The Earth has a natural temperature control system. Certain atmospheric gases are critical to this system and are known as greenhouse gases. On average, about one third of the solar radiation that hits the earth is reflected back to space. Of the remainder, some is absorbed by the atmosphere but most is absorbed by the land and oceans. The Earth's surface becomes warm and as a result emits infrared radiation. The greenhouse gases trap the infrared radiation, thus warming the atmosphere. Naturally occurring greenhouse gases include water vapour, carbon dioxide, ozone, methane and nitrous oxide, and together create a natural greenhouse effect. However, human activities are causing greenhouse gas levels in the atmosphere to increase.

Some of the effects include:

1. Temperature increase: Global average temperature may increase from 15.40C to 200C; rise of 4.60C.
   
   
   
   
   

2. Sea Level: Global Sea level may rise by upto 94 cm. getation: climate warming in the past has caused vegetation zones to shift to higher elevations, resulting in the loss of some species and ecosystems. Simulated scenarios for temperate-climate mountain sites suggest that continued warming could have similar consequences.

3. Thinning of arctic: Draft in the 1990s is over a meter thinner than two to four decades earlier due to increase in global temperatures.
4. Coastal Areas: Rising sea level would destroy weak parts of the sand belt, which is essential for the protection of lagoons and the low-lying reclaimed lands. The impacts would be very serious: One third of Egypt's fish catches are made in the lagoons. Sea level rise would change the water quality and affect most fresh water fish. Valuable agricultural land would be innundated.
5. Freash Water: Even if the world maintained the pace of the 1990s in water supply development, it would not be enough to ensure that everyone had access to safe drinkning water by 2025.
6. Diseases: Climate change and altered weather patters would affect the range (both altitude and latitude), intensity, and seasonality of many vector-borne and other infectioius diseases.