The majority of scientists are in agreement that global warming is occurring and is caused by human activities over the last two hundred years or so. Global warming is caused by the build up in the atmosphere of gases such as methane, carbon dioxide, nitrous oxide and others which have been created by the burning of fossil fuels in order to produce electricity, and for use in industries and motor vehicles. Another contribution to global is the removal of vast areas of natural forest from the planet. . The majority of carbon dioxide exchange between the atmosphere and the earth takes place in tropical forests. These environments are a sink for most of the world’s carbon. Forests are the interface for the exchange of gases between the atmosphere and the earth and deforestation has also vastly reduced this interface. The Intergovernmental Panel on Climate Change, (IPCC), formed by the UN in 1988, warns that “humanity is warming the globe to a degree that will threaten much of the world's population over the next century.”. Not only will it affect the world’s human population, but global warming is already having a major impact on the animal populations of the planet. Increases in ocean water temperatures make marine species, particularly vulnerable to climate change and the majority of this paper will be given to discussion of the animals which inhabit marine environments.
Response of Animals to Climate Change
Research has shown that four types of changes in the traits of any species may be possibly due to global warming, all of which ultimately relate to a response to a shift in temperature. At any given location, the range of species may shift either towards the poles or to higher elevations as species move to occupy areas which are compatible with their temperature tolerances. Changes in density of species may also occur. It was also found that because traits of many species are triggered by cues related to temperature, the timings of certain events such as egg-laying or migration can be affected by global warming. The researchers also discovered that morphological changes, such as body size and behavior, may occur and that distribution of genetic frequencies may also alter.
Other potential impacts of global warming on animal species include changes in community interactions, in metabolic rates of the species and extinctions. These changes apply to all cases of the species discussed in the following paper.
Marine Animals and Climate Change
Because temperatures have risen more rapidly in the mid and high latitudes of the Northern Hemisphere, these are the areas predicted to be the most affected due to climate change. Since the 1980s, temperatures have risen more rapidly in the Arctic than in other regions, and this has manifested itself in a change in whale behavior in the region. Global warming will have a detrimental effect on whales in a number of ways. The biggest impact will probably be the loss of sea ice, which will reduce suitable feeding habitats and areas for resting and breeding . Shifts in the species upon which whales prey, and changes to the food web, may cause whales to lose body condition and make them more susceptible to disease. Food sources can also become more concentrated in contaminants which whales cannot tolerate. Any reduction in sea ice will probably result in an increased anthropogenic presence in the Arctic, which will make whales more vulnerable to boat strikes, entanglement in fishing equipment and acoustic pollution . Changes in migration routes and breeding timings may also occur due to the loss of sea ice caused by global warming. Scientists have also found that sightings of particular whale species have been occurring at greater distances from their normal ranges, suggesting that the North Atlantic and Pacific ecosystems may be becoming mixed due to the depletion of sea ice. This could have lasting detrimental effects on the stability of whale populations. The long history of exploitation of the North Atlantic right whale has meant it was one of the most endangered of all the whales. Only between 300 and 350 animals still survive, and as global waters warm and contain less plankton, their source of food is being reduced, this causing increased mortality
Other marine species are also vulnerable to ocean warming caused by climate change. Marine fish and invertebrates respond to warmer temperatures by shifting to higher latitudes and into deeper waters. This will impact on global fisheries and have implications for their sustainable management and for the food security of some economies. In marine fish, climate change affects abundance and distribution, community structure, body size and trophic interactions. Studies have predicted that many coastal fisheries are particularly vulnerable to the effects of climate change, and that redistribution of fisheries catches is likely, particularly in tropical regions. One example of the effect of climate change on species redistribution is the recent and rapid increase in the warm-water red mullet (Mullus barbatus) catches, in waters surrounding the UK and UK fish stocks that used to bcommonlyon found in southern English waters have now moved as far north as the Shetland and Orkney Islands. Continual warming of tropical waters will cause fish to migrate to cooler waters once their thermal tolerance is reached. This will severely impact tropical fishing communities, particularly in developing countries, which are most vulnerable to the effects of climate change.
Whilst sea turtles suffer massive losses from the time their offspring are hatched, until they reach maturity, they face additional threats to their existence due to global warming. Turtles lay their eggs in nests on sandy beaches and return every year to the same nesting site. The predicted sea level rises could destroy these sites, leaving the turtles with nowhere to nest. Climate change will also affect the sex ratio of turtles, because it is the temperature of the nest that strongly determines the sex of the offspring. Cooler sites produce males, warmer sites produce females. Since climate change is likely to result in a change of range for turtles, and many other species, the choice of cooler sites over warmer sites is likely to have serious implications for turtle populations.
