Open Oceans
Potential climate change impacts on open oceans to consider include:
- sea temperature rise:
- accelerated warming of high altitudes and reduced seasonal sea ice zones;
- increasing stratification of ocean layers;
- changes in winds and currents;
- decreasing surface oxygen concentrations;
- sea level rise;
- biological implications:
- pelagic systems (changing species distribution, timing of peak production, regime shifts, reduced fish production);
- polar and ice-edge (sea ice and habitat loss, increasing primary production and associated trophic responses, physiological impacts leading to species range changes/extinctions);
- deep seas ( changes in carbon flux from surface impact deep sea community composition).
- ocean acidification:
- reduced pH;
- broad changes in seawater chemistry;
- impacts on marine biology:
- pelagic systems (altered plankton calcification);
- polar and ice-edge (detrimental carbonate conditions for planktons, and food web consequences).
- ocean deoxygenation:
- increase in coastal hypoxia;
- declining oxygen level in tropical areas;
- formation of "dead zones"
- carbon storage in the ocean: the uptake of CO2 into the ocean is outstripping its capacity to absorb it, which if continued may cause more severe acidification and carbonate dissolution
| Oceanic climate change policy |
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Historically it has been difficult to estimate the oceanic anthropogenic CO2 sink. However there has been much progress over the last decade in measuring oceanic CO2 and other properties to constrain the net oceanic CO2 sink. As long as atmospheric CO2 concentrations are increasing the ocean will attempt to equilibrate and in doing so will absorb a portion of this anthropogenically produced CO2. The best example of a place where the gross natural ocean is a large source of CO2, but represents a net sink for anthropogenic CO2 is in the equatorial Pacific Ocean. The coastal ocean is an important part of the global carbon cycle and it will be important to further explore the CO2 source/sink debate in the future. The policy analyses from this paper would extend to the coastal ocean, however it is far more difficult to determine the anthropogenic CO2 uptake within this regime given its heterogeneous nature. There is no doubt however that human activities both on the adjacent coastal land and also within the open ocean could have the potential to change the EEZ anthropogenic CO2 sink. Oceanic implications for climate change policy, Environmental Science and Policy, 9, 2006 (Ref. Doc. 21) |
| Fisheries |
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Evidence of the impacts of anthropogenic climate change on marine ecosystems is accumulating, but must be evaluated in the context of the “normal” climate cycles and variability which have caused fluctuations in fisheries throughout human history. The impacts on fisheries are due to a variety of direct and indirect effects of a number of physical and chemical factors, which include temperature, winds, vertical mixing, salinity, oxygen, pH and others. The direct effects act on the physiology, development rates, reproduction, behaviour and survival of individuals and can in some cases be studied experimentally and in controlled conditions. Indirect effects act via ecosystem processes and changes in the production of food or abundance of competitors, predators and pathogens. Recent studies of the effects of climate on primary production are reviewed and the consequences for fisheries production are evaluated through regional examples. Regional examples are also used to show changes in distribution and phenology of plankton and fish, which are attributed to climate. The role of discontinuous and extreme events (regime shifts, exceptional warm periods) is discussed. Changes in fish population processes can be investigated in experiments and by analysis of field data, particularly by assembling comparative data from regional examples. Although our existing knowledge is in many respects incomplete it nevertheless provides an adequate basis for improved management of fisheries and of marine ecosystems and for adapting to climate change. In order to adapt to changing climate, future monitoring and research must be closely linked to responsive, flexible and reflexive management systems. Impacts of climate change on fisheries, Journal of Marine Systems, 79, 2010 (Ref. Doc. 53) |
See Documents 1, 2, 3, 12, 13, 18, 21, 53, 61, and 62 for more information.
