Warming increases CO₂ emissions in biochar-amended cropland soil

Abstract

Biochar application is recognized as a promising strategy for enhancing soil carbon (C) sequestration, yet its influence on carbon dioxide (CO₂) emissions under a warming climate remains inadequately understood. We conducted a global meta-analysis of 2079 paired observations from 32 peer-reviewed publications to quantify the responses of CO₂ emissions in biochar-amended soils to warming and to identify their key drivers. Overall, warming increased CO₂ emissions in biochar-amended soils by 77% on average, with a 117.5% increase in croplands and a 30.9% increase in forests. The effect was strongest for woody biochars, intermediate for crop-derived biochars, and weakest for grass-derived biochars. Increases in CO₂ emissions were positively associated with warming magnitude, biochar characteristics, and soil properties. Warming magnitude was the dominant driver, followed by biochar application rate, soil C/N ratio, and biochar C/N ratio. The relative importance of these secondary drivers varies across cropland and forest ecosystems. These findings indicate that the climate mitigation potential of biochar may be overestimated if warming-induced C losses are ignored in biochar-amended cropland soil. To enhance the resilience of biochar applications, context-specific strategies should prioritize non-woody feedstocks, lower pyrolysis temperatures, and moderate application rates, particularly in vulnerable cropland systems. It is necessary to integrate the warming effects into biochar life-cycle assessments and soil C management frameworks to ensure realistic projections of its role in climate mitigation and carbon sequestration, particularly in cropland ecosystems under warming conditions.

Graphical Abstract

Keywords

Greenhouse gas / Biochar amendment / Global warming / Soil organic matter / Climate change

Highlight

•	Warming boosts CO2 emissions from biochar-amended soils by 77% on average, with a higher increase in croplands than in forests.
•	Warming magnitude is the top driver of emission changes, followed by biochar characteristics and soil properties.
•	Woody biochars induce a stronger warming response than non-woody feedstocks.
•	Biochar application needs to be optimized by integrating warming effects.

References

[1] Abdalla K, Sun Y, Zarebanadkouki M, Gaiser T, Seidel S, Pausch J. Long-term continuous farmyard manure application increases soil carbon when combined with mineral fertilizers due to lower priming effects. Geoderma, 2022, 428: 116216.

[2] Ameloot N, Graber ER, Verheijen FGA, De Neve S. Interactions between biochar stability and soil organisms: review and research needs. Eur J Soil Sci, 2013, 64: 379-390.

[3] Antonangelo JA, Sun X, Eufrade-Junior HdJ. Biochar impact on soil health and tree-based crops: a review. Biochar, 2025, 7: 51.

[4] Bamel D, Dey A, Mondal BK, Bhattacharyya R, Das D, Das S, Das TK, Dash AK. Non-abundance of cellulose and lignin in crop residue biomass increases decomposability and lowers temperature sensitivity of the process and helps in labile soil organic carbon build-up. J Soil Sci Plant Nutr, 2025, 25: 7710-7727.

[5] Bamminger C, Poll C, Sixt C, Högy P, Wüst D, Kandeler E, Marhan S. Short-term response of soil microorganisms to biochar addition in a temperate agroecosystem under soil warming. Agric Ecosyst Environ, 2016, 233: 308-317.

[6] Bamminger C, Poll C, Marhan S. Offsetting global warming-induced elevated greenhouse gas emissions from an arable soil by biochar application. Global Change Biol, 2017.

[7] Bamminger C, Poll C, Marhan S. Offsetting global warming-induced elevated greenhouse gas emissions from an arable soil by biochar application. Glob Change Biol, 2018, 24: e318-e334.

[8] Bar-On YM, Li X, O’Sullivan M, Wigneron J-P, Sitch S, Ciais P, Frankenberg C, Fischer WW. Recent gains in global terrestrial carbon stocks are mostly stored in nonliving pools. Science, 2025, 387: 1291-1295.

