Climate Topic

This lists the logos of programs or partners of NG Education which have provided or contributed the content on this page. Leveled by

Article Vocabulary

Links

• The most familiar climate classification system was developed in 1900 by Russian-German scientist Wladimir Köppen. Our MapMaker Interactive layer on climate zones is based on the Köppen climate classification system.

Tuesday, September 26, 2017

Select Text Level:

3rd Grade 6th Grade 8th Grade 12th Grade

Climate is the long-term pattern of weather in a particular area. Weather can change from hour-to-hour, day-to-day, month-to-month or even year-to-year. A regions weather patterns, usually tracked for at least 30 years, are considered its climate.

Climate System

Different parts of the world have different climates. Some parts of the world are hot and rainy nearly every day. They have a tropical wet climate. Others are cold and snow-covered most of the year. They have a polar climate. Between the icy poles and the steamy tropics are many other climates that contribute to Earths biodiversity and geologic heritage.

Climate is determined by a regions climate system. A climate system has five major components: the atmosphere, the hydrosphere, the cryosphere, the land surface, and the biosphere.

The atmosphere is the most variable part of the climate system. The composition and movement of gases surrounding the Earth can change radically, influenced by natural and human-made factors.

Changes to the hydrosphere, which include variations in temperatureand salinity, occur at much slower rates than changes to the atmosphere.

The cryosphere is another generally consistent part of the climate system. Ice sheets and glaciers reflect sunlight, and the thermal conductivity of ice and permafrost profoundly influences temperature. The cryosphere also helps regulate thermohaline circulation. This ocean conveyor belt has an enormous influence on marine ecosystems and biodiversity.

Topography

Topography and vegetation influence climate by helping determine how the Suns energy is used on Earth. The abundance of plants and the type of land cover [such as soil, sand, or asphalt] impacts evaporation and ambient temperature.

The biosphere, the sum total of living things on Earth, profoundly influences climate. Through photosynthesis, plants help regulate the flow of greenhouse gases in the atmosphere. Forests and oceans serve as carbon sinks that have a cooling impact on climate. Living organisms alter the landscape, through both natural growth and created structures such as burrows, dams, and mounds. These altered landscapes can influence weather patterns such as wind, erosion, and even temperature.

Climate Features

The most familiar features of a regions climate are probably average temperature and precipitation. Changes in day-to-day, day-to-night, and seasonal variations also help determine specific climates. For example, San Francisco, California, and Beijing, China, have similar yearly temperatures and precipitation. However, the daily and seasonal changes make San Francisco and Beijing very different. San Franciscos winters are not much cooler than its summers, while Beijing is hot in summer and cold in winter. San Franciscos summers are dry and its winters are wet. Wet and dry seasons are reversed in Beijingit has rainy summers and dry winters.

Climate features also include windiness, humidity, cloud cover, atmospheric pressure, and fogginess. Latitude plays a huge factor in determining climate. Landscape can also help define regional climate. A regions elevation, proximity to the ocean or freshwater, and land-use patterns can all impact climate.

All climates are the product of many factors, including latitude, elevation, topography, distance from the ocean, and location on a continent. The rainy, tropical climate of West Africa, for example, is influenced by the regions location near the Equator [latitude] and its position on the western side of the continent. The area receives direct sunlight year-round, and sits at an area called the intertropical convergence zone [ITCZ, pronounced itch], where moist trade winds meet. As a result, the regions climate is warm and rainy.

Microclimates

Of course, no climate is uniform. Small variations, called microclimates, exist in every climate region. Microclimates are largely influenced by topographic features such as lakes, vegetation, and cities. In large urban areas, for example, streets and buildings absorb heat from the Sun, raising the average temperature of the city higher than average temperatures of more open areas nearby. This is known as the urban heat island effect.

Large bodies of water, such as the Great Lakes in the United States and Canada, can also have microclimates. Cities on the southern side of Lake Ontario, for example, are cloudier and receive much more snow than cities on the northern shore. This lake effect is a result of cold winds blowing across warmer lake water.

Climate Classification

In 1948, American climatologist Charles Thornthwaite developed a climate classification system that scientists still use today. Thornthwaites system relies on a regions water budget and potential evapotranspiration. Potential evapotranspiration describes the amount of water evaporated from a vegetated piece of land. Indices such as humidity and precipitation help determine a regions moisture index. The lower its moisture index value, the more arid a regions climate.

The major classifications in Thornthwaites climate classification are microthermal, mesothermal, and megathermal.

Microthermal climates are characterized by cold winters and low potential evapotranspiration. Most geographers apply the term exclusively to the northern latitudes of North America, Europe, and Asia. A microthermal climate may include the temperate climate of Boston, Massachusetts; the coniferous forests of southern Scandinavia; and the boreal ecosystem of northern Siberia.

Mesothermal regions have moderate climates. They are not cold enough to sustain a layer of winter snow, but are also not remain warm enough to support flowering plants [and, thus, evapotranspiration] all year. Mesothermal climates include the Mediterranean Basin, most of coastal Australia, and the Pampas region of South America.

