Two scientists are credited with the discovery more than 100 years ago that increasing carbon dioxide in the atmosphere warms the entire planet: French researcher Jean Baptiste Fourier and Swedish scientist Svante Arrhenius. Their identification of what came to be called the greenhouse effect applies to both natural and human-produced additions of CO2.
As measurements of atmospheric CO2 levels showed steady increases after World War II (see What is the average global temperature now?), Earth system scientists looked for a corresponding rise in global average temperatures, basing their studies on the physical laws governing the greenhouse effect. By the early 1980s, climate scientists were calling this atmospheric response global warming. Not every place on Earth was expected to warm at the same rate, and rising temperatures were not the only impacts anticipated.
Boosting Earth's temperature and adding more acidity to the oceans creates wide-ranging effects that are changing all the "normal" weather and climate conditions on which we've based our agriculture, industry, and social systems (see What's the difference between climate and weather?). So some researchers talk about global climate change to convey that the situation is far more complex than temperature alone.
To some ears, "climate change" sounds less ominous than "global warming." However, the phrase was introduced by researchers not to minimize the situation but to convey the full scope of disturbances that can occur in association with changes in global temperature, such as changes in patterns of flood and drought.
Climate change glossary (U.S. EPA)