Jan Hjort


Physical Geography

73 peer reviewed publications in international journals. The publications have been cited 2768 times, of which the most cited publication accounts for 327 citations. The author has a h-index of 31.00. (Google Scholar)


I’m a Professor of Physical Geography broadly interested in Arctic, boreal and alpine environments. My research interests include geodiversity, permafrost and periglacial processes, biodiversity, physical geography of urban environments and spatial patterns of ecosystem services. I have participated in over 20 multidisciplinary projects (principal investigator (PI)/Finnish PI in 13 projects). Examples of research activities include: PI of the HYPERISK (Hybrid modelling for improved permafrost risk assessments) and ArcticSHOC (Spatial ensemble prediction of permafrost thaw, soil carbon and ground-ice in the Arctic) projects, director of the INFRAHAZARD (Geomorphic sensitivity of the Arctic region: geohazards and infrastructure) research consortium and PI of the GEOBIO (The potential of geodiversity information in biodiversity assessments) project. Moreover, I’m the national representative for the International Permafrost Association. I’m supervising or have supervised six postdoctoral researchers, 13 PhD students and ca. 90 MSc students at the University of Oulu. More information about the Physical Geography Research Group.

Research interests

  • Geodiversity
  • Permafrost and periglacial processes
  • Hazard and risk assessments
  • Biodiversity and biogeography
  • Physical geography of urban environments
  • Spatial patterns of ecosystem services

Selected publications

Karjalainen, O., Luoto, M., Aalto, J., Etzelmüller, B., Grosse, G., Jones, B.M., Lilleøren, K.S. & J. Hjort (2020). High potential for loss of permafrost landforms in a changing climate. Environmental Research Letters 15, 104065.

Alahuhta, J., Toivanen, M. & J. Hjort (2020). Geodiversity-biodiversity relationship needs more empirical evidence. Nature Ecology & Evolution 4, 2–3.

Ala-Hulkko, T., Kotavaara, O., Alahuhta, J., Kesälä, M. & J. Hjort (2019). Accessibility analysis in evaluating exposure risk to an ecosystem disservice. Applied Geography 113, 102098.

Kärnä, O.-M., Heino, J., Jyrkänkallio-Mikkola, J., Pajunen, V., Soininen, J., Tolonen, K., Tukiainen, H., Toivanen., M. & J. Hjort (2019). Does catchment geodiversity foster stream biodiversity? Landscape Ecology 34, 2469–2485.

Schrodt, F., Bailey, J.J., Kissling, W.D., Rijsdijk, K.F., Seijmonsbergen, A.C., van Ree, D., Hjort, J., Lawley, R.S., Williams, C.R.N., Anderson, M., Beier, P., van Beukering, P., Boyd, D.S., Brilha, J., Carcavilla, L., Dahlin, K.M., Gill, J.C., Gordon, J.E., Gray, M., Grundy, M., Hunter, M.L., Lawler, J.J., Monge-Ganuzas, M., Royse, K.R., Stewart, I., Record, S., Turner, W., Zarnetske, P.L. & R. Field (2019). To advance sustainable stewardship, we must document not only biodiversity but geodiversity. Proceedings of the National Academy of Sciences 116, 16155–16158.

Tukiainen, H., Alahuhta, J., Kiuttu, M., Kalliola, R. & J. Hjort (2019). Landforms contribute to plant biodiversity at alpha, beta and gamma levels. Journal of Biogeography 46, 1699–1710.

Karjalainen, O., Luoto, M., Aalto, J. & J. Hjort (2019). New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere: a comparison between permafrost and non-permafrost areas. The Cryosphere 13, 693–707.

Ala-Hulkko, T., Kotavaara, O., Alahuhta, J. & J. Hjort (2019). Mapping supply and demand of a provisioning ecosystem service across Europe. Ecological Indicators 103, 520-529

Hjort, J., Karjalainen, O., Aalto, J., Westermann, S., Romanovsky, V.E., Nelson, F.E., Etzelmüller, B. & M. Luoto (2018). Degrading permafrost puts Arctic infrastructure at risk by mid-century. Nature Communications 9: 5147. DOI:10.1038/s41467-018-07557-4

Kärnä, O.-M., Heino, J., Grönroos, M. & J. Hjort (2018). The added value of geodiversity indices in explaining variation of stream macroinvertebrate diversity. Ecological Indicators 94, 420–429.

Aalto, J., Karjalainen, O., Hjort, J. & M. Luoto (2018). Statistical forecasting of current and future circum-Arctic ground temperatures and active layer thickness. Geophysical Research Letters 45, 4889-4898.

