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Saturday, February 23, 2013
Global Warming Solutions
The evidence that humans are causing global warming is
strong, but the question of what to do about it remains controversial.
Economics, sociology, and politics are all important factors in planning
for the future.
Even if we stopped emitting greenhouse gases
(GHGs) today, the Earth would still warm by another degree Fahrenheit or
so. But what we do from today forward makes a big difference.
Depending on our choices, scientists predict that the Earth could
eventually warm by as little as 2.5 degrees or as much as 10 degrees
Fahrenheit.
A commonly cited goal is to stabilize GHG
concentrations around 450-550 parts per million (ppm), or about twice
pre-industrial levels. This is the point at which many believe the most
damaging impacts of climate change can be avoided. Current
concentrations are about 380 ppm, which means there isn't much time to
lose. According to the IPCC, we'd have to reduce GHG emissions by 50%
to 80% of what they're on track to be in the next century to reach this
level.
Is this possible?
Many people and governments are already working hard to cut greenhouse gases, and everyone can help.
Researchers
Stephen Pacala and Robert Socolow at Princeton University have
suggested one approach that they call "stabilization wedges." This means
reducing GHG emissions from a variety of sources with technologies
available in the next few decades, rather than relying on an enormous
change in a single area. They suggest 7 wedges that could each reduce
emissions, and all of them together could hold emissions at
approximately current levels for the next 50 years, putting us on a
potential path to stabilize around 500 ppm.
There are many
possible wedges, including improvements to energy efficiency and vehicle
fuel economy (so less energy has to be produced), and increases in wind
and solar power, hydrogen produced from renewable sources, biofuels
(produced from crops), natural gas, and nuclear power. There is also
the potential to capture the carbon dioxide emitted from fossil fuels
and store it underground—a process called "carbon sequestration."
In
addition to reducing the gases we emit to the atmosphere, we can also
increase the amount of gases we take out of the atmosphere. Plants and
trees absorb CO2 as they grow, "sequestering" carbon naturally.
Increasing forestlands and making changes to the way we farm could
increase the amount of carbon we're storing.
Some of these
technologies have drawbacks, and different communities will make
different decisions about how to power their lives, but the good news is
that there are a variety of options to put us on a path toward a stable
climate.
What Is Global Warming?
Glaciers are melting, sea levels are rising, cloud
forests are drying, and wildlife is scrambling to keep pace. It's
becoming clear that humans have caused most of the past century's
warming by releasing heat-trapping gases as we power our modern lives.
Called greenhouse gases, their levels are higher now than in the last
650,000 years.
We call the result global warming, but it is
causing a set of changes to the Earth's climate, or long-term weather
patterns, that varies from place to place. As the Earth spins each day,
the new heat swirls with it, picking up moisture over the oceans, rising
here, settling there. It's changing the rhythms of climate that all
living things have come to rely upon.
What will we do to slow this
warming? How will we cope with the changes we've already set into
motion? While we struggle to figure it all out, the face of the Earth as
we know it—coasts, forests, farms and snow-capped mountains—hangs in
the balance.
Greenhouse effect
The
"greenhouse effect" is the warming that happens when certain gases in
Earth's atmosphere trap heat. These gases let in light but keep heat
from escaping, like the glass walls of a greenhouse.
First,
sunlight shines onto the Earth's surface, where it is absorbed and then
radiates back into the atmosphere as heat. In the atmosphere,
“greenhouse” gases trap some of this heat, and the rest escapes into
space. The more greenhouse gases are in the atmosphere, the more heat
gets trapped.
Scientists have known about the greenhouse effect
since 1824, when Joseph Fourier calculated that the Earth would be much
colder if it had no atmosphere. This greenhouse effect is what keeps the
Earth's climate livable. Without it, the Earth's surface would be an
average of about 60 degrees Fahrenheit cooler. In 1895, the Swedish
chemist Svante Arrhenius discovered that humans could enhance the
greenhouse effect by making carbon dioxide, a greenhouse gas. He kicked
off 100 years of climate research that has given us a sophisticated
understanding of global warming.
