International environmental regimes—especially those regimes articulated in multilateral environmental agreements—have been a subject of intense interest within the scientific community over the last three decades. However, there are substantial differences of opinion regarding the effectiveness of these governance systems or the degree to which they are successful in solving the problems leading to their creation. This article provides a critical review of the literature on this topic. It extracts and summarizes what is known about the effectiveness of environmental regimes in the form of a series of general and specific propositions. It identifies promising topics for consideration in the next phase of research in this field. Additionally, it comments on the research strategies available to pursue this line of analysis. The general conclusions are that international environmental regimes can and do make a difference, although often in conjunction with a number of other factors, and that a strategy of using a number of tools combined can help to improve understanding of the determinants of success.

The transformative biophysical and socio-economic changes now occurring in the Arctic are generating new needs for governance in the circumpolar north. One common response to this challenge, the negotiation of a comprehensive Arctic treaty, is neither feasible nor necessary as a means of meeting these needs. This analysis turns instead to the idea of a regime complex, a concept that has become increasingly influential in the broader literature on international cooperation, and explores the prospects for the development of an Arctic regime complex. It argues that a number of the elements of such a complex are already in place and that others are coming into focus at this time. There is no basis for complacency here. But, current developments do provide a basis for cautious optimism regarding efforts to meet the needs for governance in the “new” Arctic.

The Arctic and the Antarctic appear to be polar opposites with regard to many matters, including the systems of governance that have evolved in the two regions. Antarctica is demilitarised, closed to economic development, open to a wide range of scientific activities, and subject to strict environmental regulations under the terms of the legally binding Antarctic Treaty of 1959 along with several supplementary measures that together form the Antarctic Treaty System (ATS). The Arctic, by contrast, is a theatre of military operations, a site of largescale industrial activities, a homeland for sizable groups of indigenous peoples, and a focus of growing concern regarding the environmental impacts of human activities. The Arctic Council, the principal international body concerned with governance at the regional level, operates under the terms of a ministerial declaration that is not legally binding; it lacks the authority to make formal decisions about matters of current interest. Digging a little deeper, however, one turns up some illuminating similarities between the governance systems operating in the antipodes. In this article, I pursue this line of thinking, setting forth a range of observations relating to (i) the history of governance in the antipodes, (ii) institutional innovations occurring in these regions, (iii) issues of membership, (iv) jurisdictional concerns, (v) the role of science, (vi) relations with the UN system, (vii) institutional interplay, and (viii) the adaptiveness of governance systems in the face of changing circumstances. The governance systems for the polar regions are not likely to converge anytime soon. Nevertheless, this analysis should be of interest not only to those concerned with the fate of Antarctica and the Arctic but also to those seeking to find effective means of addressing needs for governance in other settings calling for governance without government.