GLOBAL WARMING

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CLIMATE CHANGE AND OCEANS
Water has a very high specific heat capacity. This means that a lot of energy is needed to increase its temperature. As the Earth is 71% water, energy from the sun causes only small changes in the planet's temperature. This stops the Earth getting too hot or too cold and makes conditions possible for life. Heat is stored by the ocean in summer and released back to the atmosphere in winter. Oceans, therefore, moderate climate by reducing the temperature differences between seasons.
Global warming
Rising temperature
The largest carbon store on Earth is in sediments, both on land and in the oceans, and it is held mainly as calcium carbonate. The second biggest store is the deep ocean where carbon occurs mostly as dissolved carbonate and hydrogen carbonate ions. About a third of the carbon dioxide from fossil fuel burning is stored in the oceans and it enters by both physical and biological processes:
1. Physical Process: Carbon dioxide dissolves more easily in cold water than in warm water. It also dissolves more easily in seawater compared to pure water because seawater naturally contains carbonate ions. Cold waters sink to the deep ocean at high latitudes in the Southern Ocean and in the Nordic and Labrador Seas in the North Atlantic Ocean. These regions are therefore the major physical carbon dioxide removal areas of the ocean.
2. Biological Process: Carbon dioxide is also taken up by phytoplankton in photosynthesis and converted into plant material. Land plants and marine phytoplankton take up about the same amounts of carbon dioxide as each other but marine phytoplanktons grow much faster than land plants.
•Sufferers
By burning fossil fuels, we are releasing carbon about a million times faster than natural biological cycles do. Forests and phytoplankton can't take up the carbon dioxide fast enough to keep up with the increases in emissions and atmospheric carbon dioxide levels have, therefore, risen dramatically over the past few decades.

CONSEQUENCES OF GLOBAL WARMING ON OCEANS:---- Global warming is likely to have a number of effects on the ocean:-----Carbon dioxide dissolves more easily in cold water than in warm water so warmer temperatures will reduce the ability of the oceans to take up carbon dioxide and this will further enhance the greenhouse effect.
2. Higher temperatures are also predicted to increase the input of freshwater into the high latitude oceans. Computer models suggest that this additional freshwater comes from increased rain at mid and high latitudes and from the melting of ice sheets.
3. Ocean circulation is very sensitive to the amount of freshwater entering the system. Freshwater controls the density of seawater and therefore the ability of seawater to sink when it is cooled. If the water is too fresh, cooling won't make it dense enough to sink into the deep ocean. If water doesn't sink at high latitudes there is only wind driven forcing and therefore reduced water circulation around the oceans.
Global warming and Ocean
•Impacts on oceans
4. Warmer temperatures also cause expansion of water and, along with the additional water from ice melt, will result in a rise in sea level and may cause flooding.
5. Excess CO2 absorbed by the oceans will lead to formation of carbonic acid. This acidification will have detrimental effect shell forming creatures like the corals because it will reduce the ability of carbonate ions in the ocean needed to form shell.
6. Will lead to migration of tropical marine creatures towards temperate areas thus disturbing the food chain, food availability and biodiversity of a region. 
Researchers have found that rising temperatures in the world’s oceans will affect the development of the plankton on which most marine life feeds. It has been demonstrated that the increasing warmth caused by a changing climate will upset the natural cycles of carbon dioxide, nitrogen and phosphorous. This will affect the plankton, making it scarcer and so causing problems for fish and other species higher up the food chain.


GLOBAL WARMING & OZONE LAYER:--
Chlorofluorocarbons (CFCs) play a role in both global warming and ozone-hole formation. In the troposphere, they act as greenhouse gases. They absorb infra-red radiation coming from the surface of the Earth and, by trapping this heat close to the Earth they contribute to global warming. In the stratosphere they are broken down by high intensity ultra-violet radiation from the Sun into chlorine radicals and these have the ability destroy ozone. Other greenhouse gases, such as carbon dioxide and methane, do not have a comparable role in ozone depletion.
•Ozone layer

Since ozone prevents high intensity ultra-violet radiation from reaching the surface of the Earth and causes stratospheric warming, it can be assumed that formation of the ozone hole changes the total radiation budget of the Earth. This is, indeed, the case. However, ozone depletion and the formation of the polar ozone holes don’t lead to a further warming of the troposphere, but to a slight cooling.

•GLOBAL WARMING AND IT'S IMPACT ON OZONE LAYER:-----
1. Absorption of ultra-violet radiation by ozone molecules causes warming in the stratosphere. Some of this heat emitted in the stratosphere is transferred to the troposphere causing slight tropospheric warming as well. This warming gets lessened due to formation of ozone hole.
2. In the lower stratosphere, ozone can still act as a greenhouse gas and absorb infra-red radiation coming from the Earth's surface. So absorption of both ultra-violet and infra-red radiation by ozone leads to a warming of the upper troposphere. If ozone levels decrease, the upper troposphere will, therefore, get cooler.
3. Backscattering of solar radiation is particularly strong over the Antarctic where the strongest ozone depletion occurs. This is because the snow and ice covered ground has a very high albedo. Because of this high backscattering, only a small fraction of the extra ultra-violet radiation that enters the troposphere from ozone loss causes heating.
Overall, the cooling effect of ozone loss is the highest and decreases in ozone levels cause cooling not only in the stratosphere but also slight cooling in the troposphere.

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