Levels of greenhouse gases (GHGs)
have gone up and down over the Earth's history, but they have been
fairly constant for the past few thousand years. Global average
temperatures have stayed fairly constant over that time as well, until
recently. Through the burning of fossil fuels and other GHG emissions,
humans are enhancing the greenhouse effect and warming Earth.
Scientists
often use the term "climate change" instead of global warming. This is
because as the Earth's average temperature climbs, winds and ocean
currents move heat around the globe in ways that can cool some areas,
warm others, and change the amount of rain and snow falling. As a
result, the climate changes differently in different areas.
Aren't temperature changes natural?
The
average global temperature and concentrations of carbon dioxide (one of
the major greenhouse gases) have fluctuated on a cycle of hundreds of
thousands of years as the Earth's position relative to the sun has
varied. As a result, ice ages have come and gone.
However, for
thousands of years now, emissions of GHGs to the atmosphere have been
balanced out by GHGs that are naturally absorbed. As a result, GHG
concentrations and temperature have been fairly stable. This stability
has allowed human civilization to develop within a consistent climate.
Occasionally,
other factors briefly influence global temperatures. Volcanic
eruptions, for example, emit particles that temporarily cool the Earth's
surface. But these have no lasting effect beyond a few years. Other
cycles, such as El Niño, also work on fairly short and predictable
cycles.
Now, humans have increased the amount of carbon dioxide in
the atmosphere by more than a third since the industrial revolution.
Changes this large have historically taken thousands of years, but are
now happening over the course of decades.
Why is this a concern?
The
rapid rise in greenhouse gases is a problem because it is changing the
climate faster than some living things may be able to adapt. Also, a new
and more unpredictable climate poses unique challenges to all life.
Historically,
Earth's climate has regularly shifted back and forth between
temperatures like those we see today and temperatures cold enough that
large sheets of ice covered much of North America and Europe. The
difference between average global temperatures today and during those
ice ages is only about 5 degrees Celsius (9 degrees Fahrenheit), and
these swings happen slowly, over hundreds of thousands of years.
Now,
with concentrations of greenhouse gases rising, Earth's remaining ice
sheets (such as Greenland and Antarctica) are starting to melt too. The
extra water could potentially raise sea levels significantly.
As
the mercury rises, the climate can change in unexpected ways. In
addition to sea levels rising, weather can become more extreme. This
means more intense major storms, more rain followed by longer and drier
droughts (a challenge for growing crops), changes in the ranges in which
plants and animals can live, and loss of water supplies that have
historically come from glaciers.
Scientists are already seeing
some of these changes occurring more quickly than they had expected.
According to the Intergovernmental Panel on Climate Change, eleven of
the twelve hottest years since thermometer readings became available
occurred between 1995 and 2006.
Global Warming
The
current cycle of global warming is changing the rhythms of climate that
all living things have come to rely upon. What will we do to slow this
warming? How will we cope with the changes we've already set into
motion? While we struggle to figure it all out, the face of the Earth as
we know it—coasts, forests, farms, and snowcapped mountains—hangs in
the balance.
Effects of Global Warming
The planet is warming, from North Pole to South Pole, and everywhere
in between. Globally, the mercury is already up more than 1 degree
Fahrenheit (0.8 degree Celsius), and even more in sensitive polar
regions. And the effects of rising temperatures aren’t waiting for some
far-flung future. They’re happening right now. Signs are appearing all
over, and some of them are surprising. The heat is not only melting
glaciers and sea ice, it’s also shifting precipitation patterns and
setting animals on the move.
Some impacts from increasing temperatures are already happening.
- Ice is melting worldwide, especially at the Earth’s poles. This includes mountain glaciers, ice sheets covering West Antarctica and Greenland, and Arctic sea ice.
- Researcher Bill Fraser has tracked the decline of the Adélie penguins on Antarctica, where their numbers have fallen from 32,000 breeding pairs to 11,000 in 30 years.
- Sea level rise became faster over the last century.
- Some butterflies, foxes, and alpine plants have moved farther north or to higher, cooler areas.
- Precipitation (rain and snowfall) has increased across the globe, on average.
