-tion (within its complex chain).