The Arctic has ended the winter with one of the lowest ever recorded levels of sea ice cover, NASA research has revealed.
Arctic sea ice melts and regrows over the year, freezing throughout the winter months to reach a maximum extent in late February or March, then melting through the summer to hit a low point in early or mid-September.
The maximum sea ice cover in the middle of March – before the summer melt began – was the second lowest in the 39-year satellite record.
The 2017 measurement fell just behind last year’s record low.
The new research comes from both NASA and the National Snow and Ice Data Center (NSIDC).
A statement from NASA revealed that Arctic sea ice measurements taken in March reflect that the sea ice level is still dangerously low. The above chart shows the declining trend in these measurements
At its maximum extent this year, on March 17, Arctic sea ice cover was 5.59 million square miles (14.48 million square kilometers), which is 23,200 square miles (60,000 square kilometers) more than in 2017.
A statement form NASA said 2018’s maximum extent measures 448,000 square miles (1.16 million square kilometers) below the average maximum extents from 1981 to 2010.
This difference is larger than the the size of Texas and California combined.
Scientists said Arctic sea ice levels both during melting and growing seasons have been declining in recent decades.
The experts said the low levels of ice again this year were due to a late autumn freeze-up and persistent high air temperatures throughout the winter.
The four lowest levels of maximum sea ice cover have all been seen in the last four years.
In February, for the fourth winter in a row, an extreme heatwave was seen over the Arctic Ocean, researchers said.
A NASA statement said: ‘The Arctic has gone through repeated warm episodes this winter, with temperatures climbing more than 40 degrees above average in some regions. The North Pole even experienced temperatures above the freezing point for a few days in February.’
WHAT ARE THE EFFECTS OF LOWER SEA ICE LEVELS?
The amount of Arctic sea ice peaks around March as winter comes to a close.
NASA recently announced that the maximum amount of sea ice this year was low, following three other record-low measurements taken in 2015, 2016 and 2017.
This can lead to a number of negative effects that impact climate, weather patterns, plant and animal life and indigenous human communities.
The amount of sea ice in the Arctic is declining, and this has dangerous consequences, NASA says
Additionally, the disappearing ice can alter shipping routes and affect coastal erosion and ocean circulation.
NASA researcher Claire Parkinson said: ‘The Arctic sea ice cover continues to be in a decreasing trend and this is connected to the ongoing warming of the Arctic.
‘It’s a two-way street: the warming means less ice is going to form and more ice is going to melt, but, also, because there’s less ice, less of the sun’s incident solar radiation is reflected off, and this contributes to the warming.’
The statement also explained how the Arctic’s thickest and oldest ice could soon disappear.
‘In February, a large area of open water appeared in the sea ice cover north of Greenland, within the multiyear ice pack. Most of the opening has refrozen, but the new ice is expected to be thinner and more fragile, and a new opening might appear during the melt season,’ it said.
This could cause this region’s ice to be more prone to leaving the Arctic during the summer and, eventually, melt in the Atlantic Ocean.
NASA researcher Alek Petty said: ‘This old, thicker ice is what we expect to provide stability to the Arctic sea ice system, since we expect that ice not to be as vulnerable to melting out as thinner, younger ice. As ice in the Arctic becomes thinner and more mobile, it increases the likelihood for rapid ice loss in the summer.’
Rod Downie, head of polar programs at the World Wide Fund for Nature, said: ‘This announcement confirms the downward spiral of Arctic sea ice.
‘The Polar Regions are our planet’s air conditioning unit – and it’s breaking down during a heatwave.
‘It shows we must take urgent action to reduce greenhouse gas emissions and tackle climate change head-on before it is too late.’