- Spruce bark beetles have boomed in Alaska thanks to 20 years of warm summers. The insects have chewed up 4 million acres of spruce trees.
Other effects could happen later this century, if warming continues.
- Sea levels are expected to rise between 7 and 23 inches (18 and 59 centimeters) by the end of the century, and continued melting at the poles could add between 4 and 8 inches (10 to 20 centimeters).
- Hurricanes and other storms are likely to become stronger.
- Species that depend on one another may become out of sync. For example, plants could bloom earlier than their pollinating insects become active.
- Floods and droughts will become more common. Rainfall in Ethiopia, where droughts are already common, could decline by 10 percent over the next 50 years.
- Less fresh water will be available. If the Quelccaya ice cap in Peru continues to melt at its current rate, it will be gone by 2100, leaving thousands of people who rely on it for drinking water and electricity without a source of either.
- Some diseases will spread, such as malaria carried by mosquitoes.
- Ecosystems will change—some species will move farther north or become more successful; others won’t be able to move and could become extinct. Wildlife research scientist Martyn Obbard has found that since the mid-1980s, with less ice on which to live and fish for food, polar bears have gotten considerably skinnier. Polar bear biologist Ian Stirling has found a similar pattern in Hudson Bay. He fears that if sea ice disappears, the polar bears will as well.
Causes of Global Warming
What Causes Global Warming?
Scientists
have spent decades figuring out what is causing global warming. They've
looked at the natural cycles and events that are known to influence
climate. But the amount and pattern of warming that's been measured
can't be explained by these factors alone. The only way to explain the
pattern is to include the effect of greenhouse gases (GHGs) emitted by
humans.
To bring all this information together, the United Nations formed a group of scientists called the Intergovernmental Panel on Climate Change,
or IPCC. The IPCC meets every few years to review the latest scientific
findings and write a report summarizing all that is known about global
warming. Each report represents a consensus, or agreement, among
hundreds of leading scientists.
One of the first things scientists
learned is that there are several greenhouse gases responsible for
warming, and humans emit them in a variety of ways. Most come from the
combustion of fossil fuels in cars, factories and electricity
production. The gas responsible for the most warming is carbon dioxide,
also called CO2. Other contributors include methane released from
landfills and agriculture (especially from the digestive systems of
grazing animals), nitrous oxide from fertilizers, gases used for
refrigeration and industrial processes, and the loss of forests that
would otherwise store CO2.
Different greenhouse gases have very
different heat-trapping abilities. Some of them can even trap more heat
than CO2. A molecule of methane produces more than 20 times the warming
of a molecule of CO2. Nitrous oxide is 300 times more powerful than CO2.
Other gases, such as chlorofluorocarbons (which have been banned in
much of the world because they also degrade the ozone layer), have
heat-trapping potential thousands of times greater than CO2. But because
their concentrations are much lower than CO2, none of these gases adds
as much warmth to the atmosphere as CO2 does.
In order to
understand the effects of all the gases together, scientists tend to
talk about all greenhouse gases in terms of the equivalent amount of
CO2. Since 1990, yearly emissions have gone up by about 6 billion metric
tons of "carbon dioxide equivalent" worldwide, more than a 20 percent
increase.
Tornado Safety Tips
Tornadoes are one of nature's most powerful and
destructive forces. Here's some advice on how to prepare for a tornado
and what to do if you're caught in a twister's path.
Safety Tips
Safety Tips
- Prepare for tornadoes by gathering emergency supplies including food, water, medications, batteries, flashlights, important documents, road maps, and a full tank of gasoline.
- When a tornado approaches, anyone in its path should take shelter indoors—preferably in a basement or an interior first-floor room or hallway.
- Avoid windows and seek additional protection by getting underneath large, solid pieces of furniture.
- Avoid automobiles and mobile homes, which provide almost no protection from tornadoes.
- Those caught outside should lie flat in a depression or on other low ground and wait for the storm to pass.
Tsunamis
A tsunami is a series of ocean waves that sends surges of
water, sometimes reaching heights of over 100 feet (30.5 meters), onto
land. These walls of water can cause widespread destruction when they
crash ashore.
