State of the Planet

News from the Columbia Climate School

New IPCC Report Offers New Data, Stern Warnings, Hope

This article was originally published on GlacierHub.

glacier in austria
Pasterze Glacier in Austria, showing significant retreat. Photo: Bernd Thaller

On 8 October, the Intergovernmental Panel on Climate Change (IPCC) announced the final approval of the Special Report on Global Warming of 1.5˚C (SR1.5). This report presents the results of a thorough assessment of the differences between two levels of global warming, the 2˚C limit which was established as a firm commitment target by the 2015 Paris Agreement, and the 1.5˚C limit, which the same agreement indicated as a more ambitious level to be approached or achieved. This report gives glaciers extensive coverage, referring to them 19 times.

Georg Kaser, a glaciologist at the University of Innsbruck in Austria, offered a succinct overview of the report in an interview with GlacierHub:

The fact that this SR1.5 was produced in only 1.5 years is an incredible success, made possible by dozens of colleagues who have not only set up new socio-economical, emission, climate change, and climate change impact scenarios from scratch, but have also been able to reduce uncertainties in a way that made the distinction between 1.0, 1.5 and 2.0C possible. By doing so they have been able to show both that the 0.5C steps make serious differences and that there is still a time window–though a small one–that is open for keeping the earth at 1.5C above preindustrial levels.

Urgent Messages in the IPCC Report

The report underscores the urgency of the Paris Agreement and its ambitious target. As Patricia Pinho, an environmental policy scientist at the University of Sao Paulo in Brazil who was an author on the report, told GlacierHub in an interview, “The report shows that every degree of warming matters for livelihoods in most communities. Actions need to be taken now if suffering, disruption, and conflict are to be avoided.” She described the collaboration among the authors from a variety of natural and social science fields as an innovative aspect of the report, saying “different groups of scientists worked together as an interdisciplinary community to deliver society a message grounded in scientific evidence.”

The report presents many benefits of limiting the global temperature increase to 1.5˚C rather than allowing it to rise to 2˚C. There would be fewer heat waves, lower levels of sea level rise, less extreme loss of sea ice, of coral reefs and of endangered species, fewer droughts and lower levels of crop loss. It indicates that this target can still be achieved, though it will require a rapid reduction in the reliance on oil, gas and coal, and a firm deployment of renewable energy resources, such as wind and solar power and hydropower. Moreover, the window for this transformation is a narrow one, since global emissions would have to be reduced by half as soon as 2030, and brought down close to zero by 2050.

The New Report Discusses Glaciers Extensively

SR1.5 mentions glaciers once in each of two early key sections, presenting distinct, important features which they possess. In the Summary for Policy-Makers, the most widely read section in all IPCC reports, the report lists a set of “reasons for concern.” The reason which is listed first, because it is the most vulnerable to warming, are the “unique and threatened systems.” These systems consist of ecosystems and societies which have narrow spatial ranges which face firm climate constraints, and which have endemic species or other distinctive features which cannot be replicated. To provide specific examples of such systems, the report lists “coral reefs, the Arctic and its indigenous people, mountain glaciers, and biodiversity hotspots.”

In Chapter 1, Framing and Context, the report underscores a second crucial role of glaciers. They serve as an example of the interconnectedness of climate change impacts, a characteristic that creates interacting, compounding negative effects. In section 1.3.2. of this chapter, Drivers of Impacts, the report states “Impacts may also be triggered by combinations of factors, including ‘impact cascades’ through secondary consequences of changed systems. Changes in agricultural water availability caused by upstream changes in glacier volume are a typical example.”

Chapter 3, Impacts of 1.5˚C Global Warming on Natural and Human Systems, offers a somber note on the future of glaciers, reflecting the slowness with which glaciers respond to climate drivers. It states, “28–44% of present-day glacier volume is unsustainable in the present-day climate, so that it would eventually (over the course of a few centuries) melt, even if there were no further climate change.”

Chapter 3 contains more than half of all the references to glaciers in the report. It discusses the contribution of glacier retreat to sea level rise. It notes that the contributions of glaciers to sea level rise in the present century cannot be distinguished statistically. Current research indicates that they would be between 54-97 mm (in relation to present sea levels) for 1.5˚C, and 63-112 mm for 2˚C, using a 90% confidence interval. To explain this finding, the report states “This arises because melt during the remainder of the century is dominated by the response to warming from preindustrial to present-day levels (in turn a reflection of the slow response times of glaciers).” This chapter also notes that glacier melt will contribute to the decrease in salinity in seawater, particularly at high latitudes in the Northern Hemisphere (section 3.3.10, Ocean Chemistry).

Chapter 3 is the only one which mentions glaciers in its section on Frequently Asked Questions. In response to the first FAQ, “What are the impacts of 1.5°C and 2°C of warming?” it states “The impacts of climate change are being felt in every inhabited continent and in the oceans. But they are not spread uniformly across the globe, and different parts of the world experience impacts differently. … The impacts of any additional warming would also include stronger melting of ice sheets and glaciers.”

This chapter also describes the effects of glacier retreat on social and economic sectors. Since glaciers are a “critical resource” for tourism, they might affect this sector, though the report notes “limited analyses of projected risks associated with 1.5° versus 2°C are available.” It indicates that glacier melt will affect water security in alpine regions (section

Chapter 4, Strengthening and Implementing the Global Response, describes how glaciers can be incorporated into actions to address climate change. Section 4.3.8, Solar Radiation Modification, mentions a small-scale form of geoengineering: “covering glaciers … with reflective sheeting.” The Supplementary Material for this chapter includes a table titled “Overarching adaptation options.” This table mentions glacial lake outburst floods (GLOFs) as a risk that will increase with 1.5°C warming. It also notes disaster risk management as an adaptation option which could be implemented.

The New Report Contributes to Upcoming Climate Negotiations

The ability of glaciers to stir the human imagination may well support the contributions of the report as a key scientific input to the Katowice Climate Change Conference this December. This conference, also known as COP24 under the United Nations Framework Convention for Climate Change is designated as the context for the completion and adoption of the “rulebook” of guidelines for the implementation of the Paris Agreement. Delegates at that conference have the opportunity to provide momentum which could carry the world from the deep engagement seen in Paris to significant achievements before the crucial Global Stocktake of the Paris Agreement in 2023. That Global Stocktake will provide a full assessment of the progress towards the achievement of the purpose and goals of the agreement.

The powerful stories of glaciers, in conjunction with the other elements of SR1.5, may provide some of the motivation that is required for the world to undertake the challenging steps to reach these goals. As Pinho noted, “Even in a 1.5°C warming world, adaptation will be challenging for some regions and people around the world, especially in Small Island States in the Pacific, Southeast Asia and sub-Saharan Africa, but it still gives a better chance when compared to a 2°C world. But we also show with high confidence that climate-resilient trajectories at 1.5°C are possible and feasible, requiring transformative visions from a range of people to lead to a sustainable future for all.”

Ben Orlove is an anthropologist at the Earth Institute and the Center for Research on Environmental Decisions at Columbia University. He is the manager of GlacierHub, where this post was originally published. 

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