The Institutional Dimensions of Environmental Change: Fit, Interplay, and Scale . By Oran R. Young. Cambridge, MA: MIT Press, 2002. 221p. $55.00 cloth, $21.95 paper

Climate tipping points occur when change in a part of the climate system becomes self-perpetuating beyond a warming threshold, leading to substantial Earth system impacts. Synthesizing paleoclimate, observational, and model-based studies, we provide a revised shortlist of global “core” tipping elements and regional “impact” tipping elements and their temperature thresholds. Current global warming of ~1.1°C above preindustrial temperatures already lies within the lower end of some tipping point uncertainty ranges. Several tipping points may be triggered in the Paris Agreement range of 1.5 to <2°C global warming, with many more likely at the 2 to 3°C of warming expected on current policy trajectories. This strengthens the evidence base for urgent action to mitigate climate change and to develop improved tipping point risk assessment, early warning capability, and adaptation strategies. Description Getting tipsy Climate tipping points are conditions beyond which changes in a part of the climate system become self-perpetuating. These changes may lead to abrupt, irreversible, and dangerous impacts with serious implications for humanity. Armstrong McKay et al. present an updated assessment of the most important climate tipping elements and their potential tipping points, including their temperature thresholds, time scales, and impacts. Their analysis indicates that even global warming of 1°C, a threshold that we already have passed, puts us at risk by triggering some tipping points. This finding provides a compelling reason to limit additional warming as much as possible. —HJS Global warming greater than 1.5°C could trigger multiple climate tipping points. INTRODUCTION Climate tipping points (CTPs) are a source of growing scientific, policy, and public concern. They occur when change in large parts of the climate system—known as tipping elements—become self-perpetuating beyond a warming threshold. Triggering CTPs leads to significant, policy-relevant impacts, including substantial sea level rise from collapsing ice sheets, dieback of biodiverse biomes such as the Amazon rainforest or warm-water corals, and carbon release from thawing permafrost. Nine policy-relevant tipping elements and their CTPs were originally identified by Lenton et al. (2008). We carry out the first comprehensive reassessment of all suggested tipping elements, their CTPs, and the timescales and impacts of tipping. We also highlight steps to further improve understanding of CTPs, including an expert elicitation, a model intercomparison project, and early warning systems leveraging deep learning and remotely sensed data. RATIONALE Since the original identification of tipping elements there have been substantial advances in scientific understanding from paleoclimate, observational, and model-based studies. Additional tipping elements have been proposed (e.g., parts of the East Antarctic ice sheet) and the status of others (e.g., Arctic summer sea ice) has been questioned. Observations have revealed that parts of the West Antarctic ice sheet may have already passed a tipping point. Potential early warning signals of the Greenland ice sheet, Atlantic Meridional Overturning Circulation, and Amazon rainforest destabilization have been detected. Multiple abrupt shifts have been found in climate models. Recent work has suggested that up to 15 tipping elements are now active (Lenton et al., 2019). Hence it is timely to synthesize this new knowledge to provide a revised shortlist of potential tipping elements and their CTP thresholds. RESULTS We identify nine global “core” tipping elements which contribute substantially to Earth system functioning and seven regional “impact” tipping elements which contribute substantially to human welfare or have great value as unique features of the Earth system (see figure). Their estimated CTP thresholds have significant implications for climate policy: Current global warming of ~1.1°C above pre-industrial already lies within the lower end of five CTP uncertainty ranges. Six CTPs become likely (with a further four possible) within the Paris Agreement range of 1.5 to <2°C warming, including collapse of the Greenland and West Antarctic ice sheets, die-off of low-latitude coral reefs, and widespread abrupt permafrost thaw. An additional CTP becomes likely and another three possible at the ~2.6°C of warming expected under current policies. CONCLUSION Our assessment provides strong scientific evidence for urgent action to mitigate climate change. We show that even the Paris Agreement goal of limiting warming to well below 2°C and preferably 1.5°C is not safe as 1.5°C and above risks crossing multiple tipping points. Crossing these CTPs can generate positive feedbacks that increase the likelihood of crossing other CTPs. Currently the world is heading toward ~2 to 3°C of global warming; at best, if all net-zero pledges and nationally determined contributions are implemented it could reach just below 2°C. This would lower tipping point risks somewhat but would still be dangerous as it could trigger multiple climate tipping points. The location of climate tipping elements in the cryosphere (blue), biosphere (green), and ocean/atmosphere (orange), and global warming levels at which their tipping points will likely be triggered. Pins are colored according to our central global warming threshold estimate being below 2°C, i.e., within the Paris Agreement range (light orange, circles); between 2 and 4°C, i.e., accessible with current policies (orange, diamonds); and 4°C and above (red, triangles).