These awe-inspiring waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly it displaces the water above it and launches the rolling waves that will become a tsunami.
Most tsunamis, about 80 percent, happen within the Pacific Ocean’s “Ring of Fire,” a geologically active area where tectonic shifts make volcanoes and earthquakes common.
Tsunamis may also be caused by underwater landslides or volcanic eruptions. They may even be launched, as they frequently were in Earth’s ancient past, by the impact of a large meteorite plunging into an ocean.
Tsunamis race across the sea at up to 500 miles (805 kilometers) an hour—about as fast as a jet airplane. At that pace they can cross the entire expanse of the Pacific Ocean in less than a day. And their long wavelengths mean they lose very little energy along the way.
In deep ocean, tsunami waves may appear only a foot or so high. But as they approach shoreline and enter shallower water they slow down and begin to grow in energy and height. The tops of the waves move faster than their bottoms do, which causes them to rise precipitously.
A tsunami’s trough, the low point beneath the wave’s crest, often reaches shore first. When it does, it produces a vacuum effect that sucks coastal water seaward and exposes harbor and sea floors. This retreating of sea water is an important warning sign of a tsunami, because the wave’s crest and its enormous volume of water typically hit shore five minutes or so later. Recognizing this phenomenon can save lives.
A tsunami is usually composed of a series of waves, called a wave train, so its destructive force may be compounded as successive waves reach shore. People experiencing a tsunami should remember that the danger may not have passed with the first wave and should await official word that it is safe to return to vulnerable locations.
Some tsunamis do not appear on shore as massive breaking waves but instead resemble a quickly surging tide that inundates coastal areas.
The best defense against any tsunami is early warning that allows people to seek higher ground. The Pacific Tsunami Warning System, a coalition of 26 nations headquartered in Hawaii, maintains a web of seismic equipment and water level gauges to identify tsunamis at sea. Similar systems are proposed to protect coastal areas worldwide.
These awe-inspiring waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly it displaces the water above it and launches the rolling waves that will become a tsunami.
Most tsunamis, about 80 percent, happen within the Pacific Ocean’s “Ring of Fire,” a geologically active area where tectonic shifts make volcanoes and earthquakes common.
Tsunamis may also be caused by underwater landslides or volcanic eruptions. They may even be launched, as they frequently were in Earth’s ancient past, by the impact of a large meteorite plunging into an ocean.
Tsunamis race across the sea at up to 500 miles (805 kilometers) an hour—about as fast as a jet airplane. At that pace they can cross the entire expanse of the Pacific Ocean in less than a day. And their long wavelengths mean they lose very little energy along the way.
In deep ocean, tsunami waves may appear only a foot or so high. But as they approach shoreline and enter shallower water they slow down and begin to grow in energy and height. The tops of the waves move faster than their bottoms do, which causes them to rise precipitously.
A tsunami’s trough, the low point beneath the wave’s crest, often reaches shore first. When it does, it produces a vacuum effect that sucks coastal water seaward and exposes harbor and sea floors. This retreating of sea water is an important warning sign of a tsunami, because the wave’s crest and its enormous volume of water typically hit shore five minutes or so later. Recognizing this phenomenon can save lives.
A tsunami is usually composed of a series of waves, called a wave train, so its destructive force may be compounded as successive waves reach shore. People experiencing a tsunami should remember that the danger may not have passed with the first wave and should await official word that it is safe to return to vulnerable locations.
Some tsunamis do not appear on shore as massive breaking waves but instead resemble a quickly surging tide that inundates coastal areas.
The best defense against any tsunami is early warning that allows people to seek higher ground. The Pacific Tsunami Warning System, a coalition of 26 nations headquartered in Hawaii, maintains a web of seismic equipment and water level gauges to identify tsunamis at sea. Similar systems are proposed to protect coastal areas worldwide.
Wildfires
Uncontrolled blazes fueled by weather, wind, and dry
underbrush, wildfires can burn acres of land—and consume everything in
their paths—in mere minutes.
