Human activity has added more heat-trapping greenhouse gases (GHGs) to those already in the atmosphere. Because more of the Sun’s energy is trapped here, the atmosphere warms. This warming changes the Earth’s climate, including the frequency and intensity of rainfall, drought and heatwaves.

The Earth is a “heat engine”. Most heating from the Sun occurs at the equator because that’s where the Earth’s surface is perpendicular to the direction of inbound energy. At the poles, the angle of the Earth’s surface, relative to the direction of sunlight, is shallow, so little warming happens.

A warmer equator relative to colder polar regions creates a temperature gradient, which forces energy to flow from the equatorial regions towards the poles. The Earth redistributes this energy through its climate system, which drives the winds, rainfall-producing weather and ocean currents.

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