What is Climate Change?

How to Deal with Climate Change
Many factors contribute to climate change.  The earth’s orbit and its relationship with the sun and also the planets is one contributing factor. Variations in air flows and air masses, positions of landforms all influence climate change and have for thousands of years.

Factors that cause Climate Change can include:

  • Oceanic Circulation (thermohaline circulation, movement of water, heat redistribution, etc.)
  • Solar Radiation (warming of the ocean temperature, melting sea ice, etc.)
  • Magnetic Field
  • Earth’s Orbit (the tilt angle of the earth’s axis – rotation)
  • Plate Tectonics (mountain formation, continental drifts, etc.)
  • Volcanic Activities (volcanic ash blocking sunlight, etc.)
  • Asteroids, comets or meteor impact (collapse of food chains, addition of dust and particles – inhibiting photosynthesis, precipitation of sulphur-oxides – acid rain, etc.)
  • Human Impacts
Examples of Some Types of Climate Change Events
  • Glaciation and Ice Loss
  • Flora and Fauna (decomposition of plants – coal formation, phytoplankton, photosynthesis – glaciation, Great Oxygenation Event (GOE), extinction of plants, vertebrates and invertebrates etc.)
  • Rise and Fall of Sea Level (global cooling, sinking of mid-ocean ridges, mass extinctions, etc.)
  • Permafrost

Ozone depletion
The ozone is one of the most important filters of the UV radiation emitted by the sun.
Although the ozone belongs to an atmospheric layer between 10 and 50 kilometres high (stratosphere), it is easily affected by anthropogenic activities.

Global Warming and Greenhouse Effect
The occurrence of global warming is increasing very fast nowadays. Much of it is due to ‘man-made’ greenhouse gases, which in turn, create and increase what we call ‘greenhouse effect’. As half of the atmospheres solar radiation is transmitted as short wave radiations (UV) and absorbed by the earth surface, a part of it is radiated back into the atmosphere as long wave radiation (IR) and absorbed by suspended air particles, such as clouds and air pollution, rather than being re-emitted through the atmosphere. This ‘trapping’ of heat causes a rise of temperature in the atmosphere and the surface of the earth.

There are many different greenhouse gases, but the most important ones are:

  • Water vapour
  • Carbon dioxide (CO2)
  • Nitrous oxide (N2O)
  • Methane (CH4)
  • Chlorofluorocarbons (CFC’s)

A great part of these gases come from natural sources. For example, more than half of the nitrous oxide in the atmosphere originates from the ocean and soil; marshlands and swamps as well as grazing cattle and termites are responsible for at least one-fourth of the world’s methane emissions. Conversely, mining, the burning of fossil fuels, deforestation, industry growth, agricultural farming and other human activities account for approximately 75% of the increase in greenhouse gases.

Due to the rise in air temperature, global warming has been known to affect the level and volume of the ocean (‘thermal expansion’). The melting of glaciers cause a rise in sea levels (approximately 25 centimetres in the last 100 years, and is expected to rise another 25 cm by the end of the year 2000), which can lead to natural disasters such as severe erosion, inland floods, disappearance of wetlands, and disturbance of beaches and coastal lifestyles. The temperatures are expected to raise approximately 3oC in the next 100 years, which may seem insignificant at first glance, but the last glaciation era ended due to this same outcome.

An overheated earth’s surface due to greenhouse effects also brings about a rise in water vapour, creating an increase on the formation of clouds. These clouds will help prevent an excess of solar radiation penetrating the earth and will play a major role in cooling down the temperature that had been caused by greenhouse gas effects, avoiding, this way, an increase towards ‘global warming’. However, to global warming variations can highly affect precipitation patterns; while in some areas there may be an excess of rainfall, in others there may be more droughts, causing formation of swamps and extinctions of plant and animal species, respectively.

Cold waters act as one of the world’s major CO2 gas reductors, however, the more the temperature tends to rise on the earth, the less effective this natural mechanism becomes. Due to this effect, the excess of CO2 tends to concentrate in the atmosphere rather than being absorbed and recycled by the ocean, creating an increase in the greenhouse effect.
 

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