Download CLIMATE CHANGE AND GLOBAL WARMING I. INTRODUCTION

CLIMATE CHANGE AND GLOBAL WARMING
I. INTRODUCTION
Climate is the primary determinant of agricultural productivity. Given the fundamental role
of agriculture in human welfare, concern has been expressed by federal agencies and others
regarding the potential effects of climate change on agricultural productivity. Interest in this issue
has motivated a substantial body of research on climate change and agriculture over the past
decade.
Climate change is expected to influence crop and livestock production, hydrologic
balances, input supplies and other components of agricultural systems. However, the nature of
these biophysical effects and the human responses to them are complex and uncertain. For
example, crop and livestock yields are directly affected by changes in climatic factors such as
temperature and precipitation and the frequency and severity of extreme events like droughts,
floods, and wind storms. In addition, carbon dioxide is fundamental for plant production; rising
concentrations have the potential to enhance the productivity of agro-ecosystems. Climate change
may also change the types, frequencies, and intensities of various crop and livestock pests; the
availability and timing of irrigation water supplies; and the severity of soil erosion.
Agricultural systems are managed ecosystems. Thus, the human response is critical to
understanding and estimating the effects of climate change on production and food supply.
Agricultural systems are also dynamic; producers and consumers are continuously responding to
changes in crop and livestock yields, food prices, input prices, resource availability, and
technological change. Accounting for these adaptations and adjustments is difficult but necessary
in order to measure accurately climate change impacts. Failure to account for human adaptations,
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either in the form of short-term changes in consumption and production practices or long-term
technological changes, will overestimate the potential damage from climate change and
underestimate its potential benefits.
II. DISCUSSION
A. Definition of Climate Change and Global Warming
Climate change is the change in climate (i.e. regional temperature, precipitation, extreme
weather, etc.) caused by increase in the greenhouse effect. Climate change is a long-term change
in the statistical distribution of weather patterns over periods of time that range from decades to
millions of years. It may be a change in the average weather conditions or a change in the
distribution of weather events with respect to an average, for example, greater or fewer extreme
weather events. Climate change may be limited to a specific region, or may occur across the whole
Earth.
Global warming is a gradual increase in the overall temperature of the earth's atmosphere
generally attributed to the greenhouse effect caused by increased levels of carbon dioxide,
chlorofluorocarbons, and other pollutants.
B. Causes of Global and Regional Climate Change
Global warming is primarily a problem of too much carbon dioxide (CO2) in the
atmosphere—which acts as a blanket, trapping heat and warming the planet. As we burn fossil
fuels like coal, oil and natural gas for energy or cut down and burn forests to create pastures and
plantations, carbon accumulates and overloads our atmosphere. Certain waste management and
agricultural practices aggravate the problem by releasing other potent global warming gases, such
as methane and nitrous oxide. See the pie chart for a breakdown of heat-trapping global warming
emissions by economic sector.
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In order to find ways to mitigate these rising temperatures, we must examine the primary
causes of global and regional warming. This phenomenon is linked to both natural and human
causes. A natural cause –water vapor in the atmosphere – contributes the most to natural
greenhouse warming. Water vapor and other “greenhouse gases” such as carbon dioxide, methane,
and CFCs cause the greenhouse effect by trapping radiant heat emitted at infrared (long)
wavelengths (as opposed to shorter, solar wavelengths which can pass through the atmospheric
gases) from the earth’s surface and reradiating it back to the earth’s surface. This trapped energy
effectively creates an enclosure around the earth’s atmosphere similar to a greenhouse which not
only traps heat, but also restricts air circulation that would otherwise cause cooling. Two
additional human causes of global warming include deforestation, which adds another 1.6 billion
metric tons, and emission of other greenhouse gases (methane, CFCs, ozone, nitrous oxides) that
also contribute to the greenhouse effect.
Urban warming is driven by some of the same factors that create greenhouse gas warming:
vegetation loss, increase in mineral-based construction materials, and waste heat emissions from
combustion and electricity consumption. The loss of vegetation in urban areas, compared to that
in rural areas, reduces in cities the natural cooling provided by evapotranspiration, “the process
through which intercepted radiation is utilized by plants, soils, and water bodies to convert water
to water vapor”. Second, building materials such as asphalt, cement and roofing tile absorb more
thermal energy than the vegetation that existed prior to urbanization. Finally, some portion of the
urban heat island effect is attributable to the heat emissions from air conditioners, industry,
automobiles and other sources of heat in urban centers.
