Is a wet-bulb temperature of 35 ∘C the correct threshold for human survivability?
A wet-bulb temperature of 35 ^∘ C is widely used as the threshold for human survivability, but the wet-bulb temperature is not a particularly accurate metric for human heat stress. For a person in the shade, a more accurate metric is the heat index, which is based on a model of human thermoregulatio...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ace83c |
| _version_ | 1797736080908222464 |
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| author | Yi-Chuan Lu David M Romps |
| author_facet | Yi-Chuan Lu David M Romps |
| author_sort | Yi-Chuan Lu |
| collection | DOAJ |
| description | A wet-bulb temperature of 35 ^∘ C is widely used as the threshold for human survivability, but the wet-bulb temperature is not a particularly accurate metric for human heat stress. For a person in the shade, a more accurate metric is the heat index, which is based on a model of human thermoregulation that accounts for metabolic heat, radiation, respiratory ventilation, and finite wind speeds. The heat index has two critical values: the highest heat index for which a healthy core temperature can be maintained and the highest heat index that is survivable. It is shown here that a wet-bulb temperature of 35 ^∘ C corresponds to conditions between these two critical values. For example, in a world warmer than pre-industrial by 10 ^∘ C, about 30% of the world’s population would be exposed once or more per year to a wet-bulb temperature above 35 ^∘ C, but the heat index reveals that less than 2% would be exposed to fatal conditions while over 60% would be exposed to conditions that would cause hyperthermia. |
| first_indexed | 2024-03-12T13:08:26Z |
| format | Article |
| id | doaj.art-73c43878270c4048abc359a2ea0b0466 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T13:08:26Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-73c43878270c4048abc359a2ea0b04662023-08-28T11:14:13ZengIOP PublishingEnvironmental Research Letters1748-93262023-01-0118909402110.1088/1748-9326/ace83cIs a wet-bulb temperature of 35 ∘C the correct threshold for human survivability?Yi-Chuan Lu0https://orcid.org/0000-0003-3659-1474David M Romps1https://orcid.org/0000-0001-7649-5175Department of Physics, University of California, Berkeley , Berkeley, CA, United States of America; Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, CA, United States of AmericaClimate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, CA, United States of America; Department of Earth and Planetary Science, University of California, Berkeley , Berkeley, CA, United States of AmericaA wet-bulb temperature of 35 ^∘ C is widely used as the threshold for human survivability, but the wet-bulb temperature is not a particularly accurate metric for human heat stress. For a person in the shade, a more accurate metric is the heat index, which is based on a model of human thermoregulation that accounts for metabolic heat, radiation, respiratory ventilation, and finite wind speeds. The heat index has two critical values: the highest heat index for which a healthy core temperature can be maintained and the highest heat index that is survivable. It is shown here that a wet-bulb temperature of 35 ^∘ C corresponds to conditions between these two critical values. For example, in a world warmer than pre-industrial by 10 ^∘ C, about 30% of the world’s population would be exposed once or more per year to a wet-bulb temperature above 35 ^∘ C, but the heat index reveals that less than 2% would be exposed to fatal conditions while over 60% would be exposed to conditions that would cause hyperthermia.https://doi.org/10.1088/1748-9326/ace83cheat indexwet-bulb temperaturesurvivability |
| spellingShingle | Yi-Chuan Lu David M Romps Is a wet-bulb temperature of 35 ∘C the correct threshold for human survivability? Environmental Research Letters heat index wet-bulb temperature survivability |
| title | Is a wet-bulb temperature of 35 ∘C the correct threshold for human survivability? |
| title_full | Is a wet-bulb temperature of 35 ∘C the correct threshold for human survivability? |
| title_fullStr | Is a wet-bulb temperature of 35 ∘C the correct threshold for human survivability? |
| title_full_unstemmed | Is a wet-bulb temperature of 35 ∘C the correct threshold for human survivability? |
| title_short | Is a wet-bulb temperature of 35 ∘C the correct threshold for human survivability? |
| title_sort | is a wet bulb temperature of 35 ∘c the correct threshold for human survivability |
| topic | heat index wet-bulb temperature survivability |
| url | https://doi.org/10.1088/1748-9326/ace83c |
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