Last month, an intense diplomatic process brought to conclusion an unprecedented international effort to assess the state of the planet. If you didn’t hear about it, that’s no great surprise. The headline wasn’t exactly clicky: national representatives release the Summary for Policymakers of the Synthesis Report of the Intergovernmental Panel on Climate Change’ (IPCC) Sixth Assessment Report (AR6). But veiled in the language of diplomacy and bureaucracy, behind the initialisms and technical jargon of AR6, hides a remarkable scientific accomplishment.
Eight years in the making, AR6 reflects the collective effort of scientists from all over the world and scholars from an increasingly diverse collection of disciplines—systems theory, anthropology, sociology, geography, urban planning, behavioral sciences, gender studies, and media studies, to name but a few. It captures and represents findings from tens-of-thousands of peer-reviewed papers. One would be hard-pressed to think about another scientific or policy process that integrates such a diversity and depth of research, learning, and policy engagement. AR6 offers the most comprehensive examination of climate change yet produced, but it also, kind of slyly, does something more in bringing so many disciplines together. In tackling so many global and regional developments and trends, the authors offer a portrait—at times pointillist in its detail, at times Romantic in its daunting scale and sweep—of how the world works. Nothing—well, almost nothing—sits outside of it.
The big climate takeaways have received significant press coverage, but they are worth reiterating.
- Without immediate and deep reductions in greenhouse gas (GHG) emissions, global warming will exceed 2 degrees Celsius by around 2050. Even if strong policy steps are taken to reduce emissions now, the cumulative CO2 emissions will still exceed 1.5 degrees Celsius in the next two decades.
- The difference between 1.1 degrees, 1.5 degrees, and 2 degrees of warming in terms of impact on human well-being, ecosystem health, and even political stability is immense.
- Climatic impact drivers are increasingly difficult to isolate, and risks will cascade and compound across sectors and geographies, linking rural and urban infrastructures, populations, and economic and financial systems.
- While affecting every region of the world, climatic impact drivers and associated risks are not evenly distributed. They will be felt disproportionately by economically and socially vulnerable and marginalized communities—but make no mistake, they will be felt by high-income countries as well.
- While focused on limiting warming to 1.5 degrees, policymakers must implement adaptation policies and plans for warming that could potentially exceed 3 degrees.
- To enable the necessary transformation, systems transitions must be enabled by good, multilevel governance, including urban and regional planning, access to finance, the redirection of investments away from fossil fuels and stranded assets, behavior change, and innovation.
Pull at any of these key messages—or the dozens of others that can be found in the over 8,000 pages of analysis—and further details, figures, and debates emerge. But the remarkable accomplishment in process and scholarship achieved by AR6 also includes a particular temporal challenge: it took a long time, at least in terms of politics. Whether your lens is geopolitics, domestic politics, epidemiology, or artificial intelligence, you likely wouldn’t describe the past eight years, or even eight months, as uneventful.
As best they could, authors integrated new, peer-reviewed research approaches—even on crises that emerged during the cycle, such as the coronavirus pandemic—into the ongoing analysis. As such, in addition to the present state of climate science, the assessment offers something of a road map for emerging areas of focus. These areas are especially worthy of attention as they hint at new issue areas for both climate research and climate diplomacy and may well, owing to their newness, give rise to implementation and governance challenges.
Take the simultaneous systems transitions, a new approach featured heavily in AR6 that sought to break down the sectoral divides of the previous report cycle while opening up new pathways for transformation. The earlier reports of the AR6 cycle featured four systems transitions: urban, rural, and infrastructure; energy; land, ocean, coastal, and freshwater ecosystems; and industry. Between 2018 and 2022, a fifth—social transitions—was added. This late addition is one of the important developments of the AR6 cycle, offering demand-side strategies to reduce emissions and enable transformational adaptation. Think, for example, of urban consumption, much of which falls under the umbrella of societal choice. In 2015, when AR6 began, the urban share of global emissions was a bit over 60 percent. By 2020, that share had reached 67 to 72 percent of global emissions, with about a hundred of the largest emitting cities accounting for about 18 percent of the global carbon footprint. If you change energy consumption patterns in those cities, significant progress can be made in the larger emissions picture.
