Climate Variability and Change, their Impacts on Marine Life and Ecosystems

Abstract

The climate system is made up of five subsystems with coupling mechanisms represented by feedbacks between its components. Changes in the climate system result from internal and external forcers. Oceanic and atmospheric circulations transfer heat from tropical to polar regions and El Niño-Southern Oscillation (ENSO) is an example of the variability in atmospheric circulation and ocean-atmosphere interactions. Agricultural and industrial development based on fossil fuels have altered Earth’s subsystems and biogeochemical cycles, leading to a new geologic epoch, the Anthropocene. The anthropic increase of greenhouse gases ( CO2 , methane) results in the recent global warming. In the oceans, this has manifested as increased surface thermal stratification and marine heatwaves. Warming has affected the distribution range of organisms, led to temperature- and stratification-induced changes in phytoplankton, and altered the phenology of marine communities. The increase in short-wave UV radiation stemmed from the depletion of stratospheric ozone, or the decreasing pH trend resulting from absorption of excess CO2 by seawater (ocean acidification) are other examples of climatic changes that affect marine organisms differentially. Climate change became a matter of interest to society only recently. The biological pump and blue Carbon ecosystems are regarded as natural ocean-driven mechanisms/environments to palliate its effects.