Global Warming is caused by the effects of greenhouse gases in the atmosphere, which results in a gradual rise in the average temperature of the Earth. In other words, global warming is a sustained increase in global temperature. Global dimming is caused when the concentration of aerosols continues to increase.
The implication of this is that it causes solar radiation from the sun to be reflected, thereby causing a decrease in the amount of solar radiation coming to the surface of the Earth. Global warming is caused by greenhouse gases such as carbon dioxide, CFCs, methane, etc. In contrast, global dimming is caused by aerosols such as smoke, smog, mist that are produced when fossil fuels are burnt.
Unlike global warming that leads to a rise in the average temperature of the Earth, the temperature of the surface of the Earth is being reduced through global dimming.