Alahuhta, J., Ala-Hulkko, T., Tukiainen, H., Purola, L., Akujärvi, A., Lampinen, R. & J. Hjort (2018). The role of geodiversity in providing ecosystem services at broad scales. Ecological Indicators 91, 47–56.

Bailey, J.J, Boyd, D.S., Hjort, J., Lavers, C.P. & R. Field (2017). Modelling native and alien vascular plant species richness: at which scales is geodiversity most relevant? Global Ecology and Biogeography 26, 763–776.

Gisnås, K., Etzelmüller, B., Lussana, C., Hjort, J., Sannel, A.B.K., Isaksen, K., Westermann, S., Kuhry, P., Christiansen, H.H., Frampton, A. & J. Åkerman (2017). Permafrost map for Norway, Sweden and Finland. Permafrost and Periglacial Processes 28, 359–378.

Tukiainen, H., Bailey, J.J., Kangas, K., Field, R. & J. Hjort (2017). Combining geodiversity with climate and topography to account for threatened species richness. Conservation Biology 31, 364–375.

Hjort, J., Suomi, J. & J. Käyhkö (2016). Extreme urban-rural temperatures in the coastal city of Turku, Finland: Quantification and visualization based on a generalized additive model. Science of the Total Environment 569–570, 507–517.

Ala-Hulkko, T., Kotavaara, O., Alahuhta, J., Helle, P. & J. Hjort (2016). Introducing accessibility analysis in mapping cultural ecosystem services. Ecological Indicators 66, 416–427.

Hjort, J., Hugg, T.T., Antikainen, H., Rusanen, J., Sofiev, M., Kukkonen, J., Jaakkola, M.S. & J.J.K. Jaakkola (2016). Fine-scale exposure to allergenic pollen in the urban environment: evaluation of land use regression approach. Environmental Health Perspectives 124, 619–626. 

Hjort, J., Gordon, J.E., Gray, M. & M.L. Hunter Jr. (2015). Why geodiversity matters in valuing nature’s stage. Conservation Biology 29, 630–639.

Hjort, J., Ujanen, J., Parviainen, M., Tolgensbakk, J. & B. Etzelmüller (2014). Transferability of geomorphological distribution models: evaluation using solifluction features in subarctic and Arctic regions. Geomorphology 204, 165–176.

Hjort, J. & M. Luoto. (2013). Statistical methods for geomorphic distribution modeling. In: Shroder, J., Jr., Baas, A.C.W. (Eds.). Treatise on Geomorphology. Academic Press, San Diego, 59–73.

Hjort, J., Heikkinen, R.K. & M. Luoto (2012). Inclusion of explicit measures of geodiversity improve biodiversity models in a boreal landscape. Biodiversity and Conservation 21, 3487–3506.

Virtanen, R., Luoto, M., Rämä, T., Mikkola, K., Hjort, J., Grytnes, J.-A. & J. Birks (2010). Recent vegetation changes in the high latitude tree line ecotone are controlled by geomorphologic disturbance, productivity and diversity. Global Ecology and Biogeography 19, 810–821.

Christiansen, H.H., Etzelmüller, B., Isaksen, K., Juliussen, H., Farbrot, H., Humlum, O., Johansson, M., Ingeman-Nielsen, T., Kristensen, L., Hjort, J., Holmlund, P., Sannel, A.B.K., Sigsgaard, C., Åkerman, H.J., Foged, N., Blirka, L.H., Pernosky, M.A. & R. Ødegård (2010). The Thermal State of Permafrost in the Nordic area during IPY 2007-2009. Permafrost and Periglacial Processes 21, 156–181.

Hjort, J. & M. Luoto (2010). Geodiversity of high-latitude landscapes in northern Finland. Geomorphology 115, 109–116.

Hjort, J. & M. Luoto (2009). Interaction of geomorphic and ecologic features across altitudinal zones in a subarctic landscape. Geomorphology 112, 324–333.

Hjort, J. & M. Marmion (2008). Effects of sample size on the accuracy of geomorphological models. Geomorphology 102, 341–350.

Hjort, J. (2006). Environmental factors affecting the occurrence of periglacial landforms in Finnish Lapland: a numerical approach (PhD Thesis). Shaker Verlag, Aachen. 162 p.

Selected projects

HYPERISK: Hybrid modelling for improved permafrost risk assessments (2021–2024)


ArcticSHOC: Spatial ensemble prediction of permafrost thaw, soil carbon and ground-ice in the Arctic (2018–2022)

INFRAHAZARD: Geomorphic sensitivity of the Arctic region: geohazards and infrastructure (2015–2018)



APTA: The influence of air pollution, pollen and ambient temperature on asthma and allergies in changing climate (2013–2017)


GEOBIO: The potential of geodiversity information in biodiversity assessments (2012–2018)


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