WEBVTT FILE

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This is carbon dioxide, or CO2,

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in the Earth’s atmosphere. It is derived from a synthesis

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of observed and simulated data. Reds and yellows show regions of

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higher than average CO2, while blues show regions lower than

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average. The pulsing of the data is caused by the

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day-night cycle of plant photosynthesis at the ground.

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As CO2 is lifted away from the surface, it is rapidly spread around the world

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by high altitude winds. The high concentrations

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are from the buildup of CO2 during the Northern Hemisphere winter,

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when photosynthesis is not active.

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By July, photosynthesis in the

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vast vegetation regions north of the equator draws massive amounts

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of CO2 out of the atmosphere, resulting in low

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carbon dioxide across the entire Northern Hemisphere.

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The growth and decay of vegetation in northern lands

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cause the seasonal change in atmospheric carbon dioxide

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seen here between the March and July. While seasonal changes in vegetation

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growth control CO2 on monthly timescales, human

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activities govern long-term carbon dioxide trends.

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