[9] Bird MI, Moyo C, Veenendaal EM, Lloyd J, Frost P. Stability of elemental carbon in a savanna soil. Glob Biogeochem Cycles, 1999, 13: 923-932.

[10] Briones MJI, McNamara NP, Poskitt J, Crow SE, Ostle NJ. Interactive biotic and abiotic regulators of soil carbon cycling: evidence from controlled climate experiments on peatland and boreal soils. Glob Change Biol, 2014, 20: 2971-2982.

[11] Case SDC, McNamara NP, Reay DS, Whitaker J. Can biochar reduce soil greenhouse gas emissions from a Miscanthus bioenergy crop?. GCB Bioenergy, 2014, 6: 76-89.

[12] Chen J, Li S, Liang C, Xu Q, Li Y, Qin H, Fuhrmann JJ. Response of microbial community structure and function to short-term biochar amendment in an intensively managed bamboo (Phyllostachys praecox) plantation soil: effect of particle size and addition rate. Sci Total Environ, 2017, 574: 24-33.

[13] Chen J, Chen D, Xu Q, Fuhrmann JJ, Li L, Pan G, Li Y, Qin H, Liang C, Sun X. Organic carbon quality, composition of main microbial groups, enzyme activities, and temperature sensitivity of soil respiration of an acid paddy soil treated with biochar. Biol Fertil Soils, 2019, 55: 185-197.

[14] Chen Q, Tao B, Jiang Y, Wang J, Zhang B. Combined effects of biochar addition with varied particle size and temperature on the decomposition of soil organic carbon in a temperate forest, China. Soil Sci Plant Nutr, 2023, 69: 45-53.

[15] Chen Y, Qin W, Zhang Q, Wang X, Feng J, Han M, Hou Y, Zhao H, Zhang Z, He J-S, Torn MS, Zhu B. Whole-soil warming leads to substantial soil carbon emission in an alpine grassland. Nat Commun, 2024, 15: 4489.

[16] Cheng S, Kumar A, Lan G, Zhang W, Yu Z, Zhang S, Yu Z-G, Yao M, Lin J. Thermal sensitivity and rising greenhouse gas emissions in riparian zone soils: implications for ecosystem carbon dynamics. J Environ Manag, 2025, 381: 125194.

[17] Crombie K, Masek O, Cross A, Sohi S. Biochar - synergies and trade-offs between soil enhancing properties and C sequestration potential. GCB Bioenergy, 2015, 7: 1161-1175.

[18] Cui J, Glatzel S, Bruckman VJ, Wang B, Lai DYF. Long-term effects of biochar application on greenhouse gas production and microbial community in temperate forest soils under increasing temperature. Sci Total Environ, 2021, 767: 145021.

[19] Davidson EA, Janssens IA. Temperature sensitivity of soil carbon decomposition and feedbacks to climate change. Nature, 2006, 440: 165-173.

[20] de Jesus Duarte S, Glaser B, Pellegrino Cerri CE. Effect of biochar particle size on physical, hydrological and chemical properties of loamy and sandy tropical soils. Agronomy, 2019.

[21] Deng L, Zhu G-y, Tang Z-s, Shangguan Z-p. Global patterns of the effects of land-use changes on soil carbon stocks. Glob Ecol Conserv, 2016, 5: 127-138.

[22] Dong H, Zhang S, Lin J, Zhu B. Responses of soil microbial biomass carbon and dissolved organic carbon to drying-rewetting cycles: a meta-analysis. CATENA, 2021, 207: 105610.

[23] Dong H, Lin J, Lu J, Li L, Yu Z, Kumar A, Zhang Q, Liu D, Chen B. Priming effects of surface soil organic carbon decreased with warming: a global meta-analysis. Plant Soil, 2024, 500: 233-242.

[24] Dong H, He P, Liu M, Kuzyakov Y, Li LJ. Nitrogen availability governs priming effect induced by biodegradable microplastics through microbial life-strategies. Eur J Soil Sci, 2025.

