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:
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.
Heat Waves Have Been More Frequent
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.
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.
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.
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.
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.
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.)
Additional Resources from the National Academies
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.