Arctic amplification refers to a phenomenon in which the Arctic region experiences more rapid warming compared to the global average. Climate change is affecting temperatures around the world, but it is more pronounced in the Arctic due to various changes in weather systems, sea ice extent, and ocean circulation.
Who first introduced the concept of Arctic amplification?
The idea that global climate change would be most pronounced in polar regions was first proposed by Swedish scientist and Nobel laureate Svante Arrhenius. In 1896, Arrhenius proposed that changes in carbon dioxide levels in the Earth’s atmosphere could affect the Earth’s surface temperature, and that temperature changes would be most pronounced in regions close to the poles.
Why is climate change more pronounced in the Arctic?
There are several reasons why scientists think the effects of climate change will be more pronounced in the Arctic, many of which are interconnected.
Sea ice reduction and albedo effects
Climate change leads to Arctic albedo feedbacks, or changes in the reflectance of the Arctic surface. Ice and snow have high albedo and reflect most of the sunlight that falls on them. When they melt due to rising temperatures, dark surfaces such as ocean water and land are exposed. Because these surfaces have lower albedo, they absorb more sunlight, leading to further warming and melting in a feedback loop.
Aerosols such as black carbon (soot and dust) can settle on snow and ice, lowering their albedo and reducing their ability to reflect sunlight. This darkening of the surface can lead to increased heat absorption and further melting of ice and snow in the area.
atmospheric circulation
Differences in warming between the Arctic and lower latitudes affect atmospheric circulation patterns such as the jet stream. Weaker temperature gradients between the North Pole and mid-latitudes can make the jet stream more meandering and slower moving. These changes in air circulation could lengthen weather patterns such as heat waves and worsen Arctic warming.
ocean current
Changes in ocean circulation patterns may also contribute to Arctic expansion. Warm water from lower latitudes could be transported to the Arctic, melting ice and warming the local environment.
Cloud amount
The nature and extent of arctic clouds can also affect temperatures. Clouds can have both warming and cooling effects, depending on a variety of factors such as altitude, thickness, and composition. NASA researchers combined their CALIPSO and CloudSAT satellite observations to show that: Summer cloud cover does not slow Arctic warming. However, the same study showed an increase in autumn cloud cover in the Arctic. Increased cloud cover from fall to winter acts as a blanket, trapping heat that accumulates on the Earth’s surface and in the Arctic oceans during the summer.
Influx of warmth from the tropics
Thunderstorms are more likely to occur in the tropics, where heat moves from the ground at the equator to atmospheric levels. Global wind patterns then transport this heat to higher latitudes. This frequent heat transfer from the tropics helps offset warming near the equator, but contributes to increased warming in the Arctic.
Loss of insulating snow cover
Snow acts as an insulator, preventing heat from escaping from the ground. Reduced snowfall increases the amount of heat released from the ground into the atmosphere, contributing to global warming.
Mapping Arctic amplification using ground and satellite data
This Earth map created by NASA compares how hot or cold regions of the world are compared to the average from 1951 to 1980. The data to create this map is: GISS surface temperature analysis data It combines field data from over 20,000 weather stations, ships and buoys.
The map below visualizes the global temperature deviation in 2022 from the 1951-1980 average for each region of the world. 2022 will be the fifth warmest year on record. Arctic amplification is shown on the map as a dark red area in the Arctic region.
Mapping Arctic amplification using satellite data
Scientists are using remotely sensed data from Earth observation satellites to map Arctic amplification as well as track and study global phenomena that affect Arctic amplification.
Satellite tracking of Arctic sea ice
The European Space Agency’s CryoSat and Copernicus Sentinel-3 satellites are equipped with altimeters that can measure the thickness of Arctic sea ice. By accurately measuring the height of the ice surface relative to sea level, scientists can calculate both the thickness and volume of Arctic sea ice.
The decrease in sea ice is thought to be linked to an increase in freshwater in the ocean causing changes in the Atlantic Meridional Circulation (AMOC), which helps regulate the Earth’s climate. When seawater turns into ice, it turns into fresh ice and leaves behind salty water. This salt water is colder and heavier than other seawater, so it sinks deeper into the ocean. This sedimentation helps move water around the world as part of the global ocean thermohaline circulation.
As sea ice, which has a higher albedo and reflects more sunlight, decreases, open ocean appears in its place. Darker colored water absorbs more heat from sunlight, further contributing to ocean warming.
Satellite data is also used to measure surface temperatures, albedo, and atmospheric composition, which can influence climate conditions in the Arctic and contribute to accelerated warming in the region.
References
Arrhenius, S. (1896). XXXI. On the effect of carbonic acid in the air on the temperature of the earth’s surface. Philosophical and scientific journals in London, Edinburgh and Dublin, 41(251), 237-276.
Arrhenius, S., Holden, E. S. (1897). About the effect of carbon dioxide in the air on the Earth’s temperature. Publications of the Astronomical Society of the Pacific, 9(54), 14-24. https://www.jstor.org/stable/40670917
Candanosa, RM (June 5, 2016). New insights into the role of clouds in Arctic climate change. Climate Change: Earth’s Vital Signs – NASA. https://climate.nasa.gov/news/2449/new-insights-into-the-role-of-clouds-in-arctic-climate-change/
Esau, I., Petterson, L.H., Cancet, M., Chapron, B., Chernokulsky, A., Donlon, C., … & Johannesen, J.A. (2023). Arctic amplification and its effects: A synthesis from satellite observations. remote sensing, 15(5), 1354. https://doi.org/10.3390/rs15051354
Satellite provides key insights into Arctic amplification. (May 24, 2023). European Space Agency. https://www.esa.int/Applications/Observing_the_Earth/Space_for_our_climate/Satellites_provide_crucial_insights_into_Arctic_amplification
A world of change: global temperature. (January 29, 2020). NASA Earth Observatory. https://earthobservatory.nasa.gov/world-of-change/global-temperatures
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