by Chris Mooney is a Pulitzer price winner and a CNN climate employee. He is currently a professor of practice at the Environmental Institute of the University of Virginia.
The coherent United States have experienced another scale summer. June was unusually warm and a large heat wave was almost a third of the population at the end of the month, and July offered little relief.
This is hardly a surprise: the summer in the lower 48 is now average 1.6 degrees Fahrenheit warmer than in 1896, according to the Environmental Protection Agency.
Summer is the season in which the effects of climate change are probably obvious: it gets hotter, longer, humid and more dangerous. However, the average values are a complex reality: the experience of the country with the hot summer – and thus one of the most visceral aspects of climate change itself – is broken in the geographical sense.
Summer behaves very unpredictable when the country is heated, with major changes in some regions, especially in the west, and very steamed in the central and southeastern USA.
Compared to the summer of the past 30 years with a broad period between 1901 and 1960, the limited warming and even slight cooling are remarkably obvious in some places.
Summer time is called “Warming Loch”.
For some time, scientists have recognized the existence of the warming hole and tried to explain what it causes. They are not convinced at all that it will go on – frankly, many suspect that this is not the case. But for the time being, it stands out in such a way that it requires an explanation that has tried a lot of research.
“There are not too many places on the planet who honestly show this,” said Joseph Barsugli, climate researcher at the University of Colorado in Boulder, who made a recent topic. “It’s pretty unique, I think.”
The pattern is recognized for scientists who examine the warming trends in the United States that the recent issue of the US National Climate Assessment, which came out in 2023. Under the Trump administration, the document is no longer on the once most important government website, but is still available here. It is said that in summer “the seasonal temperatures in some regions east of the Rocky Mountains” declined “, although they add that a trend of cooling temperatures was” recently reversed “in the southeast.
This is a curiosity in the middle of a warming climate, since the general pattern is that the areas of the world heat up faster than the oceans. For example, Europe is one of the fastest warming areas in the world.
But wherever you are on earth, the type of climate change you get determines and there is an enormous amount of variability.
Scientists are still trying to understand the reasons for the curved pattern – which they sometimes refer to as “dipol” – in the US summer heating rates between the? West and east.
Everything was attributed to everything, from the cooling effects of reforestation in the southeast to “corn sweat” in the middle west, which are bound with more productive agriculture. The “sweating” refers to how the corn plants arise and more water in the air, which can then fall as a cooling rain.
Corn grows in a field near Clinton, Illinois in July. – Scott Olson/Getty Images
“I think a piece of this is the change in land use and basically the increase in agricultural intensification, which only breaks water into the atmosphere,” said Jonathan Winter, professor at Dartmouth University, who found that the warming “hole” was actually good for the maize income in the middle west.
There is also reason to assume that in the southeast, when people in the 20th century less profitable agricultural farms tasks, and the forests of steaming, the warming. In summer especially in summer, forests pull water through tree roots and transpire it into the air, which makes it wetter. In a recently published newspaper, Mallory Barnes from Indiana University and colleagues found that this had a significant cooling effect.
The reforestation “cools large areas, not only small areas,” said Barnes.
In addition, part of the phenomenon has to do with the extreme temperatures associated with the dust shell of the 1930s. This phenomenon induced by humans shows the data during this time for some parts of the United States, which makes it difficult to find a heating temperature trend today. Very warm summer temperatures in the 1930s, for example, can be felt in the temperature history of Tulsa County, Oklahoma.
The summer heat hole is also sensitive to the definition, and in the past few decades there are signs that it may decrease something.
In Southeast countries such as Alabama, Georgia, Kentucky and Tennessee, the summer temperatures in the 1960s and 1970s were very cool, but have heated up considerably since then. It is only that they didn’t necessarily go much beyond where they used to be in the 20th century. In some places, such as Tuscaloosa County, Alabama, the general change remains towards the cooling direction:
After all, the lack of warming in summer does not necessarily mean the regions in the course of the year – the summer is only a quarter of them and is averages with all others. Nevertheless, it supports the general change and is an anomaly that must be explained.
It is also important because summer when warm temperatures may be most dangerous. It is also the season that we feel the most and remember the experience of the heat.
One thing that the different hypotheses have in common is to emphasize the cooling effects of the precipitation.
For example, a group of leading researchers tried to understand in a striking article of 2023 in the Journal of Climate, why this “heated hole” mustel “has not disappeared”, how it was expected and why many climate models do not produce it.
One of her most important findings was that an increase in precipitation is the explanation. The rain comes during the summer afternoons and cools down the temperatures and holds a lid on it.
“More rain or cloudy conditions only have limited daily temperatures if they rise in a large part of the region,” said Zachary Labe, a climate scientist from Climate Central who was involved in research.
In the study, the study shows that nights in the region were heated as expected. It is the days that have not really done this.
In addition to local factors, some researchers ultimately pursue the source of further changes. They believe that a regional pattern about the eastern US -American might be rooted in the behavior of the Pacific Ocean.
It is complex to decipher what can happen, but in general, scientists believe that ocean patterns in very distant regions can have the weather and the climate. And this also includes why part of the United States may get more rain while someone else becomes dryer.
The atmospheric orientation is similar to the so -called positive phase of the “Pacific North America” pattern with a cool eastern US and a warm west, said Labe.
If the surface temperatures of the sea are warmer than normal, “in the central equatorial pacific near the datine, regardless of the period of time they are used in summer, they will receive a heat hole somewhere in the eastern USA due to increased clouds and precipitation,” said Gerald Mehl, a climate carer in the national center for atmospheric research and the connection of the Pacific and examined the connection of the Pacific.
Heavy rain flows on fans outside the Bryant -Denny Stadium in Tuscaloosa, Alabama, in August 2024. -Gary Cosby Jr./usa Today Sports/Images
The relative lack of warming was emphasized by some critics of various aspects of climate science. This includes John Christy, the state climateologist of Alabama and professor at the University of Alabama in Huntsville. Christy recently also coincided with a report on the Ministry of Energy, in which the earth did not deny that the earth was generally warmed up, but criticized “exaggerated projections of future warming”. This document has mobilized a large number of climate researchers who want to refute it.
“You can immediately see how the warming on Alabama determines the extra [greenhouse gases] is a problem like the temperatures of the past decades (which should react to the heat influence of extra [greenhouse gases]) were actually cooler than earlier decades when this influence was essentially not available, ”Christy writes.
And it is true, Alabama appears in the summer heat hole.
But because the lid of the temperatures is so closely connected to the precipitation, Barsugli warns that there is no guarantee that it will continue. The warming can jump back without suppressing anything.
“If you have a very dry year, this probably means that you will break the records with maximum temperatures,” he said. “It’s a kind of latent threat.”
It is also difficult to notice the summer heat hole primarily in central and southern states that tend to choose Republican.
It is unlikely that the temperatures themselves influence the ideology of humans, said James Druckman, political scientist at the University of Rochester, who examined the factors based on the beliefs of climate change.
“I don’t think they have a significant impact on what people think. They could marginally,” said Druckman. “I think politics has become too polarized or rooted in this topic.”
Ultimately, the question is whether the hole is finally overcome by wider trends. Experts say it could be even though they are not sure when.
“It is a war tug between the increase in precipitation and the increase in temperature,” said Winter. “At some point I expect it to dissolve. It will still be cool relative to the rest of the United States. But compared to historical temperatures, they will see climate change at some point.”
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