The first of a series of meetings, sponsored by Physicians for Social Responsibility, took place in Cambridge, Massachusetts, in February 1980, to consider the Medical Consequences of Nuclear Weapons and Nuclear War. It was followed by others elsewhere and led to the horrifying convictions that (1) it is highly unlikely that any nuclear war would be ‘limited’, and (2) no effective medical response can be conceived to deal with the human damage which would result from a nuclear attack. Consequently an organization entitled International Physicians for the Prevention of Nuclear War has been established to hold further meetings and promote general enlightenment towards avoiding widespread—even global—human carnage and environmental destruction which would accompany a nuclear war involving even a small fraction of the weapons that now exist.

The atomic bomb which was exploded over Hiroshima in August 1945 is estimated to have killed 75,000 of that city's population of 245,000 and to have destroyed two-thirds of the 90,000 buildings within the city limits. It had an explosive power equivalent to 20,000 tons of TNT, whereas many of the thermonuclear devices now deployed at the ready are some 50 times more powerful than it although still far less destructive than the most devastating contemporary weapons. Consequently the world's leaders must be brought to their senses and these horrific weapons dismantled to avoid what could be ‘the last epidemic’.

The magnitude of the problem can be gauged from the fact that at present more than 50,000 nuclear warheads are reported to be deployed and ready to launch—most of them being sufficient in destructive power to dwarf the bomb that was used against Hiroshima. Sufficient nuclear devices exist outside the United States to destroy totally every major American city. Six nations are now acknowledged possessors of nuclear weapons, and there are almost certainly others to increase the degree of instability. This situation is not so much ‘unthinkable’ as insufficiently realized or even thought about—hence the failure to reject nuclear war as a ‘viable option’ in the conduct of world affairs. Medically, any treatment programmes would be virtually useless and the costs quite staggering, so prevention becomes imperative.

Uncertainty may exist about the future likelihood of nuclear war. On the other hand, no doubt exists that nuclear weapons must be eliminated from the arsenals of the world. Even the most modest and restrained nuclear initiative by one belligerent could well be countered in kind, this in turn perhaps leading to an escalating exchange. Even the very limited attacks by the USA during World War II had a profound impact on the enmeshed humans and their artefacts, the medical and social ramifications of which continue to haunt the survivors and their offspring. However, the present paper does not dwell on the effects of nuclear weapons on humans*, but rather upon the natural environment. It summarizes the foreseeable environmental impact in quantitative terms with respect to damage from the blast-wave, the thermal pulse, and the nuclear radiation—doing so, by way of example, for a 20-kiloton atomic bomb and a 1-megaton hydrogen bomb (and also with passing mention for a 1-kiloton neutron bomb).

The effects of a nuclear war—a war in which scores to hundreds, if not thousands, of nuclear bombs might be expended—is summarized in relation to affected portions of the geosphere, the atmosphere, and the Biosphere. A nuclear attack would kill wildlife and destroy the vegetation over a large area through a combination of blast, heat, and nuclear radiation. Wildfires could well extend the zone of immediate destruction. Surface disruption and the loss of vegetation would lead to greatly accelerated wind and water erosion and ‘nutrient dumping’.

It is concluded nevertheless that an area devastated by nuclear warfare would in time recover by the natural processes of ecological succession, but far more slowly and more unpredictably than following other forms of ecological disruption.

Ecosystem values, and the functional roles of ecosystems in providing goods and services for Man, have been subjects of increasing discussion and controversy among ecologists and economists in recent years. Economists have developed economic theory based on a market model, and price or value has been set in the marketplace. However, the market system cannot account for all possible values, and fails to account for goods and services for which no market, or only imperfect markets, exist.

These non-traded goods and services are termed nonmarket values, and are categorized in the scheme we have developed either as Value II (attributable or assignable values) or as Value III (intangible or non-assignable values). The true or total value of natural systems should include not only the market values (Value I) but also these two categories of non-market values whenever decisions are made about the alteration of natural systems. Usually, only market values are incorporated by decision-makers in the management strategies of natural systems, and as a result of their omission of non-market values, numerous natural systems are being degraded or destroyed through market-goods extraction.

The examples of market and non-market values of tropical moist forests, demonstrate the range of nonmarket goods and services provided by natural ecosystems. Excessive alteration and destruction of tropical forests for extraction of market goods, damages the integrity of the forests and reduces or destroys the capacity of these ecosystems to provide valuable non-market goods and services. One can measure the value of these non-market goods and services by calculating the cost of providing them through technology. By not accounting for the public goods provided by forests, overall sustained-yield potential of the public and private goods produced by the system is reduced. These non-market values need to be incorporated in decisions about the fate of natural systems.

An attempt has been made in this paper to establish a common understanding of value for both economists and ecologists. If the problems of value determination can be viewed with a joint understanding, the political process may be influenced to provide more efficient and wiser use of the products and services of natural systems.

Freshwater environments are expected to be particularly responsive to temperature rises and changed precipitation régimes that are anticipated to result from progressive increases in atmospheric carbon dioxide from fossil-fuel combustion. Recognition of potential impacts on aquatic systems should strengthen research and management planning for the future, and provide more confident estimates of the risks from CO2 elevation than those at present available. This report briefly evaluates those aquatic impacts that are believed to be important and worthy of investigation and quantitative forecasting.

Priorities for additional research have been suggested for the issues discussed herein. These priorities vary according to the use of pertinent data, the credibility of presumed risk (which may change as, for example, climatic models are better refined), the timing in relation to prerequisite information, current efforts already under way, and the feasibility of obtaining the desired data. The ranking remains subjective, however, and debatable.

Knowledge is needed of the geomorphological characteristics of stream-channels in urban areas in order to manage the streams for recreation, biota conservation, environment enhancement, erosion control, and the discharge of stormwater runoff. This study is concerned with how urban streams in Brisbane have been substantially modified by many different human activities, and how the future behaviour of the channels is likely to be very complex because of the diversity and magnitude of these modifications.

Major water-supply dams have been constructed on three of the streams, and some flood-detention storages are soon to be constructed on another. The earth embankment of the South-east Freeway fills the upper reaches of Norman Creek, and stormwater runoff is now carried in a man-made channel. Elsewhere in this catchment, flood-flows have been modified by culverts—where the Freeway and access roads cross the drainage channels, and where the Freeway embankment occupies a substantial part of the floodplain of the Creek.

The construction of Brisbane Airport has already modified the tidal reaches of Kedron Brook, and the proposed redevelopment of the Airport will replace the existing modification with a major new floodway.

Several of the stream-channels have been deepened, widened, and straightened, for flood-mitigation purposes, with 465,000 m3 of material removed from Breakfast Creek alone. Three of the stream-channels have been used as major sources of sand and gravel for building activities in the City. Flood characteristics of the streams appear to have been changed by increased runoff from impervious surfaces when these reached a critical threshold in the urban areas, and by increased velocities of flow in piped, lined, and other, artificial stormwater channels. Construction of new artificial channels amounts to some 15 km per year.

The modifications which have occurred differ among the urban streams in Brisbane, and each stream requires individual study to assess the long-term effects of the changes. All of the streams reported on in this study have been substantially modified by human activities.