The models of climate change on marine ecosystems

Home Focus The models of climate change on marine ecosystems

Modelling is a necessary tool for assessing future impacts of climate change. A major comparative study Sarmiento simulated the effect of greenhouse gas emissions using six Atmosphere-Ocean General Circulation Models (AOGCMs) to examine which aspects of the models determine how ocean biology responds to climate. 
The study compared “realistic” emission scenarios for the period from pre-industrial to 2050 and 2090 with a control in which emissions remained at pre-industrial levels. 
In Namibia, mariculture never been a thing of the past as it was widely accepted by locals since its inception and the potential involved to increase the production, include the 1500km largely uninhabited coastline, unpolluted high quality marine waters, high natural primary productivity of the seawater, 
However, factors such as the lack of finance and the lack of interest by financial institutions to finance fish farmers as well as innovative and strategised promotion mechanisms might hamper the future expansions and development of this sector. 
Most Namibian coastal towns such as Walvis Bay and Lüderitz serve as the pillar of marine resource exploitation creating job opportunities and contribute highly to the GDP of the country as fishing sector is one of the important back bones of the Namibian economy. 
Namibia has a favorable condition for marine aquaculture and thus Lüderitz result as one of the ideal place for the exploitation of economic species such as Oysters, mussels and abalone etc. A strategised project need to be implemented that will serve as the catalyst in pin pointing vulnerabilities within the community and identify strategic mechanisms through which the community can be strengthen in order to ensure a sustainable livelihoods, food security job creation and nutrition. 
In conclusion potential individual capable of changes and amendment of strategies in accordance with the changing climatic condition are thus needed to carry out the task of environmental adjustment. 
Climate change in the 21st century could trigger fundamental and catastrophic aspects of marine ecosystem and could not be realised by many until after such century. We may summarise potential effects of climate change on fish harvests as follows:  

1) Climate change is likely to reduce the abundance of some species while increasing the abundance of others.  
2) Changes in harvests. As the abundance of a species changes, fishermen will catch more or fewer fish. 
3) Changes in fishing and processing employment. Changes in harvests affect employment opportunities in fish harvesting and processing industries.  
4) Changes in prices. Fisheries markets are highly sensitive to supply. Changes in harvests tend to have opposite effects on prices, 
5) Social stresses. Changes, particularly reductions, in income and employment may contribute to a wide variety of family and community stresses. 
6) Political conflict. Changing relative harvest levels can upset the political balance in agreements over allocation of mixed-stock fisheries both national and beyond borders. Changes in the physical environment, such as weather and ice conditions, may affect where and when fishing is physically possible as well as the costs of fishing.

Almost all of the studies exhausted estimate that there will be increasing adverse impact beyond an approximate 3-4 degree Celsius in global mean temperature. 
A continuous observation and analysis need to be carried out that will lay the foundation for improved management of fisheries and marine ecosystems therefore management advice must include a complete and transparent information on risk and uncertainties which arise from data quality and from structural deficiencies in the assessment models. 
In many instance adaptation measure are well known by marine farmers cooperate advisers and decision makers, but political will and action is often lacking thus creating a circle of under-development of the sector as the three sphere of life (social, economic and political) cannot be  separated.  

•Reverend Jan Scholtz is the //Kharas regional chairperson and !Nami#nus constituency councillor and is a holder of Diploma in Theology, B-Theo (SA), a Diploma in Youth Work and Development from the University of Zambia (UNZA), Diploma in Education III (KOK) BA (HED) from UNISA. (This article is written in his personal capacity).