Planet Earth Weekly

Climate Change and Renewable Energy: Saving Our Planet for Future Generations


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 Agrivoltaics: Growing Food for the Future

Agrivoltaics

Agrivoltaics: Food and Solar

“Agrivoltaics combines agriculture with energy efficiency while growing plants beneath solar panels.”

By Linn Smith

January 28, 2018—- Co-location means two or more groups, sharing the same place. Agrivoltaics, also known as Agrophotovoltaics, means using the same piece of land for solar power plus agriculture. Agrivoltaics, or solar farming, is a new way of growing plants, combining agriculture with energy efficiency while growing plants beneath solar panels.

Agrivoltaics: Dual Use of Land

In 1981, Adolf Goetzberger and Armin Zastrow developed the idea to improve overall production of crops. Dr. Goetzberger founded the Fraunhofer Institute for Solar Energy Systems in Germany. His work involved making solar an alternative to fossil fuels. In 1981, he published a paper titled, “Potatoes under the Collector,” which proposed a setup for solar energy systems in combination with agricultural land use.

agrivoltaics

Growing food with solar

Dr. Eicke Weber, Director of the Fraunhofer Institute stated, “In view of the dynamic worldwide growth of solar installations of the last decade and the increase in land usage resulting from solar installation systems, innovative concepts, like agrophotovoltaics (agrivoltaics) which facilitates the dual usage of agricultural land, help to further and accelerate the transformation of the global energy system.”

Dr. Goetzberger used the term Agrophotovoltaics or APV, as a method of harvesting the sun for both power and production of crops. APV is currently an ongoing project in Germany which demonstrates that land for both growing crops and solar electricity are compatible. Dual use of the land is resource efficient, reduces competition for land and opens up a new source of income for farmers.

The APV System

The APV system was installed on organic farmland in Germany in 2015. Approximately seven acres were used to produce crops under the ground-mounted solar panels, which were built about 5 yards off the ground. Four different crops were planted. The land in use not only generates electricity from the solar panels but is also growing food. The solar panels provide a uniform light distribution on the crops using reflection. To prove their theory, they also planted a control plot nearby using the same 4 crops, excluding the solar panels. The scientists wanted to determine which crops would grow best. Result: The crops under the APV system produced about 80% of that of the control crop. This experiment is ongoing and data will be analyzed in 2018.

agrivoltaics

Agrivoltaics: Growing food to feed the planet.

Agrivoltaics and Biosphere2

A similar experiment was being conducted at Biosphere2 when I visited several weeks ago. This research, headed by Barron-Gafford, Assistant Professor, revealed that the solar system above the crops created a warmer environment than normal when no plants were beneath , similar to the heat-island effect that happens in cities surrounded by cement and asphalt. He stated, “So think about it, if you get rid of all the plants when you put in renewables energy, you’ve gotten rid of that cooling potential… plants under the panels would allow the air to circulate and would take up carbon for photosynthesis by opening up their pores, or stomata, while letting water escape from their leaves and you get a warmer environment. We wanted to see if you put the cooling effect back into the system by growing plants beneath the solar panels, you can actually cool those panels back down and mitigate that heat island effect.”

When solar panels get too warm they start to lose their efficiency. By growing plants beneath the panels they can cool down and retain that efficiency, which makes for more renewable energy per parcel of land. The panels also shade the plants, reduce evaporation and the crops require less water to grow underneath.

agrivoltaics

Agrivoltaics

In the future, as world population grows, solar and land for food must not be in competition. The world population today is approximately 7.6 billion. Two hundred years ago it was 1 billion. At the close of the 21st century the population will be more than 11 billion. The question remains…will we be able to feed our planet’s population and meet the demand for clean energy?

Agrivoltaics and Clean Energy

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Climate Change: Is it in your backyard yet?

Fires will threaten homes and wildlife habitat year around.”

By Linn Smith

December 9, 2017—–Many climatologists say that people won’t change their destructive habits until the effects of climate change “are in their own backyard.”

Are we there yet?