On average, more than 100,000 wildfires, also called wildland fires or forest fires, clear 4 million to 5 million acres (1.6 million to 2 million hectares) of land in the U.S. every year. In recent years, wildfires have burned up to 9 million acres (3.6 million hectares) of land. A wildfire moves at speeds of up to 14 miles an hour (23 kilometers an hour), consuming everything—trees, brush, homes, even humans—in its path.
There are three conditions that need to be present in order for a wildfire to burn, which firefighters refer to as the fire triangle: fuel, oxygen, and a heat source. Fuel is any flammable material surrounding a fire, including trees, grasses, brush, even homes. The greater an area's fuel load, the more intense the fire. Air supplies the oxygen a fire needs to burn. Heat sources help spark the wildfire and bring fuel to temperatures hot enough to ignite. Lightning, burning campfires or cigarettes, hot winds, and even the sun can all provide sufficient heat to spark a wildfire.
Although four out of five wildfires are started by people, nature is usually more than happy to help fan the flames. Dry weather and drought convert green vegetation into bone-dry, flammable fuel; strong winds spread fire quickly over land; and warm temperatures encourage combustion. When these factors come together all that's needed is a spark—in the form of lightning, arson, a downed power line, or a burning campfire or cigarette—to ignite a blaze that could last for weeks and consume tens of thousands of acres.
These violent infernos occur around the world and in most of the 50 states, but they are most common in the U.S. West, where heat, drought, and frequent thunderstorms create perfect wildfire conditions. Montana, Idaho, Wyoming, Washington, Colorado, Oregon, and California experience some of the worst conflagrations in the U.S. In California wildfires are often made worse by the hot, dry Santa Ana winds, which can carry a spark for miles.
Firefighters fight wildfires by depriving them of one or more of the fire triangle fundamentals. Traditional methods include water dousing and spraying fire retardants to extinguish existing fires. Clearing vegetation to create firebreaks starves a fire of fuel and can help slow or contain it. Firefighters also fight wildfires by deliberately starting fires in a process called controlled burning. These prescribed fires remove undergrowth, brush, and ground litter from a forest, depriving a wildfire of fuel.
Although often harmful and destructive to humans, naturally occurring wildfires play an integral role in nature. They return nutrients to the soil by burning dead or decaying matter. They also act as a disinfectant, removing disease-ridden plants and harmful insects from a forest ecosystem. And by burning through thick canopies and brushy undergrowth, wildfires allow sunlight to reach the forest floor, enabling a new generation of seedlings to grow.
On average, more than 100,000 wildfires, also called wildland fires or forest fires, clear 4 million to 5 million acres (1.6 million to 2 million hectares) of land in the U.S. every year. In recent years, wildfires have burned up to 9 million acres (3.6 million hectares) of land. A wildfire moves at speeds of up to 14 miles an hour (23 kilometers an hour), consuming everything—trees, brush, homes, even humans—in its path.
There are three conditions that need to be present in order for a wildfire to burn, which firefighters refer to as the fire triangle: fuel, oxygen, and a heat source. Fuel is any flammable material surrounding a fire, including trees, grasses, brush, even homes. The greater an area's fuel load, the more intense the fire. Air supplies the oxygen a fire needs to burn. Heat sources help spark the wildfire and bring fuel to temperatures hot enough to ignite. Lightning, burning campfires or cigarettes, hot winds, and even the sun can all provide sufficient heat to spark a wildfire.
Although four out of five wildfires are started by people, nature is usually more than happy to help fan the flames. Dry weather and drought convert green vegetation into bone-dry, flammable fuel; strong winds spread fire quickly over land; and warm temperatures encourage combustion. When these factors come together all that's needed is a spark—in the form of lightning, arson, a downed power line, or a burning campfire or cigarette—to ignite a blaze that could last for weeks and consume tens of thousands of acres.
These violent infernos occur around the world and in most of the 50 states, but they are most common in the U.S. West, where heat, drought, and frequent thunderstorms create perfect wildfire conditions. Montana, Idaho, Wyoming, Washington, Colorado, Oregon, and California experience some of the worst conflagrations in the U.S. In California wildfires are often made worse by the hot, dry Santa Ana winds, which can carry a spark for miles.
