Daniel Aldana Cohen on urban climate mitigation

Climate scientists are used to the idea of climate mitigation. But few are involved in the nitty-gritty of what climate mitigation might look like at the local or even neighborhood level. Daniel Aldana Cohen from the Department of Sociology at the University of Pennsylvania is digging into the politics and sociology of urban carbon emissions. A dizzying array of forces are at work.

Family debates on urbanism

Daniel’s interest in the science and sociology of urban emissions arose from the same sort of incredibly implausible events and circumstances that seem to orbit nearly every guest on Forecast. This time: father was a writer and back-to-the-lander who hated cities; mother loved cities and was a children’s book publisher; family compromised by living in rural France every fourth year or so, with the rest of the time in Toronto; both parents rebelled against science; childhood faith that somebody would solve the climate change problem crushed by reality; early exposure to social justice travesties; interest in magazine writing diverted to research focus by Elizabeth Kolbert‘s brilliant work in the New Yorker on climate change.

The surprisingly simpatico interests of urban elites and urban justice

Possibly arising from his own family’s rejection of and affection for urbanism, Daniel chose to revisit the long-standing ideals of urbanism. Can we have fantastic, equitable and decarbonized cities? In a Bloomsburg-esq fantasy world, yes: government policies create a luxury economy bubbling with a glittery green stew of financial services, young professionals, walkable streets and bike paths. Think Seattle in the Amazon age. Eventually, trickle-down greening occurs, and there’s a net reduction of emissions.

Only, no, on many levels. The policies that spawned modern Manhattan also led to mass gentrification and displacement. And as Daniel shows in his contribution to Rebecca Solnit‘s blisteringly great series of atlases, a full-cost accounting for Manhattan reveals that the core of the green city is also the most rapacious consumer of carbon:

Daniel’s map for “Carboniferous” in “Nonstop Metropolis: A New York Atlas”, R Solnit and J Jelly-Schapiro, 2016. Cartography: Molly Roy; artwork: Bette Burgoyne. Underlying data from Kevin Ummel, adapted from research he did for the Center for Global Development. Courtesy of University of California Press.

Is there a way forward, to create both the cities and climate mitigation we’d like to see? Ironically, as Daniel has heard from modern urban planners, we might get the desired outcome by not talking about climate in the first place: “Social justice and climate justice actually went really well together … it’s just better not to talk about climate change at all”.   Focusing on housing, and not talking about the environment, can actually lead to the exact environmental changes that would otherwise be desired by an explicitly mitigation-focused effort. In the end, social justice and the fantasy low carbon city seem to have the same goals.

Building a new research community

This is not to say that this is an easy goal to achieve. The community working on the micro-scale processes that determine global urban emissions is tiny; academic institutions are not actively encouraging young scholars to pursue the necessary interdisciplinary work; and there is almost no literature on realistically attributing emissions to specific cities and neighborhoods (the map above represents one such effort).

Daniel is working to reach across the dauntingly-wide chasm between sociology and physical science, and runs his own podcast, Hot and Bothered at Dissent magazine. Daniel also co-authored a Nature Comment on urban sustainability, arising partly as a result of discussions I had at the 2016 American Association of Geographers annual meeting. As an aside, the AAG meetings are a great place to crash into the urban sustainability community.

Music: Sips On The High Seas (Happy Chiptune Accordion Cover) by The_Sea_Four CC BY 3.0; “Asturias” composed by Isaac Albéniz and recorded by Frank Hiemenz (“FHgitarre-classicalGUITAR” on Soundcloud) CC BY 3.0.

Amelia Shevenell, big ideas and big risks

Amelia Shevenell from the University of South Florida specializes in big ideas about paleoceanography and the Antarctic Ice Sheet. She’s also keen to push the methodological envelope, which can be risky if things go pear shaped. For Amelia, though, the work resulted in papers in Science (Mg/Ca) and Nature (TEX86).

The method, while of course important, is not the main motivation. Instead, it’s the huge, gaping holes in our knowledge of Southern Hemisphere climate variability that seem to motivate Amelia. The questioning and search for challenges was there from the start. In high school, Amelia’s uncle unleashed her on climate variability over the past century in the Durham NH area. Coring away, when I was scooping ice cream.