Is it in our own backyard? An example of “in my backyard” came in the form of a rattlesnake in my path several weeks ago. In Arizona, most of the snakes have slowed down and are more or less invisible starting in November. Because of unusually warm temperatures this year, the rattlers were slithering about in the paths of many unsuspecting people out for a stroll. 

As I took my dog for a walk one evening, my headlamp picked up a rattler about 6 feet ahead, stretched out and warming itself on the heated asphalt. I could have easily stepped on it if I hadn’t been paying attention. Warming temperatures are changing the habits of wildlife!

The California Fires

The fires in California in December are another example. Scientists have stated, “In the future there will be no fire season. Fires will threaten homes and wildlife habitat year around.”

According to insideclimatenews.org, climate change along with other factors are fueling the California fires by, “epic winds, dry brush and high humidity,” allowing a small ember to create a disaster.

In California high temperatures have caused a drought which has left much dry timber and underbrush vulnerable to fire. The slightest mishap, such as downed utility lines, a careless toss of a cigarette or embers from a campfire, can lead to a disaster. “As long as there’s fuel to burn, your chances of having a large fire increases when temperatures increase, it’s as simple as that,” said Park Williams, a Bioclimatologist.

Though research models don’t always agree, many studies show that if carbon emissions continue at a high level, extreme weather resulting in fires, flooding and hurricanes will continue to increase rapidly in strength and frequency. 

Now is the time to do your part in creating a healthy planet for present and future generations.

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Climate Change Over Geological Time

Glacial Ages and Climate

Climate Change Over Time

“Climate change at the present is of great consequence to most species including humans.

By Dr. John J. Hidore

November 15, 2017—-Planet Earth was formed about 4.5 billion years ago. Geologists have divided this long history of the planet into several pieces called eras. They are the Precambrian, Paleozoic, Mesozoic, and Cenozoic.

The Precambrian is the longest and each of the other three are shorter than the previous one. When considering climate change through geologic time, two aspects stand out. The first is that for most of geologic time Earth has been warmer than it is at present. How much warmer varied through time. The second feature that stands out is the intermittent ice ages when large portions of the earth were covered with ice.

Major Ice Ages

Relatively little is known about the long period of Precambrian time. Basically it was the period during which the earth cooled from its initial very hot state. The Paleozoic, Mesozoic, and Cenozoic eras encompass the rest of geologic time, about 570 million years. More evidence, and a greater variety of
evidence, is available about the environment during these eras. The climate of Earth varied widely during this time. However, it has been established that there were three known periods of glaciation in Precambrian time. They were:

Archeozoic 2250 million years ago (mya)
Early Precambrian: 950 million years ago
Late Precambrian: 750 million years ago

There were four major glaciations following that of the Precambrian era. They were:

Early Cambrian: 650 mya
Ordovician: 450 mya
Permo-Carboniferous: 350-250 mya
Pleistocene: 1.8 mya until recent time

Following the ice age at the end of the Precambrian, the earth rapidly warmed. For the remainder of the history of the earth, temperatures have averaged 5 degrees C (9°F) higher than at the present. These warmer conditions existed probably 90 percent of the time over the past 570 million years.

The Permo-carboniferous Ice Age

An ice age, called the Permo-carboniferous, began at the end of the Paleozoic Era. It began about 325 million years ago and lasted until about 250 million years ago. The South Pole was in the midst of the large land mass called Gondwanaland. Ice sheets moved over about half of this large land mass. What is now Antarctica and parts of Australia, India, Africa, and South America were covered with ice. The glaciation of each of these areas did not take place at precisely the same time, but they were all affected by the same climatic cooling. The Southern Hemisphere suffered widespread glaciation, but the Northern Hemisphere remained warm. The most appealing explanation for this situation is a different relative location of the land masses. The northern continents were nearer the equator and the southern land masses nearer the poles.

Climate Change

Climate Change over time.

