Biodiversity hotspots house most undiscovered plant species.

For most organisms, the number of described species considerably underestimates how many exist. This is itself a problem and causes secondary complications given present high rates of species extinction. Known numbers of flowering plants form the basis of biodiversity "hotspots"--places where high levels of endemism and habitat loss coincide to produce high extinction rates. How different would conservation priorities be if the catalog were complete? Approximately 15% more species of flowering plant are likely still undiscovered. They are almost certainly rare, and depending on where they live, suffer high risks of extinction from habitat loss and global climate disruption. By using a model that incorporates taxonomic effort over time, regions predicted to contain large numbers of undiscovered species are already conservation priorities. Our results leave global conservation priorities more or less intact, but suggest considerably higher levels of species imperilment than previously acknowledged.

Overcoming systemic roadblocks to sustainability: the evolutionary redesign of worldviews, institutions, and technologies.

A high and sustainable quality of life is a central goal for humanity. Our current socio-ecological regime and its set of interconnected worldviews, institutions, and technologies all support the goal of unlimited growth of material production and consumption as a proxy for quality of life. However, abundant evidence shows that, beyond a certain threshold, further material growth no longer significantly contributes to improvement in quality of life. Not only does further material growth not meet humanity's central goal, there is mounting evidence that it creates significant roadblocks to sustainability through increasing resource constraints (i.e., peak oil, water limitations) and sink constraints (i.e., climate disruption). Overcoming these roadblocks and creating a sustainable and desirable future will require an integrated, systems level redesign of our socio-ecological regime focused explicitly and directly on the goal of sustainable quality of life rather than the proxy of unlimited material growth. This transition, like all cultural transitions, will occur through an evolutionary process, but one that we, to a certain extent, can control and direct. We suggest an integrated set of worldviews, institutions, and technologies to stimulate and seed this evolutionary redesign of the current socio-ecological regime to achieve global sustainability.

How can a knowledge of the past help to conserve the future? Biodiversity conservation and the relevance of long-term ecological studies.

This paper evaluates how long-term records could and should be utilized in conservation policy and practice. Traditionally, there has been an extremely limited use of long-term ecological records (greater than 50 years) in biodiversity conservation. There are a number of reasons why such records tend to be discounted, including a perception of poor scale of resolution in both time and space, and the lack of accessibility of long temporal records to non-specialists. Probably more important, however, is the perception that even if suitable temporal records are available, their roles are purely descriptive, simply demonstrating what has occurred before in Earth's history, and are of little use in the actual practice of conservation. This paper asks why this is the case and whether there is a place for the temporal record in conservation management. Key conservation initiatives related to extinctions, identification of regions of greatest diversity/threat, climate change and biological invasions are addressed. Examples of how a temporal record can add information that is of direct practicable applicability to these issues are highlighted. These include (i) the identification of species at the end of their evolutionary lifespan and therefore most at risk from extinction, (ii) the setting of realistic goals and targets for conservation 'hotspots', and (iii) the identification of various management tools for the maintenance/restoration of a desired biological state. For climate change conservation strategies, the use of long-term ecological records in testing the predictive power of species envelope models is highlighted, along with the potential of fossil records to examine the impact of sea-level rise. It is also argued that a long-term perspective is essential for the management of biological invasions, not least in determining when an invasive is not an invasive. The paper concludes that often inclusion of a long-term ecological perspective can provide a more scientifically defensible basis for conservation decisions than the one based only on contemporary records. The pivotal issue of this paper is not whether long-term records are of interest to conservation biologists, but how they can actually be utilized in conservation practice and policy.

Environmental refugees: a growing phenomenon of the 21st century.

There is a new phenomenon in the global arena: environmental refugees. These are people who can no longer gain a secure livelihood in their homelands because of drought, soil erosion, desertification, deforestation and other environmental problems, together with the associated problems of population pressures and profound poverty. In their desperation, these people feel they have no alternative but to seek sanctuary elsewhere, however hazardous the attempt. Not all of them have fled their countries, many being internally displaced. But all have abandoned their homelands on a semi-permanent if not permanent basis, with little hope of a foreseeable return. In 1995, environmental refugees totalled at least 25 million people, compared with 27 million traditional refugees (people fleeing political oppression, religious persecution and ethnic troubles). The total number of environmental refugees could well double by the year 2010, and increase steadily for a good while thereafter as growing numbers of impoverished people press ever harder on overloaded environments. When global warming takes hold, there could be as many as 200 million people overtaken by sea-level rise and coastal flooding, by disruptions of monsoon systems and other rainfall regimes, and by droughts of unprecedented severity and duration.

