High potential for loss of permafrost landforms in a changing climate

The presence of ground ice in Arctic soils exerts a major effect on permafrost hydrology and ecology, and factors prominently into geomorphic landform development. As most ground ice has accumulated in near-surface permafrost, it is sensitive to variations in atmospheric conditions. Typical and regionally widespread permafrost landforms such as pingos, ice-wedge polygons, and rock glaciers are closely tied to ground ice. However, under ongoing climate change, suitable environmental spaces for preserving landforms associated with ice-rich permafrost may be rapidly disappearing. We deploy a statistical ensemble approach to model, for the first time, the current and potential future environmental conditions of three typical permafrost landforms, pingos, ice-wedge polygons and rock glaciers across the Northern Hemisphere. We show that by midcentury, the landforms are projected to lose more than one-fifth of their suitable environments under a moderate climate scenario (RCP4.5) and on average around one-third under a very high baseline emission scenario (RCP8.5), even when projected new suitable areas for occurrence are considered. By 2061-2080, on average more than 50% of the recent suitable conditions can be lost (RCP8.5). In the case of pingos and ice-wedge polygons, geographical changes are mainly attributed to alterations in thawing-season precipitation and air temperatures. Rock glaciers show air temperature-induced regional changes in suitable conditions strongly constrained by topography and soil properties. The predicted losses could have important implications for Arctic hydrology, geo- and biodiversity, and to the global climate system through changes in biogeochemical cycles governed by the geomorphology of permafrost landscapes. Moreover, our projections provide insights into the circumpolar distribution of various ground ice types and help inventory permafrost landforms in unmapped regions.Peer reviewe

Forest microclimates and climate change: importance, drivers and future research agenda

Forest microclimates contrast strongly with the climate outside forests. To fully understand and better predict how forests' biodiversity and functions relate to climate and climate change, microclimates need to be integrated into ecological research. Despite the potentially broad impact of microclimates on the response of forest ecosystems to global change, our understanding of how microclimates within and below tree canopies modulate biotic responses to global change at the species, community and ecosystem level is still limited. Here, we review how spatial and temporal variation in forest microclimates result from an interplay of forest features, local water balance, topography and landscape composition. We first stress and exemplify the importance of considering forest microclimates to understand variation in biodiversity and ecosystem functions across forest landscapes. Next, we explain how macroclimate warming (of the free atmosphere) can affect microclimates, and vice versa, via interactions with land-use changes across different biomes. Finally, we perform a priority ranking of future research avenues at the interface of microclimate ecology and global change biology, with a specific focus on three key themes: (1) disentangling the abiotic and biotic drivers and feedbacks of forest microclimates; (2) global and regional mapping and predictions of forest microclimates; and (3) the impacts of microclimate on forest biodiversity and ecosystem functioning in the face of climate change. The availability of microclimatic data will significantly increase in the coming decades, characterizing climate variability at unprecedented spatial and temporal scales relevant to biological processes in forests. This will revolutionize our understanding of the dynamics, drivers and implications of forest microclimates on biodiversity and ecological functions, and the impacts of global changes. In order to support the sustainable use of forests and to secure their biodiversity and ecosystem services for future generations, microclimates cannot be ignored.Peer reviewe

The mossy north : an inverse latitudinal diversity gradient in European bryophytes

It remains hotly debated whether latitudinal diversity gradients are common across taxonomic groups and whether a single mechanism can explain such gradients. Investigating species richness (SR) patterns of European land plants, we determine whether SR increases with decreasing latitude, as predicted by theory, and whether the assembly mechanisms differ among taxonomic groups. SR increases towards the south in spermatophytes, but towards the north in ferns and bryophytes. SR patterns in spermatophytes are consistent with their patterns of beta diversity, with high levels of nestedness and turnover in the north and in the south, respectively, indicating species exclusion towards the north and increased opportunities for speciation in the south. Liverworts exhibit the highest levels of nestedness, suggesting that they represent the most sensitive group to the impact of past climate change. Nevertheless, although the extent of liverwort species turnover in the south is substantially and significantly lower than in spermatophytes, liverworts share with the latter a higher nestedness in the north and a higher turn-over in the south, in contrast to mosses and ferns. The extent to which the similarity in the patterns displayed by spermatophytes and liverworts reflects a similar assembly mechanism remains, however, to be demonstrated.Peer reviewe

