1. Climate
.
Worldwide Climate Classifications
Climate is a measure of the average pattern of variation in temperature, humidity, atmospheric
pressure, wind, precipitation, atmospheric particle count and other meteorological variables in
a given region over long periods of time. Climate is different than weather, in that weather only
describes the short-term conditions of these variables in a given region.
2. A region's climate is generated by the climate system, which has five components: atmosphere,
hydrosphere, cry sphere, land surface, and biosphere.
The climate of a location is affected by its latitude, terrain, and altitude, as well as nearby water
bodies and their currents. Climates can be classified according to the average and the typical
ranges of different variables, most commonly temperature and precipitation. The most
commonly used classification scheme was originally developed by Vladimir Copen. The
Thornthwaite system, in use since 1948, incorporates evapotranspiration along with
temperature and precipitation information and is used in studying animal species diversity and
potential effects of climate changes. The Bergeron and Spatial Synoptic Classification systems
focus on the origin of air masses that define the climate of a region.
Paleoclimatology is the study of ancient climates. Since direct observations of climate are not
available before the 19th century, pale climates are inferred from proxy variables that include
non-biotic evidence such as sediments found in lake beds and ice cores, and biotic evidence
such as tree rings and coral. Climate models are mathematical models of past, present and
future climates. Climate change may occur over long and short timescales from a variety of
factors.
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CAUSE OF CLIMATE CHANGE
Climate change is a long term shift in weather conditions identified by changes in temperature,
precipitation, winds, and other indicators. Climate change can involve both changes in average
5. conditions and changes in variability, including, for example, extreme events. The earth climate
is naturally variable on all time scales. However, its long term state and average temperature
are regulated by the balance between incoming and outgoing energy, which determines the
earths energy balance. Learn more about the earth’s climate system here any factor that causes
a sustained change to the amount of incoming energy or the amount of outgoing energy can
lead to climate change.as these factors are external to the climate system, they are referred to
as ‘climate forces’, invoking the idea that they force or push the climate towards a new long
term state either warmer or cooler depending on the cause of cxhange. Different factors
operate on different time scales, and not all of those factors that have been responsible for
changes in earth’s climate in the distant past are relevant to contemporary climate change.
Factors that cause climate change can be divided into two categories those related to natural
processes and those related to human activity. In addition to natural causes of climate change,
changes internal to the climate system, such as variations in ocean currents or atmospheric
circulation, can also influence the climate for short periods of time. This natural internal climate
variability is superimposed on the long term forced climate change.
Natural Causes: The earth’s climate can be affected by natural factors that are external to the
climate system, such as changes in volcanic activity, solar output, and the earth’s orbit around
the sun. of these, the two factors relevant on timescales of contemporary climate change are
changes in volcanic activity and changes in solar radiation.in terms of the earth’s energy
balance, these factors primarily influence the amount of incoming energy volcanic eruptions are
episodic and have relatively short term effects on climate. Changes in solar irradiance have
contributed to climate trends over the past century but since the industrial revolution, the
effect of additions of greenhouse gases to the atmosphere has been about ten times that of
changes in the suns output.
Human Causes: climate change can also be caused by the human activities, such as the burning
of fossil fuels and the conversion of land for forestry and agriculture. Since the beginning of the
industrial revolution, these human influences on the climate systemhave increased
substantially. In addition to other environmental impacts, these activities change the land
surface and emit various substances to the atmosphere. These in turn can influence both the
amount of incoming energy and the amount of outgoing energy and can have both warming
and cooling effects on climate.
Short lived and long lived climate forces: carbon dioxide is the main cause of human induced
climate change. It has been emitted in vast quantities from the burning of fossil fuels and it is a
very long lived gas, which means it continues to affect the climate system during its long
residence time in the atmosphere. However, fossil fuel combustion, industrial processes,
agriculture, and forestry related activities emit other substances that also act as climate forces.