The Warming of the Earth

After the glaciation in the Permo-Carboniferous ice age, the earth again entered a long period of warm conditions. The period of warmth continued through most of the Mesozoic Era and the earth was free of glaciation. Temperatures were warm and rainfall was abundant on the land masses. Even the polar regions experienced mild weather. Initially, the warmer conditions resulted from the slow migrations of the large southern hemisphere land mass to the north. This carried areas that had been glaciated into warmer climates.

The Pleistocene Ice Age

The most important single environmental event since the human species has been on earth has been the oscillation between glaciation and interglacials during the Pleistocene Epoch. The epoch represents a large change from much of the last 570 million years. This ice age is the most recent of the major cold periods to occur over the history of the planet. During the time when the ice was most extensive over Earth, temperatures averaged about 4°C (7°F ) lower than those of the present. In the northern hemisphere it was perhaps 8 to 12 °C ( 14 to 22°F) lower than current temperatures. 

There is no question but what the climate of planet earth has changed frequently, and sometimes drastically, over geologic time.

Climate Change Today

Climate change at the present is of great consequence to most species including humans. There is really no way of knowing how much change will take place in the foreseeable future nor how much is due to the activity of our species. What is known is the earth is warming rapidly at this time and that all evidence points to human activity as bearing the responsibility.

Now is the time to take international action and not only support the Paris Agreement, but take even more drastic measures to curtain the warming!

Climate Change

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Puerto Rico: Rebuilding Sustainably

Renewable Resources

 

“Building sustainably in Puerto Rico can take many different forms.” 

By Linn Smith

October 19, 2017—Even though Puerto Rico is going through a devastating time after the hurricane, it is essential that we not only meet the current needs of the people, but also think about its future….rebuilding sustainably. Areas devastated by wind and flooding must not only think about immediate needs, but consider the future way climate change may threaten vulnerable coastal areas. 

There is an agreement among scientists that our warming climate is producing larger, more aggressive hurricanes, and rising oceans are leading to stronger storm surges, destroying and flooding inland areas.

Puerto Rico: Sources of Energy

According to the U.S. Energy Information Administration, Puerto Rico has some renewable solar, wind, hydropower and biomass resources, but relies primarily on imported fossil fuels to meet its energy needs, importing mostly from the U.S.

In 2016, Puerto Ricans paid more for their power than people in any other state except Hawaii, with 47% of electricity coming from petroleum, 34% from natural gas, 17% from coal and only 2% from renewable energy.

The Future of Energy in Puerto Rico

Now is the time to make decisions about Puerto Rico’s future energy needs. How will Puerto Rico get its power in the future? PREPA, the Puerto Rico Electric and Power Company, Puerto Rico’s only utility company, is mismanaged and highly in need of upgrading according to some sources. According to http://www.commondreams.org, it would be a waste to pour more money into this system. Instead, we need to invest funds into local renewables and energy efficient transportation, such as streetcars and light rail trains. 

Richard Heinberg in the article “Disaster in Puerto Rico” stated, “This is a chance to build back sustainably. People tend to maintain their status quo as long as it’s viable, but when in dire straits, they’re more likely to listen and when denial is no longer possible, people are more likely to face reality.”

Eigg renewables

Eigg uses 99% Renewable Energy

Eigg, Scottland: 99% Renewable

According to an article by David Nield, March 2017, http://www.sciencealert.com, researchers from around our planet are visiting the tiny, Scottish island of Eigg, which is using wind, solar and hydo to obtain the island’s power. This system, owned and operated by the island’s residents, has been using sustainable energy since 2009. Eigg Electric uses a combination of sustainable resources to ensure there is always energy. When back-up energy is needed, it’s supplied by several diesel generators with cables linking all the sources of energy together. Renewable energy is used 95% of the time and excess energy is stored in a bank of 100 batteries. When these batteries are full, electric heaters automatically switch on in the church and community hall so nothing is wasted. Eigg’s population has doubled since this system has been in place, but the system is still meeting the needs of the residents. The drawback is that citizens are limited to the amount of power they can use daily from the public utilities
.
Ta’u, a small island in Samoa, is also changing from diesel to renewables. Today it’s powered by 5,000 Solar City solar panels and 60 Tesla Powerpack battery storage units. The Powerpack is a massive battery, 16 Powerwall battery pods encased in a weatherproof box, that can store electricity during the day when supply is abundant and discharge it when demand goes up after the sun goes down. This system provides the island with about 99% of its needs.