SoilTemp: a global database of near-surface temperature

Current analyses and predictions of spatially-explicit patterns and processes in ecology most often rely on climate data interpolated from standardized weather stations. This interpolated climate data represents long-term average thermal conditions at coarse spatial resolutions only. Hence, many climate-forcing factors that operate at fine spatiotemporal resolutions are overlooked. This is particularly important in relation to effects of observation height (e.g. vegetation, snow and soil characteristics) and in habitats varying in their exposure to radiation, moisture and wind (e.g. topography, radiative forcing, or cold-air pooling). Since organisms living close to the ground relate more strongly to these microclimatic conditions than to free-air temperatures, microclimatic ground and near-surface data are needed to provide realistic forecasts of the fate of such organisms under anthropogenic climate change, as well as of the functioning of the ecosystems they live in. To fill this critical gap, we highlight a call for temperature time series submissions to SoilTemp, a geospatial database initiative compiling soil and near-surface temperature data from all over the world. Currently this database contains time series from 7538 temperature sensors from 51 countries across all key biomes. The database will pave the way towards an improved global understanding of microclimate and bridge the gap between the available climate data and the climate at fine spatiotemporal resolutions relevant to most organisms and ecosystem processes.Additional co-authors: Stuart W. Smith, Robert G. Björk, Lena Muffler, Simone Cesarz, Felix Gottschall, Amanda Ratier Backes, Joseph Okello, Josef Urban, Roman Plichta, Martin Svátek, Shyam S. Phartyal, Sonja Wipf, Nico Eisenhauer, Mihai Pușcaș, Pavel Dan Turtureanu, Andrej Varlagin, Romina D. Dimarco, Krystal Randall, Ellen Dorrepaal, Keith Larson, Josefine Walz, Luca Vitale, Miroslav Svoboda, Rebecca Finger Higgens, Aud H. Halbritter, Salvatore R. Curasi, Ian Klupar, Austin Koontz, William D. Pearse, Elizabeth Simpson, Michael Stemkovski, Bente Jessen Graae, Mia Vedel Sørensen, Toke T. Høye, M. Rosa Fernández Calzado, Juan Lorite, Michele Carbognani, Marcello Tomaselli, T'ai G.W. Forte, Alessandro Petraglia, Stef Haesen, Ben Somers, Koenraad Van Meerbeek, Mats P. Björkman, Kristoffer Hylander, Sonia Merinero, Mana Gharun, Nina Buchmann, Jiri Dolezal, Radim Matula, Andrew D. Thomas, Joseph J. Bailey, Dany Ghosn, George Kazakis, Miguel Angel de Pablo, Julia Kemppinen, Pekka Niittynen, Lisa Rew, Tim Seipel, Christian Larson, James D.M. Speed, Jonas Ardö, Nicoletta Cannone, Mauro Guglielmin, Francesco Malfasi, Maaike Y. Bader, Rafaella Canessa, Angela Stanisci, Juergen Kreyling, Jonas Schmeddes, Laurenz Teuber, Valeria Aschero, Marek Čiliak, František Máliš, Pallieter De Smedt, Sanne Govaert, Camille Meeussen, Pieter Vangansbeke, Khatuna Gigauri, Andrea Lamprecht, Harald Pauli, Klaus Steinbauer, Manuela Winkler, Masahito Ueyama, Martin A. Nuñez, Tudor‐Mihai Ursu, Sylvia Haider, Ronja E.M. Wedegärtner, Marko Smiljanic, Mario Trouillier, Martin Wilmking, Jan Altman, Josef Brůna, Lucia Hederová, Martin Macek, Matěj Man, Jan Wild, Pascal Vittoz, Meelis Pärtel, Peter Barančok, Róbert Kanka, Jozef Kollár, Andrej Palaj, Agustina Barros, Ana Clara Mazzolari, Marijn Bauters, Pascal Boeckx, José Luis Benito Alonso, Shengwei Zong, Valter Di Cecco, Zuzana Sitková, Katja Tielbörger, Liesbeth van den Brink, Robert Weigel, Jürgen Homeier, C. Johan Dahlberg, Sergiy Medinets, Volodymyr Medinets, Hans J. De Boeck, Miguel Portillo‐Estrada, Lore T. Verryckt, Ann Milbau, Gergana N. Daskalova, Haydn J.D. Thomas, Isla H. Myers‐Smith, Benjamin Blonder, Jörg G. Stephan, Patrice Descombes, Florian Zellweger, Esther R. Frei, Bernard Heinesch, Christopher Andrews, Jan Dick, Lukas Siebicke, Adrian Rocha, Rebecca A. Senior, Christian Rixen, Juan J. Jimenez, Julia Boike, Aníbal Pauchard, Thomas Scholten, Brett Scheffers, David Klinges, Edmund W. Basham, Jian Zhang, Zhaochen Zhang, Charly Géron, Fatih Fazlioglu, Onur Candan, Jhonatan Sallo Bravo, Filip Hrbacek, Kamil Laska, Edoardo Cremonese, Peter Haase, Fernando E. Moyano, Christian Rossi, and Ivan Nij

