【Nautilus】Are We Headed for a Sixth Extinction?

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The stability of life on Earth depends on the biogeochemical cycles of carbon, which in turn depend on poorly understood microbial ecosystems. OCEAN CHLOROPHYLL CONCENTRATIONS (NORTHERN HEMISPHERE)Composite concentration of ocean chlorophyll (red is the highest), indicating areas with the highest production of organic carbon, as measured by satellite. In contrast, measuring the degradation and release of carbon back to the atmosphere from the deep ocean or oceanic sediments is extremely difficult. NASA/Suomi NPP/Norman Kuring Five times in the last 500 million years, more than three-fourths of living species have vanished in mass extinctions. Each of these events (see Table 1) is associated with a significant change in Earth’s carbon cycle. Some scientists think that human-induced environmental change—including our massive discharges of carbon into the atmosphere—may ………………………………