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					CLIMATE CHANGE
WHAT IS CLIMATE CHANGE ?

 Climate change means any significant change
  in climate, like temperature or rainfall, over a
  30 year period or more.

 If the climate is changing, then the 30 year
  average temperature, or rainfall, or number
  of sunny days, is changing.
 It’s easy to mix up climate
 and weather! ! !
 Here’s a simple way to think about it: climate is what we
  expect (e.g. cold winters) and weather is what we get
  (e.g. rain).
Weather is what is happening in the atmosphere at any
one time: how warm, windy, sunny or humid it is. Climate is
the description of the average weather we might expect
at a given time, usually taken for several decades or
longer to average out year to year variability.

Variability might be due to a particularly hot summer or
very cold winter.

The world’s climate has been getting warmer since 1900.

However, this overall warming has not occurred evenly
across the world’s surface and different places, because
of their location and geography, are affected in different
ways.
Does the sun cause climate change?
It’s true that changes in solar activity does affect global temperatures.
Changes in the energy output of the Sun, and the Earth’s orbit around
the Sun, do have an effect on the Earth’s climate.

Ice ages have come and gone in regular cycles for nearly
three million years. There is strong evidence that these are
linked to regular variations in the Earth’s orbit around the
Sun, the so-called Milankovitch cycles. These cycles change
the amount of the Sun’s energy received by different places
on the Earth’s surface.
However, over the last 50 years, increased greenhouse gas
concentrations have had a much greater effect than changes in the
Sun's energy.
           How has the greenhouse effect changed?

Naturally occurring gases in our atmosphere, such as carbon dioxide
and methane, provide an insulating effect without which the earth
would be a frozen planet. However, levels of greenhouses gases in the
atmosphere have increased, preventing more heat escaping to Space
and leading to ‘global warming’.
Any increases in the levels of greenhouse gases in the atmosphere mean
that less heat escapes to Space and global temperatures increase - an
effect known as 'global warming'.

Over the past 150 years in the industrial era, human activities have
increased the emissions of three principal green house gases: carbon
dioxide, methane and nitrous oxide. These gases accumulate in the
atmosphere, causing concentrations to increase with time.

Carbon dioxide (CO₂) has increased from our use of fossil fuels which
we burn for use in transpor tation, energy generation, building heating
and cooling. Deforestation also releases CO2 and reduces its uptake by
plants.
Methane (CH₄) has more than doubled as a result of human activities
related to agriculture, natural gas distribution and landfills.
However, increases in methane concentrations are slowing down
because the growth of emissions has decreased over the last two
decades.
What has caused the rise in temperatures over the past 100 years?




In the first half of the 20th century global temperatures have risen
because of increases in the levels of greenhouse gases in the
atmosphere as well as changes in the amount of energy emitted by the
Sun. In the second half of the 20th century warming is mainly due to
changing greenhouse gas concentrations.
Sulphate particles from industrial emissions reflect solar radiation and
therefore act to cool climate.

These particles helped mask the warming for a few decades from 1940,
but then reductions in these pollutants,as they are the cause of poor air
quality, together with ever increasing concentrations of greenhouse
gases led to renewed warming from the 1970s.
              What is the greenhouse effect?
It is essential to human life! The natural greenhouse gas effect keeps Earth
much warmer than it would otherwise be. Without the greenhouse effect,
planet Earth would be too cold to support human life as we know it.
The temperature of the Earth is determined by the balance between
energy coming in from the Sun in the form of visible radiation (sunlight)
and energy constantly being emitted from the surface of the Earth to
outer space in the form of invisible infrared radiation (heat).

The energy coming in from the Sun can pass through the clear
atmosphere pretty much unchanged and therefore heat the surface of
the Earth. But the infrared radiation emanating from the surface of the
Earth is partly absorbed by some gases in the atmosphere, and some of
it is re-emitted downwards.

The effect of this is to warm the surface of the Earth and lower part of
the atmosphere.
This is called the greenhouse effect.
The absorbing gases in the atmosphere are primarily water
vapour (responsible for about two-thirds of the effect) and
carbon dioxide.