[25] Duval S, Tweedie R. Trim and fill: a simple funnel-plot-based method of testing and adjusting for publication bias in meta-analysis. Biometrics, 2000, 56: 455-463.

[26] Feng W, Liang J, Hale LE, Jung CG, Chen J, Zhou J, Xu M, Yuan M, Wu L, Bracho R, Pegoraro E, Schuur EAG, Luo Y. Enhanced decomposition of stable soil organic carbon and microbial catabolic potentials by long-term field warming. Glob Change Biol, 2017, 23: 4765-4776.

[27] Gao H, Tian H, Zhang Z, Xia X. Warming-induced greenhouse gas fluxes from global croplands modified by agricultural practices: a meta-analysis. Sci Total Environ, 2022.

[28] Georgiou K, Jackson RB, Vindušková O, Abramoff RZ, Ahlström A, Feng W, Harden JW, Pellegrini AFA, Polley HW, Soong JL, Riley WJ, Torn MS. Global stocks and capacity of mineral-associated soil organic carbon. Nat Commun, 2022, 13: 3797.

[29] Ghosh D, Page-Dumroese DS, Han H-S, Anderson N. Role of biochar made from low-value woody forest residues in ecological sustainability and carbon neutrality. Soil Sci Soc Am J, 2025, 89: e20793.

[30] Han M, Zhu B. Changes in soil greenhouse gas fluxes by land use change from primary forest. Glob Change Biol, 2020, 26: 2656-2667.

[31] Hedges LV, Gurevitch J, Curtis PS. The meta-analysis of response ratios in experimental ecology. Ecology, 1999, 80: 1150-1156.

[32] Hu H, Chen J, Zhou F, Nie M, Hou D, Liu H, Delgado-Baquerizo M, Ni H, Huang W, Zhou J, Song X, Cao X, Sun B, Zhang J, Crowther TW, Liang Y. Relative increases in CH4 and CO2 emissions from wetlands under global warming dependent on soil carbon substrates. Nat Geosci, 2024, 17: 26-31.

[33] Huang R, Wang Z, Xiao Y, Yu L, Gao X, Wang C, Li B, Tao Q, Xu Q, Gao M. Increases in temperature response to CO2 emissions in biochar-amended vegetable field soil. Environ Sci Pollut Res, 2022, 29: 50895-50905.

[34] Huang X, Cui C, Hou E, Li F, Liu W, Jiang L, Luo Y, Xu X. Acidification of soil due to forestation at the global scale. For Ecol Manag, 2022.

[35] Huang S, Zhu X, Fang J, Zhang X, Zhang H, Zhang Z, Wu X, Zhu X. Pyrolysis temperature dependent effects of biochar on shifting fluorescence spectrum characteristics of soil dissolved organic matter under warming. Sci Total Environ, 2023, 892: 164656.

[36] Huo C, Luo Y, Cheng W. Rhizosphere priming effect: a meta-analysis. Soil Biol Biochem, 2017, 111: 78-84.

[37] Jaafar NM, Clode PL, Abbott LK. Soil microbial responses to biochars varying in particle size, surface and pore properties. Pedosphere, 2015, 25: 770-780.

[38] Jiang RW, Galo M, Oelbermann M. Soybean and soil responses to biochar amendment in controlled environments with elevated temperature and carbon dioxide. Can J Soil Sci, 2021, 102: 65-76.

[39] Jiang Z, Zhang S, Tang C, Xiao M, Zhou J, Luo Y, Ge T, Yu B, White JC, Li Y. Divergent effects of straw and biochar on soil carbon priming are depth-dependent in subtropical Moso bamboo forests. Biol Fertil Soils, 2025.

[40] Khan MZ, Chabbi A, Hicks Pries CE, Torn MS, Rumpel C. Management impacts on whole soil warming responses of CO2 production and efflux in temperate climate. Geoderma, 2023, 440: 116725.