Tesla solar project in Hawaii.

Tesla and the Powerpack Battery

Tesla has also built a huge solar energy plant on the island of Kauai, one of Hawaii’s main islands. This project will reduce fossil fuel by 1.6 million gallons per year. The island signed a 20 year contract with Tesla to buy solar generated electricity from solar panels installed on the island for 13.9 cents per kilowatt hour. The average price of electricity in Hawaii is 37.34 cents per kwh, the highest rate in the nation. Kauai is the first major solar/storage project for Tesla. Tesla states, “We will work with energy providers around the world seeking to overcome barriers in the way of building a sustainable, renewable energy grid of their own.”

Tesla is also in the process of shipping battery packs to Puerto Rico, but details of the project have not yet been made available. Building sustainably in Puerto Rico can take many different forms and accepting help from Tesla could be a starter.

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Puerto Rico: Build Sustainably


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Solar Christmas Lights: A Review

solar Christmas

With solar Christmas lightning, no chords are necessary.

By Linn Smith

“My rating today depends on where the light energy comes from, the grid or the sun.”

September 25, 2017—-We all love driving around at Christmas time, looking at the multi-colored Christmas lights that decorate our neighborhoods. My family likes to rate them on a scale of 1-10, which would end in a discussion of the pros and cons of the lit up yard full of decorations. We had our rating scale, a one on our scale was for just a few white lights and a 10 was a yard full of colored lights and decorations.

My rating today depends on where the light energy comes from, the grid or the sun.  Is the utility bill higher in December because of an abundance of Christmas lights….or are we taking what’s free from the Sun?

Solar Christmas lights Make it a solar Christmas.

Solar Christmas Lighting

A string of Christmas lights uses a small solar panel which sticks into the ground. Some are adjustable for optimum charging with the angle of the sun.

http://www.Solartechnologyhub.com reviews several types of outdoor Christmas lighting. The Editor’s Choice is a string of lights from http://www.innootech.com. This string is almost 20 ft long, is water resistant, and fully charges in 6-8 hours. They will light up your yard for 8-10 hours and cost about $14.00. Also from this site are colorful flower solar strings for the same price. This solar string has an adjustable solar panel design for direct sunlight all year around.

Walmart has a variety of indoor/outdoor solar Christmas lights in the store and online ranging from $10-$20, plus many more stores today, such as Home Depot, are carrying them on their shelves.

Solar Christmas lights

Solar Christmas lights provide the same lighting as other lights.

Advantages of Solar Christmas Lights

1. Though Christmas lights can be relatively inexpensive when running off of grid electricity, use what is free, the sun!

2. Christmas lighting is comparable to other lighting.

3. Solar lighting withstands rain and snow.

4. No extension cords to worry about.

Whether you save a few cents or a few dollars on your electrical bill , it is still free and environmentally friendly. Think Green!

You can recycle Christmas lights at Ace Hardware, Home Depot or most recycling centers.

Go Solar!

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Conventional, Hybrid and Electrical Vehicles: What’s the Difference?

hybrid cars

Hybrid cars are better for our environmentl

“Things are slowly changing and, as our power grid across the U.S. changes, so will the energy available to the cars.”

By Linn Smith

September 6, 2017—-I drive a hybrid car and have been asked many times if I have to put gas in it. The answer is yes. The term, hybrid, has gotten more complicated in the past several years, as now there are hybrid gas-electric no plug-ins, gas-electric plug-ins and all electric vehicles. Conventional cars, which burn gas and diesel, release toxic fumes into our atmosphere, exacerbating illnesses such as asthma.
Though hybrids may still leave a carbon footprint in the manufacturing process, and with the source of electricity used to energize the electric engine, they still have a future of burning clean. As solar replaces the conventional sources of power in the production of these vehicles and clean energy is produced for our power plants, the carbon footprint decreases.