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications.Additional co-authors: Brett R. Scheffers, Koenraad Van Meerbeek, Peter Aartsma, Otar Abdalaze, Mehdi Abedi, Rien Aerts, Negar Ahmadian, Antje Ahrends, Juha M. Alatalo, Jake M. Alexander, Camille Nina Allonsius, Jan Altman, Christof Ammann, Christian Andres, Christopher Andrews, Jonas Ardö, Nicola Arriga, Alberto Arzac, Valeria Aschero, Rafael L. Assis, Jakob Johann Assmann, Maaike Y. Bader, Khadijeh Bahalkeh, Peter Barančok, Isabel C. Barrio, Agustina Barros, Matti Barthel, Edmund W. Basham, Marijn Bauters, Manuele Bazzichetto, Luca Belelli Marchesini, Michael C. Bell, Juan C. Benavides, José Luis Benito Alonso, Bernd J. Berauer, Jarle W. Bjerke, Robert G. Björk, Mats P. Björkman, Katrin Björnsdóttir, Benjamin Blonder, Pascal Boeckx, Julia Boike, Stef Bokhorst, Bárbara N. S. Brum, Josef Brůna, Nina Buchmann, Pauline Buysse, José Luís Camargo, Otávio C. Campoe, Onur Candan, Rafaella Canessa, Nicoletta Cannone, Michele Carbognani, Jofre Carnicer, Angélica Casanova-Katny, Simone Cesarz, Bogdan Chojnicki, Philippe Choler, Steven L. Chown, Edgar F. Cifuentes, Marek Čiliak, Tamara Contador, Peter Convey, Elisabeth J. Cooper, Edoardo Cremonese, Salvatore R. Curasi, Robin Curtis, Maurizio Cutini, C. Johan Dahlberg, Gergana N. Daskalova, Miguel Angel de Pablo, Stefano Della Chiesa, Jürgen Dengler, Bart Deronde, Patrice Descombes, Valter Di Cecco, Michele Di Musciano, Jan Dick, Romina D. Dimarco, Jiri Dolezal, Ellen Dorrepaal, Jiří Dušek, Nico Eisenhauer, Lars Eklundh, Todd E. Erickson, Brigitta Erschbamer, Werner Eugster, Robert M. Ewers, Dan A. Exton, Nicolas Fanin, Fatih Fazlioglu, Iris Feigenwinter, Giuseppe Fenu, Olga Ferlian, M. Rosa Fernández Calzado, Eduardo Fernández-Pascual, Manfred Finckh, Rebecca Finger Higgens, T'ai G. W. Forte, Erika C. Freeman, Esther R. Frei, Eduardo Fuentes-Lillo, Rafael A. García, María B. García, Charly Géron, Mana Gharun, Dany Ghosn, Khatuna Gigauri, Anne Gobin, Ignacio Goded, Mathias Goeckede, Felix Gottschall, Keith Goulding, Sanne Govaert, Bente Jessen Graae, Sarah Greenwood, Caroline Greiser, Achim Grelle, Benoit Guénard, Mauro Guglielmin, Joannès Guillemot, Peter Haase, Sylvia Haider, Aud H. Halbritter, Maroof Hamid, Albin Hammerle, Arndt Hampe, Siri V. Haugum, Lucia Hederová, Bernard Heinesch, Carole Helfter, Daniel Hepenstrick, Maximiliane Herberich, Mathias Herbst, Luise Hermanutz, David S. Hik, Raúl Hoffrén, Jürgen Homeier, Lukas Hörtnagl, Toke T. Høye, Filip Hrbacek, Kristoffer Hylander, Hiroki Iwata, Marcin Antoni Jackowicz-Korczynski, Hervé Jactel, Järvi Järveoja, Szymon Jastrzębowski, Anke Jentsch, Juan J. Jiménez, Ingibjörg S. Jónsdóttir, Tommaso Jucker, Radoslaw Juszczak, Róbert Kanka, Vít Kašpar, George Kazakis, Julia Kelly, Anzar A. Khuroo, Leif Klemedtsson, Marcin Klisz, Natascha