[41] Kirschbaum MUF. Will changes in soil organic carbon act as a positive or negative feedback on global warming?. Biogeochemistry, 2000, 48: 21-51.

[42] Koricheva J, Gurevitch J, Mengersen K. Handbook of meta-analysis in ecology and evolution, 2013Princeton University Press.

[43] Li J, Zhao J, Liao X, Hu P, Wang W, Ling Q, Xie L, Xiao J, Zhang W, Wang K. Pathways of soil organic carbon accumulation are related to microbial life history strategies in fertilized agroecosystems. Sci Total Environ, 2024, 927: 172191.

[44] Li S, Delgado-Baquerizo M, Ding J, Hu H, Huang W, Sun Y, Ni H, Kuang Y, Yuan MM, Zhou J, Zhang J, Liang Y. Intrinsic microbial temperature sensitivity and soil organic carbon decomposition in response to climate change. Glob Change Biol, 2024, 30: e17395.

[45] Lin J, Hui D, Kumar A, Yu Z, Huang Y. Editorial: Climate change and/or pollution on the carbon cycle in terrestrial ecosystems. Front Environ Sci, 2023.

[46] Lin J, Chen B, Dong H, Zhang W, Kumar A, Hui D, Zhang C, Shan S, Zhu B. Effects of soil moisture fluctuation and microplastics types on soil organic matter decomposition and carbon dynamics. Soil Biol Biochem, 2025.

[47] Lin J, Cheng Q, Kumar A, Zhang W, Yu Z, Hui D, Zhang C, Shan S. Effect of degradable microplastics, biochar and their coexistence on soil organic matter decomposition: a critical review. TrAC Trends Anal Chem, 2025, 183: 118082.

[48] Liu X, Zhang A, Ji C, Joseph S, Bian R, Li L, Pan G, Paz-Ferreiro J. Biochar’s effect on crop productivity and the dependence on experimental conditions—a meta-analysis of literature data. Plant Soil, 2013, 373: 583-594.

[49] Meena M, Yadav G, Sonigra P, Nagda A, Mehta T, Swapnil P, Harish MA, Kumar S. Multifarious responses of forest soil microbial community toward climate change. Microb Ecol, 2023, 86: 49-74.

[50] Mohan D, Abhishek K, Sarswat A, Patel M, Singh P, Pittman CUJr.. Biochar production and applications in soil fertility and carbon sequestration - a sustainable solution to crop-residue burning in India. RSC Adv, 2018, 8: 508-520.

[51] Murtaza G, Usman M, Iqbal J, Hyder S, Solangi F, Iqbal R, Okla MK, Al-Ghamdi AA, Elsalahy HH, Tariq W, Al-Elwany OAAI. Liming potential and characteristics of biochar produced from woody and non-woody biomass at different pyrolysis temperatures. Sci Rep, 2024.

[52] Nissan A, Alcolombri U, Peleg N, Galili N, Jimenez-Martinez J, Molnar P, Holzner M. Global warming accelerates soil heterotrophic respiration. Nat Commun, 2023.

[53] Niu S, Chen W, Liáng LL, Sierra CA, Xia J, Wang S, Heskel M, Patel KF, Bond-Lamberty B, Wang J, Yvon-Durocher G, Kirschbaum MUF, Atkin OK, Huang Y, Yu G, Luo Y. Temperature responses of ecosystem respiration. Nat Rev Earth Environ, 2024, 5: 559-571.

[54] Nogués I, Mazzurco Miritana V, Passatore L, Zacchini M, Peruzzi E, Carloni S, Pietrini F, Marabottini R, Chiti T, Massaccesi L, Marinari S. Biochar soil amendment as carbon farming practice in a Mediterranean environment. Geoderma Reg, 2023, 33: e00634.

[55] Nottingham AT, Meir P, Velasquez E, Turner BL. Soil carbon loss by experimental warming in a tropical forest. Nature, 2020, 584: 234-+.