Megathermal climates are hot and humid. These regions have a high moisture index and support rich vegetation all year. Megathermal climates include the Amazon Basin; many islands in Southeast Asia, such as New Guinea and the Philippines; and the Congo Basin in Africa.

Köppen Classification System

Although many climatologists think the Thornthwaite system is an efficient, rigorous way of classifying climate, it is complex and mapping it is difficult. The system is rarely used outside scientific publishing.

The most popular system of classifying climates was proposed in 1900 by Russian-German scientist Wladimir Köppen. Köppen observed that the type of vegetation in a region depended largely on climate. Studying vegetation, temperature, and precipitation data, he and other scientists developed a system for naming climate regions.

According to the Köppen climate classification system, there are five climate groups: tropical, dry, mild, continental, and polar. These climate groups are further divided into climate types. The following list shows the climate groups and their types:

Tropical

• Wet [rainforest]
• Monsoon
• Wet and dry [savanna]

Dry

• Arid
• Semiarid

Mild

• Mediterranean
• Humid subtropical
• Marine

Continental

• Warm summer
• Cool summer
• Subarctic [boreal]

Polar

• Tundra
• Ice cap

Tropical Climates

There are three climate types in the tropical group: tropical wet; tropical monsoon; and tropical wet and dry.

Tropical Wet: Rainforests

Places with a tropical wet climate are also known as rainforests. These equatorial regions have the most predictable weather on Earth, with warm temperatures and regular rainfall. Annual rainfall exceeds 150 centimeters [59 inches], and the temperature varies more during a day than it does over a year. The coolest temperatures, about 20° to 23° Celsius [68°-73° Fahrenheit], occurs just before dawn. Afternoon temperatures usually reach 30° to 33° Celsius [86°-91° Fahrenheit]. Rainforests experience very little seasonal change, meaning average monthly temperatures remain fairly constant throughout the year.

Tropical wet climates exist in a band extending about 10° of latitude on either side of the Equator. This part of the globe is always under the influence of the intertropical convergence zone. The ITCZ follows a pendulum-like path during the course of a year, moving back and forth across the Equator with the seasons. It moves north during summer in the Northern Hemisphere, and south during the northern winter.

Some tropical wet climates are wet throughout the year. Others experience more rainfall during the summer or winter, but they never have especially dry seasons. The U.S. state of Hawaii; Kuala Lumpur, Malaysia; and Belém, Brazil, are examples of areas with tropical wet climates.

Tropical Monsoon

Tropical monsoon climates are most found in southern Asia and West Africa. A monsoon is a wind system that reverses its direction every six months. Monsoons usually flow from sea to land in the summer, and from land to sea in the winter.

Summer monsoons bring large amounts of rainfall to tropical monsoon regions. People living in these regions depend on the seasonal rains to bring water to their crops. India and Bangladesh are famous for their monsoon climate patterns.

Tropical Wet and Dry: Savanna

Tropical wet and dry climates are sometimes called savanna climates after the grassland ecosystem defined by wet and dry periods.

Tropical wet and dry climates sit just outside the ITCZ, near the Equator. They have three seasons. One season is cool and drywhen the warm, moist ITCZ is in the opposite hemisphere. Another season is hot and dry as the ITCZ approaches. The last season is hot and wet as the ITCZ arrives and the region experiences months as a tropical wet climate.

Life in these tropical wet and dry regions depends on the wet seasons rains. During years when rains are light, people and animals suffer through drought. During especially rainy years, regions may experience flooding. Havana, Cuba; Kolkata, India; and Africas vast Serengeti Plain are in the wet and dry tropics.

Dry Climates

Regions lying within the dry climate group occur where precipitation is low. There are two dry climate types: arid and semiarid. Most arid climates receive 10 to 30 centimeters [four to 12 inches] of rain each year, and semiarid climates receive enough to support extensive grasslands.

Temperatures in both arid and semiarid climates show large daily and seasonal variations. The hottest spots in the world are in arid climates. The temperature in the arid Death Valley National Park, California, U.S., reached 56.7° Celsius [134° Fahrenheit] on July 10, 1913the highest temperature ever recorded.

Although rainfall is limited in all dry climates, there are a few parts of the world where it never rains. One of the driest places on Earth is the Atacama Desert of Chile, on the west coast of South America. Stretches of the Atacama may have never received rain in recorded history.

Semiarid regions, such as the Australian outback, usually receive between 25 and 50 centimeters [10-20 inches] of rainfall every year. They are often located between arid and tropical climate regions.

Arid and semiarid climates can occur where the movement of warm, moist air is blocked by mountains. Denver, Colorado, just east of the U.S. section of the Rocky Mountains, has this type of dry climate, known as a rain shadow.

Mild Climates

Regions with mild and continental climates are also called temperate regions. Both climate types have distinct cold seasons. In these parts of the world, climate is influenced mostly by latitude and a regions position on the continent.

