An abrupt climate change occurs throughout the world. The levels of greenhouse gas CO2 are increasing in different parts of the world. The other greenhouse gases are water vapors, methane, ozone, nitrous oxide, fluorinated gases. The greenhouse effect is a process that keeps the earth warm enough for people, plants and animals to live on. Over the past decade the surface air temperatures have not risen very much whereas the temperatures of deep oceans have risen very much. Oceans store 97% of world’s water. This water absorbed the 90% of energy of the atmosphere. The increase in the energy and temperatures of the earth is due to increase in the greenhouse gases. The human activity is changing the amount of greenhouse gases by three ways. The rain forests are cut down. The fossil fuels are being burned. The world’s population has been increased. Global warming is affecting the world. The oceans and atmosphere interact both physically and chemically. They exchange energy, water, gases and particles. This exchange influences the earth’s climate. It also changes the state of oceans. The salinity of the oceans has been changed, which accelerated the global rainfall and evaporation, which is responsible for climate change. The sea levels are expected to rise as the water expands due to rise in temperature. The sea levels also rise as a result of melting of polar caps. Rising sea levels impact many coastlines, and a large mass of humanity lives near the coasts or by major rivers. More CO2 in the atmosphere more CO2 in the oceans. This CO2 is dissolved in water and reacts with it forming carbonic acid. The water becomes more acidic. This acidification of water significantly impacts upon the health of some fish and coral species. There are many millions of species in the oceans and each will have different sensitivities to acidification and respond in different ways. It is likely that acidified sea water will alter the makeup of marine ecosystem.