For the second time in two years, Antarctic sea ice has reached record low levels, with some scientists concerned that the dramatic drops are a sign that the climate crisis is now more clearly influencing this vast, complex, and isolated region.

According to the National Snow and Ice Data Center, or NSIDC, the sea ice that surrounds Antarctica fell to 737,000 square miles (1.91 million square kilometers) on February 13, falling short of the previous record of 741,000 square miles (1.92 million square kilometers) set on February 25 last year.

Sea ice could still shrink further; the southern summer's lowest level may not be reached for another week.

The last two years have seen sea ice levels fall below 2 million square kilometers for the first time since satellites began monitoring it in 1978.

It's "not just a record low," according to Ted Scambos, a glaciologist at the University of Colorado Boulder. "It's on a precipitous downward trend."

Unlike in the Arctic, where the rate of sea ice loss has been fairly consistent as climate change has accelerated, Antarctic sea ice extent has swung up and down, making it difficult to determine how the continent and its surrounding ocean are responding to global warming.

Antarctic ice is typically thinner than Arctic ice, with higher winter highs and steeper summer declines. Climate models predicted similar declines in Antarctic sea ice to those predicted for the Arctic, but the region was behaving completely differently until recently. It reached a record high for winter sea ice extent in 2014, reaching 7.76 million square miles, lending credence to the notion that the Antarctic may be relatively insulated from global warming.

But something changed in 2016. Scientists noticed a steep downward trend. Scientists noticed a steep downward trend. Some attributed it to the usual variability of this vastly complex continent's diverse, intertwined climate systems. Scientists are concerned after two years of record-low sea ice. "The question is whether climate change has reached Antarctica. Winds, ocean currents, and ocean heat may all play a role in why sea ice is so low.

These winds, which can increase sea ice melt, have been stronger than usual, according to the NSIDC, and added to weather conditions that pump warm air to the region. The strength of the winds has been linked, in part, to the increase of planet-heating pollution as well as the hole in the ozone layer above the continent.

There are also suggestions that sea ice may be melting because of warmth trapped just below the surface of the ocean, Scambos said. “Basically, you`re getting heat stirred into the upper layer [of water] around the Antarctic,” he said. If that theory holds up and is linked to the general warming of the oceans, “then that has big implications for the stability of the Antarctic ice sheet.”

Sea ice loss may have repercussions that extend beyond Antarctica. An altered Antarctic landscape could have a significant impact on the region's wildlife, from the penguins and seals that depend on sea ice for feeding and resting to the microscopic organisms and algae that support the food chain and provide food for krill, which in turn feed many of the region's whales.

One of the regions in the Southern Hemisphere that is warming the fastest is the Antarctic Peninsula, a spindly chain of icy mountains that protrudes off the west side of the continent and points toward South America.

After recently returning from a research trip to the Antarctic Peninsula, Carlos Moffat, an oceanographer at the University of Delaware, told CNN that the low sea ice and extremely warm ocean temperatures they discovered "are dramatically different from what we have observed in the last few decades."

The Palmer Long-Term Ecological Research participant Moffat said: "This year's conditions are against a background of long-term change in this region of Antarctica." As the planet warms, scientists warn that West Antarctica's enormous Thwaites Glacier, also known as the "Doomsday Glacier," is "hanging on by its fingernails" and could rapidly retreat in the coming years.

It's too soon to determine whether the record sea ice decline is a trend. Last year, scientists said West Antarctica`s vast Thwaites Glacier – also known as the “Doomsday Glacier"—was “hanging on by its fingernails” as the planet warmed, with rapid retreat possible over the next few years. It`s too early to say whether the record sea ice decline is the new normal or whether it will bounce back, and Antarctica is known for its significant swings.

It will take some time to unpack, according to Scambos. "We're still processing a change that happened fairly quickly." The past few years have unquestionably put a dramatic cap on a trend that was only beginning to emerge after 2016.

However, he added: "It does feel like something has changed in the Antarctic and that things are fairly dramatic." Scientists will still need at least another five years of data and observations.