[56] Oliverio AM, Bradford MA, Fierer N. Identifying the microbial taxa that consistently respond to soil warming across time and space. Glob Change Biol, 2017, 23: 2117-2129.

[57] Possinger AR, Driscoll CT, Green MB, Fahey TJ, Johnson CE, Koppers MMK, Martel LD, Morse JL, Templer PH, Uribe AM, Wilson GF, Groffman PM. Increasing soil respiration in a northern hardwood forest indicates symptoms of a changing carbon cycle. Commun Earth Environ, 2025, 6: 418.

[58] Qin S, Chen L, Fang K, Zhang Q, Wang J, Liu F, Yu J, Yang Y. Temperature sensitivity of SOM decomposition governed by aggregate protection and microbial communities. Sci Adv, 2019.

[59] Rosenthal R. The file drawer problem and tolerance for null results. Psychol Bull, 1979, 86: 638-641.

[60] Saffari N, Hajabbasi MA, Shirani H, Mosaddeghi MR, Mamedov AI. Biochar type and pyrolysis temperature effects on soil quality indicators and structural stability. J Environ Manag, 2020, 261: 110190.

[61] Sarfraz R, Yang W, Wang S, Zhou B, Xing S. Short term effects of biochar with different particle sizes on phosphorous availability and microbial communities. Chemosphere, 2020.

[62] Schindlbacher A, Schnecker J, Takriti M, Borken W, Wanek W. Microbial physiology and soil CO₂ efflux after 9 years of soil warming in a temperate forest - no indications for thermal adaptations. Glob Change Biol, 2015, 21: 4265-4277.

[63] Shrivastava P, Kumar A, Tekasakul P, Lam SS, Palamanit A. Comparative investigation of yield and quality of bio-oil and biochar from pyrolysis of woody and non-woody biomasses. Energies, 2021.

[64] Su R, Wu X, Hu J, Li H, Xiao H, Zhao J, Hu R. Warming promotes the decomposition of oligotrophic bacterial-driven organic matter in paddy soil. Soil Biol Biochem, 2023, 186: 109156.

[65] Suliman W, Harsh JB, Abu-Lail NI, Fortuna A-M, Dallmeyer I, Garcia-Perez M. Influence of feedstock source and pyrolysis temperature on biochar bulk and surface properties. Biomass Bioenergy, 2016, 84: 37-48.

[66] Sun J, He F, Zhang Z, Shao H, Xu G. Temperature and moisture responses to carbon mineralization in the biochar-amended saline soil. Sci Total Environ, 2016, 569: 390-394.

[67] Terrer C, Jackson RB, Prentice IC, Keenan TF, Kaiser C, Vicca S, Fisher JB, Reich PB, Stocker BD, Hungate BA, Penuelas J, McCallum I, Soudzilovskaia NA, Cernusak LA, Talhelm AF, Van Sundert K, Piao S, Newton PCD, Hovenden MJ, Blumenthal DM, Liu YY, Mueller C, Winter K, Field CB, Viechtbauer W, Van Lissa CJ, Hoosbeek MR, Watanabe M, Koike T, Leshyk VO, Polley HW, Franklin O. Nitrogen and phosphorus constrain the CO₂ fertilization of global plant biomass. Nat Clim Change, 2019, 9: 684.

[68] Veroniki AA, Jackson D, Viechtbauer W, Bender R, Bowden J, Knapp G, Kuss O, Higgins JPT, Langan D, Salanti G. Methods to estimate the between-study variance and its uncertainty in meta-analysis. Res Synth Methods, 2016, 7: 55-79.

[69] Viechtbauer W. Conducting meta-analyses in R with the metafor package. J Stat Softw, 2010, 36: 1-48.

[70] von Luetzow M, Koegel-Knabner I. Temperature sensitivity of soil organic matter decomposition-what do we know?. Biol Fertil Soils, 2009, 46: 1-15.

