Climate change is a long-term change in the average weather patterns that have come to define Earth’s local, regional and global climates.

Climate change is caused by natural processes and human processes.

Natural processes: ocean patterns like El Niño, La Niña, volcanic activity, changes in the sun’s energy output, variations in Earth’s orbit.

Human processes: burning of fossil fuels which increases greenhouse gases trapped in the atmosphere and increases Earth's overall global temperature.

A process that occurs when gases in Earth's atmosphere trap the Sun's heat.

This process makes Earth much warmer than it would be without an atmosphere.

The greenhouse effect is one of the things that makes Earth a comfortable place to live.

Global warming is the long-term heating of Earth’s climate system observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere.

Weather: The way the atmosphere is behaving, mainly with respect to its effects upon life and human activities

Climate: The average of weather over time and space

The difference between weather and climate is that weather consists of the short-term (minutes to months) changes in the atmosphere.

The carbon cycle plays a key role in regulating Earth's global temperature and climate by controlling the amount of carbon dioxide in the atmosphere.

Over the past 200 years the oceans have absorbed 525 billion tons of carbon dioxide from the atmosphere, which is nearly half of the fossil fuel carbon emissions over this period.

The ocean absorbs much of the carbon dioxide that is released from burning fossil fuels. This extra carbon dioxide is lowering the ocean’s pH, through a process known as ocean acidification.

Since the pre-industrial period, human activities are estimated to have increased Earth’s global average temperature by about 1 degree Celsius (1.8 degrees Fahrenheit), which is increasing by 0.2 degrees Celsius (0.36 degrees Fahrenheit) each decade.

Changes observed in Earth’s climate since the early 20th century are primarily driven by human activities, particularly fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere, raising Earth’s average surface temperature.