6. Climate Impacts on Human Health
Key Points
A warmer climate is expected to both increase the risk of heat-related illnesses and
death and worsen conditions for air quality.
Climate change will likely increase the frequency and strength of extreme events (such
as floods, droughts, and storms) that threaten human safety and health.
Climate changes may allow some diseases to spread more easily.
Weather and climate play a significant role in people's health. Changes in climate affect the
average weather conditions that we are accustomed to. Warmer average temperatures will
likely lead to hotter days and more frequent and longer heat waves. This could increase the
number of heat-related illnesses and deaths. Increases in the frequency or severity of extreme
weather events such as storms could increase the risk of dangerous flooding, high winds, and
other direct threats to people and property. Warmer temperatures could increase the
concentrations of unhealthy air and water pollutants. Changes in temperature, precipitation
patterns, and extreme events could enhance the spread of some diseases.
7. The number of 100-degree days per year is projected to increase.
Source: USGCRP (2009)
The impacts of climate change on health will depend on many factors. These factors include the
effectiveness of a community's public health and safety systems to address or prepare for the
risk and the behavior, age, gender, and economic status of individuals affected. Impacts will
likely vary by region, the sensitivity of populations, the extent and length of exposure to climate
change impacts, and society's ability to adapt to change.
Although the United States has well-developed public health systems (compared with those of
many developing countries), climate change will still likely affect many Americans. In addition,
the impacts of climate change on public health around the globe could have important
consequences for the United States. For example, more frequent and intense storms may
require more disaster relief and declines in agriculture may increase food shortages.
8. Impacts from Heat Waves
Heat waves can lead to heat stroke and dehydration, and are the most common cause of
weather-related deaths.Excessive heat is more likely to impact populations in northern
latitudes where people are less prepared to cope with excessive temperatures. Young children,
older adults, people with medical conditions, and the poor are more vulnerable than others to
heat-related illness. The "urban heat island" refers to the fact that the local temperature in
urban areas is a few degrees higher than the surrounding area.
Climate change will likely lead to more frequent, more severe, and longer heat waves in the
summer (see 100-degree-days figure), as well as less severe cold spells in the winter. A recent
assessment of the science suggests that increases in heat-related deaths due to climate change
would outweigh decreases in deaths from cold-snaps.
Urban areas are typically warmer than their rural surroundings. Climate change could lead to
even warmer temperatures in cities. This would increase the demand for electricity in the
summer to run air conditioning, which in turn would increase air pollution and greenhouse gas
emissions from power plants. The impacts of future heat waves could be especially severe in
large metropolitan areas.Heat waves are also often accompanied by periods of stagnant air,
leading to increases in air pollution and the associated health effects
Climate Change Affects Human Health and Welfare
In 2008, the U.S. Global Change Research Program produced a report that analyzed the impacts
of global climate change on human health and welfare. The report finds that:
Many of the expected health effects are likely to fall mostly on the poor, the very old,
the very young, the disabled, and the uninsured.
Climate change will likely result in regional differences in U.S. impacts, due not only to a
regional pattern of changes in climate but also to regional variations in the distribution
of sensitive populations and the ability of communities to adapt to climate changes.
Adaptation should begin now, starting with public health infrastructure. Individuals,
communities, and government agencies can take steps to moderate the impacts of
climate change on human health. (To learn more, see the Health Adaptation section)
Impacts from Extreme Weather Events
The frequency and intensity of extreme precipitation events is projected to increase in some
locations, as is the severity (wind speeds and rain) of tropical storms. [1] These extreme weather
events could cause injuries and, in some cases, death. As with heat waves, the people most at
risk include young children, older adults, people with medical conditions, and the poor. Extreme
events can also indirectly threaten human health in a number of ways. For example, extreme
events can:
9. Flooded streets in New Orleans after Hurricane Katrina in 2005. Source: FEMA (2005)
Reduce the availability of fresh food and water.