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1. Greenhouse Gases
The presence of greenhouse gases in the atmosphere is a natural component of the climate
system and helps to maintain the Earth as a habitable planet (Figure 3). Greenhouse gases are
relatively transparent to incoming solar radiation, allowing the sun’s energy to pass through the
atmosphere to the surface of the Earth. The energy is then absorbed by the Earth’s surface, used in
processes like photosynthesis, or emitted back to space as infrared radiation.
Some of the emitted radiation passes through the atmosphere and travels back to space, but
some is absorbed by greenhouse gas molecules and then re-emitted in all directions. The effect of
this is to warm the Earth’s surface and the lower atmosphere. Water vapor (H2O) and carbon
dioxide (CO2) are the two largest contributors to the greenhouse effect. Methane (CH4), nitrous
oxide (N2O), chloro-fluorocarbons (CFCs) and other greenhouse gases are present only in trace
amounts, but can still have a powerful warming effect due to their heat-trapping abilities and their
long residence time in the atmosphere. Without the greenhouse effect, Earth’s average temperature
would be -0.4°F (-18°C), rather than the present 59°F (15°C).
Concentrations of greenhouse gases – and especially carbon dioxide – have risen over the
past two hundred and fifty years, largely due to the combustion of fossil fuels for energy
production. Since the Industrial Revolution in the eighteenth century the concentration of carbon
dioxide in the atmosphere has risen from about 270 parts per million (ppm) to about 370 ppm.
Concentrations of methane have also risen due to cattle production, the cultivation
of rice, and release from landfills. Nearly one-third of human-induced nitrous oxide emissions are
a result of industrial processes and automobile emissions.
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2. Land-use Change
The combustion of fossil fuels is not the only anthropogenic source of carbon dioxide.
When ecosystems are altered and vegetation is either burned or removed, the carbon stored in them
is released to the atmosphere as carbon dioxide. The principal reasons for deforestation are
agriculture and urban growth, and harvesting timber for fuel, construction, and paper. Currently,
up to a quarter of the carbon dioxide emissions to the atmosphere can be attributed to land-use
change.
3. Sulfate Aerosols and Black Carbon
Sulfate aerosols and black carbon are two important additional examples of anthropogenic
forcings. Sulfate aerosols, which enter the atmosphere naturally during volcanic eruptions, are tiny
airborne particles that reflect sunlight back to space. Industrial activity has recently increased their
concentration in the atmosphere primarily through the burning of fossil fuels containing sulfur.
Anthropogenic emissions of sulfate aerosols have been associated with a net cooling effect. Black
carbon is soot generated from industrial pollution, traffic, outdoor fires, and the burning of coal
and biomass fuels. Black carbon is formed by incomplete combustion especially of coal, diesel
fuels, biofuels and outdoor biomass burning. Soot particles absorb sunlight, both heating the air
and reducing the amount of sunlight reaching the ground.
C. Effects of Global and Regional Climate Change
As we can see, both global and regional warming are complex phenomena that are, indeed,
occurring, and have causes linked to human activity. Global warming has a plethora of predicted
effects; however, for the purposes of this document we will focus on how global and regional
climate change specifically affects cities and their populations.
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The IPCC predicts that climate change will have both positive and negative effects, but the
adverse effects will predominate with greater rates of climate change (IPCC 2001). General trends
include more hot days and heat waves, fewer cold days and cold waves, an increase in global
precipitation, greater numbers of intense precipitation events, and the destruction of ecosystems,
entire species, and biodiversity (IPCC 2001). Table 1 lists some of the other expected impacts on
urban and agricultural areas (listed to show effects on the food sources of ur ban areas) as a result
of global climate change as projected by the IPCC.
Water resources are also greatly affected by climate change. The GLRAP’s studies showed
that a warming effect caused by increased atmospheric greenhouse gas concentration will
contribute to evaporation in the Great Lakes drainage basin and in the lakes themselves, ultimately
leading to decreasing lake levels (different studies claim between 0.75-8 feet), greatly affecting
water resources in the region. Also, along with increasing temperatures comes an increased need
to water the vegetation that plays such a vital role in helping to mitigate the effects of climate
change, further taxing water resources.
