Some make light of the fact that the Japanese have announced the CO2 level at their Antarctic station (Syowa) exceeded 400 ppmv (part per million by volume) this year.
It’s unlikely we’ll see levels below 400 ppmv again in my lifetime, or yours.
We need to reduce how fast it’s rising, and we need to do it now. That of course raises the question, just how fast is it rising? I’m not talking about the instantaneous rate, which can vary for a lot of reasons. I’m referring to the persistent rate, apart from short-term fluctuations (for whatever reason).
Here’s the data from the Mauna Loa atmospheric observatory, with the seasonal cycle removed:
It’s surprising how well this fits a quadratic function of time:
The residuals from this quadratic fit don’t really show signs of persistent trends, but of fluctuations which aren’t necessarily persistent:
This argues that the quadratic trend is about as much as we can be confident of, in terms of long-term trend. If so, then the present rate of “persistent increase” is about 2.24 +/- 0.09 ppmv/yr, and it continues to accelerate at about 0.012 ppmv/yr/yr.
We can also estimate the rate of increase by a lowess smooth with a suitably chosen time scale. I get this, for the rate of increase itself:
According to this estimate, the current rate is about 2.26 ppmv/yr.
We can also look at the rate (per year) based on the month-to-month differences. This shows that the rate has been increasing over time (which we already knew), and a linear fit to the rate is statistically significant:
This estimate suggests increase at 2.3 ppmv/yr, but with a large uncertainty (+/- 0.6 ppmv).
All in all, the evidence suggests that the present long-term rate of CO2 increase is right around 2.25 ppmv/yr. Alas, there’s no sign of any slowdown in atmospheric CO2 growth; quite the contrary, it’s continuing to accelerate. Although there are brief episodes of faster and slower growth, the best estimate — so far — is near-constant acceleration.
Many nations claim that they have reduced their CO2 emissions rate. But there’s absolutely no evidence that it has had any impact on planet-wide CO2 increase. Not even a little bit. There’s not even any sign we’ve slowed down the acceleration.
Which bodes ill, not for the planet, but for the life that inhabits it. In particular, us. Making light of it is deplorable.
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