IG3IS Urban Greenhouse Gas Monitoring Webinar Series 2026: CarbonWatch-Urban: Granular CO2 emissions information for every town and city in New Zealand

Jocelyn Turnbull, Leigh Fleming, and Erika Macapagal-Taluban from Earth Sciences New Zealand

Jocelyn Turnbull holds joint appointments as a greenhouse gas research scientist at Earth Sciences New Zealand and the University of Colorado, and co-chairs the WMO Integrated Global Greenhouse Gas Information System (IG3IS) program.  She uses atmospheric greenhouse gas observations and related tracers along with modeling to understand the sources and sinks of greenhouse gases at the local, urban, and regional scales.  Current research includes combining observations and modeling to map urban emissions at fine scale to support mitigation action; assessment of the controls on the urban land carbon sink and net forest CO2 uptake; and diagnosing the changing Southern Ocean carbon sink.  Connecting emissions science to policy uptake is a key component of Jocelyn’s research. As co-chair of IG3IS, she works closely with practicing scientists and stakeholders to translate scientific results into actionable policy information.  These interactions are facilitated through workshops, working groups, and good practice guidelines.

Erika Macapagal Taluban is a PhD student at Earth Sciences New Zealand and Victoria University of Wellington. Her research focuses on using black carbon measurements to improve urban CO₂ sectoral emission estimates in New Zealand, using black carbon as a tracer for wood burning. Prior to moving to New Zealand, she worked on a range of local and international environmental and air quality research projects in her home country, the Philippines.

Urban areas produce 70-80% of fossil fuel CO2 emissions; thus, detailed urban emissions and uptake information is needed to deliver meaningful, measurable mitigation action.  CarbonWatch-Urban is a multi-tiered approach that provides fine-scale CO2 emissions and sink information for all of New Zealand’s urban areas.

They have established a high-resolution bottom-up inventory of New Zealand's fossil fuel CO2 emissions, and optimized UrbanVPRM to estimate the urban biogenic CO2 budget across New Zealand.  These bottom-up estimates are then validated and improved by atmospheric observations.

In Auckland, New Zealand’s largest city, four sites make ongoing atmospheric observations of carbon dioxide, radiocarbon-in-carbon-dioxide, methane, carbon monoxide, carbonyl sulfide, and black carbon, which we use to validate and improve the bottom-up models using city-wide atmospheric inversion and emission ratio techniques.  In Christchurch, we use suburb-scale eddy covariance and flux-gradient measurements.  For all other towns and cities, we have established a mobile laboratory that tours New Zealand every three months, measuring carbon dioxide, radiocarbon-in-carbon-dioxide, methane, carbon monoxide, carbonyl sulfide, and black carbon across New Zealand’s diverse urban climates, topographies, and urban forms.

This presentation will be split into three components: first, an overview of CarbonWatch-Urban; second, the mobile laboratory setup and first measurements; and third, an example of how black carbon measurements can be used to partition both pollutant and greenhouse gas source sectors and improve the bottom-up modeling.