Person:

Epstein, Paul

Increasing atmospheric carbon dioxide is responsible for climate changes that are having widespread effects on biological systems. One of the clearest changes is earlier onset of spring and lengthening of the growing season. We designed the present study to examine the interactive effects of timing of dormancy release of seeds with low and high atmospheric CO2 on biomass, reproduction, and phenology in ragweed plants (Ambrosia artemisiifolia L.), which produce highly allergenic pollen. We released ragweed seeds from dormancy at three 15-day intervals and grew plants in climate-controlled glasshouses at either ambient or 700-ppm CO2 concentrations, placing open-top bags over inflorescences to capture pollen. Measurements of plant height and weight; inflorescence number, weight, and length; and days to anthesis and anthesis date were made on each plant, and whole-plant pollen productivity was estimated from an allometric-based model. Timing and CO2 interacted to influence pollen production. At ambient CO2 levels, the earlier cohort acquired a greater biomass, a higher average weight per inflorescence, and a larger number of inflorescences; flowered earlier; and had 54.8% greater pollen production than did the latest cohort. At high CO2 levels, plants showed greater biomass and reproductive effort compared with those in ambient CO2 but only for later cohorts. In the early cohort, pollen production was similar under ambient and high CO2, but in the middle and late cohorts, high CO2 increased pollen production by 32% and 55%, respectively, compared with ambient CO2 levels. Overall, ragweed pollen production can be expected to increase significantly under predicted future climate conditions.

The access of almost all 270 million U.S. residents to reliable, safe drinking water distinguishes the United States in the twentieth century from that of the nineteenth century. The United States is a relatively water-abundant country with moderate population growth; nonetheless, current trends are sufficient to strain water resources over time, especially on a regional basis. We have examined the areas of public water infrastructure, global climate effects, waterborne disease (including emerging and resurging pathogens), land use, groundwater, surface water, and the U.S. regulatory history and its horizon. These issues are integrally interrelated and cross all levels of public and private jurisdictions. We conclude that U.S. public drinking water supplies will face challenges in these areas in the next century and that solutions to at least some of them will require institutional changes.

The last several years have witnessed a significant evolution in what society wants to know about global environmental risks such as climate change, ozone depletion, and biodiversity loss. Until recently, most scientific assessments of such risks focused on the anatomy of conceivable environmental changes themselves, while devoting relatively little attention to the ecosystems and societies the changes might endanger. Recently, however, questions about the vulnerability of social and ecological systems are emerging as a central focus of policy-driven assessments of global environmental risks. Meeting the growing demand for a deeper and more useful understanding of vulnerability to global change will require a dual strategy in which initiatives targeted on immediate assessment needs and research opportunities complement and feed into a longer term program for enhancing relevant knowledge bases, assessment practices, and institutional capacities. This paper makes recommendations for the design of such a strategy that emerged from an ongoing conversation between communities of decision-oriented vulnerability assessors for global environmental change issues, research-oriented vulnerability scholars generally focusing on regional scale human-environment interactions, and those conducting vulnerability assessments that assist in targeting improved intervention and mitigation strategies. It sketches an integrated framework for vulnerability-based assessments of climate and other global changes. By virtue of both concept and design this framework has the potential to improve significantly the production of policy-relevant insights into the social and environmental implications of global environmental change. This paper was prepared as a brief summary of the Workshop on Vulnerability to Global Environmental Change: Challenges for Research, Assessment and Decision Making, held on May 22-25, 2000 at Airlie House in Warrenton, Virginia.

Background: Although the issue of anthropogenic climate forcing and public health is widely recognized, one fundamental aspect has remained underappreciated: the impact of climatic change on plant biology and the well-being of human systems. Objectives: We aimed to critically evaluate the extant and probable links between plant function and human health, drawing on the pertinent literature. Discussion: Here we provide a number of critical examples that range over various health concerns related to plant biology and climate change, including aerobiology, contact dermatitis, pharmacology, toxicology, and pesticide use. Conclusions: There are a number of clear links among climate change, plant biology, and public health that remain underappreciated by both plant scientists and health care providers. We demonstrate the importance of such links in our understanding of climate change impacts and provide a list of key questions that will help to integrate plant biology into the current paradigm regarding climate change and human health.