Reporting
The change in phase or sign
The change in phase or sign of PDO certainly influences climate over longer time scales (annual to decadal). And indeed our physical infrastructure and regulatory systems seem to be designed for that type of climate regime. But, it seems that the switch from drought to atmospheric river then back that appears to be occurring over short time periods (say on the order of weeks to months) may be a new climate regime that seems that modern societies have not evolved with; such rapid changes in climate probably and apparently was not typical over the Holocene. If anything these rapid changes in weather shows us that our present-day resilience to these perturbations in weather is quite non-resilient. Hot dry dusty drought punctuated by high intensity but short lived storms followed by drought is something that our society did not arise from. Likewise, rapid and large changes in the polar jet stream have lead to conditions that some modern-day communities in the US and elsewhere seem ill equipped to handle (e.g., Jan 2014 Atlanta GA).