1. Clearly, we are not having exponential growth anymore, we're on a linear growth path.

I do not agree. The rates are slightly increasing. The later you look the steeper is the slope.

I averaged 100-month increase rates of Mauna Loa CO

_{2}:

1959-1967: + 0.77 ppm/year

1967-1975: + 1.10 ppm/year

1975-1984: + 1.50 ppm/year

1984-1992: + 1.52 ppm/year

1992-2000: + 1.59 ppm/year

2000-2009: + 1.99 ppm/year

2009-2017: + 2.34 ppm/year

2012-2020: + 2.48 ppm/year

These data are not compatible with "linear growth path".

See also the annual increase (raw data) in the attached graph. y-axis: increase in ppm/year