1.5 degrees Keeping the rise in global average temperature below 1.5 degrees Celsius will avoid the worst impacts of climate change, scientists say.
3 degrees The current likely rise in average global temperature by the year 2100 if countries keep their promises to cut emissions of greenhouse gases, which are driving climate change.
This produces carbon dioxide and other so-called greenhouse gases, which trap heat in the atmosphere and cause the planet to become warmer.
Climate change A pattern of change affecting global or regional climate, as measured by average temperature and rainfall, and how often extreme weather events like heatwaves or heavy rains happen.
CO2 Means carbon dioxide, a naturally occurring gas which is also a major product of human activity such as burning fossil fuels.