Climate Change
Global climate is changing. Most of the
warming of the past half-century is due to human activities. Some types of
extreme weather are increasing, ice is melting on land and sea, and sea level
is rising.
Climate change is a change in the statistical
distribution of weather patterns when that change lasts for an extended period
of time (i.e., decades to millions of years). Climate change may refer to a
change in average weather conditions, or in the time variation of weather
around longer-term average conditions (i.e., more or fewer extreme weather
events). Climate change is caused by factors such as biotic processes,
variations in solar radiation received by Earth, plate tectonics, and volcanic
eruptions. Certain human activities have been identified as primary causes of
ongoing climate change, often referred to as global warming.
·
Summer Arctic sea ice extent,
volume, and thickness have declined rapidly, especially north of Alaska.
Permafrost temperatures are rising and the overall amount of permafrost is
shrinking. Melting of land- and sea-based ice is expected to continue with
further warming.
·
The oceans absorb more than 90%
of the excess heat trapped by human interference with the climate system, and
this warms the oceans. Globally averaged sea level has risen steadily by about
2.4 inches over the past two decades. Greenland and Antarctica hold enough ice
to raise global sea levels by more than 200 feet if they were to melt
completely. Melt water from ice sheets could contribute anywhere from several
inches to 4.5 feet to global sea levels by the end of this century.
·
Natural variability, including
El Niño events and other recurring patterns of ocean-atmosphere interactions,
influences global and regional temperature and precipitation over timescales
ranging from months up to a decade or more.
·
Human-induced
increases in atmospheric levels of heat-trapping gases are the main cause of
observed climate change over the past 50 years. The “fingerprints” of
human-induced change also have been identified in many other aspects of the
climate system, including changes in ocean heat content, precipitation,
atmospheric moisture, and Arctic sea ice.
Global
Warming
Global warming refers to the upward temperature trend across
the entire Earth since the early 20th century, and most notably since the late
1970s, due to the increase in fossil fuel emissions since the industrial
revolution. Worldwide since 1880, the average surface temperature has gone up
by about 0.8 °C (1.4 °F), relative to the mid-20th-century baseline (of
1951-1980).
Global
Warming Impacts
·
Rising seas and increased
coastal flooding
·
Longer and more damaging
wildfire seasons
·
More destructive tsunamis
·
More frequent and intense heat
waves
·
Widespread forest death
·
Costly and growing health
impacts
·
An increase in extreme weather
events
·
Melting ice
·
Changing seasons
·
Heavier precipitation and
flooding
·
More severe droughts in some
areas
·
Increased pressure on
groundwater supplies
·
Growing risks to our
electricity supply
·
Disruptions to food supplies
·
Migration: Plant and animal
range shifts
·
Destruction of coral reefs
Greenhouse
Effect
The greenhouse effect is the way in
which heat is trapped close to the surface of the Earth by “greenhouse gases”.
These heat-trapping gases can be thought of as a blanket wrapped around the
Earth, which keeps it toastier than it would be without them. Greenhouse gases
include carbon dioxide, methane and nitrous oxides.
Greenhouse gases arise naturally, and
are part of the make-up of our atmosphere. Earth is sometimes called the
“Goldilocks” planet – it’s not too hot, not too cold, and the conditions are
just right to allow life, including us, to flourish. Part of what makes Earth
so amenable is the naturally-arising greenhouse effect, which keeps the planet
at a friendly 15 °C (59 °F) on average. But in the last century or so, humans
have been interfering with the energy balance of the planet, mainly through the
burning of fossil fuels that give off additional carbon dioxide into the air.
The level of carbon dioxide in Earth’s atmosphere has been rising consistently
for decades and traps extra heat near the surface of the Earth, causing
temperatures to rise.
Global emissions of CO2 and other heat-trapping gases
continue to rise. How much climate will change over this century and beyond
depends primarily on:
1) human activities and resulting
emissions, and
2) how sensitive the climate is to those
changes (that is, the response of global temperature to a change in radiative
forcing caused by human emissions).
