Global warming refers to the continous
rising in the average temperature of the Earth’s climate system. It is the
current change in Earth’s climate. It also refers to the increase in the
average temperature of air and sea at the Earth’s surface. Since 1971, 90% of
the warming has occured in the ocean. That is why ocean is the right place to
start understanding global warming phenomenon which occured in our blue planet.
Global warming affects the global conveyor belt and other physical properties
of ocean water.
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| The Global Conveyor Belt Source: http://science.howstuffworks.com/ |
What is the global conveyor belt? It is
the deep ocean current which is driven by density differences in the sea water.
It is also called thermohaline circulation because water density affects by its
temperature (thermo) and salinity (haline). Density is an object’s mass per
unit volume. Colder and saltier water equals denser water. When water freezes, salt does not necessarily
freeze with it. So, at the earth’s pole, large volume of dense cold and salt
water is left behind. This large volume of water sinks to the bottom and other
large volume of water replace it, creating a current. This other large volume
of water will get cold and sinks continuing the cycle. That is why the global
conveyor belt starts near the North Pole and goes to south between America and
Africa toward Antartica, partly directed by the land they face. In Antartica,
it enchanced by more cold water and divided into two direction; one of it goes
to the Indian Ocean and the other goes to the Pacific Ocean. Because both of
them is close to equator, it warms up and goes to the surface; this phenomenon
is called upwelling. When they encounter land and cannot go any farther, it
turns back to the South Atlantic Ocean and finally gets back to the North
Atlantic Ocean. Then the cycle starts again. It takes 1,000 years to complete
one full cycle around the globe.
Climate change like global warming
affects the ocean. First, it makes the ocean warmer because the ocean absorb
80% of the heat added to the Earth’s system. Second, rising in greenhouse gases
as one of the cause of global warming, causing increased atmospheric
temperature which cause the iceberg at the poles and glaciers to melt Third, the first and second effect I have
mention cause sea water level to rise. Fourth, changes in ocean temperature and
wind patterns as the result of overall climate change, will affect and change
the ocean’s major current system which is the global conveyor belt I have
explained in the second paragraph. Increased precipitation and the widespread
of ice melting caused by global warming could create a larger layer of fresh
water that would slow or prevent normal thermohaline mixing that occurs and
would affect the current offshore from Greenland and Newfoundland. The normal thermohaline circulation has
suddenly stopped and recovered in the past, causing the climate to keep
changing from warm to cold to become warm again. Fifth, the burning of fossil
fuels that increases greenhouse gas level in the atmosphere, is also changing
the chemical composition of sea water, making it more acidic.
In conclusion, if you want to learn
global warming phenomenon, it is better to learn it from the ocean, from the
physical phenomenon that happens in the ocean. Global warming affects a lot of
aspect in the ocean. It affects the temperature of the ocean and the polar ice
to melt. These events lead to the rising of sea water level. Change in ocean
temperature, wind patterns, increased precipitation, and the melting of ice
would affect and change the global conveyor belt. Besides that, the burning of
fossil fuels that causes global warming, also makes sea water more acidic.
Data Sources:
http://en.wikipedia.org/wiki/Global_warming
http://science.howstuffworks.com/environmental/earth/oceanography/ocean-current3.htm
http://www.conservation.org/Documents/Climate%20Change%20on%20the%20Ocean.pdf
http://www.neaq.org/conservation_and_research/climate_change/climate_change_and_the_oceans.php
