Achim Steiner is United Nations Under-Secretary-General and Executive Director of the United Nations Environment Programme (UNEP). Effective as of 1 March 2009, Mr Steiner was also appointed Director-General of the United Nations Office at Nairobi (UNON). Before joining UNEP, he served as Director-General of the International Union for Conservation of Nature (IUCN) from 2001 to 2006. His professional career has included assignments with governmental, non-governmental, and international organizations in various parts of the world. In Washington, where he had previously been Senior Policy Advisor of IUCN's Global Policy Unit, he spearheaded the development of new partnerships between the environmental community, the World Bank, and the United Nations system. In South-East Asia he worked as Chief Technical Advisor on a programme for sustainable management of Mekong River watersheds and community-based natural resources management. In 1998 he was appointed Secretary-General of the World Commission on Dams, based in South Africa, where he directed a worldwide programme of work to bring together the public sector, civil society, and the private sector in a global policy-making process on dams and development.

The realization that human beings need to be concerned about the only ‘life-support system’ that the Earth and its environment provides stems perhaps in part from the fact that, until fairly recently, the evolution of humankind was largely dependent on the quality of the environment and the resources it provides in terms of water, food, and favourable health conditions. These are as vital as ever, despite current levels of technology and apparent resilience in the face of often degraded environments in many parts of the world. Today, the conditions for human sustainability (i.e. water quality and quantity, food security, and health) are potentially under threat as a result of numerous human-induced factors; among these, climate change is certainly one of the more durable aspects of anthropogenic disruptions to natural resources. This article will therefore focus on the possible evolution of climate in the course of the twenty-first century and on a number of key climate impacts that may determine the future course of human societies, as well as issues that may confront them such as rivalries over natural resources and possible environmentally driven conflicts and migrations.

There are three key deficiencies in the existing body of international humanitarian law (IHL) relating to protection of the environment during armed conflict. First, the definition of impermissible environmental damage is both too restrictive and unclear; second, there are legal uncertainties regarding the protection of elements of the environment as civilian objects; and third, the application of the principle of proportionality where harm to the environment constitutes ‘collateral damage’ is also problematic. These gaps present specific opportunities for clarifying and developing the existing framework. One approach to addressing some of the inadequacies of IHL could be application of international environmental law during armed conflict. The detailed norms, standards, approaches, and mechanisms found in international environmental law might also help to clarify and extend basic principles of IHL to prevent, address, or assess liability for environmental damage incurred during armed conflict.

The relationship between international environmental law and international humanitarian law, like relationships between many other subsystems of contemporary international law, has not yet been articulated. The problem of environmental damage in international armed conflict lies at the intersection of these two branches and thus provides an ideal opportunity to investigate this relationship. Rather than simply evaluating the applicable international law rules in their context, we break them into elements that we separately assess from both (international) environmental law and international humanitarian/international criminal law perspectives. By doing so, we identify how international law rules for cross-sectoral problems may appropriately combine the existing expertise and institutional strengths of simultaneously applicable branches of international law, and also discover how an evaluation of the ultimate appropriateness of the cross-sectoral rules adopted may be substantially affected by the different frames of reference that are used by those working within the different fields.

Water scarcity, accelerated by climate change, affects water availability and may threaten peace and security. This role of water, as a contributing factor for triggering wars, sheds light on the significance of the protection of water during armed conflict. Keeping water out of war not only contributes to preserving an indispensable natural resource for life but also serves as a tool for the hostile parties to start negotiations, building trust and peace.

Little attention is paid to the obligation of ‘care’ in Article 55(1) of Additional Protocol I. Beyond a general principle of upholding environmental value in times of armed conflict, what is the scope and content of the obligation? If it is worthless, what makes it so? Since the care provision includes the same high threshold of harm found elsewhere in the environmental provisions, has this stumbling block now been removed by state practice? Rule 44 of the Customary Law Study might appear to suggest that this is so, or does it? Ultimately then, is the care obligation worth caring about?

A changing climate means more work for humanitarian organizations. Vulnerable people served by the Red Cross/Red Crescent Movement are likely to experience new patterns of disasters. In the face of these rising dangers, science-based information about likely threats can be used to reduce risk and improve resource allocation. Examples such as the 2008 emergency appeal for flood preparedness in West Africa illustrate the benefits of turning early warnings into early actions at community, national, and regional levels, at timescales ranging from hours to decades ahead of a looming threat. By making better use of a wide range of new information, humanitarian organizations can enhance their work even in the face of the rising risks of climate change.

Millions are displaced by climate-related disasters each year, and this trend is set to increase as climate change accelerates. It raises important questions about how well existing instruments actually protect people driven from their homes by climate change and natural disasters. This article first examines current protection instruments and points out gaps in them. There follows an exploration of various proposals for filling those protection gaps, with the focus on cross-border natural-disaster-induced displacement. A multi-track approach is recommended, including context-oriented and dynamic interpretation of existing law, and creation of new law. Adhering to the principle of non-refoulement, and focusing on whether return is possible, permissible, or reasonable, could be a realistic way to begin developing protection regimes for victims of natural-disaster-induced displacement.

Reparations are essential to establishing justice after armed conflicts. The question whether international law endorses an individual right to reparation has been a focal point of recent discussion in that regard. The victims of armed conflicts are, however, not only individuals but also collectives. The present article therefore examines the issue of collective reparation. While it is submitted that the question whether there is a right to such a remedy is not yet settled, it is argued that responsible parties should develop robust programmes of collective reparation.