Global warming is the accelerated warming of Earth due to an increase in greenhouse gases, particularly from the burning of fossil fuels. The accelerated warming can be measured in Earth's atmosphere and oceans. Evidence for global warming can be seen in retreating ice caps, dry lakes, increased habitat reduction for animals (think of the now-infamous polar bear on a lone iceberg), global temperature rises, shifts in weather, coral bleaching, sea-level rise and more. Global warming is the human-induced rise in global temperatures.
Climate change is the natural change in global temperatures over time. More specifically, a change in Earth's energy budget can result in both increases and decreases in global temperatures. Climate always changes. This is a fact most people tend to ignore if they decide to say they believe in climate change (or don't believe, for that matter). Ignoring the fact that climate change is not the basis for a belief system, let's examine the real differences between global warming and climate change.
Climate change occurs naturally on Earth for several reasons including the Milankovitch Cycle, volcanic eruptions, natural variance, changes in ocean circulation, albedo, and even tectonic activity. All of these events can explain why tropical and subtropical fossils can be found far more northward than the present-day tropical regions. It must be clear that climate change can and does occur. Long before humans were in the picture, climates have changed both regionally and globally.
In the media, climate change is often interchanged with the words 'global warming'. This is a mincing of words. The two are different. If you combine the two, you get this: Global warming is human-induced climate change. Global warming doubters or anti-warming activists often use the same mincing of words to detract from the issues. While a better definition, or a standardized definition, may never come about, the fact is that climate change can and does occur all the time. Global warming is a theory.
So, that brings us to the definition of a theory. This is where many non-scientists get it wrong. Theories are scientific evidence, collected over time, and accepted as a valid explanation for evidence. Theories are different than hypotheses and scientific laws. A hypothesis is an educated guess, based on knowledge, but that needs continual testing for further development (into a theory). Laws are scientific facts that are virtually incontrovertible. For instance, if you throw a ball up, it will come down. Gravity is a law of science.
What can be done? Not much. There is little that can be done to exorcise the wrong choice of words from this already huge topic. Most people, myself included, do not know enough about the world's climate system to make a judgment call or to analyze climate data. Even supercomputers spit out evidence contradictory to current scientific thought. Can I compete with a supercomputer, or the world's top climate scientists? No. So, until then, I say we encourage scientists and climatologists to find the incontrovertible proof, making global warming a law of science.