Global Warming

Global warming is a phenomenon that causes gradual rise in temperature on the Earth's surface. The current average temperature is higher than the temperature at the beginning of the Industrial Revolution (around 1750).

Scientists have been analyzing temperatures from the late 19th century since when recorded data is available. They show an increase in temperature during 1920-40, while in the next three decades the temperature became slightly cooler. The data from 1970 to the present show an increase of about 0.6 °C.

Of all the greenhouse gases that contribute to global warming and climate change, carbon dioxide is the major contributor. Cars and other vehicles, thermal power plants, airplanes, factories, and other human activities release about 23 billion tons of carbon dioxide and other greenhouse gases into atmosphere annually.

The current amount of carbon dioxide in the air is about 31% more than the 1750 level. Out of this, 75% was added by fossil fuel burning in the last two decades. The remaining 25% is attributable to deforestation, forest fires, crop stubble burning, burning forests for agriculture, and similar activities.

As the surface temperature increases the sea level rises due to the expansion of water and melting of glaciers and polar icecaps. This causes coastal flooding and inundation of coastal cities and other areas. Hot deserts will become hotter and expand destroying green areas. Disastrous storms such as hurricanes and tornadoes can make winds faster than 320 kilometers per hour destroying life and property. Weather pattern will change drastically and farming and food production will suffer.

It’s time that the governments of all countries join hands, giving up their differences, and try to reduce global warming. Similarly, people can also contribute to resolve the problem by consuming less energy or adapting to clean and green energy sources.

Greenhouse Effect

Greenhouse effect is caused by greenhouse gases in the Earth's atmosphere by absorbing infrared radiation.

In 1824 the French physicist Joseph Fourier, credited as the discoverer of greenhouse effect, first suggested that the Earth's atmosphere acts as an ‘insulator’. His observations were subsequently confirmed by other scientists. But the term ‘greenhouse effect’ was first used by the Swedish meteorologist Nils Gustaf Ekholm in 1901.

In 1896, the Swedish scientist Svante Arrhenius was the first to calculate how increase in atmospheric carbon dioxide (CO₂) will increase the Earth's surface temperature. He predicted for the first time that CO₂ emissions will cause global warming.

About 10,000 years ago CO₂ in the atmosphere was 260 to 280 parts per million (ppm), which increased to 389 ppm in 2011 due to excessive burning of fossil fuels. According to most scientists, the safe level of CO₂ in the atmosphere is 350 ppm or less.

But greenhouse effect is a natural phenomenon and an essential evil. Without this effect, the average temperature all over the earth would be −18 °C (0 °F), in place of the current average of 15 °C (59 °F). That is a fall in temperature by 33 °C, which will render the Earth too cold to support life. So, what is required is maintaining greenhouse gas emissions within safe limits by reducing burning of fossil fuels and other causes.

The four major gases that contribute to the greenhouse effect are water vapor, carbon dioxide, methane and ozone. Increase in the amount of these gases makes the air hotter, causing global warming and climate change.

Global warming can cause serious consequences such as desertification, melting of polar ice and glaciers, sea level rise and submerging of coastal areas and islands. It can also cause severe droughts and devastating floods and drastically affect farming and food production.

Greenhouse gases: a short school essay

Greenhouse gases (GHG) trap heat in the atmosphere by reflecting radiation that the Earth emits. This increases the Earth's temperature, which is the greenhouse effect.

Greenhouse gases are required in the atmosphere to some extent. For instance, if all greenhouse gases are eliminated, the average temperature will fall by 33 °C, making it difficult for life to exist. And too much of greenhouse gases will increase the atmosphere to undesirable levels.

The primary GHG are water vapor (H₂O), carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), chlorofluorocarbons (CFC) and ozone (O₃).

It is estimated by scientists that human activities have increased the atmospheric concentration of CO₂, the most harmful greenhouse gas, by 40% since the beginning of the Industrial Revolution (1750 AD).

Burning fossil fuels like oil, coal and natural gas as well as activities like livestock rearing, agriculture and deforestation push up CO₂ concentration. Livestock added 14.5% of all human-caused GHG, while transportation (all vehicles and planes) added 13% yearly.

Deforestation (cutting trees) reduces absorption of carbon dioxide by plants during photosynthesis. Raising farm animals, including cattle and others such as pigs, chickens and sheep, add methane to the atmosphere.

Water vapour is the most abundant GHG causing climate change. But human activities add more water vapor to the atmosphere through industrial heating, use of cooling towers and by creating artificial lakes.

All these human activities contribute to increase in greenhouse gases and cause global warming.

If greenhouse gas emissions are not controlled, the Earth's surface temperature would cross danger level by 2047, making life on earth difficult. And it may cross the threshold of 2 °C global warming by 2036.