He/She is a meteorologist

It is a common confusion.
I was at an event and there was to be a "debate" on a state climate change related bill. One of the sponsors was to debate an opponent of the measure.
The opposition was keen to point out, that their man was a meteorologist.
Sigh.
Climate change science is part of "climatology". It is built by "climatologists", working in groups, each with different specialties. It is a different discipline in fundamental ways.

A good explaination of the difference is provided by The Bureau of Labor Statistics:
"While meteorologists study and forecast weather patterns in the short term, climatologists study seasonal variations in weather over months, years, or even centuries. They may collect, analyze, and interpret past records of wind, rainfall, sunshine, and temperature in specific areas or regions. Some look at patterns in weather over past years to determine, for example, whether a coming season will be colder or warmer than usual. Their studies are used to design buildings, plan heating and cooling systems, and aid in effective land use and agricultural production. "
http://www.bls.gov/oco/ocos051.htm