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1. The Q10 of in situ microbial soil respiration varies with mean annual temperature, precipitation, pH, and plant cover: a meta-analysis and spatial prediction of Q10

   https://doi.org/10.1038/s41598-026-45615-w  

   Hacopian, Melanie T; Choreño-Parra, Eduardo Misael; De_Araujo, Lirio_Hadomi Aquino; Zhou, Andrea; Alster, Charlotte J; Randerson, James T; Treseder, Kathleen K (December 2026, Scientific Reports)

   Abstract The temperature sensitivity of soil microbial respiration, commonly quantified using the Q₁₀coefficient, is a key parameter in carbon cycle models. Uncovering how environmental factors affect in situ Q₁₀values can therefore provide critical insight into potential shifts in global carbon stocks under climate change. We collected data from previously published field experiments that measured soil microbial respiration across a range of temperatures. We hypothesized that the Q₁₀coefficient of in situ soil microbial respiration would vary based on environmental factors including mean annual temperature (MAT), mean annual precipitation (MAP), plant cover type, pH, soil C:N, and latitude. Linear regression revealed that Q₁₀correlates negatively with MAT and MAP and positively with pH and absolute latitude. Additionally, average Q₁₀varied significantly across different plant cover types; it was highest in mountain grasslands and lowest in tropical moist forests. Variation in microbial Q₁₀across environmental factors may arise from underlying mechanisms such as enzyme kinetics, substrate availability and complexity, and microbial adaptation. To capture patterns in Q₁₀more comprehensively, we developed a multiple linear regression model of Q₁₀based on the most individually significant environmental drivers and applied it to public datasets to generate a global map of predicted Q₁₀. Q₁₀was higher in high-latitude and high-altitude regions, where large permafrost carbon stores are vulnerable to thawing and decomposition. We also compared fits between the Q₁₀equation and a model produced from macromolecular rate theory (MMRT). We found that the MMRT model had the superior fit and may be better suited to model temperature sensitivity of complex biological reactions. Overall, our results emphasize that relationships between microbial Q₁₀and environmental variables should be accounted for in climate models. Incorporating these variations in the Q₁₀parameter, rather than using a fixed value, will help predict whether CO₂emissions will be buffered or exacerbated by soil microbial respiration under climate change. 

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2. Soil incubation methods lead to large differences in inferred methane production temperature sensitivity

   https://doi.org/10.1088/1748-9326/ad3565  

   Li, Zhen; Grant, Robert F; Chang, Kuang-Yu; Hodgkins, Suzanne B; Tang, Jinyun; Cory, Alexandra; Mekonnen, Zelalem A; Saleska, Scott R; Brodie, Eoin L; Varner, Ruth K; et al (April 2024, Environmental Research Letters)

   Abstract Quantifying the temperature sensitivity of methane (CH₄) production is crucial for predicting how wetland ecosystems will respond to climate warming. Typically, the temperature sensitivity (often quantified as a Q₁₀value) is derived from laboratory incubation studies and then used in biogeochemical models. However, studies report wide variation in incubation-inferred Q₁₀values, with a large portion of this variation remaining unexplained. Here we applied observations in a thawing permafrost peatland (Stordalen Mire) and a well-tested process-rich model (ecosys) to interpret incubation observations and investigate controls on inferred CH₄production temperature sensitivity. We developed a field-storage-incubation modeling approach to mimic the full incubation sequence, including field sampling at a particular time in the growing season, refrigerated storage, and laboratory incubation, followed by model evaluation. We found that CH₄production rates during incubation are regulated by substrate availability and active microbial biomass of key microbial functional groups, which are affected by soil storage duration and temperature. Seasonal variation in substrate availability and active microbial biomass of key microbial functional groups led to strong time-of-sampling impacts on CH₄production. CH₄production is higher with less perturbation post-sampling, i.e. shorter storage duration and lower storage temperature. We found a wide range of inferred Q₁₀values (1.2–3.5), which we attribute to incubation temperatures, incubation duration, storage duration, and sampling time. We also show that Q₁₀values of CH₄production are controlled by interacting biological, biochemical, and physical processes, which cause the inferred Q₁₀values to differ substantially from those of the component processes. Terrestrial ecosystem models that use a constant Q₁₀value to represent temperature responses may therefore predict biased soil carbon cycling under future climate scenarios. 

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3. Are the Transient and Equilibrium Climate Change Patterns Similar in Response to Increased CO2?

   https://doi.org/10.1175/JCLI-D-19-0749.1  

   Huang, Danqing; Dai, Aiguo; Zhu, Jian (September 2020, Journal of Climate)

   null (Ed.)