Corals live within a very narrow temperature range and are therefore particularly vulnerable to thermal increases in ocean water. Scientists have recently become particularly perturbed by the coral “bleaching” events which are occurring on Australia’s Great Barrier Reef in response to warmer ocean temperatures. Bleaching is an inaccurate term, because the coral is not bleached, but rather has ejected is zooxanthellae, the photosynthetic algae living within coral tissue, which gives coral its color. A mutualistic relationship between the coral and the zooxanthellae occurs where the algae is provided with protection and the elements needed for photosynthesis. In nutrient-poor tropical waters, the algae provide the oxygen and nutrients necessary for the coral’s metabolic functions and for reef building. The depth of water in which corals grow is also vitally important to their survival. Corals need light to survive and the growth of most corals is limited to the euphotic zone, which has maximum light penetration.. This means that any rise in sea level will decrease the light available for coral to survive and reproduce.
Greenhouse gas emissions have increased the amount of carbon dioxide (CO2) in the atmosphere. Atmospheric CO2 is absorbed by ocean water and is then converted to carbonic acid. Increased ocean acidification is responsible for dissolving the carbonate framework which comprises the foundation of a coral reef.
In the Caribbean, in Puerto Rico and in other tropical parts of the world, coral reefs are suffering the same fate. Although over the millions of years of their existence, reefs have cycled through deaths and rebirths due to global warming and cooling, this was an outcome of a natural global cyclical process of climate change. Today, however, the process of climate change is very rapid, man-made and its outcomes are unpredictable. Coral reefs are important breeding grounds and sources of marine biodiversity. They also are fundamental in providing one quarter of the annual fisheries catch which feeds over one billion people. The reefs also provide economic benefits from tourism and provide a barrier to coastlines from storm surge. They are also a source of vital elements from which medicines are produced and many scientists believe that coral reefs will provide many, as yet undiscovered, cures for diseases.
Terrestrial Animals and Climate Change
Mass extinction of wild animal species could possibly occur and species are globally affected. The polar bear is dependent on sea ice, using it as a platform from which to hunt prey. With the loss of sea ice currently occurring in the Artic, at approximately 9 percent per decade, not only is the polar bear’s hunting range reduced, but there is a real possibility that polar bears could become stranded as ice floes break away from the ice sheets.
The future of China’s giant panda is unclear as global warming is affecting their staple food source, bamboo. As part of a delicate ecosystem that is being affected by climate change, and living in small fragmented populations, isolated from one another, the giant panda is particularly vulnerable to any changes in their ecosystem brought about by global warming .
. The Sumatran orangutan is listed as critically endangered on the Red List of Threatened Species published by the International Union for the Conservation of Nature (IUCN). As global warming increases the frequency and duration of droughts in Indonesia, wildfires occur frequently and further fragment the orangutans’ habitat, which has already been disrupted by both illegal and legal logging. The prognosis for their future is very bleak .
More frequent and long dry periods caused by global warming are placing strain on the continued existence of the African elephant. Their range has already been reduced due to land conversion, and this is causing fragmentation of habitat and bringing the elephant into conflict with humans. They are already considered to be vulnerable and although many effective measures have been put in place, they are still being poached for their ivory.
In India, there are fewer than 3200 tigers left in the wild. The largest habitats for India’s remaining tigers are the coastal mangrove forests. Competition for resources, loss of habitat and poaching have already diminished their numbers and scientists fear that any projected sea level rise due to global warming could completely destroy the majority of their habitats, causing extinction of the species.
Many Australian frog species are particularly vulnerable to a reduction in the availability of water. As with all species discussed in this paper, climate change has had an effect on their abundance, their home range and their breeding cycles. Global warming has caused the drying out of pools in which frogs breed, resulting in the death of eggs and tadpoles. Hotter, drier conditions causes increased rates of dermal transpiration in frogs, often resulting in their deaths.
Other critical outcomes on animal species are expected to occur. Following is a list of just some of them.
Large numbers of reindeer are expected to disappear from their ranges within the next 100 years.
The young offspring of elephant seal pups are thinner because their prey is migrating to cooler waters.
Mollusks living in warm southern tidal zones are retreating northward to cooler waters .
Some birds in North America are laying their eggs much earlier than they were half a century ago
It can be seen that the effects of climate change have an enormous impact on the animal populations of the planet. Many face extinction; most face reduction in their ranges and others will need to find different sources of food. Unless the global community works together to reduce temperature increases to less than 2 (C as agreed at the recent Paris Conference on Climate Change, the existence of animal life on this planet, and consequently our own, is doomed.
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