Rare ground data confirm significant warming and drying in western equatorial Africa
Background The humid tropical forests of Central Africa influence weather worldwide and play a major role in the global carbon cycle. However, they are also an ecological anomaly, with evergreen forests dominating the western equatorial region despite less than 2,000 mm total annual rainfall. Meteor...
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PeerJ Inc.
2020-04-01
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| Online Access: | https://peerj.com/articles/8732.pdf |
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| author | Emma R. Bush Kathryn Jeffery Nils Bunnefeld Caroline Tutin Ruth Musgrave Ghislain Moussavou Vianet Mihindou Yadvinder Malhi David Lehmann Josué Edzang Ndong Loïc Makaga Katharine Abernethy |
| author_facet | Emma R. Bush Kathryn Jeffery Nils Bunnefeld Caroline Tutin Ruth Musgrave Ghislain Moussavou Vianet Mihindou Yadvinder Malhi David Lehmann Josué Edzang Ndong Loïc Makaga Katharine Abernethy |
| author_sort | Emma R. Bush |
| collection | DOAJ |
| description | Background The humid tropical forests of Central Africa influence weather worldwide and play a major role in the global carbon cycle. However, they are also an ecological anomaly, with evergreen forests dominating the western equatorial region despite less than 2,000 mm total annual rainfall. Meteorological data for Central Africa are notoriously sparse and incomplete and there are substantial issues with satellite-derived data because of persistent cloudiness and inability to ground-truth estimates. Long-term climate observations are urgently needed to verify regional climate and vegetation models, shed light on the mechanisms that drive climatic variability and assess the viability of evergreen forests under future climate scenarios. Methods We have the rare opportunity to analyse a 34 year dataset of rainfall and temperature (and shorter periods of absolute humidity, wind speed, solar radiation and aerosol optical depth) from Lopé National Park, a long-term ecological research site in Gabon, western equatorial Africa. We used (generalized) linear mixed models and spectral analyses to assess seasonal and inter-annual variation, long-term trends and oceanic influences on local weather patterns. Results Lopé’s weather is characterised by a cool, light-deficient, long dry season. Long-term climatic means have changed significantly over the last 34 years, with warming occurring at a rate of +0.25 °C per decade (minimum daily temperature) and drying at a rate of −75 mm per decade (total annual rainfall). Inter-annual climatic variability at Lopé is highly influenced by global weather patterns. Sea surface temperatures of the Pacific and Atlantic oceans have strong coherence with Lopé temperature and rainfall on multi-annual scales. Conclusions The Lopé long-term weather record has not previously been made public and is of high value in such a data poor region. Our results support regional analyses of climatic seasonality, long-term warming and the influences of the oceans on temperature and rainfall variability. However, warming has occurred more rapidly than the regional products suggest and while there remains much uncertainty in the wider region, rainfall has declined over the last three decades at Lopé. The association between rainfall and the Atlantic cold tongue at Lopé lends some support for the ‘dry’ models of climate change for the region. In the context of a rapidly warming and drying climate, urgent research is needed into the sensitivity of dry season clouds to ocean temperatures and the viability of humid evergreen forests in this dry region should the clouds disappear. |
| first_indexed | 2024-03-09T08:04:49Z |
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| id | doaj.art-c9fd326e9fa04c4d85d8b1078e33a3ee |
| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T08:04:49Z |
| publishDate | 2020-04-01 |
