As earth heats up; arctic faces disproportionate impact: NOAA

As earth heats up; arctic faces disproportionate impact: NOAA

Subject :Environment

Context:

• The once reliably frigid and frozen Arctic is becoming wetter and stormier, with shifts in its climate and seasons that are forcing local communities, wildlife and ecosystems to adapt.
• 2022 was only the Arctic’s sixth warmest year on record, researchers saw plenty of new signs this year of how the region is changing.

Signs of changing climate in the arctic region:

• September heat wave in Greenland led to excessive ice melting.
• The August 2021 heatwave caused it to rain for the first time.
• Temperatures in the Arctic Circle have been rising much more quickly than those in the rest of the planet.
• Warming in the arctic raises the sea level worldwide.

Three main factors could be increasing precipitation in different parts of the Arctic:

1. Warmer air can hold more moisture.
2. As sea ice retreats, storms can suck up more open ocean water.
3. Storms are passing over warmer water before reaching the Arctic, feeding them with more energy.

NOAA: Arctic report card:

• National Oceanic and Atmospheric Administration (NOAA) produces this report annually since 2006.
• This year’s report is produced in Chicago.
• As per the report: Rising temperatures have helped plants, shrubs and grasses grow in parts of the Arctic tundra, and 2022 saw levels of green vegetation that were the fourth highest since 2000, particularly in the Canadian Arctic Archipelago, northern Quebec and central Siberia.

Artic amplification:

• The Arctic’s extreme warming, known as Arctic amplification or polar amplification, may be due to three factors.
• One, the region’s reflectivity, or albedo is changing as the world warms.
• If the sea ice melts in the Arctic that will remove that white surface off of the ocean, and what will be exposed is this darker ocean surface that will absorb more of the sun’s heat.
• This dovetails with the second factor: changing currents.
• Ocean currents normally bring in warmer water from the Pacific, and colder water exits out of the Arctic into the Atlantic.
• But those currents may be changing because more melting ice is injecting the Arctic Ocean with freshwater, which is less dense than saltwater, and therefore floats above it.
• The missing ice also exposes the surface waters to more wind, speeding up the Beaufort Gyre in the Arctic, which traps the water it would normally expel into the Atlantic.
• This acceleration mixes up colder freshwater at the surface and warmer saltwater below, raising surface temperatures and further melting ice.
• Ocean currents influence the weather, a third factor.
• They drive the powerful polar jet stream, which moves hot and cold air masses around the Northern Hemisphere. This is a product of the temperature differences between the Arctic and the tropics.
• But as the Arctic warms, the jet stream now undulates wildly north and south. This has been injecting the Arctic with warm air in the summer and the US with extremely cold air in the winter, like during the “polar vortex” of January 2019.