The North Pole’s ice is disappearing as we watch: This year, the Arctic sea ice had the lowest winter maximum extent on record.

Every year the ice melts in the summer and grows in the winter. Although the specific date varies, it generally reaches its maximum amount in March. In 2016, that maximum was likely reached on March 24, with an extent measured at 14.52 million square kilometers.

The problem is that this number is the lowest on record (satellite measurements go back to 1979). That’s 1.12 million square kilometers lower than the average—nearly twice the area of Texas. Worse, the average itself is probably artificially low; it’s measured from 1981 to 2010, an era when global warming had already long made its effects known.

I want to be clear here: Last year’s sea ice had a maximum extent of 14.54 million square kilometers. This year’s max is technically lower than that, but statistically they are very close. However, the point still stands: Over time, the trend we’re seeing is a loss of sea ice. The 13 lowest maximum extents ever seen have all been in the past 13 years. That is very, very bad.

The Arctic has been experiencing nearly unbelievable record temperatures. December, January, and February were incredibly hot compared with normal. In that past month alone, much of the Arctic saw temperatures more than 11° C higher than average—that’s 20° F. This contributed to the record low amounts of ice seen.

“Extent” is essentially the area of ice; technically it’s measured as a region covered by more than 15 percent ice. But it’s only one way to measure the amount of ice. Volume is a better way, because you can get a thin covering of ice that adds a lot to the area but very little to the actual amount. And guess what: The volume of Arctic ice is decreasing over time as well.

Worse (and yes, things get much worse), it’s old ice that we’re seeing disappearing, ice that had been persistent. The new ice is thinner and tends to come and go with the seasons, but old ice provides a baseline. But that’s melting away as well. Every year as more of that melts in the summer, the overall amount of ice will drop.

I have little doubt that deniers will ramp up their blustery lies as they do whenever a record like this occurs. The most common one is that gain in Antarctic sea ice offsets the loss in Arctic sea ice. This is grossly misleading. Antarctic sea ice is transitory, waxing and waning over time but generally staying around the same amount, while Arctic sea ice is in a death spiral:

In fact, some computer models show that the Arctic could see an ice-free summer as early as 2040. The volume of sea ice is dropping at a rate of about 3,000 cubic kilometers per decade, and at its minimum (reached in September every year) it’s now at roughly 6,000 cubic kilometers. If this rate continues, then yes, 2040 sounds about right.

Combine this with the 420 billion tons of land ice lost from Greenland and Antarctica every year—yes, every year—and you can see we’re running history’s most dangerous experiment on the only planet that can sustain our lives. And be sure of this: We are not seeing changes due to a natural cycle. This is our fault.

The scary thing is, we’re not really sure how this will affect the climate, but no matter how you slice it, it won’t be good. The introduction of billions of tons of fresh water into the oceans can disrupt the way temperatures are regulated across the planet, with vast and severe repercussions.

I cannot stress this enough: Global warming is real, it’s disastrously affecting our climate, and the economic impact alone will be crushing. And that’s not to mention the oceans becoming acidified, extreme weather on the rise, sea levels rising, and a host of other catastrophic effects.

Remember, in November, Americans will be voting for president of the United States. On one side of the ballot will be a candidate who understands all this and will take action. On the other side will be one who actively buries his head in the sand and denies it all.

Choose wisely.