DISCUSSION: In recent weeks, weather patterns across the Eastern Seaboard have become the talk of many news outlets. From frigid cold snaps and below zero wind chills to bomb-cyclogenesis, weather patterns have gained a substantial amount of media attention. What if I told you that we, as a society, could possibly experience more of these unpredictable weather events?
Along with unpredictable weather patterns, Arctic sea ice seems to be the go-to for media attention whenever a climate or weather topic arises. Not to downplay the issue of melting sea ice, for it is a vital component of the climate system. Over the course of the past century, Arctic sea ice has seen a fluctuating but steady decline in both size and depth. On a year-to-year basis, this may not seem like the case due to some years having more ice than others, but Arctic sea ice has seen a steady, overall decline. For example, December 2016 experienced the second lowest ice extent that has been recorded by satellite data which goes back to 1979.
How does this information affect global weather patterns? Well, Arctic sea ice has a characteristic called albedo. Albedo is the overall reflectiveness of an object or given area; the higher the albedo, the higher the reflectivity. The Arctic has a high albedo due to all the white snow and ice, which reflects the Sun’s incoming radiation back out to space. This helps cool the surrounding region along with contributing to global albedo. With a melting Arctic, the albedo lowers due to less reflective snow and ice, and more open, dark ocean waters. In turn, the Arctic then absorbs more energy and heat which then warms the area.
Moreover, an Arctic with less ice means a warmer Arctic. A warmer Arctic means a weaker temperature gradient between the poles and equatorial regions. A weaker temperature gradient between the Arctic and equator can decrease the magnitude of the polar jet stream. The polar jet carries and influences global weather patterns. To explain, the jet stream is a river of fast moving air high up (roughly 11 kilometers) in the atmosphere that marks the boundary between warm air to the south and cool air to the north. Simply, the jet stream also acts as a highway in which weather systems travel upon. A weak temperature gradient has the potential to shift the jet stream and plunge Arctic air farther south than usual. Sea ice loss may present the mid-latitudes with colder winters due to the aforementioned weakening of the polar jet stream which directly influences the mid-latitudes. A weaker jet stream can present a more meridional (wavy) flow; this can possess longer-lasting and more persistent weather. Along with this, strong, slow-moving storms in the mid-latitudes have an increased potential to develop, eventually leading to greater weather extremes such as blizzards, floods, and droughts.
The Arctic acts as the “refrigeration unit” of the global climate system which balances out the much warmer Tropics. In this role, the Arctic helps regulate the energy balance between the climate system and weather circulation patterns. Large scale weather and ocean patterns rely on the temperature difference between the poles and equatorial regions. The melting of Arctic sea ice can also disrupt normal ocean circulations because of the influx of freshwater. This freshwater, inevitably warming, will create heated air to rise and change wind patterns, perturbing the jet stream further. The overall change freshwater influx can have on wind patterns can also potentially alter overall weather patterns. Ocean circulations and wind patterns both contribute to each other. When one is affected the other follows suit in an unpredictable way.
Although it is difficult to directly link changing weather patterns with climatic changes, everything within a planet’s climate system is linked. When one part is altered, all other parts respond accordingly. Future research and data are needed to either confirm or deny the claim that less sea ice can affect global weather patterns.
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©2018 Weather Forecaster Alec Kownacki