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Please Do Not Let Elon Musk Destroy the Ozone Layer
(www.splinter.com)
Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.
As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades:
How much each change to the atmosphere has warmed the world:
Recommended actions to cut greenhouse gas emissions in the near future:
Anti-science, inactivism, and unsupported conspiracy theories are not ok here.
Neither of your referenced quotes claimed that the elemental makeup of the measured particulate was synthetic. If you are referring to "Niobium and hafnium do not occur as free elements in nature", what this means is that the elements are not ever found on their own — they have only ever been found bonded to something else. Niobium makes up 0.0017% of Earth's crust and Hafnium makes up 0.00033% [source (archive)].