Arctic sea ice hits record winter lows as global warming shatters records around the world
Important Arctic sea ice it decreased to tie its lowest level in winter, the season when the snow grows, as the Earth’s warming breaks records on every continent.
Arctic sea ice levels, especially in summer, are important to Earth’s climate because without the ice reflecting sunlight, more heat energy enters the ocean. Ice of all kinds around the poles acts as the Earth’s refrigerator. The lack of sea ice in the Arctic is creating new shipping lanes and, in doing so, causing land disturbance, making previously neglected areas like Greenland more desirable.
Melting sea ice “continues to worsen over the last several decades,” NASA said in a statement.
Arctic sea ice was declared on Thursday as temperatures broke March heat records across the United States, across Mexico, Australia, North Africa and parts of Northern Europe. Meteorologist and climate historian Maximiliano Herrera, who tracks extreme temperatures, called the extreme temperatures in March “the most extreme heat event in the world’s climate history” and said on social media that the next few days will be “very bad.”
Sixteen US states have broken March heat records in the past week or so, said climate historian Christ Burt. Twenty-seven locations had temperatures in the past week high enough to tie or exceed the hottest April day on record, including St. Louis, said meteorologists.
Mexico has broken thousands of records, some of them hotter than the hottest temperatures in May, but that is nothing compared to what happened in Asia, where “thousands of thousands of monthly records” were broken by 30 to 35 degrees (17 to 19 degrees Celsius), Herrera said.
Yet at the same time earlier this week, Antarctica recorded the coldest March day anywhere on Earth at minus 105.5 degrees (minus 76.4 degrees Celsius), according to Herrera and Burt.
Strong decline in sea ice
Each year, the Arctic sea ice increases during the cold winter and decreases during the hot summer. This year, the growth was so small that its height, before it began to decrease, measured 5.52 million square kilometers (14.29 million square kilometers). That’s slightly less than last year’s 5.53 million square kilometers (14.31 million square miles), but the National Snow and Ice Data Center, which does the calculations, considers those two numbers so close that they’re a tie.
“This record low marks the beginning of the spring and summer melt season,” NSIDC senior research scientist Walt Meier said in a statement.
Samantha Burgess of the European Center for Medium-Range Weather Forecasts (ECMWF) had a similar analysis in a recent interview with AFP, saying it could result in “a potentially rapid and widespread summer melt.”
This year’s snow cover was about 525,000 square miles (1.36 million square kilometers) below the 1981 to 2010 winter high. That’s almost twice the size of Texas.
“As temperatures warm and continue to warm, especially in the temperate zone, there is less chance of snow accumulation and it will tend to be less,” Meier said. “It’s not like we’re seeing a regime change or anything. This time it’s going down slowly in the winter and at a higher rate.”
Wildlife, such as polar bears, penguins and seals, also depend on sea ice. Researchers analyzing satellite images recently found emperor penguins being forced into denser, denser groups as the sea ice beneath them rapidly disappeared during the melting season—the period when they shed their feathers and become watertight. Scientists say that only meaningful climate cooling can give the original species a chance to survive.
Summer sea ice is key
The summer melt season — which precedes the September average known as the Arctic sea ice minimum — is “a really critical time,” Meier said. Another reason is that when there is less white ice that reflects the strong summer sun, the oceans can absorb more heat. And when that happens, the Arctic warms closer to the temperatures further south and the atmospheric pressure changes. The leading theory – which is still controversial – is that those changes in the Arctic then change the movement and shape of the jet stream, moving the weather west to east and contributing to extreme weather outbreaks, he said.
Melting sea ice does not contribute to sea level rise.
The season of winter ice growth is also highly variable with climate change, so just because the Arctic reaches a record low in March, doesn’t mean summer will be a record low, Meier said.
“The winter high is really interesting,” Meier said. “It’s a sign of climate change.”
On the other side of the planet, Antarctic sea ice is greatly affected by local climate and ocean characteristics. In February, Antarctica hit its lowest level for the year and while it was less than the 30-year average, it was nowhere near the record lows of the past three years, Meier said.
