by Arctic amplification refers to the phenomenon in which the Arctic region experiences a rapid rate of temperature rise compared to the global average. While climate change affects temperatures around the world, changes are most pronounced in the Arctic region due to a variety of changes in weather systems, sea ice coverage, and ocean circulation.
Who first introduced the concept of Arctic amplification?
The understanding that global climate change will be most pronounced in the polar regions was first proposed by Nobel Prize-winning Swedish scientist Svante Arrhenius. In 1896, Arrhenius suggested that changes in carbon dioxide levels in the Earth’s atmosphere could affect the planet’s surface temperatures, and that these temperature changes would be most pronounced in regions closer to the poles.
Why is climate change more pronounced in the Arctic regions?
There are several reasons why scientists believe the effects of climate change are more pronounced in Arctic regions, and many of them are interconnected.
Reduced sea ice and albedo effect
Climate change is leading to changes in Arctic albedo feedback, or the reflectivity of the Arctic surface. Ice and snow have a high albedo and reflect most of the sunlight that falls on them. As they melt due to rising temperatures, dark surfaces such as ocean water and land are exposed. These surfaces have a lower albedo, which means they absorb more sunlight, leading to more warming and melting in the feedback loop.
Aerosols such as black carbon (soot and dust) can land on snow and ice, reducing their albedo and thus their ability to reflect sunlight. This darkening of the surface can lead to increased heat absorption and increased melting of ice and snow in the area.
Atmospheric circulation
Differential warming between the Arctic and low latitudes affects atmospheric circulation patterns, such as the jet stream. A weaker temperature gradient between the Arctic and mid-latitudes could result in a more sinuous, slower-moving jet stream. This changing air circulation can lead to long-term weather patterns, such as heat waves, which can exacerbate global warming in the Arctic.
Ocean currents
Changes in ocean circulation patterns can also contribute to Arctic amplification. Warmer water from lower latitudes may be transported to the Arctic, contributing to the melting of ice and warming of the local environment.
Cover of clouds
The nature and extent of cloud cover in the Arctic can also affect temperatures. Clouds can have a warming and cooling effect, depending on various factors such as their height, thickness and composition. NASA researchers combined CALIPSO-CloudSAT satellite observations to show this Summer cloud cover does not slow the rate of warming in the Arctic. However, the same research showed an increase in precipitation cloud cover in the Arctic. Increased cloud cover during the fall and winter months acts as a blanket that traps heat that has accumulated on the surface of the land and oceans in the Arctic during the summer.
Warmth flows from the tropics
Thunderstorms are more common in the tropics, where they transport heat from the Earth’s surface at the equator to higher levels in the atmosphere. Global wind patterns then carry this heat toward higher latitudes. This frequent transfer of heat from the tropics helps offset warming near the equator while contributing to increased warming in the Arctic.
Loss of insulating snow cover
Snow acts as an insulator, preventing heat from being released from the ground. As snow cover diminishes, the Earth loses more heat to the atmosphere, contributing to warming.
Using ground and satellite data to map the amplification of the Arctic
This global map created by NASA compares how much hotter or colder the world is compared to averages spanning the years 1951 to 1980. The data needed to create this map came from GISS surface temperature analysis Data It collects location data from more than 20,000 meteorological stations, ships and buoys.
The map below shows the worldwide temperature deviations for 2022 from the 1951-1980 average for each region of the world. 2022 is the fifth warmest year in recorded history. Arctic amplification is shown in the map with dark red areas in the Arctic regions.
Mapping the Arctic amplification using satellite data
Scientists use remotely sensed data from Earth observation satellites not only to map Arctic amplification but also to track and study the global phenomenon that affects Arctic amplification.
Satellite tracking of Arctic sea ice
The European Space Agency’s CryoSat and Copernicus Sentinel-3 satellites have altimeters that can measure the thickness of Arctic sea ice. By accurately measuring the height of the ice surface relative to ocean level, scientists can calculate the thickness and volume of Arctic sea ice.
Reduced sea ice has been linked to increased fresh water in the ocean, leading to changes in the Atlantic Ocean Overturning Circulation (AMOC) that help regulate global climate. When seawater turns to ice, it becomes fresh ice and leaves behind salt water. This salty water is colder and heavier than the rest of the seawater, so it sinks into the depths of the ocean. This sinking process helps transport water around the world as part of the global ocean thermohaline cycle.
Reduced sea ice, which has a high albedo meaning more sunlight is reflected, is being replaced by open water. Darker water absorbs more heat from sunlight, which further contributes to ocean warming.
Satellite data is also used to measure surface temperature, albedo, and atmospheric composition, all factors that can affect climate conditions in the Arctic and contribute to accelerating global warming in this region.
References
Arrhenius, S. (1896). Thirty-first. About the effect of carbonic acid in the air on Earth’s temperature. The London, Edinburgh and Dublin Philosophical and Science Journals, 41(251), 237-276.
Arrhenius, S., & Holden, S. (1897). About the effect of carbonic acid in the air on Earth’s temperature. Publications of the Astronomical Society of the Pacific, 9(54), 14-24. https://www.jstor.org/stable/40670917
Candanosa, R. M. (2016, June 5). New insights into the role of clouds in Arctic climate change. Climate Change: Vital Signs of the Planet – NASA. https://climate.nasa.gov/news/2449/new-insights-into-the-role-of-clouds-in-arctic-climate-change/
Esau, I., Pettersson, L.H., Cancet, M., Chapron, B., Chernokulsky, A., Donlon, C., … & Johannesen, JA (2023). Arctic amplification and its impact: compiled from satellite observations. Remote Sensing, 15(5), 1354. https://doi.org/10.3390/rs15051354
Satellites provide important insights into Arctic amplification. (2023, May 24). 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 temperatures. (2020, January 29). NASA Earth Observatory. https://earthobservatory.nasa.gov/world-of-change/global-temperatures
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