Climate Central reported in November: This week is a big one for our world. Atmospheric carbon dioxide (CO2) levels climbed above the 400 parts per million (ppm) at the Mauna Loa Observatory and it’s distinctly possible they won’t be back below that level again in our lifetimes.
Humans have burned enough fossil fuels to drive atmospheric CO2 to levels that world hasn’t seen in at least 400,000 years. That’s driven up temperatures, melted ice and caused oceans to acidify. Some extreme weather events around the world have become more likely and stronger because of it, and some will likely only get worse as the planet continues to warm.
Because CO2 sits in the atmosphere long after it’s burned, that means we’ve likely lived our last week in a sub-400 ppm world. It also means that the reshaping of our planet will continue for decades and centuries to come, even if climate talks in Paris in two weeks are successful. [Continue reading…]