Are there connections between the Earth's magnetic field and climate? |
| |
| Affiliation: | 1. Paléomagnétisme et Géomagnétisme, Institut de Physique du Globe de Paris, Institut de recherches associé au CNRS, 4 place Jussieu, 75231 Paris Cedex 05, France;2. Centre de Recherche et de Restauration des Musées de France, France;1. Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0225, USA;2. Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum – GFZ Telegrafenberg, D-14473 Potsdam, Germany;1. Department of Geology and Earth Environmental Sciences, Chungnam National University, Daejeon, 305-764, Republic of Korea;2. Department of Cultural Heritage Conservation Sciences, Kongju National University, Kongju, 314-701, Republic of Korea;3. Department of Earth and Environmental Sciences, Korea University, Seoul, 136-713, Republic of Korea;4. Deep-sea and Marine Georesources Research Department, Korea Institute of Ocean Science and Technology, Ansan, 426-744, Republic of Korea;5. Department of Cultural Heritage Excavation and Conservation, Dongyang University, Youngju, 750-711, Republic of Korea;1. Istituto Nazionale di Geofisica e Vulcanologia, Via Vigna Murata, 605, 00143 Roma, Italy;2. Departamento Física de la Tierra I, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Avd. Complutense s/n, 28040 Madrid, Spain;3. Instituto de Geociencias (IGEO), CSIC, UCM, Ciudad Universitaria, 28040 Madrid, Spain;4. Observatori de lʼEbre (OE), CSIC – Universitat Ramon Llull, Horta Alta 38, 43520 Roquetes, Spain;5. Università G. DʼAnnunzio, Via dei Vestini 31, 66013 Chieti, Italy;1. Institut de Physique du Globe de Paris, Université Paris Diderot, Sorbonne Paris-Cité, UMR 7154 CNRS, 1 rue Jussieu, 75238 Paris Cedex 05, France;2. Laboratoire des Sciences du Climat et de l''Environnement (CEA-CNRS-UVSQ), Domaine du CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France;3. Aix-Marseille Université, CNRS-IRD-Collège de France, UM 34 CEREGE, Technopôle de l''Environnement Arbois-Méditerranée, BP80, 13545 Aix-en-Provence, France |
| |
| Abstract: | Understanding climate change is an active topic of research. Much of the observed increase in global surface temperature over the past 150 years occurred prior to the 1940s and after the 1980s. The main causes invoked are solar variability, changes in atmospheric greenhouse gas content or sulfur due to natural or anthropogenic action, or internal variability of the coupled ocean–atmosphere system. Magnetism has seldom been invoked, and evidence for connections between climate and magnetic field variations have received little attention. We review evidence for correlations which could suggest such (causal or non-causal) connections at various time scales (recent secular variation ∼ 10–100 yr, historical and archeomagnetic change ∼ 100–5000 yr, and excursions and reversals ∼ 103–106 yr), and attempt to suggest mechanisms. Evidence for correlations, which invoke Milankovic forcing in the core, either directly or through changes in ice distribution and moments of inertia of the Earth, is still tenuous. Correlation between decadal changes in amplitude of geomagnetic variations of external origin, solar irradiance and global temperature is stronger. It suggests that solar irradiance could have been a major forcing function of climate until the mid-1980s, when “anomalous” warming becomes apparent. The most intriguing feature may be the recently proposed archeomagnetic jerks, i.e. fairly abrupt (∼ 100 yr long) geomagnetic field variations found at irregular intervals over the past few millennia, using the archeological record from Europe to the Middle East. These seem to correlate with significant climatic events in the eastern North Atlantic region. A proposed mechanism involves variations in the geometry of the geomagnetic field (f.i. tilt of the dipole to lower latitudes), resulting in enhanced cosmic-ray induced nucleation of clouds. No forcing factor, be it changes in CO2 concentration in the atmosphere or changes in cosmic ray flux modulated by solar activity and geomagnetism, or possibly other factors, can at present be neglected or shown to be the overwhelming single driver of climate change in past centuries. Intensive data acquisition is required to further probe indications that the Earth's and Sun's magnetic fields may have significant bearing on climate change at certain time scales. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
