Background to the study. Information from the present literatures suggests that the state of Uganda's climate is in agony, this study was taken to establish the factors that affect Uganda's climate to change. The chapter highlights the background of the study, statement of the problem, purpose of the study, objectives of the study, Research questions, and scope of the study. Climate change refers to the rise in average surface temperature on earth. An overwhelming scientific consensus that climatic change is due primarily to the human use of fossil fuels, which releases carbon dioxide and other greenhouse gases to air. The gas trap heat with in the atmosphere, which can have arranged of effects on eco-system, included rising sea levels, sever weather events. In addition, drought that render landscapes more susceptible to wildfires. There was broad-agreement with in scientific community that climate change was real, United States environmental protection agency (U.S.E.P. A), National Aeronautic and space Administration (N.A.S. A), National oceanic and atmospheric Administration. (N.O.A. !\). United nations frame work convention on climatic change. (U.N.F.C.C.C), Intergovernmental panel on climate change. (I.P.C.C). these were put to confirm that climate change is there and caused by human activity. Climate change can also be in other side as a result into global cooling, which is the reverse of global warming, global cooling refers to accumulation of ice in environment. Glaciation 2.3 billion year ago triggered by the evolution of oxygenic photosynthesis, which depleted the atmosphere of the greenhouse gas carbon dioxide and introduced free oxygen. Global cooling over the past 40 million years ago driven by the expansion of grass-grazer ecosystems.