Firefighters fight wildfires by depriving them of one or more of the fire triangle fundamentals. Traditional methods include water dousing and spraying fire retardants to extinguish existing fires. Clearing vegetation to create firebreaks starves a fire of fuel and can help slow or contain it. Firefighters also fight wildfires by deliberately starting fires in a process called controlled burning. These prescribed fires remove undergrowth, brush, and ground litter from a forest, depriving a wildfire of fuel.
Although often harmful and destructive to humans, naturally occurring wildfires play an integral role in nature. They return nutrients to the soil by burning dead or decaying matter. They also act as a disinfectant, removing disease-ridden plants and harmful insects from a forest ecosystem. And by burning through thick canopies and brushy undergrowth, wildfires allow sunlight to reach the forest floor, enabling a new generation of seedlings to grow.
Lightnings
Cloud-to-ground lightning bolts are a common phenomenon—about 100
strike Earth’s surface every single second—yet their power is
extraordinary. Each bolt can contain up to one billion volts of
electricity.
This enormous electrical discharge is caused by an
imbalance between positive and negative charges. During a storm,
colliding particles of rain, ice, or snow increase this imbalance and
often negatively charge the lower reaches of storm clouds. Objects on
the ground, like steeples, trees, and the Earth itself, become
positively charged—creating an imbalance that nature seeks to remedy by
passing current between the two charges.
A step-like series of
negative charges, called a stepped leader, works its way incrementally
downward from the bottom of a storm cloud toward the Earth. Each of
these segments is about 150 feet (46 meters) long. When the lowermost
step comes within 150 feet (46 meters) of a positively charged object it
is met by a climbing surge of positive electricity, called a streamer,
which can rise up through a building, a tree, or even a person. The
process forms a channel through which electricity is transferred as
lightning.
Some types of lightning, including the most common
types, never leave the clouds but travel between differently charged
areas within or between clouds. Other rare forms can be sparked by
extreme forest fires, volcanic eruptions, and snowstorms. Ball
lightning, a small, charged sphere that floats, glows, and bounces along
oblivious to the laws of gravity or physics, still puzzles scientists.
Lightning
is extremely hot—a flash can heat the air around it to temperatures
five times hotter than the sun’s surface. This heat causes surrounding
air to rapidly expand and vibrate, which creates the pealing thunder we
hear a short time after seeing a lightning flash.
Lightning is not
only spectacular, it’s dangerous. About 2,000 people are killed
worldwide by lightning each year. Hundreds more survive strikes but
suffer from a variety of lasting symptoms, including memory loss,
dizziness, weakness, numbness, and other life-altering ailments.
Hurricanes
Hurricanes are giant, spiraling tropical storms that can
pack wind speeds of over 160 miles (257 kilometers) an hour and unleash
more than 2.4 trillion gallons (9 trillion liters) of rain a day. These
same tropical storms are known as cyclones in the northern Indian Ocean
and Bay of Bengal, and as typhoons in the western Pacific Ocean.
The Atlantic Ocean’s hurricane season peaks from mid-August to late October and averages five to six hurricanes per year.
Hurricanes
begin as tropical disturbances in warm ocean waters with surface
temperatures of at least 80 degrees Fahrenheit (26.5 degrees Celsius).
These low pressure systems are fed by energy from the warm seas. If a
storm achieves wind speeds of 38 miles (61 kilometers) an hour, it
becomes known as a tropical depression. A tropical depression becomes a
tropical storm, and is given a name, when its sustained wind speeds top
39 miles (63 kilometers) an hour. When a storm’s sustained wind speeds
reach 74 miles (119 kilometers) an hour it becomes a hurricane and earns
a category rating of 1 to 5 on the Saffir-Simpson scale.
Hurricanes
are enormous heat engines that generate energy on a staggering scale.
They draw heat from warm, moist ocean air and release it through
condensation of water vapor in thunderstorms.
Hurricanes spin
around a low-pressure center known as the “eye.” Sinking air makes this
20- to 30-mile-wide (32- to 48-kilometer-wide) area notoriously calm.