Mediterranean

Mediterranean climates have warm summers and short, mild, rainy winters. Mediterranean climates are found on the west coasts of continents between 30° and 40° latitude, and along the shores of the Mediterranean Sea.

Mediterranean summers feature clear skies, cool nights, and little rain.

Humid Subtropical

Humid subtropical climates are usually found on the eastern sides of continents. In cities such as Savannah, Georgia, in the U.S.; Shanghai, China; and Sydney, Australia, summers are hot and humid. Winter can be severely cold. Precipitation is spread evenly through the year and totals 76 to 165 centimeters [30-65 inches]. Hurricanes and other violent storms are common in these regions.

Marine West Coast

Weather on both sides of a continent generally becomes cooler as latitude increases.

The marine west coast climate, a type of mild climate typical of cities such as Seattle, Washington, in the U.S. and Wellington, New Zealand, has a longer, cooler winter than the Mediterranean climate. Drizzle falls about two-thirds of winter days, and temperatures average about 5° Celsius [41° Fahrenheit].

Continental Climates

Areas with continental climates have colder winters, longer-lasting snow, and shorter growing seasons. They are the transition zones between mild and polar climates. Continental climates experience extreme seasonal changes.

The range of weather in continental climate regions makes them among the most spectacular sites for weather phenomena. In autumn, for instance, vast forests put on their annual show of brilliant color before shedding their leaves as winter approaches. Thunderstorms and tornadoes, among the most powerful forces in nature, form mostly in continental climates.

There are three types of continental climatewarm summer, cool summer, and subarctic. All these climates exist only in the Northern Hemisphere. Usually, continental climates are found in the interior of continents.

Warm Summer

Warm summer climate regions often have wet summer seasons, similar to monsoon climates. For this reason, this climate type is also called humid continental. Most of Eastern Europe, including Romania and Georgia, has warm summer climates.

Cool Summer

Cool summer climates have winters with low temperatures and snow. Cold winds, sweeping in from the Arctic, dominate winter weather.

People living in these climates have grown accustomed to the harsh weather, but those unprepared for such cold may suffer. Many of French Emperor Napoleon Bonapartes soldiers, for example, were used to the mild Mediterranean climates of France. Thousands died in bitter cold as they retreated from Russias cool summer climate in the winter of 1812.

Subarctic

North of regions with cool summer climates are regions with subarctic climates. These regions, including northern Scandinavia and Siberia, experience very long, cold winters with little precipitation. Subarctic climates are also called boreal climates or taiga.

Polar Climates

The two polar climate types, tundra and ice cap, lie within the Arctic and Antarctic Circles near the North and South Poles.

Tundra

In tundra climates, summers are short, but plants and animals are plentiful. Temperatures can average as high as 10° Celsius [50° Fahrenheit] in July. Wildflowers dot the landscape, and flocks of migratory birds feed on insects and fish. Whales feed on microscopic creatures in the regions cold, nutrient-rich waters. People have adapted to life on the tundra for thousands of years.

Ice Cap

Few organisms survive in the ice cap climates of the Arctic and Antarctic. Temperatures rarely rise above freezing, even in summer. The ever-present ice helps keep the weather cold by reflecting most of the Suns energy back into the atmosphere. Skies are mostly clear and precipitation is low. In fact, Antarctica, covered by an ice cap 1.6-kilometers [one-mile] thick, is one of the largest, driest deserts on Earth.

High Elevation Climates

Many geographers and climatologists have modified the Köppen classification system over the years, including geographer Glen Trewartha, who added a category for high-elevation climates.

There are two high elevation climate types: upland and highland. Both highland and upland climates are marked by very different temperatures and levels of precipitation. Climbing a lofty mountain or reaching a plateau can be like moving toward the poles. On some mountains, such as Mount Kilimanjaro, Tanzania, the climate is tropical at the base and polar at the summit. Often, high-elevation climate differs from one side of the mountain to the other.

Influence of Climate

The enormous variety of life on Earth is largely due to the variety of climates that exist and the climate changes that have occurred in the past.

Climate has influenced the development of cultures and civilizations. People everywhere have adapted in various ways to the climates in which they live.

Clothing

Clothing, for example, is influenced by climate. Indigenous Arctic cultures of Europe, Asia, and North America, for example, developed warm, durable, fur and animal-skin clothing. This clothing was necessary for survival in the icy climate near the North Pole. Many parkas worn by Arctic peoples are not only insulated, but waterproof. This combats both the frigid temperatures and precipitation found in polar climates.

Lightweight, papery tapa cloth, on the other hand, is part of many cultures in the warm, humid climates of Polynesia, in the South Pacific. Tapa cloth was traditionally made from dried leaves, coconut fibers, and breadfruit bark. Tapa cloth is delicate and loses strength when wet, which would be deadly near the poles but only inconvenient near the Equator.

