Prior to the 2000 election The Aspen Institute convened a distinguished group of science, business, and environment leaders as a hypothetical committee to advise the new President on global environmental policy. Experts prepared this set of policy memos to tell the President, concisely and in understandable language, "what he should know" and "what he should do" about climate change, biodiversity, population, oceans, water, food and agriculture, and other problems. A thematic summary of the groups conclusions, written by Co-chairs Donald Kennedy of Stanford University and Roger Sant of the AES Corporation, communicates the urgency of the challenges, the complexity of the interrelated issues, and the optimism necessary to tackle them.

(excerpt) The group of science, environment, and business leaders who produced and discussed these memoranda share a strong conviction that you and your administration face an array ofhistoric and urgent challenges—the kind that, with bold leadership, can be turned into exceptional opportunities.

Many of the recommendations for specific areas involve policies and tools that will not slow the nation’s economy and may even provide economic opportunities and help resolve real humanitarian concerns. This article presents a sketch ofthe broad outlines ofthe environmental problems confronting humanity and suggests some paths toward their resolution.

The first two challenges, emerging into the public consciousness only in recent decades,are rooted in the unprecedented pace ofglobal change. The global economy is linking nations and people in new and different ways. But people  are only beginning to realize the extent to which human actions are radically reshaping the global environment. Without awareness of the consequences of these actions, people have taken control ofthe planet.

Earth Systems: Processes and Issues is the ideal textbook for introductory courses in earth systems science and environmental science. Integrating the principles of the natural sciences, engineering, and economics as they pertain to the global environment, it explains the complex couplings and feedback mechanisms linking the geosphere, biosphere, hydrosphere, and atmosphere. An impressive group of internationally respected researchers and lecturers have brought together a vast wealth of teaching experience to produce this fully integrated environmental textbook. It has been designed for the wide range of courses at the first-year university level which touch upon environmental issues: in earth and atmospheric science, environmental science, biological science, oceanography, geography, civil engineering, and social science. Each chapter includes a reading list of the most important references, and problem sets will encourage students to explore the subject further. This text will favorably influence the future development of environmental studies and earth system science.

Earth Systems: Processes and Issues is the ideal textbook for introductory courses in earth systems science and environmental science. Integrating the principles of the natural sciences, engineering, and economics as they pertain to the global environment, it explains the complex couplings and feedback mechanisms linking the geosphere, biosphere, hydrosphere, and atmosphere. An impressive group of internationally respected researchers and lecturers have brought together a vast wealth of teaching experience to produce this fully integrated environmental textbook. It has been designed for the wide range of courses at the first-year university level which touch upon environmental issues: in earth and atmospheric science, environmental science, biological science, oceanography, geography, civil engineering, and social science. Each chapter includes a reading list of the most important references, and problem sets will encourage students to explore the subject further. This text will favorably influence the future development of environmental studies and earth system science.

This paper explores the significance of policy-induced technological change for the design of carbon-abatement policies. We derive analytical expressions characterizing optimal CO2 abatement and carbon tax profiles under different specifications for the channels through which technological progress occurs. We consider both R&D-based and learning-by-doing-based knowledge accumulation, and examine each specification under both a cost-effectiveness and a benefit-cost policy criterion. We show analytically that the presence of induced technological change (ITC) implies a lower time profile of optimal carbon taxes. The impact of ITC on the optimal abatement path varies. When knowledge is gained through R&D investments, the presence of ITC justifies shifting some abatement from the present to the future. However, when knowledge is generated through learning-by-doing, the impact on the timing of abatement is analytically ambiguous. Illustrative numerical simulations indicate that the impact of ITC upon overall costs and optimal carbon taxes can be quite large in a cost-effectiveness setting but typically is much smaller under a benefit-cost policy criterion. The impact of ITC on the timing of abatement is very weak, and the effect (applicable in the benefit-cost case) on total abatement over time is generally small as well, especially when knowledge is accumulated via R&D.

This review explores the potential energy, soil, and water constraints on highly productive agricultural systems. It focuses on the process of agricultural intensification during the past 50 years, and it shows that multiple constraints-as opposed to a single constraint, such as energy-are needed to assess the future sustainability of intensive agricultural production. Recent studies documenting changes in total factor productivity based on long-term experimental trials and field surveys are discussed in detail. The results of these studies are worrisome; they indicate that degradation in soil quality and in the overall natural resource base may threaten the long-run viability of several of the world's most intensive agricultural systems. Other studies are reviewed that support a more optimistic view of resource availability and the ability of improved technology and management to overcome these physical constraints. However, the combined evidence suggests that the increase in agricultural prices required to induce the necessary changes in technology could be devastating to low-income households. Most of the world's poor consume more agricultural output than they produce, and they spend up to 80% of their incomes on food.