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Exceeding 1.5°C global warming could trigger multiple climate tipping points

Achieving carbon neutral requires a comprehensive understanding of the effect of different key factors on carbon emissions. To this end, this study investigates the effect of trade openness, human capital, renewable energy and natural resource rent on carbon emissions within the framework of the environmental Kuznets curve (EKC) hypothesis. Second-generation econometric tests, Generalized Method of Moments and Fully Modified Ordinary Least Squares estimator were developed based on the aggregated dataset of 208 countries from 1990 to 2018. The results show that (i) the EKC hypothesis is validated when the effects of trade openness, human capital, renewable energy consumption, and natural resource rents are considered. The relationship between income level and carbon emissions shows an "inverted U-shaped" curve at the global level. Besides, the real GDP per capita corresponding to the EKC turning point is 19,203$. (ii) Renewable energy consumption and human capital have heterogeneous effects on carbon emissions in before- and after-EKC turning points. Specifically, renewable energy consumption has a better emission reduction effect for countries before the EKC turning point, with effects of -0.4334 and -0.1598, respectively; human capital has a better emission reduction effect for countries after the EKC turning point, with effects of -0.6311 and -0.3398, respectively.(iii) the mitigation effect of trade openness on carbon emissions is only effective in countries with weak decoupling after EKC turning points, with a mitigating effect of -0.0615. However, natural resource rents increase carbon emissions in most countries. 

Revisiting the environmental kuznets curve hypothesis in 208 counties: The roles of trade openness, human capital, renewable energy and natural resource rent.

Maritime shipping is the transmission belt of the global economy. It is also a major contributor to global environmental change through its under-regulated air, water and land impacts. It is puzzling that shipping is a lagging sector as it has a well-established global regulatory body—the International Maritime Organization. Drawing on original empirical evidence and archival data, we introduce a four-factor framework to investigate two main questions: why is shipping lagging in its environmental governance; and what is the potential for the International Maritime Organization to orchestrate emerging private ‘green shipping’ initiatives to achieve better ecological outcomes? Contributing to transnational governance theory, we find that conditions stalling regulatory progress include low environmental issue visibility, poor interest alignment, a broadening scope of environmental issues, and growing regulatory fragmentation and uncertainty. The paper concludes with pragmatic recommendations for the International Maritime Organization to acknowledge the regulatory difficulties and seize the opportunity to orchestrate environmental progress.

/pdf/orchestrating-transnational-environmental-governance-in-47ntgv7prh.pdf

Orchestrating transnational environmental governance in maritime shipping

Description Human activities have caused global temperatures to increase by 1.25°C, and the current emissions trajectory suggests that we will exceed 1.5°C in less than 10 years. Though the growth rate of global carbon dioxide emissions has slowed and many countries have strengthened their emissions targets, current midcentury net zero goals are insufficient to limit global warming to 1.5°C above preindustrial temperatures. The primary barriers to the achievement of a 1.5°C-compatible pathway are not geophysical but rather reflect inertia in our political and technological systems. Both political and corporate leadership are needed to overcome this inertia, supported by increased societal recognition of the need for system-level and individual lifestyle changes. The available evidence does not yet indicate that the world has seriously committed to achieving the 1.5°C goal.

Current global efforts are insufficient to limit warming to 1.5°C

Realization of Paris Agreement pledges may limit warming just below 2 °C

Despite the substantial and likely increasing contribution of greenhouse gas (GHG) emissions from international shipping and the related adverse impacts on global climate change, GHG emissions from international shipping are yet neither regulated by the Kyoto Protocol, nor through any other legally binding, internationally accepted regulation. This paper is looking into the governance architecture that is currently in place to regulate GHG emissions from international shipping with a view to analyze whether the institutional degree of fragmentation within this architecture is contributing to the current situation where no legally binding, internationally accepted regulation has been set up yet. Following the hypothesis that the degree and the characteristics of governance fragmentation have a crucial impact on the effectiveness and performance of a governance system, this paper focuses on the current architecture of climate change governance in international shipping and the institutional interplay between its actors. Therefore, the analytical framework builds on approaches from international environmental governance, regime theory, institutional interplay, and fragmentation in international governance architectures.

Bernd Hackmann

Papers

Realization of Paris Agreement pledges may limit warming just below 2 °C

Analysis of the governance architecture to regulate GHG emissions from international shipping