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Climate change
 

Climate change

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    Climate change Climate change Document Transcript

    • Major Assignment GE102Name: Ruci BatiriID: S11079617
    • Climate ChangeClimate, driven by the solar energy that warns the Earth and causes circulation of the atmosphereand oceans, is defines according to meteorological parameters (e.g., air temperature, rainfall, andhumidity); and exhibits natural variability. Climate is one of the two most important physicalfactors (the other being topography) determining the survival and nature of all living beings,from individuals and communities to populations and entire species, by heavily influencing thenatural systems on which they depend. This essay is about the effects in global climate that willimpact coastal environments which are sea-level rise, low-elevation and changes in oceancurrents. It will then conclude on the impacts of global climate change on coral reefs.Climatechange is defined by the Convention as “change of climate which is ascribed directly orindirectly to human activity that changesthe composition of the global atmosphere and which isin additional to natural climate variability observed over comparable time periods.Source: GoogleTo begin with climate change has affected the coastal environment greatly. Coasts are affectedby two main types of influences, terrestrial and marine, that are considered external to the coastalzone. Terrestrial influences are mostly anthropogenic in nature. They include land use changesand all the consequences of changing hydrological regimes and nutrient loading from sedimenttransport, runoff and reduction of sediments through rivers for instance, from dam and channelconstruction and extraction of river an upstream. The phenology and behavior of many speciesare linked to climate variables such as temperature, climate change will potentially lead to wide-ranging impacts on coastal ecosystems. These are some of the factors that will affect coastal
    • environments which is sea-level rise will lead to inundation of parts of the coastal zone,accelerated erosion and saline into coastal waterways and wetlands. Another factor is the low-elevation coastal deltas, floodplains and estuaries will be affected and sea grass, mangroves andsaltmarshes are particularly vulnerable to sea-level rise.Source: GoogleAdditionally, human activities are increasingly altering the Earth’s climate. These effects add tonatural influences that have been present over Earth’s history. Scientific evidence stronglyindicates that natural influences cannot explain the rapid increase in global near-surfacetemperatures observed during the second half of the 20th century. Human impacts on the climatesystem include increasing concentrations of atmospheric greenhouse gases (such as carbondioxide, chlorofluorocarbons and their substitutes, methane, nitrous oxide etc.), air pollution,increasing concentrations of airborne particles, and land alteration. A particular concern is thatatmospheric levels of carbon dioxide may be rising faster than at any time in Earth’s history,except possibly following rare events like impacts from large extraterrestrial objects. The globalclimate is changing and human activities are contributing to that change. Scientific research isrequired to improve our ability to predict around the globe. Scientific research provides a basisfor mitigating the harmful effects of global climate change through decreased human influences(e.g., slowing greenhouse gas emissions, improving land management practices), technologicaladvancement(e.g., removing carbon from the atmosphere), and finding ways for communities to
    • adapt and become resilient to extreme events.Source: GoogleFurthermore, global warming from increasing levels of greenhouse gases is expected to haveserious effects on the Pacific Ocean. The Pacific islands view climate change as a major disasterand have openly and continuously criticized the industrial nations for failure to take definitivesteps toward abating pollution of the global atmosphere. There are three distinct impacts fromthis pollution; global warning, sea level rise and climate change. Firstly, global warming fromincreasing levels of greenhouse gasses is expected to have serious effects on the Pacific Ocean.Temperature also regulates the distribution of plants and animals. Pelagic fish commonly migratealong temperature boundaries and, in some cases; this can result in fish moving away fromtraditional fishing areas. Samoa, for example, is on the edge of major tuna migrations and fishingsuccess can oscillate from extreme success to failure depending on ocean temperatureregimes.Secondly, global warning in most Pacific Islands, the people, agricultural land, tourists’resorts and infrastructure are concentrated in the coastal zones, and are thus vulnerable to anyrise in sea level. Determining how severe this problem is, or might be, is complicated by naturalshifts in sea level. For instance, over the past 16,000 years, the sea level rose some 150 meters inthe Southwest Pacific reaching its present about 6,000 years ago. Global warming is causing arise in sea level from thermal expansion as the sea warms up and from the melting of the planet’sice caps. Thirdly, the climate change that will shift rainfall patterns causing prolonged droughtsin some regions. El Nino weather patterns have become frequent since 1977, bringing anincrease in rainfall in the Northwest Pacific and a rainfall decrease in the Southwest. Each ElNino event has resulted in water shortages and drought in Papua New Guinea, Marshall Islands,Samoa, Tonga, Kiribati and Fiji. More frequent El Nino events also bring an increased risk oftropical cyclones, particularly for Tuvalu, Samoa, Tonga, Cook Islands and French Polynesia.
    • Source: GoogleMoreover, coastal ecosystems are repositories of biological diversity and provide a wide range ofgoods and services. Coral reefs are particularly important because they provide living space andsubsistence fisheries for millions of people who have developed unique cultures based aroundreef resources. It is also particularly important geographic components for many countries asthey support islands, protect fragile coastlines from wave and current erosion, permit the growthof mangroves and wetlands and effect the placing of the boundaries of Exclusive EconomicZones (EEZ) which in turn affects access to fisheries and seabed mineral resources. These aresome causes of the degrading of coral reefs. Corals, stressed by high temperatures, may ejecttheir symbiotic algae. Coral bleaching, as this is called, renders the corals less able to cope withadditional physiological stress and many of the colonies die. The current growth and futurefunctioning of coral reefs have been, and always be, intricately linked with climate and climatechange. Variations in climate will clearly affect coral reef s in the future as they have donethroughout the geological past. The changes that are occurring, particularly to the atmosphere butalso to land and sea are part of the increasing human impact on the global environment through,for instance, the enhanced greenhouse effect and damage to the protective ozone layer of theupper atmosphere. To date, the majority of damage to coral reefs around the world has beenthrough direct anthropogenic stress-the pressure applied by people to coral reefs. The majorcauses of damages are: excessive pollution from domestic, industrial and agricultural waste; poorland use practices, which increase the amounts of land derived sediments flowing onto coralreefs: and over exploitation, particularly through damaging practices such as dynamite and muro-ami fishing, which are often used to catch fish and other animals from coral reefs that are alreadyoverexploited. Coral reefs are dynamic, integrated ecosystems with the mineral constructionshared by animals and plants. With this versatility comes high diversity and complexity. Withtheir environmental setting also comes vulnerability because reefs can only exist close to the air-sea interface in warm seas or air, or on landmasses that interact with the sea, are likely to havemarked influences on the reef ecosystem.Source: Google
    • In conclusion, we are just beginning to understand the changes that we have wrought on themassive and highly complex system that is climate of our planet. We do not completelyunderstand its workings and therefore are beset with the uncertainties of climate science,specifically how accurate our climate projections will prove. Even though it is commonly agreedthat more accurate regional climate models would enable better decision making, dissentingviews insist that we do not have to wait to adopt meaningful strategies to cope with climatechange.