Global Environment Outlook 3 (GEO 3)

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OUTLOOK 2002–32

the scenarios have been presented as fairly uniform across the world, it is clear that not all regions have experienced, are experiencing, or will experience the same developments. Examining the environmental implications casts a spotlight on the differences across scenarios, regions and issues. These variations have been illustrated in the narratives, the quantitative material and the differing outcomes of particular events or trends. Sustainability First implies the most positive environmental outlook of the four scenarios. Markets First and Security First conjure up much more pessimistic pictures, but for very different reasons. This contrast is reflected in the issues that come most conspicuously to the fore in each scenario. For example, water shortages are generally more of a problem in Markets First , reflecting increasing resource demand, whereas urban pollution and loss of biodiversity are more marked in Security First , reflecting a lack of effective environmental policies. Policy First falls somewhere in between — some of the environmental targets are met, through a mainly top-down approach, whereas it is unrealistic to make significant progress on others without a broader commitment to change. LESSON TWO There can be significant delays between human actions, including policy decisions, and associated impacts on the environment, specifically: much of the environmental change that will occur over the next 30 years has already been set in motion by past and current actions many of the effects of environmentally relevant policies put into place over the next 30 years will not be apparent until long afterwards. Social and economic systems can be notoriously slow to change. The basic infrastructure of modern society, including transportation and energy systems, cannot be refashioned rapidly without great expense. Financial and political systems, and basic behaviour patterns also tend to exhibit overpowering inertia. Furthermore, even when social systems change,

resulting in reduced pressures on the environment, time lags in natural systems can delay the ultimate response to these changes. Therefore, it is important to consider not only the state of the environment at the end of the time horizon for these scenarios, but also the trends. This proviso is perhaps most clearly seen in the case of climate change impacts, which differ minimally between the scenarios in most regions over the next 30 years. This is because much of the climatic change expected to occur over the next 30 years is the result of actions that have already been taken. It is not surprising that the issues which stand out as the most difficult to tackle — halting land degradation, preserving biodiversity and ensuring access to freshwater — are all linked to climate change among other factors. The intractable nature of these impacts is also related to the fact that they are driven by fundamental human demands and are not easily amenable to technical fixes. LESSON THREE Achieving widely agreed environmental and social goals will require dramatic and coordinated action starting now and continuing for a number of years. Steps must include policies based on prevention and adaptation. The environmental implications of the various scenarios illustrate the legacy of the past decades and the level of effort that will be needed to reverse powerful trends. These challenges can only be met with robust and coordinated action at all levels of government and among many different sectors of society. The scenarios also demonstrate that it can take many years for important social and environmental indicators to diverge from one another. Given the likelihood that large numbers of people will continue to be vulnerable to environmental change, even where the scenarios point to eventual achievement of environmental goals, adaptation policies will be needed to complement mitigation policies. Among other reasons, these may be necessary to meet social goals, minimize the transient effects of environmental change, prevent irreversible losses, and maintain the enthusiasm for the necessary social and political will to achieve the long-term goals.