Recent Trends in Large Scale (Continental) Heatwaves, 1979-2020

This paper provides confirmation for the rising trend seen in extreme temperature events known as heatwaves around the world, both in areal extent and intensity. The trend is measured as temperature (T) anomalies, clearly noticeable in the temperate regions of the Northern Hemisphere. The trend suggests a weakening of the mixing currents that were present in an atmosphere with lower humidity and lower poleward heat transport.

Both are linked to radiative forcing, aka heat retention within the Earth System, by the continuously rising greenhouse gas (GHG) emissions over the last century, associated with large scale agriculture and diverse combustion operations linked to energy generation.

At the simplest level, the implications of this analysis are that the regions most likely to be affected, e.g., N hemisphere temperate regions, (see probability density, slide) will need to invest much more for the adaptation to, and mitigation of, atmospheric stationary wave like patterns leading to extended and more intense heatwaves in the summer.
More specifically, the appearance of larger islands within the atmosphere, regions of thermal and hydrodynamic (P) stability that persist longer, bound by regions (waves) with complementary T, P aspects.

Based on current data, I estimate that PDX will experience ~35-40 days of >90° F days within a decade.   Nonlinear trends in this metric, i.e., > 90° F days, have appeared recently.
Oregon’s health + care and reduced worker productivity related costs to manage these impacts will be significant unless regionally appropriate adaptive <> mitigative strategies are developed ASAP.

Global networks will be needed to objectively assess the long term damages done by the principal (largest)  GHG emitters during this period, to The People of nations that have suffered disparate losses. More specifically, people who have lost their homes and livelihoods, but did not contribute to GHG emissions in any significant measure over the last century. Regions referred to as the nations of the Global South.