On May 9, instruments atop Hawaii’s Mauna Loa volcano pegged the atmospheric concentration of carbon dioxide (CO2) — the gas that contributes most to global warming — at slightly above 400 parts per million (ppm).
On May 9, instruments atop Hawaii’s Mauna Loa volcano pegged the atmospheric concentration of carbon dioxide (CO2) — the gas that contributes most to global warming — at slightly above 400 parts per million (ppm).
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