Changes in the Climate

Climate change is reflected in a host of shifts around the globe. Scientists have been tracking the patterns in Earth’s changing temperatures, ice masses, weather events, and oceans.


Global Average Temperature Has Been Rising

Global average temperature has increased in recent decades, and the most recent decade was the warmest in the past century. Land areas and the Arctic region have experienced the greatest warming.

This video helps to visualize rising global surface temperatures. Red indicates temperatures that are higher than the long-term average. Blue indicates temperatures that are lower than the long-term average.

Visualization from NASA/Goddard Space Flight Center Scientific Visualization Studio, provided by Robert B. Schmunk (NASA/GSFC GISS). Source



Additional Resources from the National Academies

Climate Change: Evidence, Impacts, and Choices is a web resource that includes a free 36-page booklet offers answers to common questions about the science of climate change, as well as a 26-minute video, PowerPoint presentation, and image gallery.



Climate Change: Evidence & Causes is a free, 36-page booklet produced by the U.S. National Academy of Sciences and The Royal Society that describes what is well-established and where understanding is still developing in the area of climate change. It includes a Q&A, climate basics, and a figure gallery. 



Ice masses such as Arctic sea ice, permafrost, and Alpine glaciers are shrinking as Earth’s temperature warms.

Arctic Sea Ice Has Been Declining

Sea ice is frozen seawater that floats on the ocean’s surface and provides a habitat for a variety of species. The average thickness of sea ice in the Arctic Ocean has declined substantially over the past half-century.

This NASA visualization shows yearly sea ice minimums observed by satellite since 1979. In 2012, sea ice in the Arctic reached its lowest extent on record.

Visualization from Lori Perkins at NASA/Goddard Space Flight Center Scientific Visualization Studio with data provided by Rob Gerston.




The Greenland Ice Sheet Has Been Shrinking

Ice sheets, which originate on land, are in decline in the Arctic. In Greenland, ice sheet melt has increased 30 percent over the past 30 years.

This animation depicts changes in Greenland’s ice sheet mass from 2003-2009. Cool colors indicate ice mass decreases. Beige indicates increases. Overall, ice mass is decreasing; most ice is lost from Greenland’s edges.

Visualization from Luthcke, et al., "Recent Changes of the Earth's Land Ice from GRACE," presented at 2009 Fall AGU, H13G-02 (693337), Dec. 14, 2009. Source


Alpine Glaciers Have Been Receding

Nearly all of the world’s glacier systems are shrinking, and in many cases their rate of ice loss has been accelerating. These photographs document the decline of two Alaskan glaciers:

Toboggan Glacier, Prince William Sound, Alaska

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Plateau Glacier, Saint Elias Mountains, Alaska

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The decrease in global glacier volume since 1960 is summarized in this graph:

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Because warming causes more water to evaporate, climate change can alter rainfall patterns, making wet places wetter and dry places drier. This means that climate change can contribute to both increased precipitation and increased drought. Globally, there has been a rise in extreme weather events such as heat waves, drought, and heavy rainfall.

Drought Has Been More Frequent Globally

Globally, the areas affected by drought have more than doubled since the 1970s. This sequence shows the effects of a 2012 drought on the Cheyenne Bottoms Wildlife Wetlands area in central Kansas.

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Heat Waves Have Been More Frequent

Heat waves are the leading cause of weather-related illness and death in the United States. Statistics show a trend towards increased frequency and intensity of heat wave events around the world.

Heat waves often contribute to poor air quality and pose the greatest threat to vulnerable populations such as the elderly and children. A 2003 heat wave in France was associated with 14,800 excess deaths.

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Heavy Precipitation Events Have Become More Frequent

Precipitation has increased globally, as has the proportion of precipitation falling in the form of heavy rain events. This graph shows the increase in heavy rainfall events in the United States during the 20th century.

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Oceans & Sea Level

Melting ice is causing sea levels to rise substantially. In addition, carbon dioxide emissions are altering the chemistry of the world’s oceans, posing a risk to marine species.

Sea Levels Have Been Rising

Average sea level around the world has been rising and is projected to continue to rise. As glaciers and ice sheets melt, water that would have been contained in these ice formations instead flows into the ocean. In addition, climate change is causing the oceans to become warmer, which causes water to expand and contributes to rising sea levels.

Sea level has increased along most of the U.S. coast over the past 50 years, with some areas along the Atlantic and Gulf coasts experiencing increases of more than 8 inches (20 cm). Local sea level depends on changes in the global ocean, changes in local winds, and localized sinking or rising of the land.



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This video, based on a National Research Council report, looks at how sea-level rise is likely to impact the west coast of the United States.

Video based on Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future, National Research Council, 2012. Source




By 2100, average sea level is projected to rise 1.6-3.3 feet (0.5-1.0 m). Some studies suggest a rise of nearly 6 feet (2 m). Animations from the U.S. Geological Survey demonstrate how such increases would affect the coastlines of Delaware and Florida (animations launch in separate tabs).

Oceans Have Been Increasing in Acidity

In addition to contributing to the greenhouse effect, high carbon dioxide emissions since the Industrial Revolution have caused the world’s oceans to become more acidic.

Seawater absorbs about one-quarter of the carbon dioxide currently released by human activities. Most of that carbon dioxide combines with water to form carbonic acid, increasing the acidity of the ocean.

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Ocean acidity has increased roughly 30% since preindustrial times. Rising ocean acidity poses major risks for marine organisms because it makes it more difficult to grow shells, among other effects.

Phytoplankton (microscopic plant-like organisms vital to marine life) are at risk from ocean acidification. Projected levels of acidity would erode their calcium carbonate shells.

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Many other organisms, such as these sea snails, form an important component of marine food webs but are threatened by ocean acidification. (Pictured snails are healthy.)

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Additional Resources from the National Academies

Ocean Acidification: Starting with the Science   

This 20-page booklet describes the chemistry of ocean acidification. A podcast, report summaries, and other resources accompany the booklet.




The materials in the Koshland Science Museum’s Earth Lab exhibit are based on reports of the National Research Council and works of the U.S. government, and have been vetted for scientific accuracy by a panel of expert advisors.

The Greenhouse Effect

Image based on a figure from US EPA. For more information, see America's Climate Choices.

Toboggan Glacier, Alaska

Toboggan Glacier, Alaska, pictured in 1905 and 2008. Images from United States Geological Survey. Source


Plateau Glacier, Alaska

Plateau Glacier, Alaska, pictured in 1961 and 2003. Images from United States Geological Survey. Source


Drought Impacts in Kansas

U.S. Geological Survey (USGS) Landsat Missions Gallery, "Effects of Drought," U.S. Department of the Interior / USGS and NASA. Source

Heat Waves

Graph derived from EM-DAT, The International Disaster Database, Centre for Research on the Epidemiology of Disasters (CRED;, Université Catholique de Louvain, Brussels, Belgium, v12.07.

Glacier Decline

From U.S. Global Change Research Program. Global Climate Change Impacts in the United States: 2009 Report. Source

Heavy Rainfall Over the United States

Graph provided by Dr. Kenneth Kunkel at the Cooperative Institute for Climate and Satellites (CICS-NC), North Carolina State University and NOAA's National Climatic Data Center, Asheville, NC. Source

Global Mean Sea Level Rise

Data from Church, J. and N. White (2011), Sea-level rise from the late 19th to the early 21st century. Surveys in geophysics, 1573-0956. DOI: 10.1007/s10712-011-9119-1. Source

Precipitation Frequency and Intensity

From U.S. Global Change Research Program. Global Climate Change Impacts in the United States: 2009 Report. Source

Ocean Acidification

National Research Council, Ocean Acidification: Starting with the Science. Source

Erosion of calcium carbonate shells due to ocean acidification

Images courtesy of Ulf Riebesell, IFM-GEOMAR. Source

Healthy sea snails

Images courtesy of Russell Hopcroft, University of Alaska Fairbanks (UAF) and Census of Marine Life (CoML). Source