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| spelling | doaj.art-c9fd326e9fa04c4d85d8b1078e33a3ee2023-12-03T00:25:51ZengPeerJ Inc.PeerJ2167-83592020-04-018e873210.7717/peerj.8732Rare ground data confirm significant warming and drying in western equatorial AfricaEmma R. Bush0Kathryn Jeffery1Nils Bunnefeld2Caroline Tutin3Ruth Musgrave4Ghislain Moussavou5Vianet Mihindou6Yadvinder Malhi7David Lehmann8Josué Edzang Ndong9Loïc Makaga10Katharine Abernethy11Faculty of Natural Sciences, University of Stirling, Stirling, UKFaculty of Natural Sciences, University of Stirling, Stirling, UKFaculty of Natural Sciences, University of Stirling, Stirling, UKFaculty of Natural Sciences, University of Stirling, Stirling, UKElephant Protection Initiative, London, UKAgence Gabonaise d’Études et d’Observation Spatiale (AGEOS), Libreville, GabonAgence Nationale des Parcs Nationaux (ANPN), Libreville, GabonEnvironmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UKFaculty of Natural Sciences, University of Stirling, Stirling, UKAgence Nationale des Parcs Nationaux (ANPN), Libreville, GabonAgence Nationale des Parcs Nationaux (ANPN), Libreville, GabonFaculty of Natural Sciences, University of Stirling, Stirling, UKBackground The humid tropical forests of Central Africa influence weather worldwide and play a major role in the global carbon cycle. However, they are also an ecological anomaly, with evergreen forests dominating the western equatorial region despite less than 2,000 mm total annual rainfall. Meteorological data for Central Africa are notoriously sparse and incomplete and there are substantial issues with satellite-derived data because of persistent cloudiness and inability to ground-truth estimates. Long-term climate observations are urgently needed to verify regional climate and vegetation models, shed light on the mechanisms that drive climatic variability and assess the viability of evergreen forests under future climate scenarios. Methods We have the rare opportunity to analyse a 34 year dataset of rainfall and temperature (and shorter periods of absolute humidity, wind speed, solar radiation and aerosol optical depth) from Lopé National Park, a long-term ecological research site in Gabon, western equatorial Africa. We used (generalized) linear mixed models and spectral analyses to assess seasonal and inter-annual variation, long-term trends and oceanic influences on local weather patterns. Results Lopé’s weather is characterised by a cool, light-deficient, long dry season. Long-term climatic means have changed significantly over the last 34 years, with warming occurring at a rate of +0.25 °C per decade (minimum daily temperature) and drying at a rate of −75 mm per decade (total annual rainfall). Inter-annual climatic variability at Lopé is highly influenced by global weather patterns. Sea surface temperatures of the Pacific and Atlantic oceans have strong coherence with Lopé temperature and rainfall on multi-annual scales. Conclusions The Lopé long-term weather record has not previously been made public and is of high value in such a data poor region. Our results support regional analyses of climatic seasonality, long-term warming and the influences of the oceans on temperature and rainfall variability. However, warming has occurred more rapidly than the regional products suggest and while there remains much uncertainty in the wider region, rainfall has declined over the last three decades at Lopé. The association between rainfall and the Atlantic cold tongue at Lopé lends some support for the ‘dry’ models of climate change for the region. In the context of a rapidly warming and drying climate, urgent research is needed into the sensitivity of dry season clouds to ocean temperatures and the viability of humid evergreen forests in this dry region should the clouds disappear.https://peerj.com/articles/8732.pdfClimate changeTropical forestsCentral AfricaGabonLopéWarming |
| spellingShingle | Emma R. Bush Kathryn Jeffery Nils Bunnefeld Caroline Tutin Ruth Musgrave Ghislain Moussavou Vianet Mihindou Yadvinder Malhi David Lehmann Josué Edzang Ndong Loïc Makaga Katharine Abernethy Rare ground data confirm significant warming and drying in western equatorial Africa PeerJ Climate change Tropical forests Central Africa Gabon Lopé Warming |
| title | Rare ground data confirm significant warming and drying in western equatorial Africa |
| title_full | Rare ground data confirm significant warming and drying in western equatorial Africa |
| title_fullStr | Rare ground data confirm significant warming and drying in western equatorial Africa |
| title_full_unstemmed | Rare ground data confirm significant warming and drying in western equatorial Africa |
| title_short | Rare ground data confirm significant warming and drying in western equatorial Africa |
| title_sort | rare ground data confirm significant warming and drying in western equatorial africa |
| topic | Climate change Tropical forests Central Africa Gabon Lopé Warming |
| url | https://peerj.com/articles/8732.pdf |
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