Shelter

Climate also influences how civilizations construct housing. For instance, the ancient Anasazi people of southern North America built apartments into tall cliffs. The sheltered, shady area kept residents cool in the hot, dry desert climate.

The yurt is a part of the identity of many cultures across the windy, semiarid steppe of Central Asia. Yurts are a type of original mobile home, a portable, circular dwelling made of a lattice of flexible poles and covered in felt or other fabric. Yurts protect residents from fierce winds, and their portability makes them an ideal structure for nomadic and seminomadic herding cultures on the grassland.

Agriculture

The development of agriculture was very dependent on climate. Ancient agricultural civilizations, such as those in Mesopotamia and India, flourished where the climate was mild. Communities could grow crops every season, and experiment with different types of crops, livestock, and farming techniques.

The mild, Mediterranean climate in which the Roman Empire developed, for instance, allowed farmers to cultivate crops, such as wheat, olives, grapes, barley, and figs. Livestock included cattle, sheep, goats, pigs, and even honeybees.

Like the ancient Romans, ancient cultures of the Amazon Basin in South America were also able to develop agricultural practices. The chief domesticated trees in the Amazon were mostly harvested for food and medicine: Brazil nuts, Inga ynga fruit [commonly known as ice-cream beans], Amazon tree grapes, abiu [another tropical fruit], and cacao fruits [whose seeds are known as cocoa beans].

Today, farmers are still in tune with the climate. They plant certain crops according to the expected amount of rainfall and the length of the growing season. When the weather does not follow the typical climate pattern, it can mean hard times for farmers and higher food costs for consumers.

Climate Change

Climate does not change from day to day like weather, but it does change over time. The study of historic climate change is called paleoclimatology.

Climate changes happen slowly over hundreds or even thousands of years. For example, periodic glacial periods have covered large portions of Earth with ice caps. Some paleoclimatology evidence shows that the Sahara Desert was once covered by plants and lakes during a warm wet age.

Climate change can happen for many reasons. The movement of tectonic plates, volcanic activity, and the tilt of Earths axis all have effects on climate. For example, after the eruption of the island volcano of Krakatoa, Indonesia, in 1883, winters and even summers in Asia and Europe were colder and darker. Volcanic ash blocked the sun. Farmers had to adjust to shorter, weaker growing seasons. Climates around the world were changed for years.

The so-called Little Ice Age was a period of climate change extending from the 12th through the 19th centuries. The Little Ice Age was not a true glacial period, but describes colder climates around the world. In Europe, canals in Great Britain and the Netherlands were often frozen solid, allowing for ice skating. In North America, European colonists reported especially harsh winters.

Global Warming

Since the Industrial Revolution of the 19th century, human activity has begun to impact climate. The current period of climate change is sometimes called global warming.

Global warming is often associated with a runaway greenhouse effect. The greenhouse effect describes the process of certain gases [including carbon dioxide [CO2], methane, nitrous oxide [N2O], fluorinated gases, and ozone] trapping solar radiation in a planet's lower atmosphere. Greenhouse gases let the suns light shine onto Earths surface, but they trap the heat that reflects back up into the atmosphere. In this way, they act like the glass walls of a greenhouse.

The greenhouse effect is a natural phenomenon and keeps Earth warm enough to sustain life. However, human activities that include burning fossil fuels and cutting down forests release greenhouse gases into the atmosphere at an unprecedented rate.

The current period of climate change has been documented by rising temperatures, melting glaciers, and more intense weather phenomena.

Our planets temperature has risen about 1.1° C [2° F] since the late 19th century. Sixteen of the last 17 warmest years on record have occurred in the 21st century. According to NASA, not only was 2016 the warmest year on record, but eight of the 12 months that make up the year were the warmest on record for those respective months.

The current period of climate change is also associated with the massive retreat of glaciers, ice sheets, and sea ice. Warmer temperatures have reduced the number of glaciers of Montanas Glacier National Park from 150 in 1850 to just 26 today. In 2017, one of the largest icebergs ever recorded entered the ocean as a huge chunk of the Larsen C ice shelf broke off the Antarctic Peninsula. Warmer ocean temperatures and warmer ambient air temperatures likely contributed to the fracturing of the ice shelf and the massive Antarctic ice sheet associated with it. Finally, both the extent and thickness of Arctic sea ice has declined rapidly during the past several decades. The famed Northwest Passage, the treacherous route connecting the North Atlantic and North Pacific ocean basins, is now habitually free of ice and safe enough for cruise ships to navigate.

Melting glaciers and ice sheets, as well as expansion of seawater as it warms, have contributed to unprecedented sea level rise. Sea level rises at about 2.3 millimeters [0.2 inch] every year, contributing to up to 900% more frequent flooding in coastal areas.

Increasing temperatures can change the climate impacts and even the classification of a region. For instance, low-lying islands may be flooded as seawater rises. The populations of island nations, such as Maldives or Comoros, have been forced to contemplate becoming climate refugeespeople forced to leave their homes and migrate to a different region.

