Atmospheric measurements of the carbon cycle

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My research program focuses on the study of the carbon cycle from the atmospheric perspective. My group measures carbon cycle-relevant atmospheric trace gases, such as carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and carbonyl sulfide (OCS), with the goal of quantifying the exchange of carbon from the terrestrial biosphere and from urban emissions. Our research focuses on improving the atmospheric measurements themselves, and on the science derived from those measurements. About half of the carbon released by burning fossil fuels remains in the atmosphere; the other half is absorbed by the oceans and terrestrial biosphere in approximately equal proportion. A significant gap in our current understanding of the global carbon cycle is the role that the terrestrial biosphere plays in removing carbon from the atmosphere, and the role it will play under increased warming. The North American terrestrial biosphere has been a persistent net carbon sink over the past decade, but future impacts from climate change, land-use change, and disturbance are unclear. Canadian forests, for example, are now thought to be a small source of carbon to the atmosphere. My research program will develop new atmospheric measurement tools to better understand the impacts of climate variables, wildfires and other disturbance on atmospheric composition, which will in turn provide better predictions of future change. Cities are known to produce around 80% of North American CO2 emissions, and municipal governments have formed global coalitions to reduce their emissions, often faster than their federal counterparts. Less is known about the global urban contribution to CH4 emissions, but it is thought to be significant and important. Most cities use inventories to quantify emissions that are compiled from industry reports. These inventories are useful for analysing sectorial emissions, but they cannot account for emissions that are unknown or inadvertent. Therefore, emissions quantification derived from atmospheric measurements is important for verifying emissions, but they provide less detailed information about the precise source of the emission. Together, inventories and atmospheric quantification provide the most powerful policy-relevant information about emissions. My research program focuses on the Greater Toronto Area (GTA), where we have developed a facility-level CH4 emission inventory, and a dense ground-based atmospheric observatory. We will develop techniques for verifying and improving upon our CH4 inventory with our atmospheric measurements, using these techniques to evaluate policy efficacy. We will apply these techniques to quantify CO2 emissions from the GTA and engage municipal governments and other stakeholders to expand this kind of network to other cities.