Methane, nitrous oxide, ozone and several other gases
present in the atmosphere in small amounts also contribute
to the greenhouse effect. Without the greenhouse effect the
Earth would be, on average, about 33°C colder than it
presently is.
What other things can change the climate?

                 There were three volcanic eruptions big enough to
                 affect the climate in the 20thcentury.
                 There were 3 volcanic eruptions big enough to
                 affect the climate in the 20th century –

                  Agung in Indonesia (1963),
                  El Chichon in Mexico (1982) and
                  Pinatubo in the Philippines (1991).
Materials (particles) from violent volcanic eruptions can be projected
far above the highest cloud, and into the stratosphere where they can
significantly increase how much incoming solar energy is reflected.
Major volcanic eruptions can reduce average global surface
temperature by about 0.5°C for months or even years.
Evidence of climate change

 CHANGE IN NUMBER OF EXTREME
  EVENTS.
 THE CLIMATE CHANGE IN THE RECENT
  PAST.
 THE CLIMATE CHANGE IN THE PAST.
THE CLIMATE CHANGE IN THE PAST

 The Earth’s climate has always changed, long before we
  humans existed!
  There have been warmer and colder periods. For
  example, in the last ice age, 20,000 years ago, it was
  about 9°C colder than it is now.
    CLIMATE CHANGE IN THE RECENT
    PAST
   Current global temperatures are warmer than they have been during at
    least the past five centuries, probably for more than 1000 years. The 17
    warmest years on record have all occurred in the last 20 years.
    During the 20th century there have been two ‘warming phases’: from
    the 1910s to the 1940s (0.35°C), and more strongly from the 1970s
    to the present (0.55°C).
    Alongside the warming, there has been an almost worldwide reduction
    in the extent and mass of glaciers in the 20th century. We know that the
    Greenland Ice Sheet is melting, that the thickness and extent of sea ice
    in the Arctic have decreased in all seasons and that sea level is rising due
    to thermal expansion of the oceans and melting of land ice.

   Instrumental observations over the past 150 years show that air
    temperatures at the Earth’s surface have risen globall
RISING SEA LEVEL

 Sea levels rose on average by 1.7mm a year during the
  20th century. Since 1993 levels have been rising by 3mm
  a year, according to the IPCC.
 The average temperature of the oceans is also rising,
  and has increased by 0.10C over the period 1961-2003.
 Higher sea levels are partly explained by water
  expanding as it heats up and partly by melt-water from
  ice sheets and glaciers finding its way into the oceans.
 This rise in sea levels has obvious consequences for
  people living in low-lying coastal regions.
RISING SEA LEVEL THREAT TO
KIRIBATI
MELTING ICE
 Snow and ice are undergoing a "global-scale decline", according
    to the IPCC.
   Overall, the world's glaciers are on the retreat. In the extreme
    north temperatures are rising faster than the global average, and
    the area covered by Arctic sea ice has been falling since the
    1970s.
   Antarctica and Greenland contain the two largest ice sheets on
    the planet. Both are "very likely" to be shrinking, according to the
    IPCC.
   But the picture is complex. In Greenland ice is being lost around
    the coasts, but a little thickening is taking place in central
    regions.
   Western Antarctica has seen some significant melting, with
    effects inlcuding the rapid disintegration of the Larsen-B ice shelf
    in 2002
          A WARMER EARTH
 Our world is getting warmer. Over the last 100 years the
    average global surface temperature has risen by about
    0.74C.
   This seemingly small rise has already had a significant
    effect on our planet.
   For example, the record books have had to be re-written
    recently, as 11 of the 12 hottest years recorded so far have
    all taken place since 1995.
   It is "very likely" that the rising level of carbon dioxide in the
    atmosphere is the cause of climate change, according to
    the Intergovernmental Panel on Climate Change (IPCC).
   Human activities, such as burning fossil fuels, are the
    primary source behind this increase.
Extreme   Events
 As the Earth’s climate gets warmer, the likelihood of some
  extreme events such as heat waves increases. Scientists
  believe, the risk of hotter summer has doubled due to human
  activities such as fossil-fuel burning.
 Determining whether a specific, single extreme event is due to
  a specific cause, such as increasing greenhouse gases, is
  difficult for two reasons: 1) extreme events are usually caused
  by a combination of many different factors and 2) a wide range
  of extreme events is normal even in an un changing climate.
 The likelihood of some extreme events, such as heat waves,
  has increased with the changing climate, and the likelihood of
  others, such as extremely cold nights, has decreased.
 In some regions there have been increases in droughts and
  floods. The number of days of very heavy rain have in creased in
  some places. Tropical storm and hurricane frequencies vary
  considerably from year to year, but evidence suggests
  substantial increases in intensity and duration since the 1970s.
             Facts on climate change and
             health




