Southern California is renowned for its ideal weather, characterized by what many describe as a “mild Mediterranean-type climate.” Historically, this climate attracted individuals seeking improved health and the ability to cultivate diverse crops. Railroads once promoted Los Angeles as a haven for those afflicted by illnesses, due to its reputation for dry heat and minimal rain disruption.
Unexpected Climatic Shifts
This year, Southern California experienced a significant shift in climate conditions. The region’s air turned humid, akin to places like Florida and the Gulf Coast, causing discomfort for many residents. According to Daniel Swain, a UC climate scientist, the combination of high heat and deep-tropical air resulted in some of the highest recorded humidity levels in coastal Southern California, with some areas experiencing record-breaking moisture this summer.
The Impact of Climate Change and El Niño
The effects of climate change have been felt in Southern California for some time, with increased temperatures raising fire risks and exacerbating droughts. Experts predict a strong El Niño pattern this winter, potentially leading to severe coastal damage. Swain warns that addressing substantial coastal flooding, beach erosion, and bluff collapses may become challenging in the coming months.
Swain provided an analysis revealing that this summer’s humidity levels, as measured by dew point, were the highest since 1980. The data included measurements from airports like Santa Barbara, Los Angeles, Long Beach, and San Diego. Dew point readings at these locations reached levels considered oppressive, comparable to cities in Florida.
Factors Contributing to Increased Humidity
Southern California typically avoids high humidity due to the cool ocean breeze, protective mountains, and a specific weather pattern. However, this summer these defenses failed. High humidity allows less heat dissipation through sweating, making temperatures feel warmer, especially in densely populated areas like Central and South Central Los Angeles, where many homes lack air conditioning.
Health Risks and Authorities’ Warnings
Health officials have urged caution, noting symptoms of heat-related illnesses like dizziness, nausea, rapid heartbeat, and confusion. Dr. Muntu Davis, L.A. County health officer, emphasized that heat causes more U.S. fatalities each year than floods, storms, and lightning combined. At-risk groups include older adults, young children, outdoor workers, athletes, and those with chronic health issues.
Causes of the Extreme Humidity
The remnants of Hurricane Marie, formed during an active hurricane season linked to El Niño, contributed to the spike in humidity. Marie funneled tropical moisture into Southern California. Additionally, an ongoing marine heat wave has elevated ocean temperatures off California’s coast. Warm water extends from the Galápagos to Alaska, exacerbating local humidity levels.
Off the coast of Baja, ocean temperatures have soared, impacting California’s waters and contributing to record highs. Swain predicts future humidity waves, suggesting this summer’s humid conditions may not be the most extreme seen this decade.
Concerns for the Upcoming Winter
Recent coastal damage from significant waves and high tides has raised concerns. Weather forecasts warn of further beach erosion and coastal flooding, driven by elevated sea levels and Hurricane Marie’s energy. The sea level off Southern California is currently six to ten inches above average.
Forecasters are monitoring the arrival of a Kelvin wave, which could further raise sea temperatures and levels. Multiple Kelvin waves, associated with strong El Niño events, might impact California before fully subsiding.
These climatic changes are compounded by the ongoing rise in ocean temperatures fueled by human-induced global warming. As oceans warm, they expand, and melting ice sheets contribute to rising sea levels. Daniel Swain underscores the interconnectedness of global climate phenomena, reflecting their cumulative impact on local conditions in Southern California.