"Celsius" refers to a unit of measurement used to determine temperature. It is commonly used in most parts of the world, where water freezes at 0 degrees and boils at 100 degrees on the Celsius scale. Full definition
Top: The global temperature trend over time, from 1950 — 2014, in degrees Celsius per decade. (slate.com)
So what kind of impacts would you expect if global average temperatures were to rise by 2 - 8 degrees Celsius in just the next century? (climaterealityproject.org)
Two °C - weeks is an amount of heat stress equivalent to 2 weeks with temperatures 1 ° Celsius above the normal maximum. (climate.gov)