1. Rising Sea Level
Among the most serious and potentially catastrophic effects of global warming is sea level
rise, caused by a combination of melting glaciers all over the world and the “thermal expansion”
of the seas as oceans warm. By the end of the century, if nothing is done to rein in emissions of
greenhouse gases, global sea level may be three feet higher than today and rising. Rising sea level
will have severe impacts in low-lying coastal communities throughout the world.
For example, even a one-meter rise would inundate 17 percent of the country. In the United
States, where 54 percent of the population lives in close proximity to the ocean, the most vulnerable
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areas are the Southeast and Mid-Atlantic coasts. Also at risk are low-lying areas and bays such as
North Carolina’s Outer Banks, the Florida Coast, and much of southern California.
2. Melting Polar Ice
In November 2004 an international team of 300 scientists from 15 countries, including the
United States, issued a report on the impacts of climate change in the Arctic. In addition to painting
a stark picture of how climate change already is affecting the region, the report of the Arctic
Climate Impact Assessment predicted that at least half the summer sea ice in the Arctic will melt
by the end of this century, along with a significant portion of the Greenland Ice Sheet. The decline
of the Greenland Ice Sheet was the focus of a February 2006 article in the journal Science. Using
new satellite-based measurements, researchers showed that the second largest land-based ice sheet
in the world is losing ice twice as fast as scientists had estimated. A complete melting of this ice
sheet could raise global sea level by almost 20 feet within a few hundred years, a level that would
permanently flood virtually all of America’s major coastal cities.
In addition to causing sea level rise, the disappearance of polar ice actually will intensify
global warming. Because water absorbs more solar radiation than ice, as the poles lose ice cover,
more heat from the sun will be absorbed at the earth’s surface instead of being reflected back into
space by the snow and ice.
3. Loss of Mountain Glaciers and Snow Pack
In addition to the loss of polar ice, climate change is causing a worldwide loss of mountain
glaciers at all latitudes. Scientists have observed that glaciers are in retreat in all regions of the
world, from the himalayas to tropical South America to the western United States. By mid-century,
scientists say, most mountain glaciers may be gone. In addition to contributing to sea level rise,
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the melting of mountain glaciers also poses a threat to global water supplies. Billions of people
around the world depend solely on glaciers for irrigation and drinking water.
4. Changing weather patterns
Scientists predict that climate change will have a significant effect on global weather
patterns, causing both more floods and more droughts. Extended heat waves, more powerful
storms, and other extreme weather events have become more common in recent years and will
continue on this trend. These changes in weather patterns will have serious—and potentially
severe—impacts on human societies and the natural world.
5. Stronger hurricanes
The 2005 hurricane season in the Atlantic Ocean, with four Category 5 storms for the first
time in recorded history, raised questions in many Americans’ minds about the potential
connections between hurricanes and climate change. Now, scientists have confirmed that
hurricanes are becoming more intense—not just in the Atlantic but in all oceans where they occur.
Why would climate change make hurricanes stronger? The answer, scientists say, is because
hurricanes draw their strength from the heat in ocean surface waters. Therefore, as ocean waters
grow warmer, hurricanes will become more powerful on average, a trend that is already evident
over the past 35 years.
While there is no way to link one hurricane directly to climate change, hurricane Katrina,
which wreaked havoc along the U.S. Gulf Coast in August 2005, showed the potential of warm
ocean waters to contribute to stronger storms. At the same time that Katrina was exploding from a
tropical storm to a Category 5 hurricane while still at sea, the surface waters in the Gulf of Mexico
were unusually warm—about 2 degrees Fahrenheit warmer than normal for that time of year. With
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global warming causing ocean temperature to rise, we should expect hurricanes like Katrina to
become more and more common.
6. More Droughts and Flooding
Other weather impacts from climate change include a higher incidence of drought and
flooding and changes in precipitation patterns. According to the Intergovernmental Panel on
Climate Change, future changes in weather patterns will affect different regions in different ways.
In the short term, for instance, farms and forests may be more productive in some regions and less
productive at others. Among the reasons: precipitation will increase in high-latitude regions of the
world in summer and winter, while southern Africa, Australia and Central America may
experience consistent declines in winter rainfall.