Green House
Gases
The gases
in the atmosphere that absorb radiation are known as "greenhouse
gases", because they are largely responsible for the greenhouse effect.
The greenhouse effect, in turn, is one of the leading causes of global
warming. Many greenhouse gases occur naturally in the atmosphere, such as
carbon dioxide, methane, water vapor, and nitrous oxide, while others are
synthetic. Those that are man-made include the chlorofluorocarbons (CFCs),
hydrofluorocarbons (HFCs) and Perfluorocarbons (PFCs), as well as sulfur
hexafluoride (SF6).
Three
factors affect the degree to which any greenhouse gas will influence global
warming:
·
Its
abundance in the atmosphere
·
How
long it stays in the atmosphere
·
Its
global-warming potential
Carbon
dioxide has a significant impact on global warming partly because of its
abundance in the atmosphere. According to the EPA, in 2012, U.S.
greenhouse gas emissions totaled 6,526 million metric tons of carbon dioxide
equivalents, which equaled 82 percent of all human caused greenhouse
gasses. Additionally, CO2 stays in the atmosphere for thousands of years.
However,
methane is about 21 times more efficient at absorbing radiation than
CO2, giving it a high GWP rating, even though it stays in the atmosphere only
about 10 years, according to the EPA.
Water Vapor
Water Vapor is the most abundant
greenhouse gas in the atmosphere. As the temperature of the atmosphere rises,
more water is evaporated from ground storage (rivers, oceans, reservoirs,
soil). Because the air is warmer, the absolute humidity can be higher (in
essence, the air is able to 'hold' more water when it's warmer), leading to
more water vapor in the atmosphere. As a greenhouse gas, the higher
concentration of water vapor is then able to absorb more thermal IR energy
radiated from the Earth, thus further warming the atmosphere. The warmer
atmosphere can then hold more water vapor and so on and so on
Carbon
Dioxide
The natural production and absorption of
carbon dioxide (CO2) is achieved through the terrestrial biosphere and the ocean.
However, humankind has altered the natural carbon cycle by burning coal, oil,
natural gas and wood and since the industrial revolution began in the mid-1700s,
each of these activities has increased in scale and distribution. Carbon
dioxide was the first greenhouse gas demonstrated to be increasing in
atmospheric concentration with the first conclusive measurements being
made in the last half of the 20th century. Prior to the industrial revolution,
concentrations were fairly stable at 280ppm.
Today, they are around 370ppm, an
increase of well over 30 percent. The atmospheric concentration has a marked
seasonal oscillation that is mostly due to the greater extent of landmass in
the northern hemisphere and its vegetation. A greater drawdown of CO2 occurs in
the northern hemisphere spring and summer as plants convert CO2 to plant
material through photosynthesis. It is then released again in the fall and
winter as the plants decompose.
Methane
Methane (CH4) is an extremely effective
absorber of radiation, though its atmospheric concentration is less
than CO2 and its lifetime in the atmosphere is brief (10-12 years),
compared to some other greenhouse gases (such as CO2, N2O, CFCs). Methane
has both natural and anthropogenic sources. It is released as part of the
biological processes in low oxygen environments, such as in swamplands or in
rice production (at the roots of the plants).
Over the last 50 years, human activities
such as growing rice, raising cattle, using natural gas and mining coal have
added to the atmospheric concentration of methane. Direct atmospheric
measurement of atmospheric methane has been possible since the late 1970s and
its concentration rose from 1.52 ppmv in 1978 by around 1 percent per year to
1990, since when there has been little sustained increase. The current
atmospheric concentration is approximately 1.77 ppmv, and there is no
scientific consensus on why methane has not risen much since around 1990.
Tropospheric
Ozone
Ultraviolet radiation and oxygen
interact to form ozone in the stratosphere. Existing in a broad band, commonly
called the 'ozone layer', a small fraction of this ozone naturally descends to
the surface of the Earth. However, during the 20th century, this tropospheric
ozone has been supplemented by ozone created by human processes. The exhaust
emissions from automobiles and pollution from factories (as well as burning
vegetation) leads to greater concentrations of carbon and nitrogen molecules in
the lower atmosphere which, when it they are acted on by sunlight, produce
ozone. Consequently, ozone has higher concentrations in and around cities than
in sparsely populated areas, though there is some transport of ozone downwind
of major urban areas. Ozone is an important contributor to photochemical smog.
Though the lifetime of ozone is short, and is therefore not well-mixed through
the atmosphere, there is a general band of higher ozone concentration during
northern hemisphere spring and summer between 30°N and 50°N resulting from the
higher urbanization and industrial activity in this band. Concentrations of
ozone have risen by around 30 percent since the pre-industrial era, and is now
considered by the IPCC to be the third most important greenhouse gas after
carbon dioxide and methane. An additional complication of ozone is that it also
interacts with and is modulated by concentrations of methane.
Nitrous
Oxide
Concentrations of nitrous oxide also
began to rise at the beginning of the industrial revolution and is understood
to be produced by microbial processes in soil and water, including those
reactions which occur in fertilizer containing nitrogen. Increasing use of
these fertilizers has been made over the last century. Global concentration for
N2O in 1998 was 314 ppb, and in addition to agricultural sources for the gas,
some industrial processes (fossil fuel-fired power plants, nylon production,
nitric acid production and vehicle emissions) also contribute to its
atmospheric load.
Chlorofluorocarbons
Chlorofluorocarbons (CFCs) have no
natural source, but were entirely synthesized for such diverse uses as
refrigerants, aerosol propellants and cleaning solvents. Their creation was in
1928 and since then concentrations of CFCs in the atmosphere have been rising.
Due to the discovery that they are able to destroy stratospheric ozone, a
global effort to halt their production was undertaken and was extremely
successful. So much so that levels of the major CFCs are now remaining level or
declining. However, their long atmospheric lifetimes determine that some
concentration of the CFCs will remain in the atmosphere for over 100 years.
Since they are also greenhouse gas, along with such other long-lived
synthesized gases as CF4 (carbon tetrafluoride), SF6 (sulfur
hexafluoride), they are of concern. Another set of synthesized compounds called
HFCs (hydrofluorocarbons) are also greenhouse gases, though they are less
stable in the atmosphere and therefore have a shorter lifetime and less of an
impact as a greenhouse gas.
Carbon
Monoxide and other reactive gases
Carbon monoxide (CO) is not considered a
direct greenhouse gas, mostly because it does not absorb terrestrial thermal IR
energy strongly enough. However, CO is able to modulate the production of
methane and tropospheric ozone. The Northern Hemisphere contains about twice as
much CO as the Southern Hemisphere because as much as half of the global burden
of CO is derived from human activity, which is predominantly located in the
northern hemisphere. Due to the spatial variability of CO, it is difficult to
ascertain global concentrations, however, it appears as though they were
generally increasing until the late 1980s, and have since begun to decline
somewhat. One possible explanation is the reduction in vehicle emissions of CO
since greater use of catalytic converters has been made.
Volatile Organic Compounds (VOCs) also
have a small direct impact as greenhouse gases, as well being involved in
chemical processes which modulate ozone production. VOCs include non-methane
hydrocarbons (NMHC), and oxygenated NMHCs (eg. alcohols and organic acids), and
their largest source is natural emissions from vegetation. However, there are
some anthropogenic sources such as vehicle emissions, fuel production and
biomass burning. Though measurement of VOCs is extremely difficult, it is
expected that most anthropogenic emissions of these compounds have increased in
recent decades.
Other
climate forcers
Particles and aerosols in the atmosphere
can also affect climate. Human activities such as burning fossil fuels and
biomass contribute to emissions of these substances, although some aerosols
also come from natural sources such as volcanoes and marine plankton.
·
Black carbon (BC) is a
solid particle or aerosol, not a gas, but it also contributes to warming of the
atmosphere. Unlike GHGs, BC can directly absorb incoming and reflected sunlight
in addition to absorbing infrared radiation. BC can also be deposited on snow
and ice, darkening the surface and thereby increasing the snow's absorption of
sunlight and accelerating melt. For information on how BC is impacting
the Arctic, see EPA assessment Methane and Black Carbon Impacts
on the Arctic.
·
Sulfates, organic carbon, and
other aerosols can cause cooling by reflecting sunlight.
Radiative
Forcing
Radiative forcing is a measure of the
influence of a particular factor (e.g. GHGs, aerosols, or land use changes) on
the net change in Earth’s energy balance. On average, a positive radiative
forcing tends to warm the surface of the planet, while a negative forcing tends
to cool the surface.
GHGs have a positive forcing because
they absorb energy radiating from Earth’s surface, rather than allowing it to
be directly transmitted into space. This warms the atmosphere like a blanket.
Aerosols, or small particles, can have a positive or negative radiative
forcing, depending on how they absorb and emit heat or reflect light. For
example, black carbon aerosols have a positive forcing since they absorb
sunlight. Sulfate aerosols have a negative forcing since they reflect sunlight
back into space.
Greenhouse Gases and Their Characteristics
Greenhouse gas
|
|
Carbon
dioxide
|
Emitted
primarily through the burning of fossil fuels (oil, natural gas, and coal),
solid waste, and trees and wood products. Changes in land use also play a
role. Deforestation and soil degradation add carbon dioxide to the
atmosphere, while forest regrowth takes it out of the atmosphere.
|
Methane
|
Emitted
during the production and transport of oil and natural gas as well as coal.
Methane emissions also result from livestock and agricultural practices and
from the anaerobic decay of organic waste in municipal solid waste
landfills.
|
Nitrous
oxide
|
Emitted
during agricultural and industrial activities, as well as during combustion
of fossil fuels and solid waste.
|
Fluorinated
gases
|
A group
of gases that contain fluorine, including hydrofluorocarbons,
perfluorocarbons, and sulfur hexafluoride, among other chemicals. These gases
are emitted from a variety of industrial processes and commercial and
household uses and do not occur naturally. Sometimes used as substitutes for
ozone-depleting substances such as chlorofluorocarbons (CFCs).
|
The Global
Warming Potential
The Global Warming Potential (GWP) was
developed to allow comparisons of the global warming impacts of different
gases. Specifically, it is a measure of how much energy the emissions of 1 ton
of a gas will absorb over a given period of time, relative to the emissions of
1 ton of carbon dioxide (CO2). The larger the GWP, the more that a given gas
warms the Earth compared to CO2 over that time period. The time period usually
used for GWPs is 100 years. GWPs provide a common unit of measure, which allows
analysts to add up emissions estimates of different gases (e.g., to compile a
national GHG inventory), and allows policymakers to compare emissions reduction
opportunities across sectors and gases.
·
CO2, by definition, has a GWP
of 1 regardless of the time period used, because it is the gas being used as
the reference. CO2 remains in the climate system for a very long time: CO2
emissions cause increases in atmospheric concentrations of CO2 that will last
thousands of years.
·
Methane (CH4) is estimated to
have a GWP of 28–36 over 100 years . CH4 emitted today lasts about a decade on
average, which is much less time than CO2. But CH4 also absorbs much more
energy than CO2. The net effect of the shorter lifetime and higher energy
absorption is reflected in the GWP. The CH4 GWP also accounts for some indirect
effects, such as the fact that CH4 is a precursor to ozone, and ozone is itself
a GHG.
·
Nitrous Oxide (N2O) has a GWP
265–298 times that of CO2 for a 100-year timescale. N2O emitted today remains
in the atmosphere for more than 100 years, on average.
·
Chlorofluorocarbons (CFCs),
hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), perfluorocarbons
(PFCs), and sulfur hexafluoride (SF6) are sometimes called high-GWP gases
because, for a given amount of mass, they trap substantially more heat than
CO2. (The GWPs for these gases can be in the thousands or tens of thousands.)
Intergovernmental Panel on Climate
Change IPCC Global Warming Potentials - 100-Year Time Horizon
|
|||
Greenhouse Gas
|
Formula
|
Second Assessment
Reporta
|
Fourth Assessment
Reportb
|
Carbon dioxide
|
CO2
|
1
|
1
|
Methane
|
CH4
|
21
|
25
|
Nitrous oxide
|
N2O
|
310
|
298
|
Sulphur hexafluoride
|
SF6
|
23 900
|
22 800
|
Nitrogen trifluoride
|
NF3
|
-
|
17 200
|
perfluorocarbons
|
PFCs
|
=5k-10k
|
|
hydrofluorocarbons
|
(HFCs),
|
100-300
|
|
Global Emissions by Gas
At the global
scale, the key greenhouse gases emitted by human activities are:
Carbon
dioxide (CO2): Fossil
fuel use is the primary source of CO2. CO2 can also be emitted from
direct human-induced impacts on forestry and other land use, such as through
deforestation, land clearing for agriculture, and degradation of soils.
Likewise, land can also remove CO2 from the atmosphere through reforestation,
improvement of soils, and other activities.
Methane
(CH4):
Agricultural activities, waste management, energy use, and biomass burning all
contribute to CH4 emissions.
Nitrous
oxide (N2O):
Agricultural activities, such as fertilizer use, are the primary source of N2O
emissions. Fossil fuel combustion also generates N2O.
Fluorinated
gases (F-gases): Industrial processes, refrigeration, and the use of a variety of
consumer products contribute to emissions of F-gases, which include
hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride
(SF6).
Global
Emissions by Economic Sector
Global greenhouse gas emissions can also
be broken down by the economic activities that lead to their production.
Electricity and Heat Production (25%
of 2010 global greenhouse gas emissions):
·
The burning of coal, natural
gas, and oil for electricity and heat is the largest single source of global
greenhouse gas emissions.
·
The Electricity sector involves
the generation, transmission, and distribution of electricity.
·
Carbon dioxide (CO2) makes up
the vast majority of greenhouse gas emissions from the sector, but smaller
amounts of methane (CH4) and nitrous oxide (N2O) are also emitted.
·
These gases are released during
the combustion of fossil fuels, such as coal, oil, and natural gas, to produce
electricity. Less than 1 percent of greenhouse gas emissions from the sector
come from sulfur hexafluoride (SF6), an insulating chemical used in electricity
transmission and distribution equipment.
Industry (21% of 2010 global
greenhouse gas emissions):
·
Greenhouse gas emissions from
industry primarily involve fossil fuels burned on site at facilities for
energy. This sector also includes emissions from chemical, metallurgical, and
mineral transformation processes not associated with energy consumption and
emissions from waste management activities.
·
The Industry sector produces
the goods and raw materials we use every day. The greenhouse gases emitted
during industrial production are split into two categories: direct emissions
that are produced at the facility, and indirect emissions that occur off site,
but are associated with the facility's use of energy.
·
Direct emissions are produced
by burning fuel for power or heat, through chemical reactions, and from leaks
from industrial processes or equipment. Most direct emissions come from the
consumption of fossil fuels for energy. A smaller amount, roughly a third, come
from leaks from natural gas and petroleum systems, the use of fuels in
production (e.g., petroleum products used to make plastics), and chemical
reactions during the production of chemicals, iron and steel, and cement.
·
Indirect emissions are produced
by burning fossil fuel at a power plant to make electricity, which is then used
by an industrial facility to power industrial buildings and machinery.
Agriculture, Forestry, and Other Land
Use (24% of 2010 global greenhouse gas emissions):
·
Greenhouse gas emissions from
this sector come mostly from agriculture (cultivation of crops and livestock)
and deforestation. This estimate does not include the CO2 that ecosystems
remove from the atmosphere by sequestering carbon in biomass, dead organic
matter, and soils, which offset approximately 20% of emissions from this
sector.
·
Various management practices on
agricultural soils can lead to increased availability of nitrogen in the soil
and result in emissions of nitrous oxide (N2O). Specific activities that
contribute to N2O emissions from agricultural lands include the application of
synthetic and organic fertilizers, the growth of nitrogen-fixing crops, the
drainage of organic soil, and irrigation practices. Management of agricultural
soils accounts for over half of the emissions from the Agriculture economic
sector.
·
Livestock, especially ruminants
such as cattle, produce methane (CH4) as part of their normal digestive
processes. This process is called enteric fermentation, and it represents
almost one third of the emissions from the Agriculture economic sector.
·
The way in which manure from
livestock is managed also contributes to CH4 and N2O emissions. Different
manure treatment and storage methods affect how much of these greenhouse gases
are produced. Manure management accounts for about 15 percent of the total
greenhouse gas emissions from the Agriculture economic sector in the United
States.
·
Smaller sources of agricultural
emissions include rice cultivation, which produces CH4, and burning crop
residues, which produces CH4 and N2O.
Transportation (14% of 2010 global
greenhouse gas emissions):
·
Greenhouse gas emissions from
this sector primarily involve fossil fuels burned for road, rail, air, and
marine transportation. Almost all (95%) of the world's transportation energy
comes from petroleum-based fuels, largely gasoline and diesel.
·
Relatively small amounts of
methane (CH4) and nitrous oxide (N2O) are emitted during fuel combustion. In
addition, a small amount of hydrofluorocarbon (HFC) emissions are included in
the Transportation sector. These emissions result from the use of mobile air
conditioners and refrigerated transport.
Buildings (6% of 2010 global
greenhouse gas emissions):
·
Greenhouse gas emissions from
this sector arise from onsite energy generation and burning fuels for heat in
buildings or cooking in homes.
·
Combustion
of natural gas and petroleum products for heating and cooking needs emits
carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Emissions from
natural gas consumption represent about 76 percent of the direct fossil fuel
CO2emissions from the residential and commercial sectors. Coal consumption is a
minor component of energy use in both of these sectors.
·
Organic
waste sent to landfills emits CH4.
·
Wastewater
treatment plants emit CH4 and N2O.
·
Fluorinated
gases (mainly hydrofluorocarbons, or HFCs) used in air conditioning and
refrigeration systems can be released during servicing or from leaking
equipment.
Other Energy (10% of 2010 global
greenhouse gas emissions): This source of
greenhouse gas emissions refers to all emissions from the Energy sector which
are not directly associated with electricity or heat production, such as fuel
extraction, refining, processing, and transportation.
Emissions by
Country
In 2014, the top carbon
dioxide (CO2) emitters were China, the United States, the European Union,
India, the Russian Federation, and Japan. These data include CO2 emissions
from fossil fuel combustion, as well as cement manufacturing and gas flaring.
Together, these sources represent a large proportion of total global
CO2 emissions.
Increasing greenhouse gas concentrations will have many effects
Greenhouse
gas concentrations in the atmosphere will continue to increase unless the
billions of tons of our annual emissions decrease substantially. Increased
concentrations are expected to:
·
Increase
Earth's average temperature
·
Influence
the patterns and amounts of precipitation
·
Reduce ice and
snow cover, as well as permafrost
·
Raise sea
level
·
Increase
the acidity of the oceans
·
Increase
the frequency, intensity, and/or duration of extreme events
·
Shift ecosystem
characteristics
·
Increase
threats to human health
These
changes will impact our food supply, water resources, infrastructure,
ecosystems, and even our own health.
Future
temperature changes
We have already observed global warming over
the last several decades. Future temperatures are expected to change further.
Climate models project the following key temperature-related changes.
Key
global projections
·
Increases in average global
temperatures are expected to be within the range of 0.5°F to 8.6°F by 2100,
with a likely increase of at least 2.7°F for all scenarios except the one
representing the most aggressive mitigation of greenhouse gas emissions.
·
Except under the most
aggressive mitigation scenario studied, global average temperature is expected
to warm at least twice as much in the next 100 years as it has during the last
100 years.
·
Ground-level air temperatures
are expected to continue to warm more rapidly over land than oceans.
·
Some parts of the world are
projected to see larger temperature increases than the global average.
·
For every 2°F of warming,
models project about a 15% decrease in the extent of annually averaged Arctic
sea ice and a 25% decrease in the area covered by Arctic sea ice at the end of
summer (September). Note that this decrease does not contribute to sea
level rise.
·
The coastal sections of the
Greenland and Antarctic ice sheets are expected to continue to melt or slide
into the ocean. If the rate of this ice melting increases in the 21st century,
the ice sheets could add significantly to global sea level rise.
·
Glaciers are expected to
continue to decrease in size. The rate of melting is expected to continue to
increase, which will contribute to sea level rise.
·
Ocean acidification adversely
affects many marine species, including plankton, mollusks, shellfish, and
corals. As ocean acidification increases, the availability of calcium carbonate
will decline. Calcium carbonate is a key building block for the shells and
skeletons of many marine organisms. If atmospheric CO2 concentrations
double, coral calcification rates are projected to decline by more than 30%.
Adaptation/Mitigation
Many governments and organizations
across the United States and the world are already adapting to climate change.
This is important because we are already seeing the impacts of climate change –
including sea level rise, changing precipitation patterns, and more frequent
incidences of heat waves and other extreme weather events. Many impacts are
expected to grow in geographic scale, rate, or intensity as global temperatures
continue to increase.
Individuals, organizations, and
communities can take many steps to adapt to a changing climate – and to help
plants and animals cope as well.
Adaptation actions can be:
·
Reactive: responding to conditions that have already changed.
·
Anticipatory: planning for climate change before impacts have occurred.
Examples of
Adaptation
Adaptation measures are already in place
in many areas, as the examples below show. These actions can be expanded or
modified to prepare for climate change. But additional measures, such as new
technologies and policies, may also be needed. Such actions could require time
and resources to carry out, so planning now is important.
Agriculture and Food Supply
·
Develop crop varieties that are
more tolerant of heat, drought, or flooding from heavy rains.
·
Provide more shade and air flow
in barns to protect livestock from higher summer temperatures.
Coasts
·
Preserve wetlands and open
spaces to protect coastal communities from flooding and erosion from storms and
sea level rise.
·
Improve evacuation planning for
low-lying areas to prepare for increased storm surge and flooding.
Ecosystems
·
Protect and expand wildlife
habitats to allow species to migrate as the climate changes.
·
Reduce pollution, habitat loss,
and other stressors that make ecosystems more vulnerable to climate change.
Energy
·
Increase energy efficiency to
help offset rises in energy consumption, such as from more air conditioning use
as temperatures warm.
·
Strengthen energy production facilities
to withstand increased flood, wind, lightning, and other storm-related
stresses.
Human Health
·
Set up early warning systems
and emergency response plans to prepare for more extreme weather events.
·
Educate people to help them
avoid diseases that could become more prevalent as the climate changes, such as
those carried by mosquitoes or ticks.
·
Plant trees and expand green
spaces in cities to reduce the "urban heat island" effect.
Water Resources
·
Improve water use efficiency,
and build additional water storage capacity.
