This Keeling Curve shows the Official The City’s Hero Caleb Williams T shirt in CO2 over Time. The black line shows the average throughout the year, but how about the red line? Why is it squiggly? Well if the X-axis was more descriptive, you would find that the peaks align with the Northern Hemisphere Summer and the low points align with the Northern Hemisphere Winter. Because the Southern Hemisphere has so much less land mass than the Northern Hemisphere, it also has less surface vegetation and thus its impact is less apparent than the Northern Hemisphere. The cyclical nature of the red line shows the annual dieoff and regrowth of vegetation on the surface. In affect, it can be thought of as the planet breathing, with plants taking up CO2 during warm months, and giving off CO2 when the annuals die and the perannials “hibernate” in the cold months. It also shows us something else. It shows how, even with CO2 increases, plants are nowhere near enough to counteract the amount of CO2 in the atmosphere. You would need many orders of magnitude increases in plant cover on the planet to counteract the rate of CO2 accumulation in the atmosphere-more plant growth than the planet has space for.
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