Climate change has moved to front and center of the world’s environmental agenda. Global warming is the major of all the changes of climate that stand as a disaster against world’s fisheries. Global warming is an increase in the earth’s atmospheric and oceanic temperatures widely predicted to occur due to an increase in the greenhouse effect resulting especially from pollution. Global warming is expected to lead to an increase in marine diseases, harmful algal blooms, more-extreme rainfall patterns and stronger hurricanes, all of which would have a significant impact on the state’s prime fisheries. Global warming poses a potentially lethal threat to many fish species and would further add to problems already caused by over fishing and coastal pollution.
Surface water temperature had risen by about 10ºC over the past century and was expected to increase by up to another three degrees in the next 100 years if emissions caused mainly by the burning of fossil fuels continued at current rates. The ocean has huge potential as a carbon sink. The ocean is vast and hence has huge potential as a carbon sink. According to the IPCC Third Assessment Report (2001), an estimated 6.3 billion tons of carbon is released into the atmosphere every year through human activities, such as combustion of fossil fuels, approximately half of which (3.1 billion tons) is absorbed by Earth. The ocean ecosystem is thought to absorb 1.7 billion tons and the terrestrial ecosystem is thought to absorb 1.4 billion tons of carbon. From 2005-2008, the air temperature of north and South Pole was increased 3-4ºc because of Carbon absorption and presence of greenhouse gases in the atmosphere. According to Grace Satellite, every year 189 billion ice is melting in the ocean. GEO-Science and IPCC (2007) reported that the height of sea level will increase to 18-59cm till Year 2100 because of the present rate of ice-melting. It is the worst news for Bangladesh that “GERMANY-WATCH” reported recently that Bangladesh is the first and foremost vulnerable in the world because of the negative climatic change globally. Negotiations aimed at reducing greenhouse gas emissions (COP 15) was determined in the global convention among 192 countries in Copenhagen from 7-19 December, 2009 where the countries are aimed to take an account of the present global warming impacts on developing countries and to reduce the emission of greenhouse gases mainly carbon gases to <30% from the current greenhouse gas emission rate, in the first world countries. The convention was the biggest disappointment because of the non-cooperative and rational performance of the first world nations. The result of this failure will be definitely devastating for the developing and small island countries in way of saving their existence within the future world’s climatic change. In this convention, Bangladesh stood against the negative impact of climatic change with a slogan “STAND BESIDE BANGLADESH: VICTIM OF CLIMATIC CHANGE”. Presently the carbon density limit may be <350ppm and the air temperature may be +1.5ºc is declared for the future decades for developing countries like Bangladesh. In 2050 the air temperature may be +1.5ºc and sea level will increase to 45cm in Bangladesh which create the possibility to float majority coastal part of the country. In 2050, salinity of water of the coastal zone of Bangladesh will increase more than (40+5 to 7ppt) and in 2100, that will be (40 +7 to 11ppt).This devastating situation will create 200million climate refugee in 2050. In COP-15 convention, the climamatic compensation fund is declaimed 30 billion dollar for developing countries of the world and a promise was made to sanction another 100 billion dollar through 2050. EU (2009) declared 10.6 billion dollar for climamatic compensation fund for Bangladesh in Copenhagen Convention which is a lump sum to handle the future destruction of country. In present situation, it is to be sincerely verified for a developing country like Bangladesh, what is or will be the impact of global warming on fish and fisheries.
The impact of global warming on inland fisheries is beyond discussion. As the surrounding water warms up, their metabolism speeds up they digest food more rapidly, grow more quickly, and have more energy to reproduce. But fish need more food and more oxygen to support this higher metabolism. Warmer fish tend to mature more quickly, but the cost of this speedy lifestyle is often a smaller body size. They also hatch much earlier (and smaller), and reach sexual maturity earlier. This will cause a drift in genetic resource of fish and other aquatic commercial species and reduces the desired production of target species. Another problem that shown by global warming is the changing levels of precipitation where rainfall decreases, more possibility of droughts or floods, damage to productive assets (fish ponds, weirs, rice fields, etc.) ensures and less predictable wet/dry seasons which could lead to the extinction of up to 20 freshwater species that are found nowhere else in the world.
Impacts of global warming on coastal fisheries are varies such as wetland loss, salinity changes, and higher temperatures are all likely to affect finfish and shellfish in the coastal zone. However, rising sea level may substantially diminish the critical coastal habitats. A number of commercial & non-commercial marine species are vulnerable to the inundation and erosion of coastal habitat. As climate warms, fish might be able to migrate to other areas, as long as they cannot find a suitable place for spawning and for fish seed nursery.
The discussion on global warming and marine fisheries also need a floor today. Key marine organisms, such as deep-water corals and pteropods (shelled pelagic mollusks) will be profoundly affected by this phenomenon during the years to come. If the key organisms one day disappear, their natural predators will be forced to migrate elsewhere for food sources. Again, Coral reefs have proved to be particularly sensitive to warming. As surface temperatures have risen in recent years, many reefs have bleached, and with further increasing temperatures over longer periods the corals die. Global warming itself may be increasing the frequency of El Nino. According to WWF (2005), El Nino has wreaked havoc in stocks of sardines and anchovies in Peru, marine iguanas and kelp forests off California.
Today it is a well known truth that the COP-15 convention-2009 was failed to fulfill its aim to save the world. In the near future it obvious that we will be the silent witness of the greatest vandalism the world could ever saw.
References
- Broad, K., Pfaff, A.S.P. and Glantz, M.H. (1999) Climate Information and Conflicting Goals: El Nin˜o 1997-98 and the Peruvian Fishery. Public Philosophy, Environment, and Social Justice. Carnegie Council on Ethics and International Affairs, New York.
- IPCC (2001a) Climate Change 2001: Impacts, Adaptation & Vulnerability, Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Vol. Cambridge University Press, Cambridge.
- IPCC (2007) Climate Change 2007: The Physical Science Basis. Summary for Policymakers. Intergovernmental Panel on Climate Change, Geneva, 18pp.
- Report published in the daily Protom Alo, 13th, 14th & 19th December, 2009.
- www.panda.org/climate/fish
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