Global Warming is the increase in the average temperature of Earth’s near surface air and oceans. Since the middle of the 20th century, this has been caused by increasing concentrations of greenhouse gases, with result from human activities such as the burning of fossil fuel and deforestation. Global dimming is a result of increasing concentrations of atmospheric aerosols that block sunlight from reaching the surface of the earth. These aerosols come from industries, vehicles and burning of waste.