If the world depends on fossil fuels for its energy needs over the next two centuries, the U.S. National Academy of Sciences/National Research Council report Energy and Climate foresees the possibility of a peak atmospheric concentration of carbon dioxide of between 4 and 8 times the preindustrial level as occurring in A.D. 2150 to 2200. Climatic models of the general circulation of the atmosphere predict a 2–3°C rise in average temperature of the atmosphere for each doubling of the carbon dioxide content. Thus, a mean value of about 6°C increase in average atmospheric temperature would be anticipated if the models prove to be accurate and if the growth scenario used in the report were to be realized.

By these several citations from the topics before this Second International Congress of Ecology, I have tried to suggest the need and the feasibility for this discipline to play a more active role in the continuing development and improvement of the quality of human life on this planet.

The international system which is now preparing for the Development Decade of the 1980s, and the developing countries which seek their own paths—as many as are needed to match their varying environmental, social, economic, and cultural, endowments—are open to advice as to what to do in the general scientific, and most particularly in the ecological, context in which all continuing life must operate.

Six problems faced by the developed and developing worlds are discussed and possible solutions are considered. Given its relatively stable populations and adequate food supplies, the developed world must be prepared both to pay for and to encourage efforts to control pollution of the environment. Its comparative over-consumption of energy must be countered by the development of new energy sources, bearing in mind the risks involved in the use of nuclear energy. Also, great efforts must be made to assist the developing world by improving the quality and quantity of aid and by voluntary changes in world trade patterns.

The developing world's most serious problem is its exploding population which can be slowed by birth control and improved standards of living. Population growth puts pressure on cities, and makes it imperative that new sources of food be found and new agricultural techniques be developed. Population also exacerbates the difficulties of providing education in the developing world.

Hope for the future rests on Man's capacity to foresee problems and to solve them.

The internationalization of conservation activities in the form of organizations is essentially a post-World War I development. The first international initiatives were taken in North America during the first decade of the 20th century, and in 1910 other attempts were made in Europe; but it was not before 1922 that the first truly international conservation organization, the International Council for Bird Preservation (ICBP), was created. After World War II, ecology evolved rapidly as a discipline and this development led to international cooperation in conservation. U.N. organizations such as FAO and UNESCO became established. In 1948 the latter took the initiative in the creation of IUCN. ICBP founded the International Waterfowl Research Bureau (IWRB), another important organization, and IUCN took the initiative to form in 1961 the World Wildlife Fund (WWF) as a fund-raising and public relations organization.

Carlyle Lake is typical of north-temperate Canadian Shield lakes both morphometrically and in its thermal and oxygen structure; however, the Lake is chemically unusual. Input of acidic melt-water in the spring of 1974 depressed the pH of the Lake to 4.5. The buffering capacity of the Lake has been reduced to such a degree that summer pH levels are about 5.0.

Despite this relatively high acidity, the biomass of the phytoplankton community is not low for an oligotrophic circumneutral lake. Although some evidence exists that phytoplankton community biomass is reduced in lakes of pH about 4.5 or below, no such reduction was observed in Carlyle Lake. However, as the numbers of phytoplankton species are reduced when lake pH levels fall below about 5.6, it would appear that community diversity is a more sensitive indicator of acidification of lakes than is community biomass.

The Crown-of-thorns Starfish (Acanthaster planci) was perceived to be a threat to coral reefs of the Indo–West Pacific region partly as a consequence of new technology, in the form of SCUBA diving, becoming generally available. It took some years, however, for field practices to be developed which employed the new technology effectively in sampling such a phenomenon over large areas.

In Australia an emotional environmental campaign followed the publication of a report to the Queensland Government in 1969, which claimed that the Starfish was a major threat to the Great Barrier Reef, that it was probably Man-induced, and that it could be controlled. The report was neither adopted nor rejected in the period of more than a year which elapsed between its submission and its publication. As the public campaign gained momentum, official inquiries reviewed and questioned the data-base of the initial report but no attempt was made to devise, test, or implement, a more acceptable sampling procedure until 1973. In retrospect it is suggested that an early practical initiative to assess and remedy claimed defects of the initial sampling programme, would have removed the element of speculation which led to considerable heat in the Crown-of-thorns debate in Australia.

The recommendation of the official inquiries resulted in the establishment of a trust fund to give special support to research into the problem. The research thus conducted materially increased understanding of the phenomenon, but it has been claimed that vital areas of investigation were omitted, and the value of such special support has been questioned. It is suggested here that the special problems and expense of research into the ecology of remote reefs would have precluded almost all research into the Crown-of-thorns Starfish and its effects without such ad hoc support. However, it is further suggested that more direct management of the programme would have coordinated research effort and made more effective use of the facilities and support available.

The United Nations Conference on Desertification was the first occasion on which the nations of the world turned their concerted attention to the need for a comprehensive plan to halt and reverse desertification. The global annual loss to desertification is in the order of 60,000 km2. It is Man's action that degrades the land by misuse as he seeks to wrest a living from fragile ecosystems. A change to a more arid climate could be another cause, but no firm evidence is available that the climate is so changing. The Conference concluded that both the causes of desertification and the technical solutions to combating it are known. The key to combative measures is to be found in proper land-use. If desertification is to be brought to a halt by the end of the century, considerable financial resources will, however, be necessary.

The paper includes a comprehensive summary of the unpublished statements of the various national governments and some international agencies regarding their problems, an analysis of the findings of the Conference, and a brief discussion of action taken since its conclusion.