The oceans are warmer today than they were 30 years ago, and most scientists believe they will continue to warm as humans contribute more and more to greenhouse gases. Sea levels continue to rise mainly because of melting ice in Antarctica and Greenland. Keeping track of the oceans' temperatures helps scientists measure the progress of global warming; they store 1,000 times more heat from the sun than the earth's atmosphere, according to John Lyman at the National Oceanic and Atmospheric Administration Pacific Marine Environmental Laboratory, Seattle, in a 2006 study about ocean temperatures.
The effect of global warming can create serious problems with staple crops -- wheat, rice, corn, soybeans, barley and sorghum -- which account for a major portion of foods consumed by humans and animals.The snow pack of the Sierra Nevada Mountains in California has been in decline for decades, according to an Intergovernmental Panel on Climate Change (IPCC) report, and further loss of snow pack could eventually create a serious lack of water for the Central Valley farmers resulting in food shortages. Droughts reduce productivity of grazing lands, and heavy rains and flooding will be detrimental to crops.
Climate change affects the number of incidences and spread of disease. According to the Union of Concerned Scientists in Cambridge, Massachusetts, climate change influences carriers and the transmission of diseases, such as malaria, yellow fever and viral encephalitis. When it rains heavily or there are drought conditions, it could trigger outbreaks of disease, especially in poorer regions where treatment may not be adequate. Warmer, wetter weather allows for potentially greater risk of disease even in higher altitudes. Warmer global temperatures create larger areas in which offending parasites can survive.
Conflicts between nations may come about as a result of competition over natural resources that will become increasingly scarce due to climate change. Water shortages and coastal flooding may affect populations leading to migration and possible conflicts as one group infringes on another in areas where there may already be reduced supply. Conflicts over water, energy and food resources create a scenario that is troubling; therefore, it is crucial that nations maintain goodwill toward others and the environment.