Amelia had plenty of inspiration from her family, including Great Aunt Mary Sears. The family spirit of exploration and possibility was infectious, and Amelia double majored in geology and studio art. She still does pottery (example above) and, unbeknownst to her, worked for years with actor Jeff Bridges (full story at the end of the podcast).

Throughout, Amelia’s been interested in how Antarctic functions within the climate system. And it’s weird, sometimes. During the Miocene Climate Optimum, “It’s almost like we’re having ice growth during a period of warming … and nobody’s really said that out loud”. Now, Amelia is working with her colleagues to link together the deep sea records with shelf- and land-based evidence to try and understand the shockingly large ice sheet variability that seems to have happened at millennial time scales.

Getting all this done, while raising a family and going for tenure at USF, isn’t for the faint of heart. Although she was tenured at UCL, Amelia chose to return to the US for family and financial reasons (living in London on a geoscientist’s salary is, in British understatement, a bit difficult). Now, Amelia’s mom is next door and helping with child care, and her husband sounds epic. But it’s all-consuming, nonetheless.

Still, as you’ll hear in the interview, the practical realities of family and career haven’t done anything to diminish Amelia’s enthusiasm for her science!

Music: Running Waters by Jason Shaw CC BY 3.0 US; Siesta by Jahhzar CC BY-SA 3.0.

Copyright: This episode of Forecast is under a CC BY-SA 3.0 license.

Scott St. George on tree rings

Scott St. George
Scott St. George

Tree rings are one of the key tools in paleoclimate research, and might seem like nothing more than big, woody thermometers. But tree-ring science is ever evolving, constantly debated, and — while it has answered some major questions — still grapples with making the connection to broader climate questions.

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An update on the 1.5 °C warming threshold

Over the past few months I’ve discussed with a variety of guests the emerging idea of trying to keep global warming below 1.5 °C, and our family of journals has certainly been active on the topic, particularly with regard to feasibility and mitigation pathways.

From Paris Agreement climate proposals need a boost to keep warming well below 2 °C, Nature doi:10.1038/nature18307.
An example of the emissions required to get close to 1.5 (blue), versus unregulated emissions (red). There’s a lot of space in between! From Paris Agreement climate proposals need a boost to keep warming well below 2 °C, Rogelj et al., Nature doi:10.1038/nature18307.

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Rob DeConto and Antarctica in the climate system

I think I first learned of Rob DeConto when I saw his paper entitled Thresholds for Cenozoic bipolar glaciation, published soon after my arrival at Nature.  Specific and testable thresholds for the initiation of large scale glaciation in Antarctica and the Northern Hemisphere? Interesting! Continue reading →

Susan Joy Hassol and climate communication

Language is spectacularly imprecise. Susan Joy Hassol from Climate Communication has made a career out of studying how to — and how not to — use language to most effectively communicate climate science to a broad audience. Continue reading →

Ed Hawkins on policy-relevant climate science

Maybe once a year I have a nightmare that I’m back in grad school, grinding out an interminable PhD in some entirely new field. Ed Hawkins from the National Centre for Atmospheric Science actually did head back for a new degree and a new career, but, luckily for climate science, it seems to have been more of a dream than a nightmare. Continue reading →

Gabi Hegerl on detection and attribution of climate change

Gabi Hegerl is famous for her work seeking to understand the processes driving climate variability, but she was initially destined to study language arts, and started off with seven years* of schooling in Latin. Continue reading →

Jerry Mitrovica and geological influences on sea level rise

Jerry Mitrovica from Harvard University sits at the surprisingly wobbly interface between the solid Earth, oceans and ice. Trained in serious geophysics, Jerry quickly found a niche in explaining how movements of the Earth’s mantle – in three dimensions – control the apparent variation of past sea levels. In many cases, this means pointing out that many or all of our records of past sea level are fundamentally altered by processes like dynamic topography and isostatic rebound. Continue reading →

Tina van de Flierdt explains paleoceanography proxies

Tina van de Flierdt from the Department of Earth Science and Engineering at Imperial College London is an international leader in the use of geochemical proxies – particularly neodymium (Nd) – for reconstructing past ocean circulation, water masses and weathering. But her childhood and early interests pointed in a different direction. Continue reading →