Hybrid cars

Hybrid vs Electric

Types of Hybrid and Electric Vehicles

Here is the breakdown in types of hybrids and electrical cars:

1. Conventional Vehicles: Use gas or diesel fuel.

2. Hybrid no plug-in vehicles: A hybrid is a car that draws energy from 2 or more sources. These cars have a regular combustion engine and battery just like a conventional car, but they also have an electric motor and battery. They are never plugged in to outlets. According to itstillruns.com, “The Prius uses an advanced charging system that allows the battery to tap into power from the Prius’ gasoline engine while using kinetic force from braking to generate additional electricity.” The electrical engine is powered by the gas engine, plus the braking system, and kicks in when driving slowly or idling, which makes it fuel efficient and reduces emissions. These cars aren’t considered electric cars, as they rely on gas for their energy. I average about 48 mpg with mine.

3. Plug-in hybrids: These cars are considered electric hybrid cars, as they rely on a conventional outlet for power plus gas. They combine a gas engine with an electric motor and a plugin rechargeable battery. They can be plugged in to a regular 12 volt outlet, allowing then to drive miles on the energy from that outlet. When the electric battery is depleted then the conventional engine kicks in, operating on gas.

Tesla Model X

Tesla All Electric cars

4. All Electric vehicles: The batteries of these cars are charged using grid electricity. They can use a 12 volt outlet or a charging unit, like the units Tesla has installed across the U.S. They are powered entirely by electricity. The gasoline engine is replaced by an electric motor which gets its power from a controller which is powered by the rechargeable battery. The controller takes in 300 volts DC and converts it into a maximum of 240 volts AC to send to the motor.

The Environmental Impact of Cars

Many people will argue that electric cars are beneficial to the environment only if the electrical source is from renewable energy. This is true, but things are slowly changing and, as our power grid across the U.S. changes, so will the energy available to the cars. Keep fossil fuels in the ground!

Hybrids and Electric Cars

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Gothenburg Sweden: Providing Sustainability through Green Bonds

Gothenburg, Sweden

Build sustainably with green bonds.

“Local governments wield significant influence and authority that can drive environmental sustainability within their jurisdictions.”

By Linn Smith

August 6, 2017—–In the late 19th century Gothenburg developed into an industrial city. In 1987 the Minister of the Environment called parts of the city, “hell’s waiting room” which described the environment for the industrial part of the city, dirty and polluted. Chemicals were escaping into the environment and appearing in animals, fish and mother’s milk, increasing cancer risks and lowering the immune system of infants. This was the Gothenburg of yesterday!

From Industrial City to Climate Leader

Today, Gothenburg has transitioned from industrial city to a world climate leader. In 2013, it became one of the first cities in the world to issue Green Bonds. 

Bonds allow the public to invest sums of money. When a person purchases a bond they lend money to the issuer of the bond, in this case, the city of Gothenburg. In return investors are paid a specific interest rate. 

Green bonds are linked to solving our climate change disaster by providing the money necessary for a community to build sustainably. They are earmarked for environmental projects.

Gothenburg, Sweden

Go Green with Green Bonds

Building Sustainably with Green Bonds

Gothenburg offers Green Bonds to the public, which allows the city to borrow money from investors. With this money the city creates climate change projects that allow a transition from a polluted city to one of low carbon emissions and climate-resilient growth. Without the Green Bonds Gothenburg would have struggled with decisions on funding schools and daycare or moving the city toward sustainability.