Over the last 50 years, human activities – particularly the burning of fossil fuels
– have released sufficient quantities of carbon dioxide and other greenhouse
gases to affect the global climate. The atmospheric concentration of carbon
dioxide has increased by more than 30% since pre-industrial times, trapping
more heat in the lower atmosphere. The resulting changes in the global climate
bring a range of risks to health, from deaths in extreme high temperatures to
changing patterns of infectious diseases.
From the tropics to the arctic, climate and weather have powerful direct and
indirect impacts on human life. Weather extremes – such as heavy rains,
floods, and disasters like Hurricane Katrina that devastated New Orleans, USA
in August 2005 – endanger health as well as destroy property and livelihoods.
Approximately 600 000 deaths occurred worldwide as a result of weather-
related natural disasters in the 1990s, some 95% of which took place in
developing countries.
Intense short-term fluctuations in temperature can also seriously affect
health – causing heat stress (hyperthermia) or extreme cold
(hypothermia) – and lead to increased death rates from heart and
respiratory diseases. Recent studies suggest that the record high
temperatures in western Europe in the summer of 2003 were associated
with a spike of an estimated 70 000 more deaths than the equivalent
periods in previous years.
Pollen and other aeroallergen
levels are also higher in
extreme heat. These can trigger
asthma, which affects around
300 million people. Ongoing
temperature increases are
expected to increase this
burden.
Rising sea levels – another outcome of global warming – increase
the risk of coastal flooding, and could cause population
displacement. More than half of the world's population now lives
within 60 kilometres of shorelines. Floods can directly cause injury
and death, and increase risks of infection from water and vector-
borne diseases. Population displacement could increase tensions
and potentially the risks of conflict.
More variable rainfall patterns are likely to compromise the supply of
fresh water. Globally, water scarcity already affects four out of every 10
people. A lack of water and poor water quality can compromise hygiene
and health. This increases the risk of diarrhoea, which kills
approximately 2.2 million people every year, as well as trachoma (an
eye infection that can lead to blindness) and other illnesses.
Water scarcity encourages people to transport water long distances
and store supplies in their homes. This can increase the risk of
household water contamination, causing illnesses.
Climatic conditions affect diseases transmitted through water, and
via vectors such as mosquitoes. Climate-sensitive diseases are
among the largest global killers. Diarrhoea, malaria and protein-
energy malnutrition alone caused more than 3 million deaths
globally in 2004, with over one third of these deaths occurring in
Africa.
Malnutrition causes millions of deaths each year, from both a lack
of sufficient nutrients to sustain life and a resulting vulnerability to
infectious diseases such as malaria, diarrhoea, and respiratory
illnesses. Increasing temperatures on the planet and more
variable rainfalls are expected to reduce crop yields in many
tropical developing regions, where food security is already a
problem.
Steps to reduce greenhouse gas emissions or lessen the health
impacts of climate change could have positive health effects. For
example, promoting the safe use of public transportation and active
movement - such as biking or walking as alternatives to using private
vehicles - could reduce carbon dioxide emissions and improve public
health. They can not only cut traffic injuries, but also air pollution and
associated respiratory and cardiovascular diseases. Increased levels
of physical activity can lower overall mortality rates.
Climate change is already beginning to transform
life on Earth. Around the globe, seasons are shifting,
temperatures are climbing and sea levels are rising.
And meanwhile, our planet must still supply us – and
all living things – with air, water, food and safe places
to live. If we don't act now, climate change will rapidly
alter the lands and waters we all depend upon for
survival, leaving our children and grandchildren with a
very different world.
Heat-trapping gases emitted by
 power plants, automobiles, deforestation and
other sources are warming up the planet.
Scientists project that if emissions of heat-
trapping carbon emissions aren’t reduced,
average surface temperatures could increase
by 3 to 10 degrees Fahrenheit by the end of
the century.
The planet’s oceans are also warming, which
is causing dangerous consequences such as
Stronger Storms and Hurricanes
Scientific research indicates that climate
change will cause hurricanes and tropical
storms to become more intense — lasting
longer, unleashing stronger winds, and causing
more damage to coastal ecosystems and
communities.
Scientists point to higher ocean temperatures
as the main culprit, since hurricanes and
tropical storms get their energy from warm
water. As sea surface temperatures rise,
developing storms will contain more energy.
   RISING SEA LEVELS
   Sea level rise from climate change could
displace tens of millions of people.


