Climate Letter #1185

A review of recent large heatwaves occurring within regional ocean waters.  There is an observed trend toward these phenomena getting hotter, lasting longer and doing more damage.  An international working group of scientists that is keeping track makes a report.

–A separate report shows the harmful effects of warmer waters on ocean kelp forests, and why this is important.

—–

Low-level cloud cover has sharply declined in the greater Los Angeles area.  The decline occurs in the summer, and has been calculated at a stunning 25 to 50% since the 1970s.  The calculations were derived from data collected by numerous airports in the region and were matched up to another database showing that soil moisture in the region has been in a similar declining trend at the same time that the clouds were diminishing, thus adding to wildfire worries.  Previous studies have shown that low-level clouds have a distinct cooling effect, due mainly to the way they reflect sunlight, while other theories suggest that heat radiated from warm surfaces can cause these low clouds to dissipate or even prevent them from forming in the first place.  The overall effect would constitute a positive feedback once the surface has warmed enough to put this process in motion.  This knowledge has potentially widespread ramifications and is likely to get more attention.

–The California study can be found at this link:

–Reference to a related scientific study about cloud fundamentals from several years ago, which drew considerable attention at the time and is still being cited:

—–