{"type": "FeatureCollection", "features": [{"id": "10.1038/s41586-024-07274-7", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-25T16:17:51Z", "type": "Journal Article", "created": "2024-04-17", "title": "Environmental drivers of increased ecosystem respiration in a warming tundra", "description": "Abstract

Arctic and alpine tundra ecosystems are large reservoirs of organic carbon1,2. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere3,4. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain5\uffe2\uff80\uff937. This hampers the accuracy of global land carbon\uffe2\uff80\uff93climate feedback projections7,8. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1\uffe2\uff80\uff89year up to 25\uffe2\uff80\uff89years. We show that a mean rise of 1.4\uffe2\uff80\uff89\uffc2\uffb0C [confidence interval (CI) 0.9\uffe2\uff80\uff932.0\uffe2\uff80\uff89\uffc2\uffb0C] in air and 0.4\uffe2\uff80\uff89\uffc2\uffb0C [CI 0.2\uffe2\uff80\uff930.7\uffe2\uff80\uff89\uffc2\uffb0C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22\uffe2\uff80\uff9338%] (n\uffe2\uff80\uff89=\uffe2\uff80\uff89136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n\uffe2\uff80\uff89=\uffe2\uff80\uff899) and continued for at least 25\uffe2\uff80\uff89years (n\uffe2\uff80\uff89=\uffe2\uff80\uff89136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.Arctic and alpine tundra ecosystems are large reservoirs of organic carbon1,2. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere3,4. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain5\uffe2\uff80\uff937. This hampers the accuracy of global land carbon\uffe2\uff80\uff93climate feedback projections7,8. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1\uffe2\uff80\uff89year up to 25\uffe2\uff80\uff89years. We show that a mean rise of 1.4\uffe2\uff80\uff89\uffc2\uffb0C [confidence interval (CI) 0.9\uffe2\uff80\uff932.0\uffe2\uff80\uff89\uffc2\uffb0C] in air and 0.4\uffe2\uff80\uff89\uffc2\uffb0C [CI 0.2\uffe2\uff80\uff930.7\uffe2\uff80\uff89\uffc2\uffb0C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22\uffe2\uff80\uff9338%] (n\uffe2\uff80\uff89=\uffe2\uff80\uff89136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n\uffe2\uff80\uff89=\uffe2\uff80\uff899) and continued for at least 25\uffe2\uff80\uff89years (n\uffe2\uff80\uff89=\uffe2\uff80\uff89136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2\uffc2\uffa0m 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\uffe2\uff80\uff90km2resolution for 0\uffe2\uff80\uff935 and 5\uffe2\uff80\uff9315\uffc2\uffa0cm 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\uffe2\uff80\uff90km2pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse\uffe2\uff80\uff90grained air temperature estimates from ERA5\uffe2\uff80\uff90Land (an atmospheric reanalysis by the European Centre for Medium\uffe2\uff80\uff90Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10\uffc2\uffb0C (mean\uffc2\uffa0=\uffc2\uffa03.0\uffc2\uffa0\uffc2\uffb1\uffc2\uffa02.1\uffc2\uffb0C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6\uffc2\uffa0\uffc2\uffb1\uffc2\uffa02.3\uffc2\uffb0C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (\uffe2\uff88\uff920.7\uffc2\uffa0\uffc2\uffb1\uffc2\uffa02.3\uffc2\uffb0C). The observed substantial and biome\uffe2\uff80\uff90specific offsets emphasize that the projected impacts of climate and climate change on near\uffe2\uff80\uff90surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil\uffe2\uff80\uff90related 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.