A Look at Climate Change Effects On San Diego County

by on December 7, 2017 · 0 comments

in San Diego

Photo by Doug Porter

By Cynthia Wootton and Angela Deegan / SanDiego350

A recent presentation by Dr. Veerabhadran Ramanathan of UCSD’s Scripps Institution of Oceanography on climate change held locally (at the San Diego City Council Environment Committee meeting), made us wonder what climate change might look like here in San Diego County.

Typically, weather events will conform to two characteristics of climate change: more extreme and, generally, more frequent weather events.

Heat Spells

With climate change, “heat spells increase in temperature, frequency and duration, while cold spells decrease.” And it’s probable that more of the heatwaves will be humid — according to Alexander Gershunov, and others at the Scripps Institution of Oceanography at UC San Diego.

On June 20, 2017, NBC 7 reported that Ocotillo Wells, a desert city, “hit an all-time high of 124 degrees, breaking the all-time San Diego County high of 122 set in 2016” and was ”only 10 degrees shy of the hottest temperature ever recorded on earth.”

Water shortages

The San Diego Foundation report on climate impacts in San Diego predicts a 12 percent reduction in the runoff and stream flow that replenish the area’s major water sources. Meanwhile, by 2035, demand for water is expected to increase by 46 percent.

“Our reports tap the latest science to best understand how climate change will impact our region, in terms of water, precipitation and wildfires,” said Emily Young, vice-president of community impact at the San Diego Foundation. “We found the major impact is on water supply.”

Water shortages affect us as water consumers in our homes and yards, but also affects wildlife and crop production. Agriculture, ecosystems, and urban areas compete for reduced water. More groundwater is used to meet demand and levels have been declining for decades.

Sea level rise and flooding

Sea level rise from global warming will affect low-lying areas of the county. But other causes of flooding that we already experience — storm surge and extreme high tides — will amplify the effects. King tides (the very highest tides) are getting more severe and reaching farther into San Diego than ever.

The San Diego ZIP code with the most people exposed to a rising sea in San Diego is 92109 — Mission Beach and Pacific Beach — with 2,608 people living below 3 feet elevation.

A recent example of a king tide flooding event was in November 2016, with street flooding near Midway Drive and Barnett Avenue at Windansea Beach, La Jolla.

Rain storms and flooding

The region will have 16 percent fewer rainy days, but 8 percent more rain during large, intense storms, which could lead to more frequent flooding, according to the San Diego Foundation report.

In addition to property damage and disruption of transportation, flooding leads to our ocean becoming more polluted. Flooding carries urban runoff such as pesticides and herbicides. Also, when wetlands are flooded, they can’t perform their function of stopping pollution from flowing into the ocean or blocking beach erosion. Severe storms and floods can inundate sewage systems, causing backups on properties. Floodwater often contains infectious organisms and viruses, causing public health issues.

Some examples of flooding from rainfall in the last few years include November 3, 2015, when San Diego recorded a one-day total of 1.09 inches of rainfall, setting a daily rainfall record. Elsewhere 0.10 to 1.5 inches of rain fell – heaviest in southern San Diego County. It resulted in flooding in Spring Valley and Lemon Grove with water up to the doors of some vehicles and several roads closed.

Then in early January 2016, a series of storms hit southern California with moderate to heavy rain. This came after several years of drought. Floods buried cars in Ocean Beach and Mission Valley. High water rescues occurred on 1.6 around San Diego. Small mudslides, including boulders on highways, were reported near Ramona and Rancho San Diego.

Storms like these are likely to get more intense with climate change, bringing with them more severe consequences.


Global warming will likely heighten the risk of large, more difficult to control wildfires scorching the western United States, including San Diego. “Climate absolutely affects fire because it affects how flammable the fuels are,” according to LeRoy Westerling, a professor at UC Merced who has been studying climate and wildfires for the past 15 years.

With the increase in drought and heat that climate change brings, trees are vulnerable. If they don’t die directly from drought, they are more vulnerable to attack by pests which can kill them. They then become fuel for wildfires.

Pests are “taking advantage of the longer summer season which grants them longer breeding circles and faster reproduction” according to Jason Funk, a senior climate scientist with the Union of Concerned Scientists. Our Forest Service reports that “Over the past five decades, numbers of “exotic pests” have “increased from 10 to 33 percent.”

A 2010 Cal Fire report identified the gold-spotted oak borer (GSOB) as an emerging non-native pest in San Diego County that is “of great concern to forest pest management staffs”. The report indicated that GSOB covered an area of about thirty square miles in the interior of San Diego County and has killed over three quarters of the mature black oak and coast live oak in the impacted area.

Some of the major fires in San Diego include the October 2007 Witch Creek Fire which required evacuations of residents in Del Mar area, Chula Vista, Poway and Scripps Ranch, and two Indian Reservations — Mesa Grande and Barona. Twenty two burn victims had to be airlifted from CalFire’s Potrero station. In November 2003, wildfires caused “over one billion dollars in damages. The Cedar Fire itself consumed 273,246 acres and killed 15 people.” It broke records as “the largest recorded wildfire in California history, and the second costliest fire in U.S. History.

General changes

The climate change effects above are interrelated and together will cause us more distress. Extreme Weather events can cause (and exacerbate) health problems, power outages and lead to people being displaced from their homes temporarily or even losing their homes. Many things that we love about San Diego will change.

Additionally, we need to factor in the additional stressor of population growth that will accompany these climate change effects. In July 2016, the population of San Diego County was estimated at 3.3 million. By 2050, the forecast is nearly 4 million.


Fortunately, there is hope. After the shameful US decision to pull out of the Paris Agreement, which aims to limit global temperature rise to below 2 degrees Celsius, a bi-partisan coalition of states dubbed the “U.S. Climate Alliance” formed. This alliance is committed to the goal of reducing greenhouse gas emissions consistent with the goals of the Paris Agreement.

And locally, the City of San Diego adopted a strong Climate Action Plan in 2015 – a plan which includes a goal of 100% of the electricity used in the city being from renewable sources by the year 2035.

Dr. Ramanathan and other experts believe that we can prevent “the gravest threats from taking place”. He says California is a “petri dish for international efforts to slow global warming under legislation signed by Gov. Jerry Brown” to cut emissions by 40% by 2030.

But we must act fast. According to Bill McKibben, co-founder of international climate action group 350.org, “If we don’t win very quickly on climate change, then we will never win.

Get involved

There is ample opportunity to get involved in climate solutions in San Diego. SanDiego350 is dedicated to stopping the worst effects of climate change through education, outreach and public policy advocacy. We train volunteers to be effective climate advocates and get involved in important local climate campaigns such as Community Choice Energy. In coalition with other local groups, SanDiego350 is working on campaigns to reduce greenhouse gas emissions to protect San Diegans, our kids and future generations from the ravages of climate change.

See how you can get involved by contacting our Volunteer Coordinator at volunteer@sandiego350.org! Let’s act now for a safer, more hospitable San Diego for all.

Cynthia Wootton is actively working for many environmental, political groups and social justice groups. She is on the Sierra Club Conservation Committee Board.

Angela Deegan has been a member of SD350 since 2011. She lives and works in La Mesa.

This first appeared at San Diego Free Press

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