New consumers: The influence of affluence on the environment.

Growing consumption can cause major environmental damage. This is becoming specially significant through the emergence of over 1 billion new consumers, people in 17 developing and three transition countries with an aggregate spending capacity, in purchasing power parity terms, to match that of the U.S. Two of their consumption activities have sizeable environmental impacts. First is a diet based strongly on meat, which, because it is increasingly raised in part on grain, puts pressure on limited irrigation water and international grain supplies. Second, these new consumers possess over one-fifth of the world's cars, a proportion that is rising rapidly. Global CO(2) emissions from motor vehicles, of which cars make up 74%, increased during 1990-1997 by 26% and at a rate four times greater than the growth of CO(2) emissions overall. It is in the self-interest of new consumer countries, and of the global community, to restrict the environmental impacts of consumption; this restriction is achievable through a number of policy initiatives.

Changes in the use and management of forests for abating carbon emissions: issues and challenges under the Kyoto Protocol.

The global carbon cycle is significantly influenced by changes in the use and management of forests and agriculture. Humans have the potential through changes in land use and management to alter the magnitude of forest-carbon stocks and the direction of forest-carbon fluxes. However, controversy over the use of biological means to absorb or reduce emissions of CO(2) (often referred to as carbon 'sinks') has arisen in the context of the Kyoto Protocol. The controversy is based primarily on two arguments: sinks may allow developed nations to delay or avoid actions to reduce fossil fuel emissions, and the technical and operational difficulties are too threatening to the successful implementation of land use and forestry projects for providing carbon offsets. Here we discuss the importance of including carbon sinks in efforts to address global warming and the consequent additional social, environmental and economic benefits to host countries. Activities in tropical forest lands provide the lowest cost methods both of reducing emissions and reducing atmospheric concentrations of greenhouse gases. We conclude that the various objections raised as to the inclusion of carbon sinks to ameliorate climate change can be addressed by existing techniques and technology. Carbon sinks provide a practical available method of achieving meaningful reductions in atmospheric concentrations of carbon dioxide while at the same time contribute to national sustainable development goals.

Tracking the ecological overshoot of the human economy.

Sustainability requires living within the regenerative capacity of the biosphere. In an attempt to measure the extent to which humanity satisfies this requirement, we use existing data to translate human demand on the environment into the area required for the production of food and other goods, together with the absorption of wastes. Our accounts indicate that human demand may well have exceeded the biosphere's regenerative capacity since the 1980s. According to this preliminary and exploratory assessment, humanity's load corresponded to 70% of the capacity of the global biosphere in 1961, and grew to 120% in 1999.

Economic reasons for conserving wild nature.

On the eve of the World Summit on Sustainable Development, it is timely to assess progress over the 10 years since its predecessor in Rio de Janeiro. Loss and degradation of remaining natural habitats has continued largely unabated. However, evidence has been accumulating that such systems generate marked economic benefits, which the available data suggest exceed those obtained from continued habitat conversion. We estimate that the overall benefit:cost ratio of an effective global program for the conservation of remaining wild nature is at least 100:1.

Depletion of tropical moist forests: A comparative review of rates and causes in the three main regions

Abstract Information on depletion of tropical moist forests throughout the world is reviewed, including its causes, course and consequences in Latin America, Africa and Southeast Asia. Primary, or undisturbed, forest under goes varying degrees of perturbation depending on exploitation practices. Timber exploitation has been particularly important in Southeast Asia. Slash-and-burn agriculture often follows due to improved access. Shifting cultivation is especially important in Africa, where high population pressure makes the access roads opened for logging an even stronger catalyst to entrance of slash-and-burn farmers. Cattle raising is a major cause in Latin America, often influenced by foreign market pressures and government policies.

Resumo Informações sobre a depleção das florestas úmidas tropicais no mundo são revisadas, inclusive das suas causas, tendências e conseqüências na América Latina, África e Suleste da Ásia. Floresta primária, ou seja não perturbada, sofre diferentes graus de mudança dependendo das práticas de exploração. Exploração de madeira tem sido particularmente importante no Suleste da Asia. Agricultura itinerante muitas vezes segue devido ao acesso melhorado. Agricultura migratória é especialmente importante na Africa, onde pressão populacional alta faz com que estradas de acesso abertas para a retirada da madeira se tornam um catalisador ainda mais forte, levando à entrada de agricultores itinerantes. Pecuária é uma causa principal na América Latina, muitas vezes influenciada por pressões de mercados estrangeiros e por políticas governamentais.