Global Warming- A Warning

What is Global Warming?

Global warming is the increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation. As the Earth is getting hotter, disasters like hurricanes, droughts and floods are getting more frequent. Over the last 100 years, the average temperature of the air near the Earth´s surface has risen a little less than 1° Celsius (0.74 ± 0.18°C, or 1.3 ± 0.32° Fahrenheit).

Causes of Global Warming

Almost 100% of the observed temperature increase over the last 50 years has been due to the increase in the atmosphere of greenhouse gas concentrations like water vapour, carbon dioxide (CO2), methane and ozone. Greenhouse gases are those gases that contribute to the greenhouse effect (see below). The largest contributing source of greenhouse gas is the burning of fossil fuels leading to the emission of carbon dioxide.

The Greenhouse Effect

When sunlight reaches Earth's surface some is absorbed and warms the earth and most of the rest is radiated back to the atmosphere at a longer wavelength than the sun light. Some of these longer wavelengths are absorbed by greenhouse gases in the atmosphere before they are lost to space. The absorption of this longwave radiant energy warms the atmosphere. These greenhouse gases act like a mirror and reflect back to the Earth some of the heat energy which would otherwise be lost to space. The reflecting back of heat energy by the atmosphere is called the "greenhouse effect".

Without it, the Earth's average temperature would be a chilling -18 degrees Celsius, even despite the sun's constant energy supply. In a world like this life on Earth would probably have never emerged from the sea. Thanks to the greenhouse effect, however, heat emitted from the Earth is trapped in the atmosphere, providing us with a comfortable average temperature of 14 degrees. Sunrays enter the glass roof and walls of a greenhouse. But once they heat up the ground, which in turn heats up the air inside the greenhouse, the glass panels trap that warm air and temperatures increase. But our planet has no glass walls; the only thing that comes close to acting as such is our atmosphere. But unfortunately, in here, processes are way more complicated.

Global warming causes by Greenhouse effect

Greenhouse gases in the atmosphere (see above) act like a mirror and reflect back to the Earth a part of the heat radiation, which would otherwise be lost to space. The higher the concentration of green house gases like carbon dioxide in the atmosphere, the more heat energy is being reflected back to the Earth. The emission of carbon dioxide into the environment mainly from burning of fossil fuels (oil, gas, petrol, kerosene, etc.) has been increased dramatically over the past 50 years, see given graph.

Effects of Global Warming

The major eefect of global warming is increase of temperature on the earth by about 3° to 5° C (34° to 41° Fahrenheit) by the year 2100.

Some impacts from increasing temperatures are already happening.

* Ice is melting worldwide, especially at the Earth's poles. This includes mountain glaciers, ice sheets covering West Antarctica and Greenland, and Arctic sea ice.
* Researcher Bill Fraser has tracked the decline of the Adélie penguins on Antarctica, where their numbers have fallen from 32,000 breeding pairs to 11,000 in 30 years.
* Sea level rise became faster over the last century.
* Some butterflies, foxes, and alpine plants have moved farther north or to higher, cooler areas.
* Precipitation (rain and snowfall) has increased across the globe, on average.
* Spruce bark beetles have boomed in Alaska thanks to 20 years of warm summers. The insects have chewed up 4 million acres of spruce trees.

Other effects could happen later this century, if warming continues.

* Sea levels are expected to rise between 7 and 23 inches (18 and 59 centimeters) by the end of the century, and continued melting at the poles could add between 4
and 8 inches (10 to 20 centimeters).
* Hurricanes and other storms are likely to become stronger.
* Species that depend on one another may become out of sync. For example, plants could bloom earlier than their pollinating insects become active.
* Floods and droughts will become more common. Rainfall in Ethiopia, where droughts are already common, could decline by 10 percent over the next 50 years.
* Less fresh water will be available. If the Quelccaya ice cap in Peru continues to melt at its current rate, it will be gone by 2100, leaving thousands of people who rely on
it for drinking water and electricity without a source of either.
* Some diseases will spread, such as malaria carried by mosquitoes.
* Ecosystems will change-some species will move farther north or become more successful; others won't be able to move and could become extinct. Wildlife research
scientist Martyn Obbard has found that since the mid-1980s, with less ice on which to live and fish for food, polar bears have gotten considerably skinnier. Polar bear
biologist Ian Stirling has found a similar pattern in Hudson Bay. He fears that if sea ice disappears, the polar bears will as well.