Interrupt communication, utility, and health care services.
Contribute to carbon monoxide poisoning from portable electric generators used during
and after storms.
Increase stomach and intestinal illness among evacuees.
Contribute to mental health impacts such as depression and post-traumatic stress
disorder (PTSD).
Increases in Ozone
Scientists project that warmer temperatures from climate change will increase the frequency of
days with unhealthy levels of ground-level ozone, a harmful air pollutant, and a component in
smog.
Ozone chemistry. Source: NASA (2012)
Ground-level ozone can damage lung tissue and can reduce lung function and inflame
airways. This can increase respiratory symptoms and aggravate asthma or other lung
diseases. It is especially harmful to children, older adults, outdoor workers, and those
with asthma and other chronic lung diseases.
Ozone exposure also has been associated with increased susceptibility to respiratory
infections, medication use, doctor visits, and emergency department visits and hospital
admissions for individuals with lung disease. Some studies suggest that ozone may
increase the risk of premature mortality, and possibly even the development of asthma.
10. Ground-level ozone is formed when certain air pollutants, such as carbon monoxide,
oxides of nitrogen (also called NOX), and volatile organic compounds, are exposed to
each other in sunlight. Ground-level ozone is one of the pollutants in smog.
Changes in Fine Particulate Matter
Particulate matter is the term for a category of extremely small particles and liquid droplets
suspended in the atmosphere. Fine particles include particles smaller than 2.5 micrometers
(about one ten-thousandth of an inch). These particles may be emitted directly or may be
formed in the atmosphere from chemical reactions of gases such as sulfur dioxide, nitrogen
dioxide, and volatile organic compounds.
Inhaling fine particles can lead to a broad range of adverse health effects, including
premature mortality, aggravation of cardiovascular and respiratory disease,
development of chronic lung disease, exacerbation of asthma, and decreased lung
function growth in children.
Sources of fine particle pollution include power plants, gasoline and diesel engines,
wood combustion, high-temperature industrial processes such as smelters and steel
mills, and forest fires.
Due to the variety of sources and components of fine particulate matter, scientists do not yet
know whether climate change will increase or decrease particulate matter concentrations
across the Bangladesh.A lot of particulate matter is cleaned from the air by rainfall, so
increases in precipitation could have a beneficial effect. At the same time, other climate-related
changes in stagnant air episodes, wind patterns, emissions from vegetation and the chemistry
of atmospheric pollutants will likely affect particulate matter levels. Climate change will also
affect particulates through changes in wildfires, which are expected to become more frequent
and intense in a warmer climate.
Changes in Allergens
Climate change may affect allergies and respiratory health. The spring pollen season is already
occurring earlier in the United States due to climate change. The length of the season may also
have increased. In addition, climate change may facilitate the spread of ragweed, an invasive
plant with very allergenic pollen. Tests on ragweed show that increasing carbon dioxide
concentrations and temperatures would increase the amount and timing of ragweed pollen
production.
11. EPA Report on Air Quality and Climate Change
Climate change could increase surface-level ozone concentrations in areas where
pollution levels are already high.
Climate change could make U.S. air quality management more difficult.
Policy makers should consider the potential impacts of climate change on air quality
when making air quality management decisions.
Impacts from Climate-Sensitive Diseases
Changes in climate may enhance the spread of some diseases. Disease-causing agents, called
pathogens, can be transmitted through food, water, and animals such as deer, birds, mice, and
insects. Climate change could affect all of these transmitters.
Food-borne Diseases
Higher air temperatures can increase cases of salmonella and other bacteria-related
food poisoning because bacteria grow more rapidly in warm environments. These
diseases can cause gastrointestinal distress and, in severe cases, death.
Flooding and heavy rainfall can cause overflows from sewage treatment plants into
fresh water sources. Overflows could contaminate certain food crops with pathogen-
containing feces.