Another late addition, perhaps more theoretical and even more nascent, can be found in the concept of climate resilient development (CRD). The balance and relationship between adaptation and mitigation has long plagued the IPCC’s work. Despite these difficulties and the division of the IPCC process into working groups that separate adaptation and mitigation, AR6 authors increasingly work to bridge the bureaucratic and conceptual divide, an effort best captured in policy terms in the idea of CRD. The framework seeks to pursue climate and development goals in an integrated manner that increases their effectiveness, extending the concepts of adaptation and resilience beyond discrete projects and short-term time horizons to include longer-term transformations to deliver sustainability and equity. As one set of working group authors noted, the opportunities for CRD are not equally distributed geographically and are diminishing. Cities and urban areas, the authors also concluded, offer especially critical locations for pursuing adaptation and mitigation simultaneously.
It is in this increased attention to cities and urban areas that a third development from AR6 can be found. The next report cycle will examine cities and urban areas for its first special report. To lay out an initial framework, more than forty AR6 authors, in collaboration with city officials and industry leaders, reviewed the entirety of AR6 for urban-relevant material and produced summaries for urban-focused policymakers. The reports, parts of the Summary for Urban Policymakers initiative, were released at COP27. The findings offer global and regional perspective on local challenges.
- Even with strong reductions in emissions, many cities and urban areas will be increasingly exposed to more frequent drought, floods, extreme heat waves, and storm surges, as well as more intense cyclones.
- Sea-level rise will continue to have increasing implications even if warming is stabilized. By 2100, coastal flooding in cities from sea-level rise will affect between 158 million to 510 million people and expose between $7.9 billion and $12.7 billion of infrastructural assets to flood damage.
- In both urban and rural settings, impacts affect the marginalized. This is especially true in the smaller and medium-sized cities of Asia, Africa, and Central and South America. In Africa, for example, nearly 60 percent of the population lives in informal settlements and is particularly vulnerable due to limited employment opportunities and infrastructure.
- Urbanization differs by region, but transformation is needed in all city typologies. Many cities in the Global South are currently at early stages of urban development and seeing significant infrastructure buildup. Established cities, meanwhile, must address aging infrastructure. In all cases, the associated demand for materials comes with potentially high levels of embodied emissions.
In this heightened focus on the local and regional, it’s tempting to see in the science a mirror of a fractured world, but the truth is much to the contrary. The increased attention to cities and urban areas and regions is done to advance efficacy, impact, equity, and the quality of scientific knowledge. It links up governance and stakeholders, horizontally and vertically, bringing together the urban and the nation-state. The systems transitions approach does much the same, seeking solutions rather than silos. These systems offer one way to think about a globalized planet, since sectors such as manufacturing stretch across multiple systems, such as urban and infrastructure, and the impact of major projects and local habits are felt across regions and ecosystems.
But here’s the thing about the sweeping knowledge and planetary road map captured in AR6: the Synthesis Report’s Summary for Policymakers was adopted by member states and their climate diplomats, a formal option not available cities, civil society, and industry, despite their extensive advocacy and expertise on the issues. And while the reports themselves are infused with the environmental results of globalization, they take a more neutral position on international order. Myriad, necessary actions by nation-states are detailed, but no state or states are called out, let alone the relationships between them, in any scholarly way.
The absence of geopolitics from IPCC assessment reports could easily be called out as a failure, but it’s better understood as a feature. Other than the plenary approval of the Summaries for Policymakers—geopolitics in action—the science and knowledge captured in the main reports are meant to be kept separate and protected from diplomatic and national interests, and the price for doing so is quietism on geopolitical developments. The AR6 authors have done their work. It’s now time for those focused on foreign policy and diplomacy to weave their expertise into the cycle’s remarkable assessment of the state of the planet.