Middle to late Holocene chironomid-inferred July temperatures for the central Northwest Territories, Canada

Upiter, Lindsay; Vermaire, Jesse C.; Patterson, R. Timothy; Crann, Carley; Galloway, Jennifer M.; Macumber, Andrew; Neville, Lisa A.; Swindles, Graeme T.; Falck, Hendrik; Roe, Helen; Pisaric, Michael F. J.

doi:10.1007/s10933-014-9775-5

Cited by 29 publications

(91 citation statements)

References 49 publications

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“…Although the randomTF function in palaeoSig is now being used routinely to test peatland and lake transfer functions reconstructions (e.g. Amesbury et al, 2013;Upiter et al, 2014), we question its usefulness in this context. It is a statistical tool for testing the amount of variance explained by the transfer function compared to randomly generated models.…”

Section: Discussionmentioning

confidence: 99%

Evaluating the use of testate amoebae for palaeohydrological reconstruction in permafrost peatlands

Swindles

Amesbury

Turner

et al. 2015

Palaeogeography, Palaeoclimatology, Palaeoecology

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Evaluating the use of testate amoebae for palaeohydrological reconstruction in permafrost peatlands, Palaeogeography, Palaeoclimatology, Palaeoecology (2015), doi: 10.1016/j.palaeo.2015 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D AbstractThe melting of high-latitude permafrost peatlands is a major concern due to a potential positive feedback on global climate change. We examine the ecology of testate amoebae in permafrost peatlands, based on sites in Arctic Sweden (~200 km north of the Arctic Circle). Multivariate statistical analysis confirms that water-table depth and moisture content are the dominant controls on the distribution of testate amoebae, corroborating the results from studies in mid-latitude peatlands. We present a new testate amoeba-based water table transfer function and thoroughly test it for the effects of spatial autocorrelation, clustered sampling design and uneven sampling gradients. We find that the transfer function has good predictive power; the best-performing model is based on tolerance-downweighted weighted averaging with inverse deshrinking (performance statistics with leave-one-out cross validation: R 2 = 0.87, RMSEP = 5.25 cm). The new transfer function was applied to a short core from Stordalen mire, and reveals a major shift in peatland ecohydrology coincident with the onset of the Little Ice Age (c. AD 1400). We also applied the model to an independent contemporary dataset from Stordalen and find that it outperforms predictions based on other published transfer functions. The new transfer function will enable palaeohydrological reconstruction from permafrost peatlands in Northern Europe, thereby permitting greatly improved understanding of the long-term ecohydrological dynamics of these important carbon stores as well as their responses to recent climate change.

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Section: Discussionmentioning

confidence: 99%

Evaluating the use of testate amoebae for palaeohydrological reconstruction in permafrost peatlands

Swindles

Amesbury

Turner

et al. 2015

Palaeogeography, Palaeoclimatology, Palaeoecology

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“…Other factors might relate to treeline and albedo. Upiter et al (2015) show that treelines moved at a rate of 20 km year −1 associated with warming of 1-2°C (summer chironomid inferred air temperatures at Danny's Lake). As treelines move further north, darker surfaces lower albedo and thus may enhance warming-a feature that may be picked up more strongly on a finer spatial scale.…”

Section: Increased Spatial Resolutionmentioning

confidence: 99%

Climate change and the long-term viability of the World’s busiest heavy haul ice road

Mullan¹,

Swindles

Patterson

et al. 2016

Theor Appl Climatol

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Climate models project that the northern high latitudes will warm at a rate in excess of the global mean. This will pose severe problems for Arctic and sub-Arctic infrastructure dependent on maintaining low temperatures for structural integrity. This is the case for the economically important Tibbitt to Contwoyto Winter Road (TCWR)-the world's busiest heavy haul ice road, spanning 400 km across mostly frozen lakes within the Northwest Territories of Canada. In this study, future climate scenarios are developed for the region using statistical downscaling methods. In addition, changes in lake ice thickness are projected based on historical relationships between measured ice thickness and air temperatures. These projections are used to infer the theoretical operational dates of the TCWR based on weight limits for trucks on the ice. Results across three climate models driven by four RCPs reveal a considerable warming trend over the coming decades. Projected changes in ice thickness reveal a trend towards thinner lake ice and a reduced time window when lake ice is at sufficient thickness to support trucks on the ice road, driven by increasing future temperatures. Given the uncertainties inherent in climate modelling and the resultant projections, caution should be exercised in interpreting the magnitude of these scenarios. More certain is the direction of change, with a clear trend towards winter warming that will reduce the operation time window of the TCWR. This illustrates the need for planners and policymakers to consider future changes in climate when planning annual haulage along the TCWR.

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“…() inferred a warming period between 1160 and 1360 AD on Southampton Island (Nunavut, Canada) based on chironomid assemblages. In the central Northwest Territories (Canada), chironomid‐inferred temperature reconstructions have shown a warming which occurred between 1 and 0.7k cal a BP (Upiter et al ., ). Arseneault and Payette () also observed a warming trend based on tree rings at the treeline in north‐western Quebec.…”

Section: Discussionmentioning

confidence: 99%

Major postglacial summer temperature changes in the central coniferous boreal forest of Quebec (Canada) inferred using chironomid assemblages

Bajolle

Larocque‐Tobler²,

Gandouin

et al. 2018

J Quaternary Science

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Chironomid head capsules preserved in lake sediments were used to reconstruct 8200 years of summer temperatures in the boreal forest of north‐eastern Canada. Two training sets were used derived from Canadian and Eastern Canadian transfer functions. Both models reconstructed similar climate patterns, but the Canadian model provided temperatures generally 2–3 °C lower than the Eastern Canadian model. Three main thermal changes inferred by chironomids were: (i) the Holocene Thermal Maximum, which occurred between 8 and 5k cal a BP, with temperatures generally higher than today's, maximum temperatures between 8 and 6.5k cal a BP, and an average of + 0.9 °C; (ii) the Medieval Climate Anomaly around 1.1–1.2k cal a BP with an amplitude of + 0.7 °C; and (iii) a colder period reconstructed between the 14th and 19th centuries, corresponding to the Little Ice Age, with summer temperatures on average −0.5 °C lower than the climate normal. For each of these three climatic events, the timing and the amplitude of changes were similar with other published regional, North American and Northern Hemisphere records.

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Middle to late Holocene chironomid-inferred July temperatures for the central Northwest Territories, Canada

Cited by 29 publications

References 49 publications

Evaluating the use of testate amoebae for palaeohydrological reconstruction in permafrost peatlands

Evaluating the use of testate amoebae for palaeohydrological reconstruction in permafrost peatlands

Climate change and the long-term viability of the World’s busiest heavy haul ice road

Major postglacial summer temperature changes in the central coniferous boreal forest of Quebec (Canada) inferred using chironomid assemblages

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