   Abstract After a CO 2 increase, whether the early transient and final equilibrium climate change patterns are similar has major implications. Here, we analyze long-term simulations from multiple climate models under increased CO 2 , together with the extended simulations from CMIP5, to compare the transient and equilibrium climate change patterns under different forcing scenarios. Results show that the normalized warming patterns (per 1 K of global warming) are broadly similar among different forcing scenarios (including abrupt 2 × CO 2 , 4 × CO 2 , and 1% CO 2 increase per year) and during different time periods, except for the first 50 years or so when warming is weaker over the North Atlantic and Southern Ocean but stronger over most continents. During the first 200 years, this consistency is stronger over land than over ocean, but is lower in midlatitudes than other regions. Normalized precipitation change patterns are also similar, albeit to a lesser degree, among different forcing scenarios and across different time periods, although noticeable differences exist during the first few hundred years with smaller increases over the tropical Pacific. Precipitation over many subtropical oceans and land areas decreases consistently under different forcing scenarios and over all time periods. In particular, the transient and near-equilibrium change patterns for both surface air temperature and precipitation are similar over most of the globe, except for the North Atlantic warming hole, which is mainly a transient feature. The Arctic amplification and land–ocean warming contrast are largest during the first 100–200 years after CO 2 quadrupling but they still exist in the equilibrium response. 

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4. Current-climate sea ice amount and seasonality as constraints for future Arctic amplification

   https://doi.org/10.1088/2752-5295/acf4b7  

   Linke, Olivia; Feldl, Nicole; Quaas, Johannes (September 2023, Environmental Research: Climate)

   Abstract The recent Arctic sea ice loss is a key driver of the amplified surface warming in the northern high latitudes, and simultaneously a major source of uncertainty in model projections of Arctic climate change. Previous work has shown that the spread in model predictions of future Arctic amplification (AA) can be traced back to the inter-model spread in simulated long-term sea ice loss. We demonstrate that the strength of future AA is further linked to the current climate’s, observable sea ice state across the multi-model ensemble of the 6th Coupled Model Intercomparison Project (CMIP6). The implication is that the sea-ice climatology sets the stage for long-term changes through the 21st century, which mediate the degree by which Arctic warming is amplified with respect to global warming. We determine that a lower base-climate sea ice extent and sea ice concentration (SIC) in CMIP6 models enable stronger ice melt in both future climate and during the seasonal cycle. In particular, models with lower Arctic-mean SIC project stronger future ice loss and a more intense seasonal cycle in ice melt and growth. Both processes systemically link to a larger future AA across climate models. These results are manifested by the role of climate feedbacks that have been widely identified as major drivers of AA. We show in particular that models with low base-climate SIC predict a systematically stronger warming contribution through both sea-ice albedo feedback and temperature feedbacks in the future, as compared to models with high SIC. From our derived linear regressions in conjunction with observations, we estimate a 21st-century AA over sea ice of 2.47–3.34 with respect to global warming. Lastly, from the tight relationship between base-climate SIC and the projected timing of an ice-free September, we predict a seasonally ice-free Arctic by mid-century under a high-emission scenario. 

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5. Projected near‐future flooding and warming increase graminoid biomass in a high‐latitude coastal wetland

   https://doi.org/10.1111/1365-2745.14418  

   Petit_Bon, Matteo; Leffler, A Joshua; Kelsey, Katharine C; Williams, Tyler J; Beard, Karen H (December 2024, Journal of Ecology)

   Abstract: With rapid climate warming, some coastal high‐latitude ecosystems are experiencing more frequent tidal floods. Yet little is known about tundra plant‐community responses to flooding, and whether Arctic warming may modulate such responses.In a 2‐year, full‐factorial field experiment in coastal tundra wetlands of the Yukon‐Kuskokwim (Y‐K) Delta (western Alaska), we simulated periodic tidal flood events at two severities under both ambient and warmed summer conditions and measured above‐ground plant‐community responses. Low‐severity flooding represented overbank flooding 1 day per month, which is consistent with projections in the next 5 years. High‐severity flooding represented a more impactful flooding regime (three consecutive days per month) that is projected to occur in the next 10 years. Our warming treatment (+1°C) also represented a change projected in the next 10 years.Regardless of temperature, high‐severity flooding increased graminoid biomass by >45%, in turn increasing live plant‐community biomass by >18%. Low‐severity flooding had similar, though weaker, effects. Flooding had overall negative effects on both forb and shrub biomass, though shrub responses were weaker. Only during the second summer, warming increased graminoid biomass by 20% and tended to increase shrub biomass, regardless of flooding. Concurrently, warming enhanced standing‐dead graminoid biomass by 20%, while high‐severity flooding decreased it by 15%. Therefore, wet tundra that was both flooded and warmed had the greatest proportion of graminoids and total live biomass, but standing‐dead biomass comparable to that of unmanipulated wet tundra. While our manipulations simulated flooding and warming regimes expected in the wetlands of the Y‐K Delta over the same, near‐future (5‐to‐10 years) time frame, flooding had stronger effects than warming. What is striking is the rate at which graminoid increases occurred, becoming apparent after only two monthly flood events in the first experimental year. Flooding‐induced decreases in standing‐dead biomass suggests that the incorporation of dead plant material into the litter layer might be facilitated by tidal floods. These rapid increases in plant biomass and potentially biomass turnover, especially of graminoids, which are characterized by high‐quality litter, may have major implications for carbon and nutrient cycling of more frequently flooded coastal ecosystems in a warmer Arctic. 

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