Kljun, Alexander Knohl, Johannes Kobler, Jozef Kollár, Martyna M. Kotowska, Bence Kovács, Juergen Kreyling, Andrea Lamprecht, Simone I. Lang, Christian Larson, Keith Larson, Kamil Laska, Guerric le Maire, Rachel I. Leihy, Luc Lens, Bengt Liljebladh, Annalea Lohila, Juan Lorite, Benjamin Loubet, Joshua Lynn, Martin Macek, Roy Mackenzie, Enzo Magliulo, Regine Maier, Francesco Malfasi, František Máliš, Matěj Man, Giovanni Manca, Antonio Manco, Tanguy Manise, Paraskevi Manolaki, Felipe Marciniak, Radim Matula, Ana Clara Mazzolari, Sergiy Medinets, Volodymyr Medinets, Camille Meeussen, Sonia Merinero, Rita de Cássia Guimarães Mesquita, Katrin Meusburger, Filip J. R. Meysman, Sean T. Michaletz, Ann Milbau, Dmitry Moiseev, Pavel Moiseev, Andrea Mondoni, Ruth Monfries, Leonardo Montagnani, Mikel Moriana-Armendariz, Umberto Morra di Cella, Martin Mörsdorf, Jonathan R. Mosedale, Lena Muffler, Miriam Muñoz-Rojas, Jonathan A. Myers, Isla H. Myers-Smith, Laszlo Nagy, Marianna Nardino, Ilona Naujokaitis-Lewis, Emily Newling, Lena Nicklas, Georg Niedrist, Armin Niessner, Mats B. Nilsson, Signe Normand, Marcelo D. Nosetto, Yann Nouvellon, Martin A. Nuñez, Romà Ogaya, Jérôme Ogée, Joseph Okello, Janusz Olejnik, Jørgen Eivind Olesen, Øystein Opedal, Simone Orsenigo, Andrej Palaj, Timo Pampuch, Alexey V. Panov, Meelis Pärtel, Ada Pastor, Aníbal Pauchard, Harald Pauli, Marian Pavelka, William D. Pearse, Matthias Peichl, Loïc Pellissier, Rachel M. Penczykowski, Josep Penuelas, Matteo Petit Bon, Alessandro Petraglia, Shyam S. Phartyal, Gareth K. Phoenix, Casimiro Pio, Andrea Pitacco, Camille Pitteloud, Roman Plichta, Francesco Porro, Miguel Portillo-Estrada, Jérôme Poulenard, Rafael Poyatos, Anatoly S. Prokushkin, Radoslaw Puchalka, Mihai Pușcaș, Dajana Radujković, Krystal Randall, Amanda Ratier Backes, Sabine Remmele, Wolfram Remmers, David Renault, Anita C. Risch, Christian Rixen, Sharon A. Robinson, Bjorn J.M. Robroek, Adrian V. Rocha, Christian Rossi, Graziano Rossi, Olivier Roupsard, Alexey V. Rubtsov, Patrick Saccone, Clotilde Sagot, Jhonatan Sallo Bravo, Cinthya C. Santos, Judith M. Sarneel, Tobias Scharnweber, Jonas Schmeddes, Marius Schmidt, Thomas Scholten, Max Schuchardt, Naomi Schwartz, Tony Scott, Julia Seeber, Ana Cristina Segalin de Andrade, Tim Seipel, Philipp Semenchuk, Rebecca A. Senior, Josep M. Serra-Diaz, Piotr Sewerniak, Ankit Shekhar, Nikita V. Sidenko, Lukas Siebicke, Laura Siegwart Collier, Elizabeth Simpson, David P. Siqueira, Zuzana Sitková, Johan Six, Marko Smiljanic, Stuart W. Smith, Sarah Smith-Tripp, Ben Somers, Mia Vedel Sørensen, José João L. L. Souza, Bartolomeu Israel Souza, Arildo Souza Dias, Marko J. Spasojevic, James D. M. Speed, Fabien Spicher, Angela Stanisci, Klaus Steinbauer, Rainer Steinbrecher, Michael Steinwandter, Michael Stemkovski, Jörg G. Stephan, Christian Stiegler, Stefan