As a result of these changes, agriculture in developing countries will be especially at risk.
Wheat, for example, may virtually disappear as a crop in Africa, while experiencing substantial
declines in Asia and South America.
D. Effects on Human Health
A recent United Nations report blamed climate change, along with worsening air and water
quality and poor disposal of solid waste, for an increase in malaria, cholera and lower respiratory
tract infections in African societies. Africans also are suffering from the effects of reduced crop
yields and decreased availability of water. The U.N. report on Africa provides an early glimpse of
some of the ways in which scientists say climate change will affect people’s health in the decades
to come, no matter where they live.
Climate change can affect human health directly (for example, because of extreme
temperatures and heat waves) and indirectly (for example, by contributing to the spread of
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infectious disease or threatening the availability and quality of food and water). The elderly, the
infirm and the poor will be especially at risk.
E. Effects on Ecosystems
Climate change holds the potential of inflicting severe damage on the ecosystems that
support all life, from hazards to coral reefs due to warmer and more acidic ocean waters to threats
to polar bears because of declines in sea ice. Ecosystems around the world already are reacting to
a warming world.
For example, one study found that 130 species, including both plants and animals, have
responded to earlier spring warming over the last 30 years. These organisms have changed their
timing of flowering, migration and other spring activities. The changes occurred regardless of
regional difference and were linked directly to enhanced greenhouse warming. Researchers also
have established that climate change is driving some species to extinction. For instance, in the past
20 years dozens of species of mountain frogs in Central America have disappeared because of a
disease that formerly did not occur where they live. In 2006, a paper in the journal Nature revealed
that the disease-causing organism, a fungus, has spread to higher elevations as a result of humaninduced climate change
In other scientific findings, biologists have observed changes in Arctic ecosystems as a
result of sea ice loss, including changes in fish populations in southern reaches of the Arctic seas.
And researchers predict that if ocean warming continues (along with ocean acidification from
rising atmospheric concentrations of carbon dioxide), the world’s coral reefs will be at risk from
an increase in “coral bleaching,” which can ultimately kill the corals and endanger the fish and
other creatures that depend on the reefs.
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F. Adaptation and adjustment of agricultural systems to climate change
That agricultural systems adapt to prevailing climate conditions is well documented. The
consistent pattern of growth in global yields over the past 50 yrs. (of approximately 2% per annum)
suggests that crop yields will be higher in the future, with or without climate change. This growth
is, in part, due to adoption of new technologies. The nature of the response is important because
failure to account for adaption responses in assessments will overstate the potential negative
impacts or understate potential positive gains associated with climate change.
Several studies (both structural and spatial analogue) describe substantial opportunities for
adaptation to offset negative effects of climate change, but adaptation is not without costs. Changes
in technology imply research and development costs, along with the costs of farm-level adoption,
including possible physical and human capital investments. Changes in climate may add stress to
local and regional agricultural economies already dealing with long-term economic changes in
agriculture. In addition, there may be barriers to adaptation that limit responses, such as the
availability of and access to financial resources and technical assistance, as well as the availability
of other inputs, such as water and fertilizer. Uncertainty about the timing and rate of climate change
also limits adaptation and, if expectations are incorrect, could contribute to the costs associated
with transition and disequilibrium.
There are other factors that influence the adoption of new technologies. For example, rates
and levels of adaptation depend on the risk preferences of farmers. Subsistence farmers have
evolved farming practices that are suited to a diverse set of crops, primarily serving local or
regional markets. These crops and methods may not produce the highest expected net returns, but
may be more tolerant of climatic variability.
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In contrast, technologically driven farming systems have contributed to a dramatic growth
in global agricultural productivity. For example, selective plant breeding has led to high-yielding
varieties of wheat, rice, and coarse grains such as maize, barley and sorghum which have added
greatly to the world’s food supply. Improved crop varieties and other technological advances result
from intensive programs of research and development, driven by ongoing investments. However,
these technologically driven farming systems may be more sensitive to climatic variability.
