California is Heating Up, but It’s Oh, So Much Worse in the Cities
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California is Heating Up, but It’s Oh, So Much Worse in the Cities. Steve LaDochy, Professor Department of Geosciences & Environment, CSULA. Conference on Global Modernities, California State University, Los Angeles, May 4 th , 2013. WHAT IS THE URBAN HEAT ISLAND?.

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California is Heating Up, but It’s Oh, So Much Worse in the Cities

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California is heating up but it s oh so much worse in the cities

California is Heating Up, but It’s Oh, So Much Worse in the Cities

Steve LaDochy, Professor

Department of Geosciences & Environment, CSULA

Conference on Global Modernities, California State University, Los Angeles, May 4th, 2013


California is heating up but it s oh so much worse in the cities

WHAT IS THE URBAN HEAT ISLAND?

Cities tend to be warmer than their rural surroundings, with the peak of the “island” being located in the Central Business District.


California is heating up but it s oh so much worse in the cities

During hot weather, urban temperatures retain heat well into the nighttime.


The urban environment

The Urban Environment

Figure 3.29


California is heating up but it s oh so much worse in the cities

Urban materials tend to be less reflective and store heat to be released at night.


California is heating up but it s oh so much worse in the cities

Urban Heat Island-History

The phenomenon was first investigated and described by Luke Howard in the 1810s, although he was not the one to name the phenomenon.[1] The temperature difference usually is larger at night than during the day, and is most apparent when winds are weak. Seasonally, UHI is seen during both summer and winter. The main cause of the urban heat island is modification of the land surface by urban development which uses materials which effectively retain heat. Waste heat generated by energy usage is a secondary contributor.[2] As a population center grows, it tends to expand its area and increase its average temperature. The less-used term heat island refers to any area, populated or not, which is consistently hotter than the surrounding area.[3]


California is heating up but it s oh so much worse in the cities

California temperatures have risen about 2oF from 1950-2000, while urban areas have heated up much faster.


California is heating up but it s oh so much worse in the cities

Urban Heat Island Grows as Cities Grow


California is heating up but it s oh so much worse in the cities

  • HEAT KILLS

  • Heat kills by taxing the human body beyond its abilities. In a normal year, about 175 Americans succumb to the demands of summer heat.

  • Among the large continental family of natural hazards, only the cold of winter -- not lightning, hurricanes, tornadoes, floods, or earthquakes -- takes a greater toll.

  • In the 40-year period from 1936 through 1975, nearly 20,000 people were killed in the United States by the effects of heat and solar radiation. In the disastrous heat wave of 1980, more than 1,250 people died.


California is heating up but it s oh so much worse in the cities

  • HEAT KILLS

  • Heat kills by taxing the human body beyond its abilities. In a normal year, about 175 Americans succumb to the demands of summer heat.

  • In the 40-year period from 1936 through 1975, nearly 20,000 people were killed in the United States by the effects of heat and solar radiation. In the disastrous heat wave of 1980, more than 1,250 people died.


California is heating up but it s oh so much worse in the cities

2003 KILLER HEAT WAVES CROSSES EUROPE

2003 Heat Wave: between twenty to thirty-five thousand people -- the majority dying in the hottest period during the first two weeks in August.

The worst hit was France which lost more than 14,000 of it mostly elderly population in the unrelenting heat recorded as high as 104 degrees - temperatures that didn't cool down even at night. The event marks the 2003 European heat wave as the hottest summer in the northern hemisphere.


California is heating up but it s oh so much worse in the cities

About 15,000 deaths were related to the 2003 heat wave mostly in French cities where elderly were not prepared for 100+ temperatures.


California is heating up but it s oh so much worse in the cities

The Great Russian Heat Wave of 2010 is one of the most intense, widespread, and long-lasting heat waves in world history. Only the European heat wave of 2003, which killed 35,000 - 50,000 people, and the incredible North American heat wave of July 1936, which set all-time extreme highest temperature records in fifteen U.S. states, can compare. All of these heat waves were caused by a highly unusual kink in the jet stream that remained locked in place for over a month. The jet stream is an upper-level river of air, between the altitudes of about 30,000 - 40,000 feet (10,000 - 12,000 meters).


