Climate is the prevailing conditions of temperature, rainfall, humidity, wind, etc... that are characteristic of a certain region over a long period of time usually exceeding 20 years. Earth's climate changes naturally between warmth and ice ages but the changes occur over thousands of years. Within the last 150 years, industrial, agricultural and civic activities have resulted in acceleration of these changes due to the accumulation in the atmosphere of earth of increasing concentrations of certain gases known as the greenhouse gases (GHGs). These include: CO2, methane, NOx, CFCs, ...This resulted in warming of the earth's surface mean temperature, deep ocean warming, melting of the alpine and polar ice caps and the spread of certain diseases, among other changes. Several of these changes have affected human health. Heat waves have resulted in increased death rates especially among the elderly and those suffering from cardio-respiratory diseases. The effect of cold, stormy weather is less pronounced. Increased air pollution will cause more photochemical pollutants and increased pollens and fungal spores resulting in more asthma and respiratory ailments.
People living in temperate climates will suffer less but lower socio-economic standards will exacerbate their sufferings. Due to migration of disease vectors and increase of their activity, vector-borne diseases will spread beyond their current geographical limits. Infectious diseases are now emerging, resurging and undergoing redistribution on a global scale. Pests will flourish. There will be more water-borne and food-borne diseases. Malnutrition will result from reduced crop production due to loss of land and water resources, farm animal diseases and destruction of fisheries. Extreme weather
events will be more frequent and more severe. Floods will cause death, injury and destruction of land, crops and property and displacement of population resulting in overcrowding, poor hygiene, malnutrition and disease epidemics. Drought will cause malnutrition and disease, and storms will cause death and destruction. Sea level rise will cause inundation of coastal areas, loss and salinization of fertile land and displacement of population. In Egypt, water resources may increase by 30% or be reduced. Parts of the Nile Delta will be submerged and 8.5 million people will be displaced from their homes. There are interactions between global warming and ozone depletion which will result in an increase in UVB exposure.Abbreviations :GHGs : Greenhouse gases CFCs : Chlorofluorocarbons UVR : Ultraviolet rays UVB : Ultraviolet B rays. Greenhouse gases – Extreme weather events – sea level rise – Ozone  olet rays UVB : Ultraviolet B rays.