But the eye is surrounded by a circular “eye wall” that hosts the
storm’s strongest winds and rain.
These storms bring destruction
ashore in many different ways. When a hurricane makes landfall it often
produces a devastating storm surge that can reach 20 feet (6 meters)
high and extend nearly 100 miles (161 kilometers). Ninety percent of all
hurricane deaths result from storm surges.
A hurricane’s high
winds are also destructive and may spawn to rnadoes. Torrential rains
cause further damage by spawning floods and landslides, which may occur
many miles inland.
The best defense against a hurricane is an
accurate forecast that gives people time to get out of its way. The
National Hurricane Center issues hurricane watches for storms that may
endanger communities, and hurricane warnings for storms that will make
landfall within 24 hours.
Floods
There are few places on Earth where people need not be concerned
about flooding. Any place where rain falls is vulnerable, although rain
is not the only impetus for flood.
A flood occurs when water
overflows or inundates land that's normally dry. This can happen in a
multitude of ways. Most common is when rivers or streams overflow their
banks. Excessive rain, a ruptured dam or levee, rapid ice melting in the
mountains, or even an unfortunately placed beaver dam can overwhelm a
river and send it spreading over the adjacent land, called a floodplain.
Coastal flooding occurs when a large storm or tsunami causes the sea to
surge inland.
Most floods take hours or even days to develop,
giving residents ample time to prepare or evacuate. Others generate
quickly and with little warning. These flash floods can be extremely
dangerous, instantly turning a babbling brook into a thundering wall of
water and sweeping everything in its path downstream.
Disaster
experts classify floods according to their likelihood of occurring in a
given time period. A hundred-year flood, for example, is an extremely
large, destructive event that would theoretically be expected to happen
only once every century. But this is a theoretical number. In reality,
this classification means there is a one-percent chance that such a
flood could happen in any given year. Over recent decades,
possibly due to global climate change, hundred-year floods have been
occurring worldwide with frightening regularity.
Earthquakes
Earthquakes, also called temblors, can be so tremendously
destructive, it’s hard to imagine they occur by the thousands every day
around the world, usually in the form of small tremors.
Some 80
percent of all the planet's earthquakes occur along the rim of the
Pacific Ocean, called the "Ring of Fire" because of the preponderance of
volcanic activity there as well. Most earthquakes occur at fault zones,
where tectonic plates—giant rock slabs that make up the Earth's upper
layer—collide or slide against each other. These impacts are usually
gradual and unnoticeable on the surface; however, immense stress can
build up between plates. When this stress is released quickly, it sends
massive vibrations, called seismic waves, often hundreds of miles
through the rock and up to the surface. Other quakes can occur far from
faults zones when plates are stretched or squeezed.
Scientists
assign a magnitude rating to earthquakes based on the strength and
duration of their seismic waves. A quake measuring 3 to 5 is considered
minor or light; 5 to 7 is moderate to strong; 7 to 8 is major; and 8 or
more is great.
On average, a magnitude 8 quake strikes somewhere
every year and some 10,000 people die in earthquakes annually.
Collapsing buildings claim by far the majority of lives, but the
destruction is often compounded by mud slides, fires, floods, or
tsunamis. Smaller temblors that usually occur in the days following a
large earthquake can complicate rescue efforts and cause further death
and destruction.
Avalanches
While avalanches are sudden, the warning signs are almost
always numerous before they let loose. Yet in 90 percent of avalanche
incidents, the snow slides are triggered by the victim or someone in the
victim's party. Avalanches kill more than 150 people worldwide each
year. Most are snowmobilers, skiers, and snowboarders.
Many
avalanches are small slides of dry powdery snow that move as a formless
mass. These "sluffs" account for a tiny fraction of the death and
destruction wrought by their bigger, more organized cousins. Disastrous
avalanches occur when massive slabs of snow break loose from a
mountainside and shatter like broken glass as they race downhill. These
moving masses can reach speeds of 80 miles (130 kilometers) per hour
within about five seconds. Victims caught in these events seldom escape.