Water-borne Diseases
Heavy rainfall or flooding can increase water-borne parasites such as Cryptosporidium
and Giardia that are sometimes found in drinking water. These parasites can cause
gastrointestinal distress and in severe cases, death.
Heavy rainfall events cause storm water runoff that may contaminate water bodies used
for recreation (such as lakes and beaches) with other bacteria.The most common illness
contracted from contamination at beaches is gastroenteritis, an inflammation of the
stomach and the intestines that can cause symptoms such as vomiting, headaches, and
fever. Other minor illnesses include ear, eye, nose, and throat infections.
12. Animal-borne Diseases
Mosquitoes favor warm, wet climates and can spread diseases such as West Nile virus.
The geographic range of ticks that carry Lyme disease is limited by temperature. As air
temperatures rise, the range of these ticks is likely to continue to expand northward.
Typical symptoms of Lyme disease include fever, headache, fatigue, and a characteristic
skin rash.
In 2002, a new strain of West Nile virus, which can cause serious, life-altering disease,
emerged in the United States. Higher temperatures are favorable to the survival of this
new strain.
The spread of climate-sensitive diseases will depend on both climate and non-climate factors.
The United States has public health infrastructure and programs to monitor, manage, and
prevent the spread of many diseases. The risks for climate-sensitive diseases can be much
higher in poorer countries that have less capacity to prevent and treat illness.
Effects of Climate Change on Agriculture
There are innumerable potential effects climate change could have on agriculture. It could
affect crop growth and quality, livestock health, and pests.
Agriculture feeds and clothes the world. Although the long-term effects of climate change are
still largely unknown, scientists can observe short-term effects of climate change on crops and
animals. In addition, scientists can prognosticate about the changes that are likely to occur in
agriculture if global climate change causes changes in temperatures and rainfall.
13. Crops
Data have shown that levels of atmospheric CO2 are increasing. Research is being conducted to
determine what types of plant responses can be expected from these changes (see section on CO2
increase below). Others worry that climate change is going to permanently alter weather patterns,
temperatures, and rainfall. NOAA data show that for much of the Southeast, annual average
rainfall has been relatively constant or slowly increasing; air temperatures are slightly lower than
100 years ago. However, the frequency of rainfall events greater than 2 inches is increasing,
leading to longer dry periods between rain events. Crop yields are likely affected by these
changes to some extent already, but it is not clear if future changes will be catastrophic or not.
Plants are surprisingly resilient, and can withstand a variety of conditions while still being
productive. In addition, other factors such as location, soil fertility, crop varieties, and
management practices will all affect future yields. Below we list some of the effects we could
expect for agriculture due
to various aspects of
climate change.
Temperature Increase
Many scientists project
that the average
temperatures throughout
the US will rise in the next
few decades. Much of this
warming could occur at
night, but the models are
not clear on this. If
temperatures increase,
cooler areas of the country
might be more habitable
for some of the main food
crops grown in the US –
thus, expanding the areas in which certain crops could be grown or moving their ranges north.
For example, less frequent freezes could allow citrus to move north from its current range in
Florida to other areas of the Southeast. In areas where crops are being grown in their warmest
productive temperature ranges already, heat stress or increased disease could reduce yields.
However, research on new crop varieties and technological advances could improve yields in
spite of reductions due to temperature increases. A report from the IPCC (Intergovernmental
Panel on Climate Change) is optimistic that general crop yields for the next century could
increase in a range from 5-20% during the first few decades of the 21st century, and they expect
the crop yield to remain somewhat steady (but positive) through the rest of the century. If climate
change reduces the global amount of arable land, however, total yields could still decrease.
Figure A: Botrytic Bunch Rotting in Grapes
14. Carbon Dioxide Increase
Scientists are in agreement that the levels of atmospheric CO2 (carbon dioxide) have increased in
recent years. Prior to the Industrial Revolution, they were measured at 280 parts per million by
volume (ppmv); currently the levels are around 380 ppmv. These levels have been steadily
increasing by 1.9 ppm yearly since the year 2000, largely as a result of fossil fuel burning.
