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At tropical latitudes, more energy is received because it has less atmosphere to travel through. But due to the Earth's curvature, there is more atmosphere to travel through at the poles so energy is lost more by reflection and scattering.
The sun's rays are more concentrated on tropical latitudes because the intensity of insolation is greatest where the sun strikes vertically. But due to the Earth's curvature, the sun strikes the Poles at a smaller angle over a much larger area, so energy is lost.
The Albedo Effect is greater at the Poles due to snow and ice cover, meaning energy is reflected more than it is absorbed.
At the tropics, dark forest vegetation absorbs energy and stores it. However, the climate of the Poles allow for very little vegetation, so not much energy is stored.
Due to the Earth's tilt, seasons occur. At the Poles this means six months of darkness. The Tropics have fairly even insolation all year round.
