Positive degree-day sums in the Alps: a direct link between glacier melt and international climate policy
Annual balances of eight alpine glaciers were slightly negative for 1961–90 and highly negative for 1991–2018. We explain this by changes in positive degree-day sums and summer temperatures extrapolated to the median altitudes of the glaciers. We test a new way of calculating degree-day sums that pe...
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2022-10-01
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| Series: | Journal of Glaciology |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143021001404/type/journal_article |
| _version_ | 1811155742034493440 |
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| author | Roger J. Braithwaite Philip D. Hughes |
| author_facet | Roger J. Braithwaite Philip D. Hughes |
| author_sort | Roger J. Braithwaite |
| collection | DOAJ |
| description | Annual balances of eight alpine glaciers were slightly negative for 1961–90 and highly negative for 1991–2018. We explain this by changes in positive degree-day sums and summer temperatures extrapolated to the median altitudes of the glaciers. We test a new way of calculating degree-day sums that performs better than the traditional method which used daily mean temperatures. Annual degree-day sums are highly correlated with May–September temperatures as suggested in 1866 by Karl von Sonklar. We find moderate correlations between annual balances and degree-day sums, and with May–September temperatures. Calculated degree-day factors for the eight glaciers cover the reported range for snow and ice ablation, while the temperature sensitivity of annual balance is from −0.4 to −1.0 m w.e. for a +1°C temperature change. We accurately predict mean balances for 1991–2018 using May–September temperatures in regression models calibrated for 1961–90. May–September temperatures in the Alps have already increased ~+3°C since 1880 and, if temperatures continue to rise, these glaciers will shrink rapidly. As annual balances are already negative for present-day temperatures, these glaciers will not be ‘safe’ under the further temperature increase permitted by the Paris Agreement. |
| first_indexed | 2024-04-10T04:39:39Z |
| format | Article |
| id | doaj.art-7ad4ecb798f140998f4d410a139f93d1 |
| institution | Directory Open Access Journal |
| issn | 0022-1430 1727-5652 |
| language | English |
| last_indexed | 2024-04-10T04:39:39Z |
| publishDate | 2022-10-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj.art-7ad4ecb798f140998f4d410a139f93d12023-03-09T12:41:19ZengCambridge University PressJournal of Glaciology0022-14301727-56522022-10-016890191110.1017/jog.2021.140Positive degree-day sums in the Alps: a direct link between glacier melt and international climate policyRoger J. Braithwaite0https://orcid.org/0000-0002-0387-7591Philip D. Hughes1Department of Geography, School of Environment, Education and Development (SEED), University of Manchester, Manchester M13 9PL, UKDepartment of Geography, School of Environment, Education and Development (SEED), University of Manchester, Manchester M13 9PL, UKAnnual balances of eight alpine glaciers were slightly negative for 1961–90 and highly negative for 1991–2018. We explain this by changes in positive degree-day sums and summer temperatures extrapolated to the median altitudes of the glaciers. We test a new way of calculating degree-day sums that performs better than the traditional method which used daily mean temperatures. Annual degree-day sums are highly correlated with May–September temperatures as suggested in 1866 by Karl von Sonklar. We find moderate correlations between annual balances and degree-day sums, and with May–September temperatures. Calculated degree-day factors for the eight glaciers cover the reported range for snow and ice ablation, while the temperature sensitivity of annual balance is from −0.4 to −1.0 m w.e. for a +1°C temperature change. We accurately predict mean balances for 1991–2018 using May–September temperatures in regression models calibrated for 1961–90. May–September temperatures in the Alps have already increased ~+3°C since 1880 and, if temperatures continue to rise, these glaciers will shrink rapidly. As annual balances are already negative for present-day temperatures, these glaciers will not be ‘safe’ under the further temperature increase permitted by the Paris Agreement.https://www.cambridge.org/core/product/identifier/S0022143021001404/type/journal_articleClimate changeglacier mass balanceglacier meteorology |
| spellingShingle | Roger J. Braithwaite Philip D. Hughes Positive degree-day sums in the Alps: a direct link between glacier melt and international climate policy Journal of Glaciology Climate change glacier mass balance glacier meteorology |
| title | Positive degree-day sums in the Alps: a direct link between glacier melt and international climate policy |
| title_full | Positive degree-day sums in the Alps: a direct link between glacier melt and international climate policy |
| title_fullStr | Positive degree-day sums in the Alps: a direct link between glacier melt and international climate policy |
| title_full_unstemmed | Positive degree-day sums in the Alps: a direct link between glacier melt and international climate policy |
| title_short | Positive degree-day sums in the Alps: a direct link between glacier melt and international climate policy |
| title_sort | positive degree day sums in the alps a direct link between glacier melt and international climate policy |
| topic | Climate change glacier mass balance glacier meteorology |
| url | https://www.cambridge.org/core/product/identifier/S0022143021001404/type/journal_article |
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