Human caused climate change
Climate change has occurred throughout geological history and has been a major force for evolution. It is now evident that in recent time, 63% of greenhouse gases responsible for climate change originate from human-induced carbon dioxide and human-caused climate change is substantially affecting species, populations and communities of aquatic animals and vegetation throughout the wild.
Aquatic systems are affected by human-caused climate change in the following ways: (1) increasing sea surface temperature; (2) greater warming of water around 500m depth; (3) increases in incident solar radiation; (4) rise in sea level; (5) greater stratification and shallowing of the mixed layer, causing reduction in nutrient inputs from deeper waters; (6) an increase in surface winds resulting in extreme wind events; (7) a general decline in surface currents; (8) slowing down of the thermohaline circulation; (9) a change in seawater chemistry, including a decline in pH; and (10) changing rainfall causing fluctuations in salinity in seawater environments and flow in freshwater environments. In addition, shifts in aquatic systems significantly impact on aquatic species in a number of ways, including: distribution change of indigenous and non-indigenous species causing native species that are not currently threatened to become threatened; local extinction of endemic aquatic species; shifts in abundance, distribution and seasonality, shifts in spawning cues and mortality.