CO2-plant effects do not account for the gap between dryness indices and projected dryness impacts in CMIP6 or CMIP5
Recent studies have found that terrestrial dryness indices like the Palmer Drought Severity Index (PDSI), Standardized Precipitation Evapotranspiration Index (SPEI), and Aridity Index calculated from future climate model projections are mostly negative, implying a drying land surface with warming. Y...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2021-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/abd8fd |
| _version_ | 1797747831716446208 |
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| author | Jacob Scheff Justin S Mankin Sloan Coats Haibo Liu |
| author_facet | Jacob Scheff Justin S Mankin Sloan Coats Haibo Liu |
| author_sort | Jacob Scheff |
| collection | DOAJ |
| description | Recent studies have found that terrestrial dryness indices like the Palmer Drought Severity Index (PDSI), Standardized Precipitation Evapotranspiration Index (SPEI), and Aridity Index calculated from future climate model projections are mostly negative, implying a drying land surface with warming. Yet, the same models’ future runoff and bulk soil moisture projections instead show regional signals of varying sign, and their vegetation projections show widespread greening, suggesting that the dryness indices could overstate climate change’s direct impacts. Most modeling studies have attributed this gap to the indices’ omission of CO _2 -driven stomatal closure. However, here we show that the index-impact gap is still wide even in future-like model experiments that switch off CO _2 effects on plants. In these simulations, mean PDSI, Aridity Index, and SPEI still decline broadly with strong warming, while mean runoff, bulk soil moisture, and vegetation still respond more equivocally. This implies that CO _2 -plant effects are not the dominant or sole reason for the simulated index-impact gap. We discuss several alternative mechanisms that may explain it. |
| first_indexed | 2024-03-12T15:57:13Z |
| format | Article |
| id | doaj.art-f48dff3b11614121b59bbb1754a5f4de |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:57:13Z |
| publishDate | 2021-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-f48dff3b11614121b59bbb1754a5f4de2023-08-09T14:53:31ZengIOP PublishingEnvironmental Research Letters1748-93262021-01-0116303401810.1088/1748-9326/abd8fdCO2-plant effects do not account for the gap between dryness indices and projected dryness impacts in CMIP6 or CMIP5Jacob Scheff 0https://orcid.org/0000-0003-1294-3447Justin S Mankin1https://orcid.org/0000-0003-2520-4555Sloan Coats2Haibo Liu3Department of Geography and Earth Sciences, University of North Carolina Charlotte , Charlotte, NC, United States of AmericaDepartment of Geography and Department of Earth Sciences, Dartmouth College , Hanover, NH, United States of America; Lamont-Doherty Earth Observatory , Columbia University, Palisades, NY, United States of AmericaDepartment of Earth Sciences, University of Hawai’i at Mānoa , Honolulu, HI, United States of AmericaLamont-Doherty Earth Observatory , Columbia University, Palisades, NY, United States of AmericaRecent studies have found that terrestrial dryness indices like the Palmer Drought Severity Index (PDSI), Standardized Precipitation Evapotranspiration Index (SPEI), and Aridity Index calculated from future climate model projections are mostly negative, implying a drying land surface with warming. Yet, the same models’ future runoff and bulk soil moisture projections instead show regional signals of varying sign, and their vegetation projections show widespread greening, suggesting that the dryness indices could overstate climate change’s direct impacts. Most modeling studies have attributed this gap to the indices’ omission of CO _2 -driven stomatal closure. However, here we show that the index-impact gap is still wide even in future-like model experiments that switch off CO _2 effects on plants. In these simulations, mean PDSI, Aridity Index, and SPEI still decline broadly with strong warming, while mean runoff, bulk soil moisture, and vegetation still respond more equivocally. This implies that CO _2 -plant effects are not the dominant or sole reason for the simulated index-impact gap. We discuss several alternative mechanisms that may explain it.https://doi.org/10.1088/1748-9326/abd8fdclimate changedroughtaridityCO2-plant effectsEarth system modelsfuture projections |
| spellingShingle | Jacob Scheff Justin S Mankin Sloan Coats Haibo Liu CO2-plant effects do not account for the gap between dryness indices and projected dryness impacts in CMIP6 or CMIP5 Environmental Research Letters climate change drought aridity CO2-plant effects Earth system models future projections |
| title | CO2-plant effects do not account for the gap between dryness indices and projected dryness impacts in CMIP6 or CMIP5 |
| title_full | CO2-plant effects do not account for the gap between dryness indices and projected dryness impacts in CMIP6 or CMIP5 |
| title_fullStr | CO2-plant effects do not account for the gap between dryness indices and projected dryness impacts in CMIP6 or CMIP5 |
| title_full_unstemmed | CO2-plant effects do not account for the gap between dryness indices and projected dryness impacts in CMIP6 or CMIP5 |
| title_short | CO2-plant effects do not account for the gap between dryness indices and projected dryness impacts in CMIP6 or CMIP5 |
| title_sort | co2 plant effects do not account for the gap between dryness indices and projected dryness impacts in cmip6 or cmip5 |
| topic | climate change drought aridity CO2-plant effects Earth system models future projections |
| url | https://doi.org/10.1088/1748-9326/abd8fd |
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