Here's another sign climate change could be happening more quickly than anyone expected.
A new study from Environment Canada says the spring snow cover is disappearing at a much faster rate than scientists anticipated.
Researchers say that's important for a number of reasons.
Arctic snow essentially helps keep the Earth cool, because it's bright and reflects a lot of heat and energy from the sun back out to space.
If that snow melts faster than normal, the darker ground underneath it is exposed earlier and absorbs more heat and energy from the sun.
That contributes to warming up the planet and has implications for wildlife, vegetation and ground temperatures.
It can also warm the permafrost, alter the timing of spring runoff into rivers and lead to earlier plant growth in spring.
Scientists studied 40 years of snow data from across the Arctic from April to June. They found that the Arctic snow cover has declined even faster than the Arctic sea ice.
This past summer, the Arctic sea ice dropped to an all-time low. Scientists from the U.S. National Snow and Ice Data Centre said an area of ice bigger than Alberta disappeared.
"What we discovered was that there is a significant reduction in the amount of snow cover, particularly in May and June... and the rate of that decline is actually slightly faster than the loss of summer sea ice," said Dr. Chris Derksen, a research scientist for Environment Canada and one of the study's authors.
"If you remove snow cover earlier, you're creating the potential to send warmer air out over the ocean. It can't be good for sea ice if you lose the snow early," Derksen says.
Not only that, but the researchers say the changes in the past five years were "profound."
Since 1980, the blanket of snow that stays in the Arctic at the end of in spring has decreased by two-thirds - from roughly 9 million square kilometres to about 3 million.
And the study says that the five lowest snow covers in June have all happened in the past five years.
In North America, there have been record lows in three of the past five years. In Eurasia, there have been record lows set every year since 2008.
It's also worth noting that snow isn't arriving any earlier in the fall either.
Derksen says greenhouse gas emissions are a big reason for the changes.
"I think it's just important that we realize what the impacts of increasing temperatures are across the Arctic and that these impacts on snow cover and sea ice then have follow-on impacts on the Arctic climate system and the global climate system."
He acknowledges that when it comes to climate, five to 10 years is not a very long time. But he says the changes researchers have seen in that time are significant.
"The climate models project that we'll be seeing these changes, but they project them further out into the future," he said.
"Certainly the past shows some very strong changes that when you compare them to the sea ice and you see the major changes in the summer sea ice as well, that does suggest this Arctic-wide change driven by warming surface temperatures."
The study is published in the latest Geophysical Research Letters, the journal of the American Geophysical Union.