NASA spends a lot of its time gazing into the depths of the cosmos, but one of the great things about having high-powered cameras orbiting our planet is that you can easily observe changes to Earth as well. NASA uses that power to provide data on sea ice levels via the National Snow and Ice Data Center, which records the seasonal changes in the amount of sea ice and plots trends over time. Now, in its most recent data dump, the group is once again sounding the global warming alarm, and things aren’t looking good.

According to the most recent readings, the annual sea ice maximum — that is, the point at which the most Arctic sea ice is present, on a per-year basis — has been at its lowest points over the past four years. That means that out of all the recorded data, 2015, 2016, 2017, and 2018 were lower than every other year, and the numbers aren’t even close.

Arctic sea ice goes through relatively predictable changes over the course of each year. At its thickest, which typically occurs from late February to early April, its maximum is recorded, and this important data point offers an overall glimpse at how the Earth’s temperature is changing on the larger timeline.

Variations are expected on a year-to-year basis, but the long-term trends reveal that the planet is indeed getting warmer, and as sea ice levels drop we get closer to reaching (if we haven’t already reached) the all-important “tipping point” at which the planet may not be able to recover from the changes humanity has wrought.

“The Arctic sea ice cover continues to be in a decreasing trend and this is connected to the ongoing warming of the Arctic,” Claire Parkinson, a senior climate scientist at NASA’s Goddard Space Flight Center, said in a statement. “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.”

Later this year, NASA is planning to launch a new satellite that will keep a continuous eye on sea ice levels and measure their thickness constantly. This tool will give scientists an even better idea of how the season changes are shaping the long-term trends, though at this point it’s hard to imagine it will deliver anything but bad news.