Gothenburg, Sweden

Gothenburg goes green with Green Bonds

Projects Funded by Green Bonds

Some of the projects funded by Green Bonds are:

• Large scale production of biogas, providing high efficiency in production and recycling of waste heat for district heating and electricity.
• Electric cars for city and companies, with 100% electric cars in the city fleet.
• Energy efficient traffic lights
• Sustainable housing. These buildings use green electricity. Estimation shows that the sustainable housing built so far will avoid 50-60 tons of Co2
emissions in the atmosphere annually.
• Tree planting. 1710 trees have been planted since the projects funded by Green Bonds started, with a focus on a green cityscape, which effects the
urban air quality and temperatures of nearby buildings.(See https://planetearth5.com/tag/heat-islands/)
• Sustainable transportation. Improvements to the city’s bicycle infrastructure. The city offers 1,000 bikes with 69 stations in the city to leave
your bike. You can pick up a bike, ride it to your destination and drop it off at the nearest station.
• A sustainable airport. All energy at the Gothenburg airport comes from renewable sources. Heat is generated by biomass boilers. There are also
charging stations for electric cars. Take off fees for airplanes are reduced for those with lower emissions of nitrogen oxides and hydrocarbons. 75%
of the airport shuttle buses run on RME, a biofuel made from rapeseed (related to canola oil.)
• The city’s SJ trains run entirely on renewable electricity from wind and hydro power.
• A sustainable port. Gothenburg is a coastal city. Ferries and ships which are docked in Gothenburg are encouraged to connect to an onshore power
supply, which is a source of clean energy. “Providing an onshore power supply for vessels at berth can result in significant environmental gains.
Carbon dioxide emission decrease substantially and emissions of sulphur dioxide and nitric oxide are reduced to a minimum. Onshore connections also
provide a quieter environment and cleaner working conditions.”
• The largest ultrafilter built in Scandinavia. City water is treated by ultrafilter to assure the highest quality of drinking water for its citizens.

Linking Investments to Green Projects

Green Bond investing has led to greater interest by citizens in the environment, plus it creates a link between investments and speeding up green projects. 

Other cities are following suit. Toronto issued Green Bonds to finance a heat, power and cooling solar plant. Johannesburg just issued green bonds to finance green projects that will reduce greenhouse emissions and contribute to a sustainable city.

The California Sustainability Alliance said it well. “Local governments wield significant influence and authority that can drive environmental sustainability within their jurisdictions” and further influence the global greening of our planet!

Gothenburg-Green Bonds

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Solar Uses in the West: Monitoring the Irrigation Ditch

solar water monitor

Solar monitors the flow of water.

“It’s predicted that in the future, solar will be the main source for controlling our water systems in the West.”

By Linn Smith

June 23, 2017—In the eastern section of the U.S., water is easily obtainable. In the west, where dry land prevails, water rights are taken seriously.

How is water diverted to arid land? Irrigation ditches are man made channels that deliver water to homes, farms or industries. They have head gates on creeks and water sources to divert water to these arid regions.

solar monitor

Monitor water flow through solar

Water Rights

In the West and Southwest U.S., a person diverting water through a canal needs legal rights, because there are many demands on the water between individuals, industries and cities. In the 1800’s miners depended on water rights for mining of gold and other minerals, and pioneers depended on water rights to irrigate crops far away from the stream.

Colorado developed the Prior Appropriation Doctrine which is still in use today. It states that, “The first person to divert water and apply it to a beneficial use has a prior or senior right to the water over any other user who seeks to use water at a later time.” This secures the amount and date of senior users. Water rights in Colorado are property rights and can be bought, sold or rented apart from the land through which they run, if the water is put to beneficial use.

In New Mexico a person needs to obtain a permit through the State Engineer Office. The office will evaluate and determine if water is available and would not impair existing water rights.

Solar

Solar monitors the flow of water in irrigation ditch

Irrigating

In New Mexico I helped surface irrigate (flood irrigate) a friend’s ranch from an irrigation canal, which ran above ground. Irrigating consisted of opening the irrigation gate by hand and allowing water from the canal to run over the horse pasture. We were able to control the amount of water on the pasture by sliding the gate down when the water was sufficient for healthy pasture growth. This has been the most common type of irrigation in most parts of the world.

solar for irrigation

The irrigation ditch runs through this horse pasture to keep it green and usable.

