يؤثر الاحتباس الحراري على المحيطات من عدة نواحٍ، إذ يمكن أن تكون له أثار على مستويات سطح البحر، والسواحل، وتحمض المحيطات، وتيارات المحيط، ومياه البحر، ودرجات حرارة سطح البحر، والمد والجزر، وقاع البحر، والطقس، بالإضافة لتحفيز العديد من التغييرات في الكيمياء الحيوية للمحيطات؛ وكل هذه الأمور تؤثر على سير المجتمع. (ar)
Among the effects of climate change on oceans are: an increase in sea surface temperature as well as ocean temperatures at greater depths, more frequent marine heatwaves, a reduction in pH value, a rise in sea level from ocean warming and ice sheet melting, sea ice decline in the Arctic, increased upper ocean stratification, reductions in oxygen levels, increased contrasts in salinity (salty areas becoming saltier and fresher areas becoming less salty), changes to ocean currents including a weakening of the Atlantic meridional overturning circulation, and stronger tropical cyclones and monsoons. All these changes have knock-on effects which disturb marine ecosystems. The root cause of these observed changes is the Earth warming due to anthropogenic emissions of greenhouse gases, such as for example carbon dioxide and methane. This leads inevitably to ocean warming, because the ocean is taking up most of the additional heat in the climate system. Some of the additional carbon dioxide in the atmosphere is taken up by the ocean (via carbon sequestration), which leads to ocean acidification of the ocean water. It is estimated that the ocean takes up roughly a quarter of total anthropogenic CO2 emissions. Warming of the ocean surface due to higher air temperatures leads to increased ocean temperature stratification. The decline in mixing of the ocean layers stabilises warm water near the surface while reducing cold, deep water circulation. The reduced up and down mixing reduces the ability of the ocean to absorb heat, directing a larger fraction of future warming toward the atmosphere and land. Energy available for tropical cyclones and other storms is expected to increase, nutrients for fish in the upper ocean layers are set to decrease, as is the capacity of the oceans to store carbon. Warmer water cannot contain as much oxygen as cold water. As a result, the gas exchange equilibrium changes to reduce ocean oxygen levels and increase oxygen in the atmosphere. Increased thermal stratification may lead to reduced supply of oxygen from the surface waters to deeper waters, and therefore further decrease the water's oxygen content. The ocean has already lost oxygen throughout the water column, and oxygen minimum zones are expanding worldwide. These changes disturb marine ecosystems, which can accelerate species extinctions or create population explosions, thus changing the distribution of species, and impact coastal fishing and tourism. Increase of water temperature will also have a devastating effect on various oceanic ecosystems, such as coral reefs. The direct effect is the coral bleaching of these reefs, which live within a narrow temperature margin, so a small increase in temperature would have a drastic effect in these environments. Ocean acidification and temperature rise will also affect the productivity and distribution of species within the ocean, threatening fisheries and disrupting marine ecosystems. Loss of sea ice habitats due to warming will severely impact the many polar species which depend on this sea ice. Many of these climate change pressures interact, compounding the pressures on the climate system and on ocean ecosystems. (en)
Les effets du réchauffement climatique sur les océans fournissent des informations sur les différents effets du réchauffement climatique sur les océans. Le réchauffement climatique peut affecter le niveau de la mer, les côtes, l'acidification des océans, les courants océaniques, l'eau de mer, les températures de surface de la mer, les marées, le fond marin, les conditions météorologiques et déclencher plusieurs changements dans la bio-géochimie des océans ; tous ces éléments affectent le fonctionnement d'une société. (fr)
يؤثر الاحتباس الحراري على المحيطات من عدة نواحٍ، إذ يمكن أن تكون له أثار على مستويات سطح البحر، والسواحل، وتحمض المحيطات، وتيارات المحيط، ومياه البحر، ودرجات حرارة سطح البحر، والمد والجزر، وقاع البحر، والطقس، بالإضافة لتحفيز العديد من التغييرات في الكيمياء الحيوية للمحيطات؛ وكل هذه الأمور تؤثر على سير المجتمع. (ar)
Les effets du réchauffement climatique sur les océans fournissent des informations sur les différents effets du réchauffement climatique sur les océans. Le réchauffement climatique peut affecter le niveau de la mer, les côtes, l'acidification des océans, les courants océaniques, l'eau de mer, les températures de surface de la mer, les marées, le fond marin, les conditions météorologiques et déclencher plusieurs changements dans la bio-géochimie des océans ; tous ces éléments affectent le fonctionnement d'une société. (fr)
Among the effects of climate change on oceans are: an increase in sea surface temperature as well as ocean temperatures at greater depths, more frequent marine heatwaves, a reduction in pH value, a rise in sea level from ocean warming and ice sheet melting, sea ice decline in the Arctic, increased upper ocean stratification, reductions in oxygen levels, increased contrasts in salinity (salty areas becoming saltier and fresher areas becoming less salty), changes to ocean currents including a weakening of the Atlantic meridional overturning circulation, and stronger tropical cyclones and monsoons. All these changes have knock-on effects which disturb marine ecosystems. The root cause of these observed changes is the Earth warming due to anthropogenic emissions of greenhouse gases, such as fo (en)