Heat in the atmosphere may increase the interaction of diverse weather systems. Unusually arid climates in a semiarid region may prolong droughts, for instance. In regions with mild climates, the increased atmospheric moisture associated with humid climates may increase the likelihood of hurricanes and typhoons.

Climate change is also impacting organisms and species range. Organisms that have adapted to one climate may have to migrate or adapt to warmer temperatures. Manatees, for instance, are marine mammals native to tropical waters. As temperatures increase, manatees have been migrating as far north as New York City, New York. Polar bear populations, on the other hand, are venturing farther south as Arctic sea ice becomes more scarce.

Climate change can be mitigated through reducing greenhouse-gas emissions. This can mean investing in new technologies, relying more on renewable energy sources, making older equipment more energy-efficient, or changing consumer behavior.

Climate influences the vegetation of a region.

Photograph by Paul Nicklen, National Geographic

Climograph

A climograph depicts the highs and lows of temperature and precipitation over a set period of time. Climographs can summarize daily, monthly, yearly, or decades-long weather patterns to help climatologists identify a regions climate.

Did the Language You Speak Evolve Due to Heat?

Some research indicates that the concentration of a languages vowels and consonants may be due in some part to the climate of the languages region. Vowel-heavy languages, such as Hawaiian, may have been influenced by pockets of warm air that can punch into a sound wave, making it harder to distinguish consonants such as k and ch.

Geographic Perspective

British geographer Andrew John Herbertson described climate like this: "Climate is what we expect, weather is what we get."

The Big Chill
Antarcticas frigid climate makes it the only continent on Earth with no permanent human residents. The coldest temperature ever recorded at ground level on Earth-89.2° Celsius [-128.5°Fahrenheit]was at Vostok Station, Antarctica.

abundance

Noun

large amount.

adapt

Verb

to adjust to new surroundings or a new situation.

adjust

Verb

to change or modify something to fit with something else.

agriculture

Noun

the art and science of cultivating land for growing crops [farming] or raising livestock [ranching].

ambient

Adjective

having to do with the surrounding area or environment.

Anasazi

Noun

[1200 BCE-1300 CE] people and culture native to what is now the southwestern United States. Also called Ancestral Puebloans.

ancient

Adjective

very old.

ancient Rome

Noun

civilization founded on the Mediterranean Sea, lasting from the 8th century BCE to about 476 CE.

Arctic

Noun

region at Earth's extreme north, encompassed by the Arctic Circle.

arid

Adjective

dry.

arid climate

Noun

[dry climate] region that receives 10 to 30 centimeters [4-12 inches] of rain each year.

asphalt

Noun

chemical compound made of dark, solid rocks and minerals often used in paving roads.

atmosphere

Noun

layers of gases surrounding a planet or other celestial body.

atmospheric pressure

Noun

force per unit area exerted by the mass of the atmosphere as gravity pulls it to Earth.

axis

Noun

an invisible line around which an object spins.

basin

Noun

a dip or depression in the surface of the land or ocean floor.

biodiversity

Noun

all the different kinds of living organisms within a given area.

biosphere

Noun

part of the Earth where life exists.

boreal climate

Adjective

region that experiences long, cold winters with very little precipitation. Also called a subarctic or tundra climate.

boreal climate

Adjective

region that experiences long, cold winters with very little precipitation. Also called a subarctic or tundra climate.

burrow

Noun

small hole or tunnel used for shelter.

canal

Noun

artificial waterway.

carbon sink

Noun

area or ecosystem that absorbs more carbon dioxide than it releases.

civilization

Noun

complex way of life that developed as humans began to develop urban settlements.

classify

Verb

to identify or arrange by specific type or characteristic.

cliff

Noun

steep wall of rock, earth, or ice.

climate

Noun

all weather conditions for a given location over a period of time.

climate change

Noun

gradual changes in all the interconnected weather elements on our planet.

climate group

Noun

one of five classifications of the Earth's climates: tropical, dry, mild, continental, and polar.

climate refugee

Noun

person forced to leave his or her home and community because of climate change.

climate type

Noun

division within a climate group.

climatologist

Noun

person who studies long-term patterns in weather.

cloud cover

Noun

amount of sky covered with clouds.

complex

Adjective

complicated.

coniferous forest

Noun

land covered by trees with thin needles instead of flat leaves.

continent

Noun

one of the seven main land masses on Earth.

continental climate

Noun

climate group that experiences extreme seasonal change. Continental climates are only found in the Northern Hemisphere.

cool summer climate

Noun

region that experience cool summers and snowy winters.

crop

Noun

agricultural produce.

cryosphere

Noun

icy part of the Earth's waterincluding icebergs, glaciers, and ice caps.

cultivate

Verb

to encourage the growth of something through work and attention.

culture

Noun

learned behavior of people, including their languages, belief systems, social structures, institutions, and material goods.

dam

Noun

structure built across a river or other waterway to control the flow of water.