G. Things we can do against global warming
By now, we all know that global warming is a fact. But for many of us, it’s difficult to
understand how our actions are contributing to the problem. It doesn’t feel like we’re polluting
when we switch on our television or do our laundry. We pass the blame for global warming off on
the government and big business. But that is exactly how the problem of global warming crept up
on us: we can’t see the damage we are doing to the environment, and we keep hoping someone
else will solve the problem.
However, the truth is that global warming is being caused by the actions of nearly every
individual on Earth. Nearly every choice you make as a consumer affects the environment, from
the automobile you drive, the products you buy, and the amount of electricity you consume. Here
is a list of ten things that will help you reduce global warming, heal the environment, and save
money.
1) Drive wisely
A quarter of the carbon dioxide emitted in the U.S. comes from automobiles (1). To reduce
your contribution to global climate change, drive only when necessary. Also, try doing all of your
weekly errands in one trip. By not driving back home between each errand you save carbon
emissions. If you are purchasing a new car, choose something that is fuel efficient or better yet,
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purchase a hybrid electric vehicle. Whatever type of vehicle you choose to drive, make sure your
tires are fully inflated and your engine is operating efficiently.
2) Write to your government
Coal-burning power plants are the biggest contributors to global climate change, and yet
the technology to reduce their output of carbon dioxide already exists (2). The only thing that
prevents this new technology from being utilized is political will. A process called carbon capture
and storage (CCS) would substantially reduce the carbon dioxide emitted by power plants, but few
power plants utilize this technology (2). Write to your leaders and tell them you demand tighter
regulations for coal-burning power plants.
3) Support renewable energy
Renewable energy sources, unlike fossil fuels, will never run out. This is because
renewable forms of energy, such as wind, solar, and hydroelectric power, all come from forces of
nature which never stop. Renewable energy also has the benefit of being much cleaner than energy
obtained from coal, gasoline, and natural gas (3). Sign up for clean energy if it is available where
you live. If it is not available, call your local utility provider and ask them why clean energy is not
available in your area.
4) Replace regular light bulbs with fluorescent bulbs
Compact fluorescent light bulbs consume 60% less energy than conventional incandescent
light bulbs (4). If every household in the U.S. changed to fluorescent light bulbs, we could prevent
more than 90 billion pounds of carbon dioxide from being emitted into the atmosphere (4). That
would be equivalent to taking 10 million cars off the road (5).
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5) Save energy and money at home
Small changes around your home can reduce carbon dioxide emissions, and also save you
money on your monthly energy bill. For instance, almost half of the electricity we use goes to
heating and cooling our homes (4). By raising your thermostat just a few degrees in the summer,
and lowering it a few degrees in the winter, you will be saving money and the environment (4).
Even something as simple as replacing the dirty air filter on your furnace can save 350 pounds of
carbon dioxide a year (4).
6) Use less water
It takes energy to heat water. By using less water, you are also using less energy. Installing a low
flow shower head and washing your clothes in cold water can save 850 pounds of carbon dioxide
a year (4). Turning your hot water heater down to 120 degrees can save you even more money on
your energy bill and reduce your energy consumption further (4).
7) Purchase energy-efficient household appliances
Replacing old appliances with energy efficient models can save electricity and cut down on
greenhouse gases. When shopping for new appliances, look for the Energy Star label. This insures
that your appliances will be energy-efficient. You can also browse for new appliances at
www.energystar.gov to find the latest in energy-efficient technology.
8) Plant a tree
In its lifetime, a single tree will absorb one ton of carbon dioxide (4). The shade provided by trees
can also reduce your cooling bills in the summertime by as much as 15% (4). As part of the
photosynthesis process, trees take in carbon dioxide and produce oxygen. If we don’t replace the
trees lost to deforestation, carbon dioxide levels will continue to rise.
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9) Reduce, Reuse, Recycle
By recycling old newspapers, plastic containers, and aluminum soda cans, you prevent
carbon emissions (5). It takes energy to extract and process the raw materials used to manufacture
plastic and metal containers, and producing paper goods requires logging. If you want to do more,
be sure to purchase products made from recycled materials. This completes the "cycle" in recycle.
10) Get more people involved
Global warming isn’t being caused by a small group of people. We’re all contributing to global
warming in our daily lives. When compared to the immensity of global warming, these tips may
seem like small measures, but they become powerful when we all do our part. Tell five friends
about how you are helping reduce the effects of global warming in your home. Write a letter to
your local newspaper that encourages residents in your area to take up the cause of global warming.