As the Earth heats up, sea levels rise because warmer
water takes up more room than colder water, a process
known as thermal expansion. Melting glaciers compound
the problem by dumping even more fresh water into the
oceans.
Digitally retouched picture of La Manga del Mar in Murcia
to show before (top) and after (below) a rise in sea level.
                            Increased
                            Risk of
                            Drought



Higher temperatures
increase the amount of moisture that evaporates from land and
water, leading to drought in many areas.
 Lands affected by drought are more vulnerable to flooding once
rain falls.
As temperatures rise globally, droughts will become more frequent
and more severe, with potentially devastating consequences for
agriculture, water supply and human health. This phenomenon has
already been observed in some parts of Asia and Africa, where
droughts have become longer and more intense.
                                     Increased
                                     Risk of
                                     Floods
In a warmer future climate, most climate models
project decreased summer rainfall and increased
winter rainfall in most parts of the northern
middle and high latitudes. Along with the risk of
summer drought, there is an increased chance of
episodes of intense rainfall and flooding. More
flooding is also expected in the Asian monsoon
region and other tropical areas and in a number
of major river basins.
Climate change could one-fourth of the
Earth's species to be headed for extinction
by 2050.
Rising temperatures are changing weather
and vegetation patterns across the globe,
forcing animal species to migrate to new,
cooler areas in order to survive.

The rapid nature of climate change is likely
to exceed the ability of many species to
migrate or adjust. Experts predict that one-
fourth of Earth’s species will be headed for
extinction by 2050 if the warming trend
continues at its current rate
   Heat-Related Illness and Disease


Climate change brings health risks to the
world's most vulnerable communities.
As temperatures rise, so do the risks of
heat-related illness and even death for the
most vulnerable human populations.
In 2003, for example, extreme heat waves caused
more than 20,000 deaths in Europe and more than
1,500 deaths in India. Scientists have linked the
deadly heat waves to climate change and warn of
more to come.
In addition to heat-related illness, climate change
may increase the spread of infectious diseases,
mainly because warmer temperatures allow
disease-carrying insects, animals and microbes to
survive in areas where they were once thwarted by
cold weather.
Diseases and pests that were once limited to the tropics
— such as mosquitoes that carry malaria — may find
hospitable conditions in new areas that were once too
cold to support them.
The World Health Organization (WHO) estimates that
climate change may have caused more than 150,000
deaths in the year 2000 alone, with an increase in deaths
likely in the future.
               Economic Loss and Damage
Climate change is already affecting economies around
the world.
Declining crop yields could put hundreds of thousands of people at
risk for starvation.
Climate change is affecting businesses and economies at home and
around the world. If action is not taken to curb global carbon emissions,
climate change could cost between 5 and 20 percent of the annual
global gross domestic product, according to a British government
report. In comparison, it would take 1 percent of GDP to lessen the
most damaging effects of climate change, the report says.
These global costs will be felt by local communities and businesses:
Globally, more intense hurricanes and downpours could cause billions
of dollars in damage to property and infrastructure. Declining crop
yields due to prolonged drought and high
temperatures, especially in Africa, could put
hundreds of thousands of people at risk for
starvation.
High sea temperatures also threaten the survival
of coral reefs, which generate an estimated $375
billion per year in goods and services.

				
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