| When sunlight enters the Earth's atmosphere, some | | | | industrialization. Since the beginning of the Industrial |
| of its solar radiation is reflected back to space while | | | | Revolution, atmospheric concentrations of carbon |
| most of the radiation is absorbed by the Earth, which | | | | dioxide have increased by nearly 30%, the |
| warms the surface of the land and sea. As the Earth | | | | concentration of methane have more than doubled |
| is warmed, heat in the form of infrared radiation is | | | | and the concentrations of nitrous oxide have risen |
| radiated back into the space. However, much of the | | | | about 15%. |
| heat does not escape from the atmosphere but | | | | Scientists believe that the combustion of fossil fuels |
| remains trapped by the greenhouse gases,causing | | | | and the other human activities such as increased |
| the atmosphere to be warmed. | | | | deforestation and industrial production are the |
| At the same time, the greenhouse gases also radiate | | | | primary reasons for the increased concentrations of |
| infrared rays towards the surface of the Earth. In | | | | atmospheric carbon dioxide.As the concentration of |
| this respect, greenhouse gases in the atmosphere | | | | greenhouse gases rises, the greenhouse effect |
| behave a lot like the glass panel panes of a | | | | becomes more pronounced., trapping more heat in |
| greenhouse. This is why this phenomenon is known | | | | the atmosphere and raising the Earth's average |
| as the greenhouse effect.The greenhouse effect is | | | | temperature. |
| important because without it, the Earth would be too | | | | Such an overall rise int he temperature of the Earth's |
| cold for living organisms to survive. | | | | atmosphere is called global warming. The increase in |
| Carbon dioxide, chlorofluorocarbons (CFCs), methane, | | | | atmospheric temperature is high enough to cause |
| nitrous oxide, low level ozone and water vapor make | | | | changes in the global climate.Over the last 40 years, |
| up the greenhouse gases. With the exception of | | | | the Earth's average temperature has increased by |
| CFCs, most of the greenhouse gases occur naturally. | | | | about 0.2 - 0.3 Celsius. In the absence of emission |
| However, all of them are also produced as a result of | | | | control policies, carbon dioxide concentrations are |
| human activities. | | | | projected to be 30-150% higher than today's levels |
| Today, data collected around the world show a | | | | and the Earth's average temperature may rise |
| steady increase in the concentration of greenhouse | | | | between 1.5 Celsius and 4.5 Celsius by 2100. |
| gases in tandem with rapid development and | | | | |