data

Plural Noun

[singular: datum] information collected during a scientific study.

delicate

Adjective

fragile or easily damaged.

desert

Noun

area of land that receives no more than 25 centimeters [10 inches] of precipitation a year.

drizzle

Noun

very light rain.

drought

Noun

period of greatly reduced precipitation.

drought

Noun

period of greatly reduced precipitation.

dry

Adjective

arid or lacking in moisture.

dry season

Noun

time of year with little precipitation.

durable

Adjective

strong and long-lasting.

ecosystem

Noun

community and interactions of living and nonliving things in an area.

efficient

Adjective

performing a task with skill and minimal waste.

elevation

Noun

height above or below sea level.

emission

Noun

discharge or release.

enormous

Adjective

very large.

Equator

Noun

imaginary line around the Earth, another planet, or star running east-west, 0 degrees latitude.

erosion

Noun

act in which earth is worn away, often by water, wind, or ice.

eruption

Noun

release of material from an opening in the Earth's crust.

evaporation

Noun

process by which liquid water becomes water vapor.

evapotranspiration

Noun

loss of water from the Earth's soil by evaporation into the atmosphere and transpiration by plants.

farming

Noun

the art, science, and business of cultivating the land for growing crops.

flood

Verb

to overflow or cover in water or another liquid.

flourish

Verb

to thrive or be successful.

fog

Noun

clouds at ground level.

forest

Noun

ecosystem filled with trees and underbrush.

fossil fuel

Noun

coal, oil, or natural gas. Fossil fuels formed from the remains of ancient plants and animals.

freshwater

Adjective

having to do with a habitat or ecosystem of a lake, river, or spring.

frigid

Adjective

very cold.

gas

Noun

state of matter with no fixed shape that will fill any container uniformly. Gas molecules are in constant, random motion.

geographer

Noun

person who studies places and the relationships between people and their environments.

geologic

Adjective

having to do with the physical formations of the Earth.

glacial period

Noun

time of long-term lowering of temperatures on Earth. Also known as an ice age.

glacier

Noun

mass of ice that moves slowly over land.

global warming

Noun

increase in the average temperature of the Earth's air and oceans.

grassland

Noun

ecosystem with large, flat areas of grasses.

Great Lakes

Noun

largest freshwater bodies in the world, located in the United States and Canada. Lake Huron, Lake Ontario, Lake Michigan, Lake Erie, and Lake Superior make up the Great Lakes.

greenhouse effect

Noun

phenomenon where gases allow sunlight to enter Earth's atmosphere but make it difficult for heat to escape.

greenhouse gas

Noun

gas in the atmosphere, such as carbon dioxide, methane, water vapor, and ozone, that absorbs solar heat reflected by the surface of the Earth, warming the atmosphere.

growing season

Noun

period in the year when crops and other plants grow rapidly.

harvest

Noun

the gathering and collection of crops, including both plants and animals.

herding

Noun

practice of caring for roaming groups of livestock over a large area.

heritage

Noun

cultural or family background.

high-elevation climate

Noun

climate group found in mountains and plateaus.

humid continental

Noun

[continental climate] region that experiences cold winters and warm, wet summers. Also called a warm summer climate.

humidity

Noun

amount of water vapor in the air.

humid subtropical climate

Noun

region that experiences cool winters and hot humid summers.

hurricane

Noun

tropical storm with wind speeds of at least 119 kilometers [74 miles] per hour. Hurricanes are the same thing as typhoons, but usually located in the Atlantic Ocean region.

hydrosphere

Noun

all the Earth's water in the ground, on the surface, and in the air.

iceberg

Noun

large chunks of ice that break off from glaciers and float in the ocean.

ice cap climate

Noun

region where temperatures rarely rise above freezing.

ice sheet

Noun

thick layer of glacial ice that covers a large area of land.

ice shelf

Noun

mass of ice that floats on the ocean but remains attached to the coast.

inconvenience

Verb

to disturb or bother.

indigenous

Adjective

characteristic to or of a specific place.

Industrial Revolution

Noun

change in economic and social activities, beginning in the 18th century, brought by the replacement of hand tools with machinery and mass production.

influence

Verb

to encourage or persuade a person or organization to act a certain way.

insulate

Verb

to cover with material to prevent the escape of energy [such as heat] or sound.

interaction

Noun

relationship between two or more forces, objects, or organisms.

Intertropical Convergence Zone [ITCZ]

Noun

belt of low-pressure air currents that circle the Earth at the Equator. Also known as the Monsoon Zone.

lake effect

Noun

process where cold winds blowing over a relatively warm lake cause rapid cloud formation and precipitation.

land cover

Noun

physical material at the very top surface of the Earth, such as grass.

landscape

Noun

the geographic features of a region.

latitude

Noun

distance north or south of the Equator, measured in degrees.

lattice

Noun

strips of wood or other material assembled in a crisscross pattern.

Little Ice Age

Noun

[~1600-~1850] period of cooling climate [~1° Celsius], documented largely in the Northern Hemisphere.

livestock

Noun

animals raised forhuman use.

marine

Adjective

having to do with the ocean.

marine mammal

Noun

an animal that lives most of its life in the ocean but breathes air and gives birth to live young, such as whales and seals.

marine west coast climate

Noun

[mild climate] region that experiences rain and long, cool winters.

medicine

Noun

substance used for treating illness or disease.

Mediterranean climate

Noun

[mild climate] region that experiences mild winters and warm summers.

megathermal

Adjective

climate pattern characterized by high temperatures and abundant moisture.

Mesopotamia

Noun

ancient region between the Tigris and Euphrates Rivers, today lying mostly in Iraq.

mesothermal

Adjective

climate characterized by a moderate amount of heat.

microclimate

Noun

small area where the climate differs within a larger climate region, such as "heat islands" in a city.

microscopic

Adjective

very small.

microthermal

Adjective

climate characterized by cold winters.

migrate

Verb

to move from one place or activity to another.

mild climate

Noun

climate group that experiences seasonal temperature changes. Also called a temperate climate.

mitigate

Verb

to lower the severity of a natural or human condition.

moisture index

Noun

method for monitoring soils water budget, based on the concept of potential evapotranspiration.

monsoon

Noun

seasonal change in the direction of the prevailing winds of a region. Monsoon usually refers to the winds of the Indian Ocean and South Asia, which often bring heavy rains.

mound

Noun

hill built by people.

navigate

Verb

to plan and direct the course of a journey.

Northwest Passage

Noun

waterway connecting the Atlantic and Pacific Oceans.

nutrient

Noun

substance an organism needs for energy, growth, and life.

ocean basin

Noun

depression in the Earth's surface located entirely beneath the ocean.

Outback

Noun

remote, sparsely populated interior region of Australia.

paleoclimatology

Noun

study of the atmosphere of prehistoric Earth.

Pampas

Noun

flat grasslands of South America.

parka

Noun

hip-length, waterproof winter coat with a hood.

pendulum

Noun

object suspended from a point, able to swing back and forth.

periodic

Adjective

occasional.

permafrost

Noun

permanently frozen layer of the Earth's surface.

phenomena

Plural Noun

[singular: phenomenon] any observable occurrence or feature.

photosynthesis

Noun

process by which plants turn water, sunlight, and carbon dioxide into water, oxygen, and simple sugars.

plateau

Noun

large region that is higher than the surrounding area and relatively flat.

polar

Adjective

having to do with the North and/or South Pole.

polar climate

Noun

climate group found within the Arctic and Antarctic Circles.

pole

Noun

extreme north or south point of the Earth's axis.

Polynesia

Noun

island group in the Pacific Ocean between New Zealand, Hawaii, and Easter Island.

portable

Adjective

able to be easily transported from one place to another.

potential evapotranspiration

Noun

amount of water evaporated from an area of continuous, uniform vegetation that covers the whole ground and that is well supplied with water.

precipitation

Noun

all forms in which water falls to Earth from the atmosphere.

predictable

Adjective

regular or able to be forecasted.

prolong

Verb

to extend the duration of something.

proximity

Noun

nearness.

rainforest

Noun

area of tall, mostly evergreen trees and a high amount of rainfall.

rain shadow

Noun

dry land on the side of a mountain facing away from prevailing winds.

rainy season

Noun

time of year when most of the rain in a region falls.

region

Noun

any area on Earth with one or more common characteristics. Regions are the basic units of geography.

renewable energy

Noun

energy obtained from sources that are virtually inexhaustible and replenish naturally over small time scales relative to the human life span.

retreat

Verb

to go back to a familiar or safe place.

rigorous

Adjective

demanding, disciplined, or harsh.

salinity

Noun

saltiness.

sand

Noun

small, loose grains of disintegrated rocks.

savanna

Noun

type of tropical grassland with scattered trees.

Scandinavia

Noun

region and name for some countries in Northern Europe: Iceland, Norway, Sweden, Finland, and Denmark.

scarce

Adjective

rare.

sea level rise

Noun

increase in the average reach of the ocean. The current sea level rise is 1.8 millimeters [.07 inch] per year.

seasonal

Adjective

likely to change with the seasons.

seawater

Noun

salty water from an ocean or sea.

semiarid climate

Noun

[dry climate] region that receives between 25 and 50 centimeters [10-20 inches] of rainfall every year.

semi-nomadic

Adjective

people or communities who follow their food source for long periods of time, but can also live settled lives.

Siberia

Noun

region of land stretching across Russia from the Ural Mountains to the Pacific Ocean.

soil

Noun

top layer of the Earth's surface where plants can grow.

solar radiation

Noun

light and heat from the sun.

species range

Noun

native, geographic area in which an organism can be found. Range also refers to the geographic distribution of a particular species.

spectacular

Adjective

dramatic and impressive.

steppe

Noun

dry, flat grassland with no trees and a cool climate.

subarctic climate

Noun

region that experiences long, cold winters with very little precipitation. Also called a boreal or tundra climate.

taiga

Noun

evergreen forest in cool, northern latitudes. Also called boreal forest.

tapa cloth

Noun

lightweight cloth made by pounding the bark of the paper mulberry tree.

technique

Noun

method of doing something.

tectonic plate

Noun

massive slab of solid rock made up of Earth's lithosphere [crust and upper mantle]. Also called lithospheric plate.

temperate

Adjective

moderate.

temperature

Noun

degree of hotness or coldness measured by a thermometer with a numerical scale.

temperature

Noun

degree of hotness or coldness measured by a thermometer with a numerical scale.

thermal conductivity

Noun

measure of the ability of a material to transfer heat.

thermohaline circulation

Noun

ocean conveyor belt system in which water moves between the cold depths and warm surface in oceans throughout the world.

thunderstorm

Noun

cloud that produces thunder and lightning, often accompanied by heavy rains.

topography

Noun

study of the shape of the surface features of an area.

topography

Noun

study of the shape of the surface features of an area.

tornado

Noun

a violently rotating column of air that forms at the bottom of a cloud and touches the ground.

trade wind

Noun

winds that blow toward the Equator, from northeast to southwest in the Northern Hemisphere and from southeast to northwest in the Southern Hemisphere.

transition zone

Noun

area between two natural or artificial regions.

treacherous

Adjective

very dangerous.

tropical climate

Noun

climate group that experiences hot, wet summers.

tropical monsoon climate

Noun

region that experiences the monsoon winds, which bring heavy rain.

tropical wet and dry climate

Noun

region that experiences three seasons: cool, hot, and wet.

tropical wet climate

Noun

region that experiences hot temperatures and heavy rainfall all year. Also called a rain forest climate.

tropics

Plural Noun

region generally located between the Tropic of Cancer [23 1/2 degrees north of the Equator] and the Tropic of Capricorn [23 1/2 degrees south of the Equator].

tundra climate

Noun

region that experiences short summers and long winters.

typhoon

Noun

tropical storm with wind speeds of at least 74 miles [119 kilometers] per hour. Typhoons are the same thing as hurricanes, but usually located in the Pacific or Indian Ocean region.

uniform

Adjective

exactly the same in some way.

unprecedented

Adjective

never before known or experienced.

upland climate

Noun

[high-elevation climate] region found on and around large plateaus.

urban area

Noun

developed, densely populated area where most inhabitants have nonagricultural jobs.

urban heat island

Noun

city area that is always warmer than the surrounding area.

variation

Noun

difference.

vegetation

Noun

all the plant life of a specific place.

volcanic ash

Noun

fragments of lava less than 2 millimeters across.

volcano

Noun

an opening in the Earth's crust, through which lava, ash, and gases erupt, and also the cone built by eruptions.

warm summer climate

Noun

region that experiences cool winters and warm, wet summers. Also called a humid continental climate.

water budget

Noun

budget of the incoming and outgoing water from a region, including rainfall, evaporation, runoff, and seepage; often used to estimate evapotranspiration.

weather

Noun

state of the atmosphere, including temperature, atmospheric pressure, wind, humidity, precipitation, and cloudiness.

weather pattern

Noun

repeating or predictable changes in the Earth's atmosphere, such as winds, precipitation, and temperatures.

weather system

Noun

movement of warm or cold air.

wind

Noun

movement of air [from a high pressure zone to a low pressure zone] caused by the uneven heating of the Earth by the sun.

yurt

Noun

portable circular dwelling made of a criss-crossed wooden frame covered in felt and popular in Central Asia.

Articles & Profiles

• Iowa State University: Climate Classification-Thornthwaite System
• National Geographic Magazine: Climate Connections
• NASA: What are climate and climate change?
• National Weather Service: About Climate Normals

Instructional Content

• National Geographic Education: Of Cod and Climate
• National Geographic Education: What is the Future of Earths Climate
• National Geographic Education: Constructing/Interpreting Climate Graphs

Maps

• National Geographic Education: MapMaker Interactive-Climate Zones
• Institute for Veterinary Public Health: Maps of Köppen-Geiger Climate Classification

Websites

• Arizona State University and the World Meteorological Organization: Climate Extremes Archive

• Credits

  Media Credits

  The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

  Director

  Tyson Brown, National Geographic Society
  

  Author

  National Geographic Society
  

  Production Managers

  Gina Borgia, National Geographic Society
  Jeanna Sullivan, National Geographic Society
  

  Program Specialists

  Sarah Appleton, National Geographic Society
  Margot Willis, National Geographic Society
  

  Producer

  Clint Parks
  

  Last Updated

  Sept. 26, 2017

• User Permissions

  For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.

  Media

  If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.

  Text

  Text on this page is printable and can be used according to our Terms of Service.

  Interactives

  Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.