| Title | Tundra ponds as initiators of peat plateau thaw, northern Hudson Bay Lowland, Manitoba |
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| Author | Dyke, L D; Sladen, W E |
| Source | Arctic vol. 75, no. 3, 2022 p. 364-377, https://doi.org/10.14430/arctic75150  Open Access |
| Image |  |
| Year | 2022 |
| Alt Series | Natural Resources Canada, Contribution Series 20210411 |
| Publisher | Arctic Institute of North America |
| Document | serial |
| Lang. | English |
| Media | paper; digital; on-line |
| File format | pdf |
| Province | Manitoba |
| NTS | 42P; 43; 53I; 53J; 53O; 53P; 54 |
| Area | Churchill; Hudson Bay; James Bay; Nelson River |
| Lat/Long WENS | -96.0000 -80.0000 59.0000 51.0000 |
| Subjects | environmental geology; Nature and Environment; peat; permafrost; climate; modelling; Hudson Bay Lowlands |
| Illustrations | photographs; location maps; graphs; schematic cross-sections; tables |
| Program | Climate Change
Geoscience Permafrost |
| Released | 2022 09 12 |
| Abstract | Frozen peat in permafrost regions poses a potential source of increased greenhouse gas production should these deposits thaw. Ponds on frozen peat plateaus in northern Manitoba are numerically modelled
as heat sources to determine their potential to promote thaw. Modelling indicates that anticipated climate warming of approximately 2?C between 2020 and 2050 will produce taliks up to a few metres thick beneath ponds a few tens of metres across.
However, active-layer thickness in the subaerial parts of peat plateaus will not increase beyond the peat thickness. These findings assume 1) a climate warming rate under a moderately effective intervention in greenhouse gas production, 2) pond
freezing regimes that represent both rapid ice formation and ice formation delayed by rapid snow accumulation, and 3) snow thermal conductivities that anticipate snow conductivity increase during the freeze interval. These conditions and properties
may turn out to be less conducive to talik expansion than the values that will actually occur. Despite these uncertainties, peat plateau pond sizes and plateau margin positions can be monitored to ascertain the onset of accelerated thawing.
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| Summary | (Plain Language Summary, not published)
Frozen peat plateaus in northern Manitoba are maintaining their frozen state under the present climate. This paper examines the sensitivity of these
frozen peat plateau surfaces to climate warming. To do this we analyze ponds on frozen peat plateaus as heat sources to determine their potential to degrade permafrost. Air and ground temperature records for the area, as well as projected air
temperature increases based on the climate models, are incorporated into a numerical heat flow model. Our results suggest that by 2050, thawing of a few metres will take place beneath shallow ponds on peat plateaus if climate warming continues at the
same rate as the last few decades. However, thawing will not progress beyond the peat thickness in the adjacent peat plateaus. If climate warming continues for two to three decades, pond expansion and peat plateau thaw will likely
accelerate. |
| GEOSCAN ID | 329246 |
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