| 英文摘要: | Sustainably managing coupled ecological–economic systems requires not only an understanding of the environmental factors that affect them, but also knowledge of the interactions and feedback cycles that operate between resource dynamics and activities attributable to human intervention. The socioeconomic dynamics, in turn, call for an investigation of the behavioural drivers behind human action. We argue that a multidisciplinary approach is needed in order to tackle the increasingly pressing and intertwined environmental challenges faced by modern societies. Academic contributions to climate change policy have been constrained by methodological and terminological differences, so we discuss how programmes aimed at cross-disciplinary education and involvement in governance may help to unlock scholars' potential to propose new solutions.
Dealing with climate change requires enhanced integration between ecology and economics, but such partnerships are also essential in addressing a wide range of challenges in achieving a sustainable future1. Many recipes for preserving the Earth's climate from dangerous change have been proposed. The delayed damaging effect of greenhouse-gas (GHG) emissions and their transboundary nature (independently of the source, all emissions increase the world's stock of concentrations) aggravate the problem. Hence prescriptions for addressing the global external cost arising from human activity are bound to be multifaceted and to rely on various instruments and methodologies. Traditional theories of collective action have, until recently, shed a pessimistic light on the prospects of self-organization in limiting the use of communal resources to a sustainable level. This is in part due to Hardin's 'tragedy of the commons', whose policy implication was to rely on coercion in the form of either privatization or government intervention2, 3. Although more recent work has demonstrated that under a wide range of circumstances, communities are able to self-restrain and avoid resource overexploitation4, global cooperation at the scale required to reduce emissions and decarbonize the economy may be difficult to sustain without sanctions. In fact, the present lack of a supranational institution for regulating global carbon emissions sets the stage for free-riding, that is, individual countries have an incentive to delay curbing emissions and rely on the mitigation efforts of others. Does this gloomy picture change when we shift attention from gradual global warming to abrupt changes in the climate system, that is, drastic and potentially irreversible ecological shifts? The threat of an impending low-probability, high-impact disaster might be imagined to be a stimulus to mitigation efforts. One might think that humanity would rise to the challenge of a rapid transition to a carbon-free economy once alerted by early warning signals such as the climate system has been providing us; but that has not been the case. Inaction remains the norm, and delaying the economic costs of mitigation, while engaging in repeated rounds of negotiations without addressing the root causes of global warming, is common practice. Even with agreement, 'solutions' might not be achievable. We may have already passed a critical threshold, such as the 350 parts per million by volume atmospheric CO2 required to safeguard polar ice sheets5. Even if we haven't already crossed a planetary boundary for dangerous climatic change, we must still be able to identify future early warning signals and collectively agree on large-scale action in the face of incentives for individual countries to free-ride. Lastly, should a global agreement be struck in response to a perceived threat, uncertainty regarding the amount of time and the degree of effort required to reverse course and contain atmospheric CO2 within a safe operating space will persist. Clearly, we need to develop and implement a framework for global cooperative action that is robust to structural scientific uncertainties (as well as to uncertainty about societal responses to mitigation policies). Collective action can resolve commons problems at smaller scales4, 6; the challenge is in extending those principles to achieve enforceable agreements among nations towards a sustainable future7. Threshold uncertainty surfaces in the latest IPCC Summary for Policymakers8. The authors state that: “There is high confidence that sustained warming greater than some threshold would lead to the near-complete loss of the Greenland ice sheet over a millennium or more, causing a global mean sea level rise of up to 7 m. Current estimates indicate that the threshold is greater than about 1 °C (low confidence) but less than about 4 °C (medium confidence) global mean warming with respect to pre-industrial.” In sum, obstacles to climate cooperation are compounded by deep scientific uncertainty concerning the timing and magnitude of climate change impacts9, 10. Avoiding a tipping point leading to catastrophic climate events is much more difficult when its location is hard to pinpoint11, a feature that cannot be disregarded, given the recently reported plurality of thresholds for abrupt climate change5, 12, 13. Furthermore, the link between emissions and climate change is also subject to error propagation14, meaning that we cannot attribute with certainty an emergency to increases in climate radiative forcing. Yet, the evidence that long-lived global warming can be attributed to anthropogenic causes is strong8. How can science inform the debate on reaching an international agreement to keep temperature increases within acceptable boundaries? More broadly, what type of science–society interface is conducive to better management of global environmental commons? An interdisciplinary effort is needed to address policy-relevant problems and explore appropriate economic instruments to deal with present-day environmental concerns15. The time is ripe for economists and ecologists, along with other physical and social scientists, to join forces to analyse individual and collective behaviour with the lens that is most appropriate given the research question at hand, rather than within disciplinary boundaries16. The insular nature of the social sciences and their especially tenuous academic link with ecology and Earth sciences (Fig. 1), have hindered the study of coupled social–ecological systems. Progress has been made in bridging the gaps1, 16, 17, 18, 19, but collaborations across the sciences need to identify better the intertwined drivers of successful commons' management.
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