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Urban Emissions: Autodesk's Emma Stewart on Science-Based GHG Goals for Cities (#SustyGoals 10)

Image credit: Alamy

Autodesk helped pioneer the corporate practice of setting science-based greenhouse gas (GHG) emissions reduction goals with its open-source methodology, C-FACT, or Corporate Finance Approach to Climate-Stabilizing Targets. The effectiveness of this approach was validated late last year when Autodesk topped the ranking in the Climate Counts report Assessing Corporate Emissions Performance Through the Lens of Climate Science. Now, Autodesk has taken the next logical step by customizing its C-FACT metric for use by cities, a key customer group for the company.

In this tenth installment of the #SustyGoals series, #NewMetrics channel co-curator Bill Baue speaks with C-FACT co-creator Emma Stewart, Head of Sustainability Solutions at Autodesk. Emma and Bill will be speaking on the New Opportunities for Leadership in Goal-Setting: On to the Next Level of Science-Based Goals panel at #SB14sd, along with GHG Protocol director Pankaj Bhatia and Vanderbilt University Business professor Jeff Gowdy.

Bill Baue: What prompted you to modify the C-FACT science-based GHG reduction target-setting methodology (originally geared for companies) for use by cities? Do cities represent a particularly effective "leverage point" for creating systems change (to riff on Dana Meadows)?

Emma Stewart: We are now an urban species. For the first time in human history, over 50 percent of humanity lives in cities and, by all accounts, this percentage will only continue to grow.

Cities are clearly the world’s engines of economic growth, accounting for about 70 percent of global GDP today, and even more as the balance of humans tips from 50 percent to 70 percent urban between now and 2050. In some regions, The Brookings Institute recently pointed out, trade between cities even outstrips trade between nations. Indeed, quite like the ancient city-states of Athens and Rome, today’s cities such as Beijing, Delhi, London and New York have become the political and economic nucleus of their respective regions.

In resource terms, cities have historically represented an opportunity to do more with less. Urban density leads to efficiencies of scale — economic growth can be produced with less land and basic needs such as food, water, shelter and security can be provided through networks, rather than generated in isolation. But on the flip side, cities represent the majority of humankind’s energy and natural resources consumption. Now home to half the world’s population, today’s cities represent roughly 60-80 percent of the world’s energy consumption, according to Pike Research.

I was speaking at a conference on the subject of sustainable cities, and asked the Mayor of Manchester how his city had set their GHG target, which is one of the few that roughly aligns with scientific recommendations. He explained that the city had relied on the Tyndall Centre on Climate Change at the University of Manchester, a world-class institute for scientific research on the subject. It dawned on me that most cities aren’t lucky enough to have such a center, let alone have them derive the city’s targets, so I started investigating whether tailoring C-FACT for cities might be worthwhile. CDP Cities, which works with over 100 cities globally, assured us it would, so we embarked on the project.

Baue: For background, can you give a brief overview of the basics of C-FACT for companies?

Emma Stewart,
speaker at
Sustainable Brands 2014
San Diego

Stewart: It is a scientifically-based, business-friendly approach to GHG target setting that recognizes companies are GHG emitters but also simultaneously create economic value. In other words, companies should aim to reduce their GHGs in line with scientific and policy climate stabilization targets but do so proportional to their relative contribution to global GDP, not more, not less. It is best explained by the 6-min video tutorial, white paper and FAQ at

Baue: What changes did you have to make to apply this methodology to cities? Are there ways that the two work synergistically, or are they really quite separate?

Stewart: As with the original C-FACT for corporations, the C-FACT methodology offers city leaders a step-by-step method for calculating GHG reduction targets that are in line with scientific climate-stabilization targets from the Intergovernmental Panel on Climate Change (IPCC), and in proportion to cities' relative GDP growth. It seeks to offer a fair, verifiable, and flexible methodology that uniquely combines intensity and absolute targets for cities of varying sizes, GHG footprints and growth prospects. It allows cities to align their targets with the reduction pathways recommended by the scientific community for stabilizing the climate, but also in proportion to their cities' relative contribution to the economy. In other words, it is aggressive only to the degree needed to attain climate stabilization, not more, not less.

In tailoring C-FACT for cities, we primarily grappled with:

  • how to define a city’s “value add”
  • whether we could find publicly available data, since a key principle of C-FACT is verifiability, which requires using only public data.

With the invaluable guidance of Daniel Aronson, then of Deloitte’s Sustainability Practice, we concluded that:

  • the most commonly accepted, and most replicable, way to define “value add” was to use GDP
  • if we used the McKinsey Global Institute’s Cityscope database, we could offer publicly available data for 600 cities, and we would provide a GDP look-up table for cities not in that database.

Baue: Where do cities currently stand on their GHG reduction targets — do they typically fall as short as companies' targets do, when compared to the ambition required by climate science?

Stewart: Governments at the more regional and local level have begun to set reduction targets as a matter of course, and have formed networks such as C40 and CDP Cities (of which Autodesk was a founding sponsor) to support one another’s efforts.

At the international level, 110 cities representing approximately 300 million people have published emissions reports to CDP Cities (up from 48 cities in 2011). Of these, many have published citywide emissions reduction targets. For instance, according the 2013 CDP data, Atlanta and Baltimore, have both pledged to reduce citywide emissions by 15 percent between 2010 and 2020. New York City has pledged to reduce its citywide emissions by 30 percent between 2005 and 2030.

This public disclosure is an encouraging step, but citywide targets for GHG reduction vary widely in both methodology and level of detail. Therefore, while some cities are taking initial steps to reduce their GHG emissions, they still lack a uniform standard for setting carbon-reduction targets.

Baue: Are you aware of cities using C-FACT? What has their experience been?

Stewart: I gather from Daniel Aronson that Palo Alto has used it to help inform science-based targets for further reductions. That is a great development, since the City of Palo Alto has been at the forefront on setting aggressive goals.

Baue: Yes, Palo Alto Chief Sustainability Officer Gil Friend confirmed that with me. Final question now: First companies, then cities — what do you see as the "next frontier" for addressing climate change and other sustainability impacts?

Stewart: The next frontier is for cities and corporations alike to set science-based targets, since otherwise the risks of surpassing planetary thresholds will have devastating consequences on their ability to survive and thrive.

I’m delighted that three influential organizations — WRI, CDP and WWF — have forged an initiative to provide standard guidance on creating such targets, just as WRI has brought standardization to GHG footprinting. Hopefully that work will benefit from all of the difficult decisions that went into developing C-FACT.

As an internationally recognized expert on sustainability context, online stakeholder engagement, and sustainability communications, Bill Baue designs systemic transformation. He's co-founder of a number of companies and initiatives:

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