Solar Powered Water Moniters

Recently a solar monitor was added to an irrigation ditch nearby, which runs through farmland and continues to a large lake. The gate of the irrigation ditch was previously open and closed by hand, but now a solar monitor opens and closes the gate to prevent flooding from unused water in the ditch.

solar

Solar to monitor irrigation ditch

In an article, Solar-Powered Automation on Irrigation Delivery Systems, it states, “The most popular do it yourself solar automation model consists of a 1/16 inch horsepower gear motor, a bicycle-type lift apparatus, (chain and sprocket) and a cover over the gate stem which contains a gate position sensor and limit switches. The gate system is usually powered by 1 or 2 deep-cycle batteries which are charged by a 20-40 watt solar panel. The gear is attached to the 12 volt DC gear motor with an industrial chain.”

irrigation ditch

Water flows through irrigation ditch to lake

It’s predicted that in the future, solar will be the main source for controlling our water systems in the West, from pumping up groundwater for cattle to monitoring the amount of water in irrigation ditches. Again, sunshine prevails!

Solar!


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Urban Heat Islands: Their Effects and Solutions

the heat island effect

Heat Island prevent heat from escaping cities.

“As urban areas grow a person’s health will be connected to the build up of heat and pollution in the city…..it will become essential to build green.”

By Linn Smith

April 20, 2017—–If you live in a city you probably have noticed how much cooler it is in the summertime when you take a drive in the country. Drive back toward the city, with its concrete buildings, and you feel the great intensiveness of a hot summer day. There’s a name for this city heat….the urban heat island effect.

What is a Heat Island?

An urban heat island describes a large area of buildings and concrete (cities) that has temperatures which are higher than the countryside surrounding them. According to http://www.epa.gov, “The annual mean air temperature of a city with 1 million people or more can be 1.8–5.4°F (1–3°C) warmer than its surroundings. In the evening, the difference can be as high as 22°F (12°C).” With global warming the temperatures of the heat islands will continue to increase.

Urban heat profile

Urban areas hold heat.

What Causes the Build Up of Heat?

As you enter a city you may notice concrete and asphalt surrounding you—-buildings, parking lots, streets and side walks. The concrete and asphalt absorb the sun’s heat rather than reflecting it, causing surface temperatures to rise. The rise in temperature also causes a depletion of vegetation resulting in less shade and moisture in the air. The resulting heat requires an increase in energy consumption—air conditioning which results in greater electrical use. This  cycle  keeps revolving—a catch 22 in which there is no escape from the merry-go-round of negative conditions from heat build-up.

Smog and Heat Islands

Cities can also cause “hotspots” of pollution. This smog can trap heat over a city, holding in the gases from coal burning facilities and vehicle emissions, not allowing them to escape into the atmosphere (the greenhouse effect). In addition, the closely built structures resist air flow, keeping the air trapped in the city, unlike the countryside which cools off as the air flows more freely.

Health Effects of Heat Islands

Some of the more obvious effects of heat islands are discomfort, breathing problems, heat stroke and exhaustion. But they can also be related to cardiovascular disease, sleep deprivation, depression and many more!

urban heat island

Build Green

Minimizing the Heat Island Effect

New technologies for minimizing heat islands are rapidly being developed. Several techniques currently in use for developing green urban areas are:

*Cut down on heat absorbing materials, such as asphalt and cement, by using more reflective surfaces for paved areas.The pavement can be enhanced by using reflective aggregate, a reflective or clear binder or a reflective surface coating.
*Plant trees that shade streets and paved areas.
*Use white roof membranes instead of black.
*Create a green roof–rooftop gardens.
*Create rooftop decks made from wood.
*Increase shade around buildings.
*Use energy efficient appliances and equipment which cut down on electrical use.

As National Geographic summarized, “Urban heat islands can have worse air and water quality than their rural neighbors. They often have lower air quality because there are more pollutants (waste products from vehicles, industry, and people) being pumped into the air. These pollutants are blocked from scattering and becoming less toxic by the urban landscape: buildings, roads, sidewalks, and parking lots.”

As urban areas grow a person’s health will be connected to the build up of heat and pollution in the city…..it will become essential to build green. The planning stage for this is now!

Urban Heat Islands

building green

build green