Avalanches are most common during and in the 24 hours right after a
storm that dumps 12 inches (30 centimeters) or more of fresh snow. The
quick pileup overloads the underlying snowpack, which causes a weak
layer beneath the slab to fracture. The layers are an archive of winter
weather: Big dumps, drought, rain, a hard freeze, and more snow. How the
layers bond often determines how easily one will weaken and cause a
slide.
Storminess, temperature, wind, slope steepness and
orientation (the direction it faces), terrain, vegetation, and general
snowpack conditions are all factors that influence whether and how a
slope avalanches. Different combinations of these factors create low,
moderate, considerable, and high avalanche hazards.
If caught in
an avalanche, try to get off the slab. Not easy, in most instances.
Skiers and snowboarders can head straight downhill to gather speed then
veer left or right out of the slide path. Snowmobilers can punch the
throttle to power out of harm's way. No escape? Reach for a tree. No
tree? Swim hard. The human body is three times denser than avalanche
debris and will sink quickly. As the slide slows, clear air space to
breathe. Then punch a hand skyward.
Once the avalanche stops, it
settles like concrete. Bodily movement is nearly impossible. Wait—and
hope—for a rescue. Statistics show that 93 percent of avalanche victims
survive if dug out within 15 minutes. Then the survival rates drop fast.
After 45 minutes, only 20 to 30 percent of victims are alive. After two
hours, very few people survive.
Calculators
William Seward Burroughs Born 1857 Rochester, N.Y - Died 1898
In 1885, Burroughs filed his first patent for a calculating machine. However, his 1892 patent was for an improved calculating machine with an added printer. William Seward Burroughs invented the first practical adding and listing machine - National Inventors Hall of Fame.
In 1885, Burroughs filed his first patent for a calculating machine. However, his 1892 patent was for an improved calculating machine with an added printer. William Seward Burroughs invented the first practical adding and listing machine - National Inventors Hall of Fame.
CANDY
The history of candy dates back to ancient peoples who must have
snacked
on sweet honey straight from bee hives. The first candy confections
were fruits and nuts rolled in honey. The manufacturing of sugar began
during the middle ages and at that time sugar was so expensive that only
the rich could afford candy made from sugar. Cacao, from which
chocolate is made, was re-discovered in 1519 by Spanish explorers in
Mexico.
ROBOTS
The word robotics comes from Runaround, a short story published in 1942
by Isaac Asimov. One of the first robots Asimov wrote about was a
robo-therapist. A Massachusetts Institute of Technology Professor,
Joseph Weizenbaum, wrote the Eliza program in 1966, a modern counterpart
to Asimov's fictional character. Weizenbaum initially programmed Eliza
with 240 lines of code to simulate a psychotherapist. The program
answered questions with questions.
RADIO
Radio owes its development to two other inventions, the telegraph and the telephone, all three technologies are closely related. Radio technology began as "wireless telegraphy".
Radio can refer to either the electronic appliance that we listen with
or the content listened to. However, it all started with the discovery
of "radio waves" - electromagnetic waves that have the capacity to
transmit music, speech, pictures and other data invisibly through the
air. Many devices work by using electromagnetic waves including: radio,
microwaves, cordless phones, remote controlled toys, television
broadcasts, and more.
AEROSOL SPRAY CAN
The
forerunner of the aerosol can was invented by Erik Rotheim of Norway.
On November 23, 1927, Rotheim patented a can with a valve and propellant
systems - it could hold and dispense liquids.
The first aerosol can (a can than contains a propellant [a liquefied gas
like flurocarbon] and has a spray nozzle) was invented in 1944 by Lyle
David Goodloe and W.N. Sullivan. They were working for the U.S.
Department of Agriculture and were trying to find a way to spray and
kill malaria carrying mosquitos during World War II for the soldiers
overseas. The "clog-free" spray valve was invented by Robert H. Abplanal
in 1953.
The first spray paint was invented by Edward H. Seymour in 1949.
Seymour's wife Bonnie had given him the idea of an aerosol applicator
for paint. The first spray paint he developed was aluminum colored.
Seymour formed the company, Seymour of Sycamore, Inc. of Chicago, USA,
which is still in operation.
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