There’s been a spate of articles claiming that a new CERN/CLOUD project paper shows that cosmic rays are the real cause of climate change:
A major scientific study is casting fresh doubt on the theory of man-made climate change. In fact, this latest research shows it may be something far beyond the control of humans.
Research by the prestigious European Organization of Nuclear Research supports the theory that periods of earth warming are caused by solar activity and so-called cosmic rays, rather than by human activity.
The findings of the landmark study, dubbed CLOUD, are rocking climate science.
The exact value of climate sensitivity depends on which feedbacks you include, the climate state you start with, and what timescale you’re interested in. While the Earth has ice sheets the total climate sensitivity to CO2 is up to 8°C: 1.2°C direct warming, 1.8°C from fast feedbacks, 1°C from greenhouse gas feedbacks, and nearly 4°C from ice albedo feedbacks. The slow feedbacks have historically occurred over centuries to millennia, but could become significant this century. Including CO2 itself as a feedback would make climate sensitivity even higher, except for the weathering feedback which operates on a geologic timescale. (Emphasis mine)
CO2 alone, not CO2e, of 450ppm is likely to give us an ice-free planet – eventually.