This is carbon dioxide, or CO2,
in the Earth’s atmosphere. It is derived from a synthesis
of observed and simulated data. Reds and yellows show regions of
higher than average CO2, while blues show regions lower than
average. The pulsing of the data is caused by the
day-night cycle of plant photosynthesis at the ground.
As CO2 is lifted away from the surface, it is rapidly spread around the world
by high altitude winds. The high concentrations
are from the buildup of CO2 during the Northern Hemisphere winter,
when photosynthesis is not active.
By July, photosynthesis in the
vast vegetation regions north of the equator draws massive amounts
of CO2 out of the atmosphere, resulting in low
carbon dioxide across the entire Northern Hemisphere.
The growth and decay of vegetation in northern lands
cause the seasonal change in atmospheric carbon dioxide
seen here between the March and July. While seasonal changes in vegetation
growth control CO2 on monthly timescales, human
activities govern long-term carbon dioxide trends.