[71] Walker TWN, Kaiser C, Strasser F, Herbold CW, Leblans NIW, Woebken D, Janssens IA, Sigurdsson BD, Richter A. Microbial temperature sensitivity and biomass change explain soil carbon loss with warming. Nat Clim Chang, 2018, 8: 885-889.

[72] Wang D, Fonte SJ, Parikh SJ, Six J, Scow KM. Biochar additions can enhance soil structure and the physical stabilization of C in aggregates. Geoderma, 2017, 303: 110-117.

[73] Wei X, Shao M, Gale W, Li L. Global pattern of soil carbon losses due to the conversion of forests to agricultural land. Sci Rep, 2014, 4: 4062.

[74] Xue K, Yuan MM, Shi ZJ, Qin Y, Deng Y, Cheng L, Wu L, He Z, Van Nostrand JD, Bracho R, Natali S, Schuur EAG, Luo C, Konstantinidis KT, Wang Q, Cole JR, Tiedje JM, Luo Y, Zhou J. Tundra soil carbon is vulnerable to rapid microbial decomposition under climate warming. Nat Clim Change, 2016, 6: 595.

[75] Yang Y, Sun K, Han L, Chen Y, Liu J, Xing B. Biochar stability and impact on soil organic carbon mineralization depend on biochar processing, aging and soil clay content. Soil Biol Biochem, 2022, 169: 108657.

[76] Zhang S, Yu Z, Lin J, Zhu B. Responses of soil carbon decomposition to drying-rewetting cycles: a meta-analysis. Geoderma, 2020.

[77] Zhang X, Zhang Q, Zhan L, Xu X, Bi R, Xiong Z. Biochar addition stabilized soil carbon sequestration by reducing temperature sensitivity of mineralization and altering the microbial community in a greenhouse vegetable field. J Environ Manag, 2022.

[78] Zhao Y, Lin J, Cheng S, Wang K, Kumar A, Yu Z-G, Zhu B. Linking soil dissolved organic matter characteristics and the temperature sensitivity of soil organic carbon decomposition in the riparian zone of the Three Gorges reservoir. Ecol Indic, 2023, 154: 110768.

[79] Zheng J, van Groenigen KJ, Hartley IP, Xue R, Wang M, Zhang S, Sun T, Yu W, Ma B, Luo Y, Shi Z, Luo Z. Temperature sensitivity of bacterial species-level preferences of soil carbon pools. Geoderma, 2025, 456: 117268.

[80] Zhou M, Xiao Y, Zhang X, Sui Y, Xiao L, Lin J, Cruse RM, Ding G, Liu X. Warming-dominated climate change impacts on soil organic carbon fractions and aggregate stability in Mollisols. Geoderma, 2023, 438: 116618.

[81] Zhou J, Zhang S, Lv J, Tang C, Zhang H, Fang Y, Tavakkoli E, Ge T, Luo Y, Cai Y, Yu B, White JC, Li Y. Maize straw increases while its biochar decreases native organic carbon mineralization in a subtropical forest soil. Sci Total Environ, 2024.

[82] Zhou J, Tang C, Vancov T, Fu S, Fang Y, Ge T, Dong Y, Luo Y, Yu B, Cai Y. Biochar mitigates the suppressive effects of nitrogen deposition on soil methane uptake in a subtropical forest. Agric Ecosyst Environ, 2026, 395: 109951.

[83] Zhu X, Chen B, Zhu L, Xing B. Effects and mechanisms of biochar-microbe interactions in soil improvement and pollution remediation: a review. Environ Pollut, 2017, 227: 98-115.

Funding

Natural Science Foundation of Zhejiang Province(LZ25C030003)

Zhejiang Forestry Science and Technology Project(2026F1065-3)

“Pioneer” and “Leading Goose” R&D Program of Zhejiang(2025C02097)

Chongqing Municipal Education Commission(KJZD-K202503502)

RIGHTS & PERMISSIONS

The Author(s)