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These maps show how excessively hot it is in Europe and the U.S.

The heat, which has killed hundreds in Portugal and Spain, is unprecedented in many areas

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A historic and deadly heat wave has been scorching western Europe, killing hundreds in Spain and Portugal. Temperatures spiked to 115 degrees on the Iberian Peninsula amid bone-dry conditions, fueling wildfires and displacing thousands of people in France. The mercury topped 100 degrees (38 Celsius) in Britain on Monday and is expected to surge higher Tuesday.

U.K. braces for record temperatures as ‘heat apocalypse’ hits Europe

For the first time, the U.K. Met Office has issued a red warning for heat, its most extreme alert. The warning, in effect through Tuesday, includes Birmingham, Oxford, Nottingham and London.

Wales already established its highest temperature on record Monday, and England could be next Tuesday, with temperatures as high as 104 degrees (40 Celsius).

At the same time, another heat wave is brewing across the pond in the United States — one that produced a tie for Salt Lake City’s highest temperature Sunday and could bring readings as high as 113 degrees in Texas and Oklahoma on Tuesday.

A third heat wave is simmering in Central Asia.

These heat waves fit into a pattern of increasingly frequent, intense and prolonged events catalyzed by climate change. Human activities are pushing already high-end heat into record territory.

These seven maps and graphics illustrate their gravity and historic nature:

1. Temperatures 36 degrees (20 Celsius) above normal in U.K.

A good indicator of how unusual an event this is can be found through looking at anomalies, or departures from average. The above map is in Celsius, but the color scheme is telling.

Showing anomalies up to 20 Celsius or 36 Fahrenheit, it’s an illustration of just how far current temperatures are deviating from the norm. A typical July afternoon in the U.K. would feature readings in the low- to mid- 70s (low 20s Celsius), but peak temperatures are expected to end up on either side of 100 degrees Fahrenheit (38 Celsius). Remember how far north the United Kingdom is: London sits at a latitude slightly north of Calgary.

2. A glimpse into the future

The predicted maximum temperature in the U.K. through Tuesday could approach 40 Celsius (104 degrees), which would set a new national record, smashing the previous mark of 101.7 degrees (38.7 Celsius) set in Cambridge, eastern England, on July 25, 2019.

In 2020, the U.K. Met Office released projections indicating that such heat will become commonplace by 2050 because of human-caused climate change.

Already, climate warming has substantially boosted the odds of temperatures this extreme.

“The chances of seeing 40°C [104 degrees] days in the U.K. could be as much as 10 times more likely in the current climate than under a natural climate unaffected by human influence,” said Nikos Christidis, a climate attribution scientist at the Met Office. “The likelihood of exceeding 40°C anywhere in the U.K. in a given year has also been rapidly increasing, and, even with current pledges on emissions reductions, such extremes could be taking place every 15 years in the climate of 2100.”

3. Unprecedented mid-level temperatures

This is a depiction of output from the European weather model as early as Friday, July 8, when models began to key into the exceptional nature of the ongoing event in Europe.

It plots 850 millibar temperatures, or those a little less than a mile above the ground. Instead of showing the raw temperature, however, the plot maps readings based on percentile. Anything in magenta is listed in the color bar below as “record max” — in other words, the weather model hasn’t projected temperatures that hot at that time of year, altitude and location before. In other words, the air mass at the mid-levels is unprecedented.

Unsurprisingly, hot air aloft leads to even hotter air near the surface. That supports record readings that are both remarkable and deadly.

4. Worse than the past

One of the U.K.'s most notorious heat waves occurred 46 years ago, a prolonged event that set many records. While this heat wave has not matched the 1976 heat wave for longevity (the U.K. saw 15 consecutive days of temperatures above 32 Celsius), it is projected to be more intense. The maximum temperature during the 1976 heat wave was 35.9 Celsius (96.6 degrees) compared to the 40 Celsius forecast for this event.

That should not be surprising considering how much the climate has warmed since the 1970s. The U.K.'s average temperature has warmed by more than 0.5 Celsius (0.9 degrees) since the mid-1970s, according to the Royal Society.

5. Records falling in real time

This plot from ingests real time observations from weather stations and compares it to historical data; it is from 2 p.m. Monday local time. Anything in red marks a city breaking a daily record high; magenta represents a station that’s tying or breaking a monthly record temperature, and black circles with an “x” inside denote the matching or exceeding of an all-time maximum temperature.

A number of black circles can be seen in southeastern parts of the U.K., in particular around England, underscoring the unprecedented nature of the event.

On Monday, the temperature in Wales rose to 98.8 degrees (37.1 Celsius), the highest on record. The high of 91.4 degrees (33 Celsius) in Dublin marked Ireland’s highest air temperature of the 20th and 21st centuries.

6. 100s from Mexico to Canada

It’s not often you see triple digits spanning the full south to north extent of the United States, from the tip of where southern Texas meets Mexico to the North Dakota-Manitoba border. Yet that was the forecast for Monday, and Tuesday could be even hotter for the southern Plains. About 40 million people are under heat alerts in the Lower 48 states.

Highs of up to 109 degrees are anticipated in the Dakotas on Monday, and Tuesday could feature a reading of 112 degrees in Wichita Falls, Tex. Triple-digit temperatures will continue to fester there for at least the next week, with unusually hot temperatures lasting for the forecastable future.

The heat has already set significant records. On Sunday, Salt Lake City climbed to 107 degrees — tying its all-time high. Dodge City, Kan., hit 109 degrees both weekend days, matching its highest observed July temperature. Even as far north as Glasgow, Mont., it hit 108 degrees Sunday, among its top 10 highest temperatures observed in any month.

7. A third heat wave in Central Asia

In addition to the central U.S. and western Europe, central Asia is also baking. In other words, three exceptional heat waves are affecting the Northern Hemisphere.

The map below plots temperature anomalies which are 11 degrees Celsius (20 Fahrenheit) or greater over the Plateau of Tibet into central Asia.

In Tibet, the hot summer sun is heating the high terrain, allowing warm air atop the plateau to rise and create a “thermal low” that draws in warm, moist air from the Bay of Bengal and Arabian Sea. That’s what sparks the annual monsoon there.