|(Click pic to make big. Once per customer, please.)|
This year MLO's weekly CO2 value peaked at 397.12 ppm, a 2.16 ppm increase from last year.
So it would need to increase by 2.88 ppm next year to reach 400 ppm, which is unlikely -- it will happen only if there is a strong El Nino in the fall and winter. (And there might be.)
But it will definitely(*) happen by 2014.
(*) Except in the case of planetary catastrophe, or Craig Venter's product escapes his lab and goes exponentially rogue.