Development of a 350ppm community carbon budget in Eugene, Oregon

In the absence of national greenhouse gas emissions regulations, cities and county agencies across the United States have pursued a patchwork of emissions reduction targets and approaches to achieve those targeted goals. Some regions currently aim to meet efforts in mitigation with ambitious reduction targets that go beyond those pursued at national or international levels (e.g., UNFCCC, Paris, 2015). In 2014 The City of Eugene (Oregon, USA) City Council passed the Climate Recovery Ordinance which, in addition to outlining City emissions targets for 2020 and 2030, requested a proposal to adopt a community greenhouse gas reduction target consistent with achieving a global atmospheric carbon dioxide concentration of 350ppm by the year 2100. A 350ppm 2100 target, if achieved, could keep global average temperature rise to within 1°C by century-end but would necessarily limit cumulative fossil fuel carbon emissions to 500GtC (currently 375GtC). In contrast to historically-based approaches to greenhouse gas mitigation targets typically established by cities, the request of a community target based on a 350ppm target required the development of new methods by the City of Eugene. Collaborating with a Thriving Earth Exchange (TEX) scientist and working with a peer review team of regional analysts, the City of Eugene City Manager's Office produced a report which described a methodology for establishing a 350ppm community carbon budget and led a multi-session dialog with Eugene City Council members on possible action towards this goal. Here, we describe the methods developed and the collaborative effort which made it possible. The work led to the recent Eugene City Council adoption of an ambitious community-wide greenhouse gas emission reduction goal of 7.6% per year, consistent with global emissions reductions needed to achieve an atmospheric carbon dioxide concentration 350ppm by 2100.