Carbon dioxide is critical to photosynthesis (and thus plant growth). Scientists agree that even
small increases in carbon dioxide result in more plant growth. It is likely that higher levels of
carbon dioxide will result in higher harvestable crop yields. However, this depends critically on
the availability of sufficient water and nutrients necessary for plant growth. Some scientists
believe that one drawback to this increased productivity will be crops with lower nutrient and
protein levels. If true, this could have a significant, widespread impact on long-term human
health if additional fertilizers were not incorporated into crop production.
Weeds, Pests and Disease
While crops are expected to
respond to increased CO2
with strong vegetative
growth, other plants are also
thought to respond in a
similar fashion. Weeds have
become more prolific and are
expected to invade new
habitats as global warming
increases. For example,
researchers at Duke
University found that poison
ivy is actually becoming
more toxic as levels of
atmospheric carbon dioxide increase. Studies have also shown that herbicides become less
effective in a higher carbon dioxide environment, meaning that higher rates of herbicides will be
necessary to achieve the same levels of control. Insect pests, some of which carry plant diseases,
could become more prolific and widespread as temperatures increase. If pests live longer and
reproduce more each year, it is possible that they could spread crop diseases into new production
areas. It is also possible that increases in temperature, moisture and carbon dioxide could result
in higher populations of destructive pests.
Irrigation and Rainfall
Figure B: Corn Earworm Larvae Damaging Corn Kernels
15. Changes in climate may also impact the water availability and water needs for agriculture. If
temperature increases and more sporadic rainfall events result from global warming, it is possible
that irrigation needs could increase in the future. For example, rainfall in parts of the
southeastern US states has increased about 10% over the past century. However, part of this
increase may be due to changes in the frequency of tropical storms. Tropical storms usually
result in rainfall events greater than 2 inches in a day which occur at irregular intervals; these are
less useful in an agricultural sense than are rainfall events that occur more frequently, even with
lower accumulations. Plants growing in a high carbon dioxide environment may have lower
water needs. In addition, widespread increased humidity will slow transpiration, further reducing
the need for water. However, these benefits will probably be overshadowed by the lack of
available water due to increased droughts and heat waves. The crops will transpire more heavily
than when under “normal” growing conditions, and would likely need more water to adjust to
these climactic changes. In anticipation of these changes, plant breeders are currently working to
develop new varieties of crops that are considered to be drought tolerant, and more adaptable to
varying levels of temperature and moisture.
Livestock
While crops could be impacted by climate
change, it is likely that farm animals would
be even more susceptible to changes in the
climate.
Temperature Increases
It is expected that increased air temperatures
will cause more stress on livestock. Both
humans and livestock are warm-blooded
animals, so both are affected by increased
heat and humidity. During stifling heat,
livestock reproduction declines as well as
their appetite. Decreased appetite will
lengthen the time needed for the livestock to
reach their target weight (most animals only
eat about half of normal quantities when
they are heat-stressed). Stress can also
increase the incidence of sickness, decrease
rates of reproduction, and increase fighting
among animals in confinement. In some
areas, night-time temperatures are even more
above average than daytime temperatures
during heat-waves, which has resulted in increased mortality rates. Despite the warmer winter
temperatures, global warming could have a negative overall impact upon livestock.
Feed Quality
Figure C
Image from Bridget Lassiter
16. As indicated above, increased carbon dioxide may result in feed and forage that is less nutritious
even if there is more of it. It is likely that growers would be forced to use feed additives in order
to see the expected growth gains in livestock, and to avoid illnesses. This increased cost to the
grower would result in increased food costs to the consumer. Availability could also decrease if
there is not enough water and nutrients in stressed soils to keep up with plant growth.
Disease
Insect parasites and diseases could also become more prolific as global warming progresses.
