The climate is sensitive to changes. If it was not, all the charts including long time frames would show horizontal lines. That it is sufficiently sensitive causes natural variability. The PDO went negative over a decade ago for some nonrandom reason. As we don’t know what that reason was, we could call it a cycle. Call it natural variability as many have, or noise. If there was a pause, the climate was sensitive to something that offset CO2. If there is a current acceleration, it’s still sensitive to something complimenting CO2 or if you prefer, can no longer hold CO2’s effects back. If we allow variable sensitivity we then allow variable natural variability. We change the control variable as we did, and the reaction is a tiny fraction of what is expected. It that case studies are done looking at large circulations to explain that. Those circulations too are claimed to be sensitive to changes. Cooling circulations were caused by CO2. Or some claim it’s a background of noise and cooling circulations will certainly reverse. A background of noise means the climate sometimes is not sensitive to changes, but I claim it is. Or it might mean its sensitivity is variable and sometimes hypersensitive. Variable natural variability might be this:
The Indian Pacific Warm Pool mostly sits there insensitive to anything. Its natural variability goes dormant. As the pool builds it becomes more sensitive to factors that would collapse it and start an El Nino. It does collapse and likewise the natural variability is let out and observed because the IPWP was highly sensitive to changes for a time. The ENSO region has variable natural variability because of variable sensitivity.
A post of mine here: