A CLIMATE-ORIENTED APPROACH 

FOR LEARNERS OF ALL AGES

Climate Literacy

The Essential Principles 

of Climate Sciences

A Guide for Individuals and Communities

Second Version: March 2009

www.climatescience.gov
Cl

Throughout its history, Earth’s climate has varied, 

reflecting the complex interactions and dependencies 

of the solar, oceanic, terrestrial, atmospheric, and 

living components that make up planet Earth’s 

systems. For at least the last million years, our 

world has experienced cycles of warming and cooling 

that take approximately 100,000 years to complete. 

Over the course of each cycle, global average 

temperatures have fallen and then risen again by 

about 9°F (5°C), each time taking Earth into an ice 

age and then warming it again. This cycle is believed 

associated with regular changes in Earth’s orbit 

that alter the intensity of solar energy the planet 

receives. Earth’s climate has also been influenced on 

very long timescales by changes in ocean circulation 

that result from plate tectonic movements. Earth’s 

climate has changed abruptly at times, sometimes 

as a result of slower natural processes such as 

shifts in ocean circulation, sometimes due to sudden 

events such as massive volcanic eruptions. Species 

and ecosystems have either adapted to these past 

climate variations or perished.

While global climate has been relatively stable 

over the last 10,000 years—the span of human 

civilization—regional variations in climate patterns 

have influenced human history in profound ways, 

playing an integral role in whether societies thrived 

or failed. We now know that the opposite is also 

true: human activities—burning fossil fuels and 

deforesting large areas of land, for instance—have 

had a profound influence on Earth’s climate. In its 

2007 Fourth Assessment, the Intergovernmental 

Panel on Climate Change (IPCC) stated that it had 

“very high confidence that the global average net 

effect of human activities since 1750 has been one 

of warming.” The IPCC attributes humanity’s global 

warming influence primarily to the increase in 

three key heat-trapping gases in the atmosphere: 

carbon dioxide, methane, and nitrous oxide. The 

U.S. Climate Change Science Program published 

findings in agreement with the IPCC report, stating 

that “studies to detect climate change and attribute 

its causes using patterns of observed temperature 

change in space and time show clear evidence 

of human influences on the climate system (due 

to changes in greenhouse gases, aerosols, and 

stratospheric ozone).”1

To protect fragile ecosystems and to build 

sustainable communities that are resilient to 

climate change—including extreme weather and 

climate events—a climate-literate citizenry is 

essential. This climate science literacy guide 

identifies the essential principles and fundamental 

concepts that individuals and communities should 

understand about Earth’s climate system. Such 

understanding improves our ability to make 

decisions about activities that increase vulnerability 

to the impacts of climate change and to take 

precautionary steps in our lives and livelihoods that 

would reduce those vulnerabilities.

1. Temperature Trends in the Lower Atmosphere: Steps for Understanding 

 and Reconciling Differences. Thomas R. Karl, Susan J. Hassol, 

 Christopher D. Miller, and William L. Murray, editors, 2006. A Report 

 by the Climate Change Science Program and the Subcommittee on Global 

 Change Research, Washington, DC.
WHAT IS CLIMATE SCIENCE 

LITERACY?

Climate Science Literacy is an understanding of your 

influence on climate and climate’s influence on you 

and society. 

A climate-literate person: 

•	 understands the essential principles of Earth’s 

climate system,

•	 knows how to assess scientifically credible 

information about climate,

•	 communicates about climate and climate change 

in a meaningful way, and

•	 is able to make informed and responsible 

decisions with regard to actions that may 

affect climate.

WHY DOES CLIMATE SCIENCE 

LITERACY MATTER?

•	 During the 20th century, Earth’s globally 

averaged surface temperature rose by 

approximately 1.08°F (0.6°C). Additional 

warming of more than 0.25°F (0.14°C) has 

been measured since 2000. Though the total 

increase may seem small, it likely represents an 

extraordinarily rapid rate of change compared to 

changes in the previous 10,000 years.

•	 Over the 21st century, climate scientists expect 

Earth’s temperature to continue increasing, 

very likely more than it did during the 20th 

century. Two anticipated results are rising 

global sea level and increasing frequency and 

intensity of heat waves, droughts, and floods. 

These changes will affect almost every aspect of 

human society, including economic prosperity, 

human and environmental health, and 

national security.

•	 Scientific observations and climate model results 

indicate that human activities are now the 

primary cause of most of the ongoing increase in 

Earth’s globally averaged surface temperature.

•	 Climate change will bring economic and 

environmental challenges as well as 

opportunities, and citizens who have an 

understanding of climate science will be better 

prepared to respond to both.

•	 Society needs citizens who understand the 

climate system and know how to apply 

that knowledge in their careers and in 

their engagement as active members of 

their communities.

•	 Climate change will continue to be a significant 

element of public discourse. Understanding 

the essential principles of climate science will 

enable all people to assess news stories and 

contribute to their everyday conversations as 

informed citizens.

CLIMATE SCIENCE LITERACY IS A 

PART OF SCIENCE LITERACY.

“Science, mathematics, and technology have a 

profound impact on our individual lives and our 

culture. They play a role in almost all human 

endeavors, and they affect how we relate to one 

another and the world around us. . . . Science 

Literacy enables us to make sense of real-world 

phenomena, informs our personal and social 

decisions, and serves as a foundation for a lifetime 

of learning.” 

From the American Association for the Advancement 

of Science, Atlas of Science Literacy, Volume 2, 

Project 2061. 

People who are climate science literate know 

that climate science can inform our decisions 

that improve quality of life. They have a basic 

understanding of the climate system, including 

the natural and human-caused factors that affect 

it. Climate science literate individuals understand 

how climate observations and records as well 

as computer modeling contribute to scientific 

knowledge about climate. They are aware of the 

fundamental relationship between climate and 

human life and the many ways in which climate has 

always played a role in human health. They have the 

ability to assess the validity of scientific arguments 

about climate and to use that information to support 

their decisions.
CLIMATE SCIENCE LITERACY IS AN 

ONGOING PROCESS.

No single person is expected to understand 

every detail about all of the fundamental climate 

science literacy concepts. Full comprehension 

of these interconnected concepts will require a 

systems-thinking approach, meaning the ability to 

understand complex interconnections among all of 

the components of the climate system. Moreover, as 

climate science progresses and as efforts to educate 

the people about climate’s influence on them and 

their influence on the climate system mature, public 

understanding will continue to grow.

Climate is an ideal interdisciplinary theme for 

lifelong learning about the scientific process and the 

ways in which humans affect and are affected by the 

Earth’s systems. This rich topic can be approached 

at many levels, from comparing the daily weather 

with long-term records to exploring abstract 

representations of climate in computer models to 

examining how climate change impacts human and 

ecosystem health. Learners of all ages can use 

data from their own experiments, data collected by 

satellites and other observation systems, or records 

from a range of physical, chemical, biological, 

geographical, social, economic, and historical 

sources to explore the impacts of climate and 

potential adaptation and mitigation strategies. 

HOW DO WE KNOW WHAT IS 

SCIENTIFICALLY CORRECT?

The Peer Review Process

Science is an on-going process of making 

observations and using evidence to test hypotheses. 

As new ideas are developed and new data are 

obtained, oftentimes enabled by new technologies, 

our understanding evolves. The scientific community 

uses a highly formalized version of peer review to 

validate research results and our understanding 

of their significance. Researchers describe their 

experiments, results, and interpretations in 

scientific manuscripts and submit them to a 

scientific journal that specializes in their field of 

science. Scientists who are experts in that field 

serve as “referees” for the journal: they read the 

manuscript carefully to judge the reliability of the 

research design and check that the interpretations 

are supported by the data. Based on the reviews, 

journal editors may accept or reject manuscripts 

or ask the authors to make revisions if the study 

has insufficient data or unsound interpretations. 

Through this process, only those concepts that 

have been described through well-documented 

research and subjected to the scrutiny of other 

experts in the field become published papers in 

science journals and accepted as current science 

knowledge. Although peer review does not guarantee 

that any particular published result is valid, it does 

provide a high assurance that the work has been 

carefully vetted for accuracy by informed experts 

prior to publication. The overwhelming majority of 

peer-reviewed papers about global climate change 

acknowledge that human activities are substantially 

contributing factors.

A meltwater stream on the Greenland Ice Sheet flows into the

ice through a tunnel called a moulin. About half of the loss 

of Greenland’s ice mass flows into the North Atlantic Ocean

as melt water. Liquid water, which is denser than ice, can 

penetrate through the ice sheet, lubricating the underside, and 

also accelerate ice loss. Warmer temperatures cause melting 

in the summer months, which leads to faster flow, drawing

more of the ice sheet down to warmer, lower altitudes.

Source: Roger J. Braithwaite, The University of Manchester, UK
INFORMED CLIMATE 

DECISIONS REQUIRE AN 

INTEGRATED APPROACH.

In the coming decades, scientists expect climate 

change to have an increasing impact on human and 

natural systems. In a warmer world, accessibility 

to food, water, raw materials, and energy are likely 

to change. Human health, biodiversity, economic 

stability, and national security are also expected 

to be affected by climate change. Climate model 

projections suggest that negative effects of climate 

change will significantly outweigh positive ones. 

The nation’s ability to prepare for and adapt to new 

conditions may be exceeded as the rate of climate 

change increases.

Reducing our vulnerability to these impacts 

depends not only upon our ability to understand 

climate science and the implications of climate 

change, but also upon our ability to integrate and 

use that knowledge effectively. Changes in our 

economy and infrastructure as well as individual 

attitudes, societal values, and government policies 

will be required to alter the current trajectory of 

climate’s impact on human lives. The resolve of 

individuals, communities, and countries to identify 

and implement effective management strategies for 

critical institutional and natural resources will be 

necessary to ensure the stability of both human and 

natural systems as temperatures rise.

This climate science literacy document focuses 

primarily on the physical and biological science 

aspects of climate and climate change. Yet as 

nations and the international community seek 

solutions to global climate change over the coming 

decades, a more comprehensive, interdisciplinary 

approach to climate literacy—one that includes 

economic and social considerations—will play a vital 

role in knowledgeable planning, decision making, 

and governance. A new effort is in development 

within the social sciences community to produce 

a companion document that will address these 

aspects of climate literacy. Together, these 

documents will promote informed decision-making 

and effective systems-level responses to climate 

change that reflect a fundamental understanding 

of climate science. It is imperative that these 

responses to climate change embrace the following 

guiding principle.

Agricultural engineers 

inspect a dry stream.

Source: Scott Bauer, USDA 
a. Climate information can be used to reduce

vulnerabilities or enhance the resilience of 

communities and ecosystems affected by 

climate change. Continuing to improve scientific 

understanding of the climate system and the 

quality of reports to policy and decision-makers 

is crucial.

b. Reducing human vulnerability to the impacts

of climate change depends not only upon 

our ability to understand climate science, 

but also upon our ability to integrate that 

knowledge into human society. Decisions 

that involve Earth’s climate must be made 

with an understanding of the complex interconnections among the physical and biological 

components of the Earth system as well as 

the consequences of such decisions on social, 

economic, and cultural systems. 

c. The impacts of climate change may affect the

security of nations. Reduced availability of 

water, food, and land can lead to competition 

and conflict among humans, potentially 

resulting in large groups of climate refugees.

d. Humans may be able to mitigate climate

change or lessen its severity by reducing 

greenhouse gas concentrations through 

processes that move carbon out of 

the atmosphere or reduce greenhouse 

gas emissions.

e. A combination of strategies is needed to reduce

greenhouse gas emissions. The most immediate 

strategy is conservation of oil, gas, and coal, 

which we rely on as fuels for most of our 

transportation, heating, cooling, agriculture, 

and electricity. Short-term strategies involve 

switching from carbon-intensive to renewable 

energy sources, which also requires building 

new infrastructure for alternative energy 

sources. Long-term strategies involve 

innovative research and a fundamental change 

in the way humans use energy.

f. Humans can adapt to climate change by

reducing their vulnerability to its impacts. 

Actions such as moving to higher ground to 

avoid rising sea levels, planting new crops 

that will thrive under new climate conditions, 

or using new building technologies represent 

adaptation strategies. Adaptation often requires 

financial investment in new or enhanced 

research, technology, and infrastructure.

g. Actions taken by individuals, communities,

states, and countries all influence climate. 

Practices and policies followed in homes, 

schools, businesses, and governments can 

affect climate. Climate-related decisions made 

by one generation can provide opportunities 

as well as limit the range of possibilities open 

to the next generation. Steps toward reducing 

the impact of climate change may influence the 

present generation by providing other benefits 

such as improved public health infrastructure 

and sustainable built environments.

h

GUIDING PRINCIPLE 

FOR INFORMED 

CLIMATE DECISION:

Humans can take actions to reduce 

climate change and its impacts.

Source: NASA Goddard Space Flight Center Image by Reto Stöckli (land surface, shallow water, clouds)

This spectacular “blue marble” image is the most detailed true-color image 

of the entire Earth to date. Using a collection of satellite-based observations, 

scientists and visualizers stitched together months of observations of 

the land surface, oceans, sea ice, and clouds into a seamless, true-color 

mosaic of every square kilometer (.386 square mile) of our planet.
Climat

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CLIMATE LITERACY:

The Essential Principles 

of Climate Science

Each essential principle is supported by fundamental 

concepts comparable to those underlying the National 

Science Education Standards (NSES) and the American 

Association for the Advancement of Science (AAAS) 

Benchmarks for Science Literacy.
a. Sunlight reaching the Earth can heat the land,

ocean, and atmosphere. Some of that sunlight is 

reflected back to space by the surface, clouds, 

or ice. Much of the sunlight that reaches Earth is 

absorbed and warms the planet.

b. When Earth emits the same amount of energy as

it absorbs, its energy budget is in balance, and its 

average temperature remains stable.

c. The tilt of Earth’s axis relative to its orbit around the

Sun results in predictable changes in the duration 

of daylight and the amount of sunlight received 

at any latitude throughout a year. These changes 

cause the annual cycle of seasons and associated 

temperature changes.

1 The the r

Source: Modified from the Marian Koshland Science Museum of the National Academy of Sciences’ “Global Warming: Facts & Our Future” 2004

The greenhouse effect is a natural 

phenomenon whereby heat-trapping gases 

in the atmosphere, primarily water vapor, 

keep the Earth’s surface warm. Human 

activities, primarily burning fossil fuels and 

changing land cover patterns, are increasing 

the concentrations of some of these gases, 

amplifying the natural greenhouse effect. 

d. Gradual changes in Earth’s rotation and orbit around

the Sun change the intensity of sunlight received in 

our planet’s polar and equatorial regions. For at least 

the last 1 million years, these changes occurred in 

100,000-year cycles that produced ice ages and the 

shorter warm periods between them.

e. A significant increase or decrease in the Sun’s

energy output would cause Earth to warm or cool. 

Satellite measurements taken over the past 30 years 

show that the Sun’s energy output has changed only 

slightly and in both directions. These changes in the 

Sun’s energy are thought to be too small to be the 

cause of the recent warming observed on Earth.
a. Earth’s climate is influenced by interactions involving

the Sun, ocean, atmosphere, clouds, ice, land, and 

life. Climate varies by region as a result of local 

differences in these interactions. 

b. Covering 70% of Earth’s surface, the ocean exerts

a major control on climate by dominating Earth’s 

energy and water cycles. It has the capacity to 

absorb large amounts of solar energy. Heat and 

water vapor are redistributed globally through 

density-driven ocean currents and atmospheric 

circulation. Changes in ocean circulation caused by 

tectonic movements or large influxes of fresh water 

from melting polar ice can lead to significant and 

even abrupt changes in climate, both locally and on 

global scales.

c. The amount of solar energy absorbed or radiated

by Earth is modulated by the atmosphere and 

depends on its composition. Greenhouse gases—

such as water vapor, carbon dioxide, and methane—

occur naturally in small amounts and absorb and 

release heat energy more efficiently than abundant 

atmospheric gases like nitrogen and oxygen. Small 

increases in carbon dioxide concentration have a 

large effect on the climate system. 

d. The abundance of greenhouse gases in the

atmosphere is controlled by biogeochemical cycles 

that continually move these components between 

their ocean, land, life, and atmosphere reservoirs. 

The abundance of carbon in the atmosphere is 

reduced through seafloor accumulation of marine 

sediments and accumulation of plant biomass and is 

increased through deforestation and the burning of 

fossil fuels as well as through other processes.

e. Airborne particulates, called “aerosols,” have a

complex effect on Earth’s energy balance: they can 

cause both cooling, by reflecting incoming sunlight 

back out to space, and warming, by absorbing and 

releasing heat energy in the atmosphere. Small 

solid and liquid particles can be lofted into the 

atmosphere through a variety of natural and manmade processes, including volcanic eruptions, sea 

spray, forest fires, and emissions generated through 

human activities.

f. The interconnectedness of Earth’s systems means

that a significant change in any one component of 

the climate system can influence the equilibrium of 

the entire Earth system. Positive feedback loops 

can amplify these effects and trigger abrupt changes 

in the climate system. These complex interactions 

may result in climate change that is more rapid 

and on a larger scale than projected by current 

climate models. 

2

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Source: Astronaut photograph ISS015-E- 10469, courtesy NASA/JSC Gateway to Astronaut Photography of Earth.

Solar power drives Earth’s climate. Energy 

from the Sun heats the surface, warms the 

atmosphere, and powers the ocean currents. 
Lie 

on is nd 

a. Individual organisms survive within specific ranges

of temperature, precipitation, humidity, and sunlight. 

Organisms exposed to climate conditions outside their 

normal range must adapt or migrate, or they will 

perish. 

b. The presence of small amounts of heat-trapping

greenhouse gases in the atmosphere warms Earth’s 

surface, resulting in a planet that sustains liquid 

water and life.

c. Changes in climate conditions can affect the health

and function of ecosystems and the survival of entire 

species. The distribution patterns of fossils show 

evidence of gradual as well as abrupt extinctions 

related to climate change in the past.

d. A range of natural records shows that the last 10,000

years have been an unusually stable period in Earth’s 

climate history. Modern human societies developed 

during this time. The agricultural, economic, and 

transportation systems we rely upon are vulnerable if 

the climate changes significantly.

e. Life—including microbes, plants, and animals and

humans—is a major driver of the global carbon cycle 

and can influence global climate by modifying the 

chemical makeup of the atmosphere. The geologic 

record shows that life has significantly altered the 

atmosphere during Earth’s history.

Source: Steve Fisher

Kelp forests and their associated 

communities of organisms live in cool 

waters off the coast of California.
a. Climate is determined by the long-term pattern

of temperature and precipitation averages and 

extremes at a location. Climate descriptions can 

refer to areas that are local, regional, or global in 

extent. Climate can be described for different time 

intervals, such as decades, years, seasons, months, 

or specific dates of the year.

b. Climate is not the same thing as weather. Weather

is the minute-by-minute variable condition of the 

atmosphere on a local scale. Climate is a conceptual 

description of an area’s average weather conditions 

and the extent to which those conditions vary over 

long time intervals.

c. Climate change is a significant and persistent change

in an area’s average climate conditions or their 

extremes. Seasonal variations and multi-year cycles 

(for example, the El Niño Southern Oscillation) that 

produce warm, cool, wet, or dry periods across 

different regions are a natural part of climate 

variability. They do not represent climate change.

d. Scientific observations indicate that global climate

has changed in the past, is changing now, and will 

change in the future. The magnitude and direction of 

this change is not the same at all locations on Earth.

e. Based on evidence from tree rings, other natural

records, and scientific observations made around the 

world, Earth’s average temperature is now warmer 

than it has been for at least the past 1,300 years. 

Average temperatures have increased markedly 

in the past 50 years, especially in the North Polar 

Region.

f. Natural processes driving Earth’s long-term climate

variability do not explain the rapid climate change 

observed in recent decades. The only explanation 

that is consistent with all available evidence is that 

human impacts are playing an increasing role in 

climate change. Future changes in climate may be 

rapid compared to historical changes.

g. Natural processes that remove carbon dioxide from

the atmosphere operate slowly when compared 

to the processes that are now adding it to the 

atmosphere. Thus, carbon dioxide introduced into 

the atmosphere today may remain there for a 

century or more. Other greenhouse gases, including 

some created by humans, may remain in the 

atmosphere for thousands of years.

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Source: National Snow and Ice Data Center, W. O. Field, B. F. Molnia

Muir Glacier, August 

1941, William O. Field

Muir Glacier, August 

2004, Bruce F. Molnia 
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a. The components and processes of Earth’s climate

system are subject to the same physical laws as the 

rest of the Universe. Therefore, the behavior of the 

climate system can be understood and predicted 

through careful, systematic study. 

b. Environmental observations are the foundation for

understanding the climate system. From the bottom 

of the ocean to the surface of the Sun, instruments 

on weather stations, buoys, satellites, and other 

platforms collect climate data. To learn about past 

climates, scientists use natural records, such as tree 

rings, ice cores, and sedimentary layers. Historical 

observations, such as native knowledge and personal 

journals, also document past climate change.

c. Observations, experiments, and theory are used to

construct and refine computer models that represent 

the climate system and make predictions about its 

future behavior. Results from these models lead to 

better understanding of the linkages between the 

atmosphere-ocean system and climate conditions 

and inspire more observations and experiments. Over 

time, this iterative process will result in more reliable 

projections of future climate conditions.

Source: B. Longworth © 2008 

A rosette device containing 36 seawater samples 

is retrieved in the Southern Ocean. Seawater 

samples from various depths are analyzed 

to measure the ocean’s carbon balance.

d. Our understanding of climate differs in important

ways from our understanding of weather. Climate 

scientists’ ability to predict climate patterns months, 

years, or decades into the future is constrained 

by different limitations than those faced by 

meteorologists in forecasting weather days to weeks 

into the future.1

e. Scientists have conducted extensive research on the

fundamental characteristics of the climate system and 

their understanding will continue to improve. Current 

climate change projections are reliable enough to help 

humans evaluate potential decisions and actions in 

response to climate change.

1. Based on “Climate Change: An Information Statement 

 of the American Meteorological Society,” 2007 
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a. The overwhelming consensus of scientific studies on

climate indicates that most of the observed increase 

in global average temperatures since the latter part 

of the 20th century is very likely due to human 

activities, primarily from increases in greenhouse 

gas concentrations resulting from the burning of 

fossil fuels.2

b. Emissions from the widespread burning of fossil

fuels since the start of the Industrial Revolution 

have increased the concentration of greenhouse 

gases in the atmosphere. Because these gases can 

remain in the atmosphere for hundreds of years 

before being removed by natural processes, their 

warming influence is projected to persist into the 

next century.

c. Human activities have affected the land, oceans, and

atmosphere, and these changes have altered global 

climate patterns. Burning fossil fuels, releasing 

chemicals into the atmosphere, reducing the amount 

of forest cover, and rapid expansion of farming, 

development, and industrial activities are releasing 

carbon dioxide into the atmosphere and changing 

the balance of the climate system.

d. Growing evidence shows that changes in many

physical and biological systems are linked to humancaused global warming.3 Some changes resulting 

from human activities have decreased the capacity 

of the environment to support various species and 

have substantially reduced ecosystem biodiversity 

and ecological resilience.

e. Scientists and economists predict that there will

be both positive and negative impacts from global 

climate change. If warming exceeds 2 to 3°C (3.6 to 

5.4°F) over the next century, the consequences of 

the negative impacts are likely to be much greater 

than the consequences of the positive impacts.

Society relies heavily on energy 

that is generated by burning fossil 

fuels—coal, oil, and natural gas.

Source:: A. Palmer, 2008

2. Based on IPCC, 2007: The Physical Science Basis: 

 Contribution of Working Group I

3. Based on IPCC, 2007: Impacts, Adaptation and 

 Vulnerability. Contribution of Working Group II
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a. Melting of ice sheets and glaciers, combined with the

thermal expansion of seawater as the oceans warm, 

is causing sea level to rise. Seawater is beginning to 

move onto low-lying land and to contaminate coastal 

fresh water sources and beginning to submerge 

coastal facilities and barrier islands. Sea-level rise 

increases the risk of damage to homes and buildings 

from storm surges such as those that accompany 

hurricanes.

b. Climate plays an important role in the global

distribution of freshwater resources. Changing 

precipitation patterns and temperature conditions 

will alter the distribution and availability of 

freshwater resources, reducing reliable access to 

water for many people and their crops. Winter 

snowpack and mountain glaciers that provide water 

for human use are declining as a result of global 

warming.

c. Incidents of extreme weather are projected to

increase as a result of climate change. Many 

locations will see a substantial increase in the 

number of heat waves they experience per year 

and a likely decrease in episodes of severe cold. 

Precipitation events are expected to become less 

frequent but more intense in many areas, and 

droughts will be more frequent and severe in 

areas where average precipitation is projected to 

decrease.2

d. The chemistry of ocean water is changed by

absorption of carbon dioxide from the atmosphere. 

Increasing carbon dioxide levels in the atmosphere 

is causing ocean water to become more acidic, 

threatening the survival of shell-building marine 

species and the entire food web of which they are a 

part.

e. Ecosystems on land and in the ocean have been

and will continue to be disturbed by climate change. 

Animals, plants, bacteria, and viruses will migrate 

to new areas with favorable climate conditions. 

Infectious diseases and certain species will be able 

to invade areas that they did not previously inhabit.

f. Human health and mortality rates will be affected

to different degrees in specific regions of the world 

as a result of climate change. Although cold-related 

deaths are predicted to decrease, other risks are 

predicted to rise. The incidence and geographical 

range of climate-sensitive infectious diseases—

such as malaria, dengue fever, and tick-borne 

diseases—will increase. Drought-reduced crop 

yields, degraded air and water quality, and increased 

hazards in coastal and low-lying areas will contribute 

to unhealthy conditions, particularly for the most 

vulnerable populations.3

Iowa National Guard preparing to 

put sandbags in place on a levee 

in Kingston, Iowa, to protect 

roughly 50,000 acres of farmland 

threatened by flood waters.

Source: Iowa National Guard photo by Sgt. Chad D. Nelson
Key

Weather The specific conditions of the atmosphere at a particular place and time, measured 

in terms of variables that include temperature, precipitation, cloudiness, humidity, air 

pressure, and wind. 

Weather Forecast A prediction about the specific atmospheric conditions expected for a 

location in the short-term future (hours to days).

Climate The long-term average of conditions in the atmosphere, ocean, and ice sheets and 

sea ice described by statistics, such as means and extremes.

Climate Forecast A prediction about average or extreme climate conditions for a region in 

the long-term future (seasons to decades).

Climate Variability Natural changes in climate that fall within the normal range of extremes

for a particular region, as measured by temperature, precipitation, and frequency of events. 

Drivers of climate variability include the El Niño Southern Oscillation and other phenomena.

Climate Change A significant and persistent change in the mean state of the climate or 

its variability. Climate change occurs in response to changes in some aspect of Earth’s 

environment: these include regular changes in Earth’s orbit about the sun, re-arrangement of 

continents through plate tectonic motions, or anthropogenic modification of the atmosphere.

Global Warming The observed increase in average temperature near the Earth’s surface 

and in the lowest layer of the atmosphere. In common usage, “global warming” often refers 

to the warming that has occurred as a result of increased emissions of greenhouse gases 

from human activities. Global warming is a type of climate change; it can also lead to other 

changes in climate conditions, such as changes in precipitation patterns.

Climate System The matter, energy, and processes involved in interactions among Earth’s 

atmosphere, hydrosphere, cryosphere, lithosphere, biosphere, and Earth-Sun interactions.

Likely, Very Likely, Extremely Likely, Virtually Certain These terms are used by th

Intergovernmental Panel on Climate Change (IPCC) to indicate how probable it is that a 

predicted outcome will occur in the climate system, according to expert judgment. A result 

that is deemed “likely” to occur has a greater than 66% probability of occurring. A “very 

likely” result has a greater than 90% probability. “Extremely likely” means greater than 95% 

probability, and “virtually certain” means greater than 99% probability.

Mitigation Human interventions to reduce the sources of greenhouse gases or enhance the 

sinks that remove them from the atmosphere.

Vulnerability The degree to which physical, biological, and socio-economic systems are

susceptible to and unable to cope with adverse impacts of climate change. 2

Adaptation Initiatives and measures to reduce the vulnerability of natural and human 

systems against actual or expected climate change effects.3

Fossil fuels Energy sources such as petroleum, coal, or natural gas, which are derived from 

living matter that existed during a previous geologic time period.

Feedback The process through which a system is controlled, changed, or modulated in 

response to its own output. Positive feedback results in amplification of the system output; 

negative feedback reduces the output of a system.

Carbon Cycle Circulation of carbon atoms through the Earth systems as a result of 

photosynthetic conversion of carbon dioxide into complex organic compounds by plants, 

which are consumed by other organisms, and return of the carbon to the atmosphere as 

carbon dioxide as a result of respiration, decay of organisms, and combustion of fossil fuels.

1. Temperature Trends in the Lower Atmosphere: Steps for Understanding 

 and Reconciling Differences. Thomas R. Karl, Susan J. Hassol, 

 Christopher D. Miller, and William L. Murray, editors, 2006. A Report 

 by the Climate Change Science Program and the Subcommittee on Global 

 Change Research, Washington, DC.

2. Based on IPCC, 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II

3. Based on IPCC, 2007: Mitigation of Climate Change. Contribution of Working Group III
Recycled Content Paper Second Version: March 2009

ABu

Current Science and Educational Partners:

American Association for the 

Advancement of Science Project 2061

American Meteorological Society

Association of Science-Technology 

Centers

Bowman Global Change

Centers for Disease Control & 

Prevention

Challenger Center for Space 

Science Education

Climate Literacy Network

College of Exploration

Cooperative Institute for Research in 

Environmental Sciences

Federation of Earth Science 

Information Partners

Lawrence Hall of Science, University 

of California, Berkeley

National Environmental Education 

Foundation

National Geographic Education 

Programs

National Institute of Standards & 

Technology

National Oceanic and 

Atmospheric Administration

National Science Teachers 

Association

North American Association For 

Environmental Education

Sally Ride ScienceTM

TERC Inc.

The GLOBE Program

The National Center for 

Atmospheric Research

University Corporation for 

Atmospheric Research

U.S. Geological Survey

U.S. Forest Service

U.S. Global Change Research Program / 

Climate Change Science Program

1717 Pennsylvania Avenue, NW Suire 250 Washington DC 20006 USA

+1.202.223.6262 (Voice) + 1.202.223.3065 (Fax)

http://www.climatescience.gov

climate.literacy@climatescience.gov

 Fu

For future revisions and changes 

to this document or to see 

documentation of the process used 

to develop this brochure, please visit 

www.climate.noaa.gov/education. 

In addition, further information 

relating to climate literacy and climate 

resources can be found at:

• earthobservatory.nasa.

• www.epa.gov/climatecha

• http://nsdl.

• www.education.noaa.

Climate Literacy: The Essential Principles of Climate 

Science presents information that is deemed 

important for individuals and communities to know 

and understand about Earth’s climate, impacts of 

climate change, and approaches to adaptation or 

mitigation. Principles in the guide can serve as 

discussion starters or launching points for scientific 

inquiry. The guide aims to promote greater climate 

science literacy by providing this educational 

framework of principles and concepts. The guide 

can also serve educators who teach climate science 

as a way to meet content standards in their science 

curricula.

Development of the guide began at a workshop 

sponsored by the National Oceanic and Atmospheric 

Administration (NOAA) and the American 

Association for the Advancement of Science (AAAS). 

Multiple science agencies, non-governmental 

organizations, and numerous individuals also 

contributed through extensive review and comment 

periods. Discussion at the National Science 

Foundation- and NOAA-sponsored Atmospheric 

Sciences and Climate Literacy workshop contributed 

substantially to the refinement of the document.

To download this guide and related documents, 

visit www.climatescience.gov.

For an up to date list of partners please refer to U.S Climate 

Change Science Program at http://www.climatescience.gov.

This document has been reviewed by the following Federal agencies. Any opinions, findings,

and conclusions or recommendations expressed in this material are those of the author(s) 

and do not necessarily reflect the views of the National Science Foundation.