The increasing number and frequency of heat waves experienced around the globe over the past year are adding to the growing body of evidence that global warming is a real danger to human civilization. In 2016 alone, major heat waves, many of them deadly record-breakers, were experienced in Africa, India, the Middle East, and the United States. New South Wales in Australia is currently suffering through more record-breaking temperatures, seeing spikes of 47ºC (117ºF), 12ºC above normal for this time of year.

But while many of these events have been occurring during summer in their respective regions, this winter has also seen multiple temperature spikes in the Arctic, bringing temperatures up to the freezing mark, hampering this year’s already record-low ice growth.

Adding to the growing mountain of surreal temperature anomalies is the recent heat wave experienced in Oklahoma last week, where February 11 saw temperatures in the upper-eighties across the state, with some regions in the southwest seeing temperature spikes in the upper nineties. The city of Mangum reached a high of 100ºF, a full 56ºF above normal for this time of year, and roughly 5ºF higher than the July average for the region.

It’s no small irony that Oklahoma is the home state of Republican Senator James Inhofe, who attempted to debunk global warming at this time of year in 2015, by bringing a snowball onto the Senate floor, arguing that if global warming was real, why was it so cold outside?

Needless to say, Inhofe was confusing the separate, albeit connected, concepts of weather and climate — a single weather event isn’t necessarily indicative of what is happening with the world’s climate overall. And to be fair, the same rule discounting Inhofe’s argument would apply to the recent temperature spike in OK, in that a single anomaly doesn’t make for a trend. But that’s where the similarities between both arguments end: the cold snap Inhofe was capitalizing on was just that, a cold snap. But OK’s recent heat wave is part of a larger trend, where the number of record-high temperatures in the United States alone has been increasing over the decades.

In a stable climate, the ratio of record high to record low temperatures would remain at roughly 1:1, as it was during the 1950s — 1.09 record highs for every one record low. The 1960s and 1970s saw a dip in the ratio: 0.77:1 and 0.78:1 respectively, but the numbers started to skew toward the record highs again in the 1990s, where the decade saw the ratio rise to 1.36 to 1. In the decade following that, it increased even further to 2.04:1.

As of this writing, over the last 365 days the U.S., that ratio has rocketed to 4.76 record highs for every 1 record low — and this number keeps climbing. The Third US National Climate Assessment is warning that, “Prolonged periods of high temperatures and the persistence of high nighttime temperatures have increased in many locations (especially in urban areas) over the past half century.” They expect that by the middle of this century, U.S. citizens can expect to see a four-to-sixfold increase in the number of days breaking 95ºF (35ºC).