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III. CONCLUSION
One of the biggest problems facing the world today is global warming. Many scientists
believe that our production of carbon dioxide and other greenhouse gases is having a heating effect
on the atmosphere, and this could be very dangerous for human life.
Human-induced climate change has contributed to changing patterns of extreme weather
across the globe, from longer and hotter heat waves to heavier rains. From a broad perspective, all
weather events are now connected to climate change. While natural variability continues to play a
key role in extreme weather, climate change has shifted the odds and changed the natural limits,
making certain types of extreme weather more frequent and more intense.
While our understanding of how climate change affects extreme weather is still developing,
evidence suggests that extreme weather may be affected even more than anticipated. Extreme
weather is on the rise, and the indications are that it will continue to increase, in both predictable
and unpredictable ways.
Many problems could result from global warming. One of the biggest problems is rising
sea level. This could result in the flooding of low lying coastal areas and cities. Some countries
might even disappear completely! Another problem caused by global warming is changes in
weather patterns. Many areas of the world are experiencing increased hurricanes, floods, and other
unusual weather. A third problem associated with global warming is the effect on animals. Fish
populations could be affected, while some insects which spread disease might become more
common.
There are several things we can do to solve the problem of global warming. One solution
is to stop producing C02. We can do this by switching from oil, coal and gas to renewable energy.
Another solution is to plant more trees. Trees absorb carbon dioxide and produce oxygen, which
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is not a greenhouse gas. A third solution is to use less energy and to recycle more products.
Generating electricity is one of the main sources of carbon dioxide. If we use less electricity, we
will produce less C02.
The greenhouse gases that are already in the atmosphere because of human activity will
continue to warm the planet for several centuries. In other words, some level of continued climate
change is inevitable, meaning that humanity is going to have to take action to adapt to a warming
world. however, scientists say it is still possible—and necessary—to reduce the magnitude of
climate change by “stabilizing” atmospheric concentrations of greenhouse gases. This means
stopping these concentrations from rising further, chiefly by achieving substantial reductions in
emissions of carbon dioxide and other greenhouse gases from human sources.
The consensus among climate scientists is that worldwide emissions of greenhouse gases
need to start a long-term decline within the next decade or two. According to the Intergovernmental
Panel on Climate Change, the world needs to reduce total emissions by about 50 to 80 percent
(compared to a business-as-usual scenario) in order to stabilize atmospheric greenhouse gas
concentrations and avoid dangerous climatic change. The science makes it abundantly clear: the
time to act is now. The world is already facing severe consequences; we must respond to the
overwhelming scientific evidence and take strong action to reduce the greenhouse gas
emissionsthat cause climate change.
In conclusion, if we make small changes now in the way we live, we can avoid huge
changes in the future. Scientists, governments and individuals must work together to overcome
this threat.
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IV. REFERENCES
http://www.int-res.com/articles/cr/11/c011p019
http://urpl.wisc.edu/ecoplan/content/lit_climate.pdf
http://www.fao.org/docrep/015/i2490e/i2490e04c.pdf
http://urpl.wisc.edu/ecoplan/content/lit_climate.pdf
http://www.ou.nl/Docs/Opener/NW/LECHe/LECHe_Module1_Textbook_2012.pdf
National Academy of Sciences (NAS). 2001. “Climate Change Science: An Analysis of Some Key
Questions. “National Academies Press. 42 pp.
Intergovernmental Panel on Climate Change. 2001. “ Climate Change 2001: Synthesis Report
;Summary for Policymakers”. See http://www.ipcc.ch/pub/un/syreng/spm.pdf
World Meteorological Organization. 2005. WMO Statement on the Status of the Global Climate
in 2005. http://www.wmo.ch/ web/wcp/wcdmp/statement/html/WMO998_E.pdf
Hoegh-Guldberg, O., 2001. “Climate Change, Coral Bleaching, and the Future of the World’s
Coral
Reefs”.
http://www.reef.edu.au/OhG/res-pic/hG%20papers/hoeghGuldberg%201999.pdf
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V. PICTORIALS RELATED TO CLIMATE CHANGE AND GLOBAL WARMING
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