Provincial nitrogen footprints highlight variability in drivers of reactive nitrogen emissions in Canada
Nitrogen (N) footprints are one method to quantify consumer driven reactive nitrogen (Nr) emissions. Canada is a highly urbanized yet economically natural resource-dependent country, providing an illustrative case study to examine attribution of Nr emissions to per capita consumption, either domesti...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2021-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ac1e3b |
| _version_ | 1827870178332901376 |
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| author | Sibeal McCourt Graham K MacDonald |
| author_facet | Sibeal McCourt Graham K MacDonald |
| author_sort | Sibeal McCourt |
| collection | DOAJ |
| description | Nitrogen (N) footprints are one method to quantify consumer driven reactive nitrogen (Nr) emissions. Canada is a highly urbanized yet economically natural resource-dependent country, providing an illustrative case study to examine attribution of Nr emissions to per capita consumption, either domestically or abroad. Yet, considered only at the national scale, N footprints may obscure absolute and relative contributions of local drivers to Nr emissions. We apply a top-down N footprint approach drawing from national N budgets, emissions inventories, and agricultural statistics to estimate sub-national (provincial) drivers of Nr emissions across Canada. We calculate per capita provincial Nr footprints from four primary sectors in 2018: (a) crop production, (b) animal production, (c) wastewater treatment, and (d) fossil fuel burning. We estimate that Canada’s total N footprint is 995.7 Gg Nr yr ^−1 , which equates to an average per capita footprint nationally of 27.1 kg Nr capita ^−1 yr ^−1 . The largest national contributions come from a few key (sub)sectors, including transport, beef consumption, and wastewater treatment. Provincial per capita N footprints vary widely, with the largest (Saskatchewan 50.3 kg Nr cap ^−1 yr ^−1 ) more than double the smallest (Ontario 22.0 kg Nr cap ^−1 yr ^−1 ). Most variation across provinces is due to the fossil fuels sector, including emissions from energy generation and the oil and gas industry. We therefore compare our top-down approach for the fossil fuels sector with bottom-up N footprints and territorial emissions methodologies. Per capita N emissions vary considerably across these approaches. For example, Alberta’s per-capita fossil fuel Nr emissions are 45.9, 23.0, and 6.3 kg Nr cap ^−1 yr ^−1 using territorial, top-down and bottom-up footprint approaches, respectively. This analysis demonstrates the challenges of attributing Nr emission for export-oriented economies. Our study provides novel insights on sub-national drivers of Nr emissions, emphasizing the need to consider how heterogeneous geographic contexts contribute to national N footprints. |
| first_indexed | 2024-03-12T15:53:11Z |
| format | Article |
| id | doaj.art-c3c3da666e6c4aaaa08033cdbbe2999c |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:53:11Z |
| publishDate | 2021-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-c3c3da666e6c4aaaa08033cdbbe2999c2023-08-09T15:04:11ZengIOP PublishingEnvironmental Research Letters1748-93262021-01-0116909500710.1088/1748-9326/ac1e3bProvincial nitrogen footprints highlight variability in drivers of reactive nitrogen emissions in CanadaSibeal McCourt0https://orcid.org/0000-0003-1850-9932Graham K MacDonald1https://orcid.org/0000-0002-7120-1366Department of Geography, McGill University , Montreal H3A 0B9, CanadaDepartment of Geography, McGill University , Montreal H3A 0B9, CanadaNitrogen (N) footprints are one method to quantify consumer driven reactive nitrogen (Nr) emissions. Canada is a highly urbanized yet economically natural resource-dependent country, providing an illustrative case study to examine attribution of Nr emissions to per capita consumption, either domestically or abroad. Yet, considered only at the national scale, N footprints may obscure absolute and relative contributions of local drivers to Nr emissions. We apply a top-down N footprint approach drawing from national N budgets, emissions inventories, and agricultural statistics to estimate sub-national (provincial) drivers of Nr emissions across Canada. We calculate per capita provincial Nr footprints from four primary sectors in 2018: (a) crop production, (b) animal production, (c) wastewater treatment, and (d) fossil fuel burning. We estimate that Canada’s total N footprint is 995.7 Gg Nr yr ^−1 , which equates to an average per capita footprint nationally of 27.1 kg Nr capita ^−1 yr ^−1 . The largest national contributions come from a few key (sub)sectors, including transport, beef consumption, and wastewater treatment. Provincial per capita N footprints vary widely, with the largest (Saskatchewan 50.3 kg Nr cap ^−1 yr ^−1 ) more than double the smallest (Ontario 22.0 kg Nr cap ^−1 yr ^−1 ). Most variation across provinces is due to the fossil fuels sector, including emissions from energy generation and the oil and gas industry. We therefore compare our top-down approach for the fossil fuels sector with bottom-up N footprints and territorial emissions methodologies. Per capita N emissions vary considerably across these approaches. For example, Alberta’s per-capita fossil fuel Nr emissions are 45.9, 23.0, and 6.3 kg Nr cap ^−1 yr ^−1 using territorial, top-down and bottom-up footprint approaches, respectively. This analysis demonstrates the challenges of attributing Nr emission for export-oriented economies. Our study provides novel insights on sub-national drivers of Nr emissions, emphasizing the need to consider how heterogeneous geographic contexts contribute to national N footprints.https://doi.org/10.1088/1748-9326/ac1e3bnitrogenfootprintvirtual nitrogenagriculturefossil fuelsgreenhouse gas emissions |
| spellingShingle | Sibeal McCourt Graham K MacDonald Provincial nitrogen footprints highlight variability in drivers of reactive nitrogen emissions in Canada Environmental Research Letters nitrogen footprint virtual nitrogen agriculture fossil fuels greenhouse gas emissions |
| title | Provincial nitrogen footprints highlight variability in drivers of reactive nitrogen emissions in Canada |
| title_full | Provincial nitrogen footprints highlight variability in drivers of reactive nitrogen emissions in Canada |
| title_fullStr | Provincial nitrogen footprints highlight variability in drivers of reactive nitrogen emissions in Canada |
| title_full_unstemmed | Provincial nitrogen footprints highlight variability in drivers of reactive nitrogen emissions in Canada |
| title_short | Provincial nitrogen footprints highlight variability in drivers of reactive nitrogen emissions in Canada |
| title_sort | provincial nitrogen footprints highlight variability in drivers of reactive nitrogen emissions in canada |
| topic | nitrogen footprint virtual nitrogen agriculture fossil fuels greenhouse gas emissions |
| url | https://doi.org/10.1088/1748-9326/ac1e3b |
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