Climate and Global Change

Warm near the equator and cold at the poles, our planet is able to support a variety of living things because of its diverse regional climates. The average of all these regions makes up Earth's global climate. Climate has cooled and warmed throughout Earth history for various reasons. Rapid warming like we see today is unusual in the history of our planet. The scientific consensus is that climate is warming as a result of the addition of heat-trapping greenhouse gases which are increasing dramatically in the atmosphere as a result of human activities.

Earth's global average surface <a href="/earth/climate/ipcc_feb2007.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">warming</a> relative to the 1980-1999 average over the past 100 years is shown in the black line. Predictions of the amount of warming in the future are shown by the red, green, and purple lines. These predictions, developed with <a href="/earth/climate/cli_models.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">computer models</a>, make different assumptions about how many <a href="/earth/climate/cli_greengas.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">greenhouse gases</a> we release into the atmosphere in the future.<p><small><em> A Windows to the Universe image based on a graph from the IPCC 4th Assessment Report</em></small></p>Roaming across Arctic <a href="/earth/polar/sea_ice.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">sea ice</a>, <a href="/earth/polar/polar_bears_jan07.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">polar bears</a> peer through cracks in the ice to look for ringed seals, their favorite food, in the water below. Almost all of a polar bear's food comes from the sea. The <a href="/earth/polar/sea_ice.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">floating sea ice</a> is a perfect vantage point for the bears as they hunt for food. Unfortunately, the amount of sea ice floating in the <a href="/earth/polar/polar_north.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">Arctic region</a> is shrinking each year, and getting farther apart.<p><small><em>Image courtesy of Ansgar Walk. Creative Commons Attribution-Share Alike 2.5 Generic license.</em></small></p>Coral animals build reefs in warm, tropical seawater. However, <a href="/earth/changing_planet/ocean_temperatures_intro.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">seawater can be too warm</a> for their liking. If waters get too warm, coral animals lose the algae that live within their little bodies, a process called coral bleaching. Without the algae, corals have less nutrition. Unless cooler temperatures return, allowing algae to return, the coral dies.<p><small><em>Credit: UNC</em></small></p>As temperatures rise and soil moisture decreases, plants are stressed, which can lead to <a href="/earth/climate/crops_withering.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">crop withering</a>. <a href="/teacher_resources/online_courses/health/events_health.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">Droughts</a> accompanied by increased temperatures can lead to famine, social and political disruptions. Scientists are helping with early identification of drought that might trigger food shortages. Watch the NBC Learn video - <a href="/earth/changing_planet/withering_crops_intro.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">Changing Planet: Withering Crops</a> to find out more.<p><small><em>Image taken by Tomas Castelazo, Creative Commons <a href=&quot;http://creativecommons.org/licenses/by/3.0/deed.en&quot;>Attribution 3.0 Unported</a> license.</em></small></p>A <a href="http://iopscience.iop.org/1748-9326/8/2/024035/article">study</a> of over 40,000 written entries in Irish Annals and ice core measurements shows a strong correlation between <a href="http://www.windows2universe.org/earth/interior/eruptions.html">volcanic eruptions</a> and extreme cold weather in Ireland over a 1200 year period, from 431 to 1649. During this time up to 48 volcanic eruptions were identified in Greenland ice core records through deposition of volcanic sulfate in annual layers of ice. Find out more about <a href="http://www.windows2universe.org/earth/climate/geosphere_volcanoes_influence_on_climate.html">volcanoes and climate</a>.<p><small><em>Image Courtesy of Marco Fulle</em></small></p>Scientists are concerned that melting Arctic sea ice will increase the amount of fresh water in the <a href="/earth/polar/arctic_currents.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">Beaufort Gyre</a>, which could spill out into the Atlantic and cause major climate shifts in North America and Western Europe. Watch the <a href="/earth/changing_planet/freshwater_arctic.html&edu=elem&dev=1/earth/Atmosphere/moons/triton_atmosphere.html">Changing Planet: Fresh Water in the Arctic video</a>.<p><small><em> Courtesy of Jack Cook, WHOI (<a href="http://www.whoi.edu">Woods Hole Oceanographic Institute</a>)</em></small></p>

Explore Climate and Global Change

What Is Climate?

How do you know to pack your bathing suit and sunhat for a trip to a tropical island or pack ...Read more

What Controls the Climate System?

The Sun Climate can change if there is a change in the amount of solar energy that gets to ...Read more

Climates of the Past (Paleoclimates)

The climate of Earth has been changing for billions of years! It warmed and cooled many times ...Read more

Our Changing Planet

Our planet is changing rapidly. Check out videos and lesson plans for key climate change indicators ...Read more

Effects of Climate Change Today

Have you ever taken your temperature to see if you are getting sick? Scientists have been taking ...Read more

Climate Change in Polar Regions

Some parts of the world are warming faster than others. The Arctic is warming twice as fast ...Read more

El Nino and Other Climate Events

Sometimes the way the air moves around in the atmosphere changes.The way water moves through ...Read more

The Role of Clouds in Climate

Clouds are an important part of Earth's weather and climate. Scientists use computer models ...Read more

Energy Choices and Climate Change

The choices we make about the sources of the energy we use and the amount of energy we use affect ...Read more

The Intergovernmental Panel on Climate Change

The IPCC is a group of hundreds of experts from more than 100 countries ...Read more

Tackling the Global Warming Challenge

By sending greenhouse gases into the air, we have made Earth’s greenhouse effect stronger.  ...Read more

More about Climate and Global Change

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Did you know?

Did you know that greenhouse gases are increasing rapidly in the Earth's atmosphere?

Did you know that the Arctic is warming?

 

Earth and Space Science Concept of the Day

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Ozone layer
xOzone layer : A range of altitudes in Earth's stratosphere which has a higher concentration of ozone molecules.

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Research Highlights

Geologists Uncover Major Ancient Human Ancestor in South Africa

Scientists in South Africa have discovered two fossil skeletons that are about two million years old. These skeletons are of a young male and adult female of a species that had never been found before....Read more


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