Stoll, Martin Svátek, Miroslav Svoboda, Torbern Tagesson, Andrew J. Tanentzap, Franziska Tanneberger, Jean-Paul Theurillat, Haydn J. D. Thomas, Andrew D. Thomas, Katja Tielbörger, Marcello Tomaselli, Urs Albert Treier, Mario Trouillier, Pavel Dan Turtureanu, Rosamond Tutton, Vilna A. Tyystjärvi, Masahito Ueyama, Karol Ujházy, Mariana Ujházyová, Domas Uogintas, Anastasiya V. Urban, Josef Urban, Marek Urbaniak, Tudor-Mihai Ursu, Francesco Primo Vaccari, Stijn Van de Vondel, Liesbeth van den Brink, Maarten Van Geel, Vigdis Vandvik, Pieter Vangansbeke, Andrej Varlagin, G.F. Veen, Elmar Veenendaal, Susanna E. Venn, Hans Verbeeck, Erik Verbrugggen, Frank G.A. Verheijen, Luis Villar, Luca Vitale, Pascal Vittoz, Maria Vives-Ingla, Jonathan von Oppen, Josefine Walz, Runxi Wang, Yifeng Wang, Robert G. Way, Ronja E. M. Wedegärtner, Robert Weigel, Jan Wild, Matthew Wilkinson, Martin Wilmking, Lisa Wingate, Manuela Winkler, Sonja Wipf, Georg Wohlfahrt, Georgios Xenakis, Yan Yang, Zicheng Yu, Kailiang Yu, Florian Zellweger, Jian Zhang, Zhaochen Zhang, Peng Zhao, Klaudia Ziemblińska, Reiner Zimmermann, Shengwei Zong, Viacheslav I. Zyryanov, Ivan Nijs, Jonathan Leno

Statistical upscaling of ecosystem CO2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties

The regional variability in tundra and boreal carbon dioxide (CO2) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990-2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to analyze the spatial patterns and drivers of CO2 fluxes and test the accuracy and uncertainty of different statistical models. CO2 fluxes were upscaled at relatively high spatial resolution (1 km(2)) across the high-latitude region using five commonly used statistical models and their ensemble, that is, the median of all five models, using climatic, vegetation, and soil predictors. We found the performance of machine learning and ensemble predictions to outperform traditional regression methods. We also found the predictive performance of NEE-focused models to be low, relative to models predicting GPP and ER. Our data compilation and ensemble predictions showed that CO2 sink strength was larger in the boreal biome (observed and predicted average annual NEE -46 and -29 g C m(-2) yr(-1), respectively) compared to tundra (average annual NEE +10 and -2 g C m(-2) yr(-1)). This pattern was associated with large spatial variability, reflecting local heterogeneity in soil organic carbon stocks, climate, and vegetation productivity. The terrestrial ecosystem CO2 budget, estimated using the annual NEE ensemble prediction, suggests the high-latitude region was on average an annual CO2 sink during 1990-2015, although uncertainty remains high

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications.publishedVersio

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications