It's a tremendous loss that we're looking at here.
Arctic sea ice hit its second-lowest level in recorded history on Saturday, which scientist called an ominous sign of continued global warming.
The sea ice now covers 1.6 million square miles. That sounds like a lot, but from 1979 to 2000, it was 1 million square miles larger on average.
This GIF from the National Sea and Ice Data Center breaks down the difference.
Center director Mark Serreze said the record for smallest sea ice size was set in 2007, and this year avoided that mark by only 3,800 square miles.
Researchers said the continued shrinking of the sea ice could have disastrous effects soon. Reduced sea ice could mess with the jet stream, which could further increase dangerous "weather anomalies" worldwide, Penn State climate scientist Michael Mann said.
What happens in the Arctic doesn't stay in the Arctic.
What happened this year?
This was an unusual year for sea ice, in that an outbreak in storms didn't keep the waters cool as they usually would. Plus, sea ice levels were abnormally low in the winter.
Here are five things you might not know about climate change.
The Associated Press contributed to this report.