INTRODUCTION

" It is He Who has spread out the earth for (His) creatures: Therein is fruit and date palms, producing spathes (enclosing dates); Also corn, with (its) leaves and stalk for fodder, and sweet-smelling plants. Then which of the favours of your Lord will ye deny?"
<Qur'an-Al Rahman 55:10-13>

The earth’s climate is predicted to change because human activities are altering the chemical composition of the atmosphere through the buildup of greenhouse gases – primarily carbon dioxide, methane, and nitrous oxide. The heat-trapping property of these gases is undisputed. Although uncertainty exists about exactly how earth’s climate responds to these gases, global temperatures are rising.

• What is the Greenhouse Effect?

The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere (water vapour, carbon dioxide, nitrous oxide, and methane) trap energy from the sun. Without these gases, heat would escape back into space and Earth’s average temperature would be about 60ºF(16ºC) colder. Because of how they warm our world, these gases are referred to as greenhouse gases.

Sunlight enters the Earth's atmosphere, passing through the blanket of greenhouse gases. As it reaches the Earth's surface, land, water, and biosphere absorb the sunlight’s energy. Once absorbed, this energy is sent back into the atmosphere. Some of the energy passes back into space, but much of it remains trapped in the atmosphere by the greenhouse gases, causing our world to heat up. Without the natural “greenhouse effect,” temperatures would be much lower than they are now, and life as known today would not be possible.
Instead, thanks to greenhouse gases, the earth’s average temperature is more hospitable 60ºF(16ºC). However, problems may arise when the atmospheric concentration of greenhouse gases increases.

The increase of gas emission began with the Industrial Revolution. Indeed before this period, human activities released very few gases into the atmosphere.But by changing our agricultural and industrial practices. and now through population growth, fossil fuel burning, and deforestation, we are affecting the mixture of gases in the atmosphere.

• Why are greenhouse gas concentrations increasing?

Scientists generally believe that the combustion of fossil fuels and other human activities are the primary reason for the increased concentration of carbon dioxide.
Plant respiration and the decomposition of organic matter release more than 10 times the CO2 released by human activities; but these releases have generally been in balance during the centuries leading up to the industrial revolution with carbon dioxide absorbed by terrestrial vegetation and the oceans.
What has changed in the last few hundred years is the additional release of carbon dioxide by human activities. Fossil fuels burned to run cars and trucks, heat homes and businesses, and power factories are responsible for about 98% of U.S. carbon dioxide emissions, 24% of methane emissions, and 18% of nitrous oxide emissions.
Increased agriculture, deforestation, landfills, industrial production, and mining also contribute a significant share of emissions. In 1997, the United States emitted about one-fifth of total global greenhouse gases. The UK with 1% of the world's population produces 2.3% of the world's CO2.
Estimating future emissions is difficult, because it depends on demographic, economic, technological, policy, and institutional developments. Several emissions scenarios have been developed based on differing projections of these underlying factors.
For example, by 2100, in the absence of emissions control policies, carbon dioxide concentrations are projected to be 30-150% higher than today’s levels, says the Intergovernmental Panel on Climate Change (IPCC).

Consequences of global warming