New diseases may also emerge in the Southeast that were once considered to inhabit only
tropical areas. It is expected that in cases of increased heat stress and humidity, most livestock
will not be able to fight these diseases without the use of costly medicines.
What can we do about climate change?
From a science education perspective, one major thing that can be done about climate change to
support education efforts that help individuals and societies make informed decisions about
climate change. Climate science must be integrated as practical knowledge into society so that
understanding the complex physical and biological interconnections are relevant to decision
making in social, economic, political, cultural, and educational system. While information alone
is not enough to prepare society for the immediate and long term challenges of human influences
on climate, without a scientifically informed understanding of the causes and effects 0f climate
change, it will be difficult or impossible to reduce vulnerabilities or enhance the resilience of
communities and ecosystem affected by climate change.
The two most important strategies for addressing climate change are mitigation and adaptation.
The two strategies are related and overlap to a degree, but the basic distinction is that mitigation
means limiting the amount of climate change which occurs, primarily by reducing greenhouse
gas concentrations, while adaptation means changing the way we as a society we live in response
to the changing climate.
Mitigation to reduce greenhouse gas emissions entails the reduction and conversation of oil, gas,
and coal, the fossil fuels that are used in transportation, heating and cooling, agriculture and
electricity generation. Replacing carbon intensive fuels with renewable and alternative energy
sources is key to “decarbonizing” the current energy infrastructure, which will require
transforming the global economy that is currently fueled primarily by carbon based energy
sources.in order for mitigation to be successful, it is necessary to understand how humans
currently consume energy and how that impacts the climate, and then make appropriate decisions
to minimize that impact. There are already a number of energy sources which produce electricity
at costs comparable to coal and natural gas, and improving the efficiency and availability of
those technologies is a major area of research. Many private homeowners and schools generate
their electricity with solar panels, showing students and their neighbors that these technologies
are available and affordable. Simple measures to increase household energy efficiency, to drive
17. less by biking carpooling and riding public transit, and to ship our food shorter distance all play
important roles in averting future climate change.
Adaptingtoclimate change isalsocrucial since,no matterhow successful mitigationefforts are;the
changesalreadyoccurringare predictedtoincrease inthe yearsanddecadestocome,requiringserious
planningtominimizerisks,vulnerabilities,andimpacts.Adaptation strategiesthatcommunities are
alreadyimplementinginclude.
Buildingseawall andmovingawayfromvulnerable coastsinordertoavoidsea level rise andstorm
surges.
Diversifyingcropsandusing dripirrigationforagriculture.
Buildingnewpublicworkssuchassewers,bridges andaqueductstohandle changesinrainfall and
flooding.
Trainingpublichealthprofessionalsforincreasedhealthimpactsandemergingdiseases.
Developingwildlifeconversationplansandnew migrationcorridorstoprotectendangerspecies.
Designingbuildingstoconserve andevengenerateenergy.
Demonstratingstrategiesandlife styles forincreased sustainabilityandresilience…...
Because there isa lag betweenincreasedgreenhousegasemission andincreasedwarming, evenif all
greenhouse gasemissionstoppedtoday,itwouldtake decades beforetemperature, rainfall,andother
effectsof humancausedclimate change of humancausedclimate change wouldbegintoabate.so
adaption andmitigationwill inevitablyproceedinparallel.Climate change will affecteverypartof
society.The response toclimate change throughmitigationandadaptationhastoinvolve individualand
familiesathome,studentsandeducatorsin schools,leadersandworkersinorganization,andlocal,
state,national andinternationalgovernmental bodies.The actionswe take anddecisionswe make can
create opportunitiesorlimitthe optionsforthe nextgeneration.Ideally,byreducingthe effectsand
adaptingto climate change,the presentgenerationwillimproveitsowncondition, withbenefitssuchas
higherqualityof life andpublichealth,while helpingfuturegenerationsthroughitsforesightand
planning.
