The ocean plays a major role in regulating climate by storing and transferring heat around the globe, absorbing carbon dioxide, and influencing cloud cover and precipitation. The burning of fossil fuels is causing excessive amounts of carbon dioxide to accumulate and trap excess heat in the Earth system, resulting in climate change. Ocean warming dominates the energy stored in the Earth system in the last 40-50 years and accounts for approximately 93% of the excess heat accumulated between 1971 and 2010. This warming has a direct impact on the ocean and is projected to create critical hazards for many ocean ecosystems and coastal communities by causing sea level rise, thermal stress and oxygen loss.
Sustained ocean observations are key to understanding the ocean’s role in climate and predicting regional and global climate. Data and information from ocean observations is and will continue to play a major role in manager and policy maker decisions on how to respond to and and mitigating global climate change.
Sea Level Rise
Climate change causes sea level rises due to the thermal expansion of water as it warms and the melting of land ice. the In a warming earth, sea level will most likely rise for over 95% of the global ocean with areas near glaciers and ice sheets likely to experience sea level fall (because land rises with the reduced weight of melting ice) by 2100. Greenhouse gases in the last 200 years have committed us to millennia of sea level rise. The pace and magnitude at which seas will permanently flood and reconfigure present-day coastal ecosystems will have profound consequences on human societies. Earth observations allow scientists to track sea level rise and make predictions for regional seal level rise. This information allows managers and policy makers to make informed decisions about efforts to reduce greenhouse gas emissions and management of coastal communities.
Warming oceans can cause thermal stress in a variety of marine organisms including ecologically important coral reefs. When corals are stressed by changes in temperature, light or nutrient levels they can expel the symbiotic algae living in their tissues. This process, referred to as coral bleaching is commonly caused by thermal stress. While corals can recover from bleaching events, the likelihood of recovery decreases under extended periods of stress. Monitoring ocean temperatures allows scientists to predict and track thermal stress in marine organisms.
Decreasing Ocean Oxygen Levels
One of the major climate stressor of open ocean ecosystems is a loss of oxygen content caused by decreased absorption of oxygen by warmer water, decreased ocean mixing in some areas and changes in biological activity. The concentration of dissolved oxygen is a major determinant of the distribution and abundance of marine species globally. Open ocean oxygen loss has already been recorded in nearly all ocean basins during the second half of the 20th century. Ocean observations provide data and information that allows scientists to track this climate change side effect and determine its impacts on marine ecosystems.