California is heating up but it s oh so much worse in the cities

St. Louis Frequency of Warm, Humid Air Masses

St. Louis experienced an average of three annual

three-day-or-longer runs of dangerously hot air masses

in the 1940s. That number has more than doubled,

to an average of seven such heat waves today.


California is heating up but it s oh so much worse in the cities

Chicago & St. Louis Air Mass Frequency Trends:

Cold Weather Type- Dry Polar (DP)

Chicago: 7.3 less DP days today than in the 1940’s

St. Louis: 3.7 less DP days today than in the 1040’s


California is heating up but it s oh so much worse in the cities

Source: Heat in the Heartland, UCS


California is heating up but it s oh so much worse in the cities

Source: Heat in the Heartland, UCS


California is heating up but it s oh so much worse in the cities

New Orleans, LA. electrical load can increase steadily once temperatures begin to exceed about 68–77°F (20–25°C). Other areas of the country show similar demand curves as temperatures rise. (EPA)


California is heating up but it s oh so much worse in the cities

New York City Energy Consumption rises with temperatures.

“Right now, we average about 14 days each summer above 90 degrees [in New York]. In a couple decades, we could be experiencing 30 days or more” .

“So we have two forces—urban heat islands and global warming—that are reinforcing each other and are going to create hot, hot conditions for more than half the world’s population,” Gaffin explains. “How do we make cities more habitable in the future?”


California is heating up but it s oh so much worse in the cities

Phoenix’ Urban Heat Island


California is heating up but it s oh so much worse in the cities

Summer nights are warming even faster in Phoenix, Arizona.


California is heating up but it s oh so much worse in the cities

Heat Waves in Southern California: Are They Becoming More Frequent and Longer Lasting?

Arbi Tamrazian, UC Berkeley , Steve LaDochy, California State University, Los Angeles,

Josh Willis and William C. Patzert, JPL


California is heating up but it s oh so much worse in the cities

Acclimatization to Heat Waves in Rome


California is heating up but it s oh so much worse in the cities

Mitigation: Trees and vegetation


California is heating up but it s oh so much worse in the cities

Mitigation: Cool Roofs


California is heating up but it s oh so much worse in the cities

COOL ROOFS

Potential net energy savings from changing roof reflectivity. Savings are measured in dollars. Note that the net savings are the savings of cooling energy use less the penalties of heating energy use.


California is heating up but it s oh so much worse in the cities

Mitigation: Green Roofs


California is heating up but it s oh so much worse in the cities

For example, researchers at

the University of California at Davis have estimated

that for every 1,000 deciduous trees in California’s

Central Valley, stormwater runoff is reduced nearly

1 million gallons—a value of almost $7,000.4 Clearly,

preserving trees reduces polluted stormwater discharges

and the need for engineered controls to replace

those lost functions. When those trees are cut down

and their functions are lost, those costs are passed on

to municipal governments, which then pass them on

to their citizens.


California is heating up but it s oh so much worse in the cities

Mitigation: Cool Pavements


California is heating up but it s oh so much worse in the cities

MITIGATION STRATEGIES


California is heating up but it s oh so much worse in the cities

GREEN (ECO)CITIES

Ecocity (sustainable city): an ecologically healthy city. It is to enhance the health and quality of life of their inhabitants and maintain the ecosystems on which they depend. It minimizes the input of energy, water and food and its wastes, output of heat, air pollution, and water pollution.


California is heating up but it s oh so much worse in the cities

http://www.harc.edu/Projects/CoolHouston/About/Video

Cool Houston


California is heating up but it s oh so much worse in the cities

The aerial photograph at left of Washington, DC, shows the amount of green space and vegetation present in 2002. The photo at

right shows how this same area would look in 2025 after a proposed 20-year program to install green roofs on 20% of city buildings

over 10,000 square feet.


California is heating up but it s oh so much worse in the cities

Street planters in Portland, OR, are used in

highly developed urban areas to introduce

green space and manage stormwater runoff.


California is heating up but it s oh so much worse in the cities

Questions?


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