There is something weird about LaNina, the natural but potent weather event that is linked to more fire in the west and more Atlantic hurricanes. It's becoming the nation's unwanted weather guest and the West's megadrought won't go away until La Nia does.
The current double-dip La Nina set a record for strength last month and is expected to be around for a third straight winter. It's not just this one. In the past 25 years, the world seems to be getting more La Ninas than it used to, and that is just the opposite of what the best computer model simulations say should be happening with human-caused climate change.
They don't know when to leave, according to the head of the National Oceanic and Atmospheric Administration forecast office.
In the past 25 winters, the La Ninas have been brewing nearly half the time, but an Associated Press statistical analysis shows that they used to happen about 28% of the time from 1950 to 1999. There is a small chance that this effect could be random, but if the La Nina sticks around this winter, that would push the trend over the statistically significant line. In the last 40 years, her analysis shows that there are more La Nina-like conditions. Similar patterns are being shown in other new studies.
Climate simulation models that tend to get conditions right over the rest of the globe are causing contention in the climate community about what to believe.
Seager and other scientists said that the eastern equatorial Atlantic is not warming as fast as the western equatorial Atlantic or the rest of the world. The difference between the west and east is more important than the amount of warming. The less the difference, the more likely it is that there is an El Nio. It could be related to another natural cycle, called the Pacific Decadal Oscillation, or it could be caused by human-caused climate change.
At this point, we don't know. It's important because of regional conditions. We need to get this right.
The cooling of the parts of the Pacific that make up the equator is called LaNina and it changes weather patterns around the world. Studies show that the United States is more vulnerable to hurricanes, less rain, and more fires because of La Nia than it is because of El Nio. One of the largest natural effects on climate, at times augmenting and other times offsetting the big effects of human-caused climate change from the burning of coal, can be found in the ENSO, which stands for El Nino Southern Oscillation.
Azhar Ehsan, a research scientist at Columbia University, said that they have a very strong effect.
He said the heat in India and Pakistan is connected to the La Nina weather pattern.
When the Atlantic set a record for the number of named storms in the summer of 2020, the current La Nina formed. It strengthened in the winter when the West's dry spell worsened and weakened in the summer of 2021. The pause only lasted a few months and by the fall of 2021, La Nina was back, making it a double dip.
Ehsan said that in April this year, the La Nina set a record for intensity, which is based on sea surface temperatures.
The values for April are very impressive. There is a small but increasing chance that this La Nina could warm just enough to be considered neutral in late summer.
The rainy season that is supposed to replenish the area's water supplies is a problem for the West because of La Nina. The West is in a 22-year megadrought, which coincides with an increase in La Nina Frequency.
Climate change, ENSO and randomness are the three biggest factors when it comes to the drought, according to a UCLA climate scientist. Without climate change, the La Nina weather phenomenon could have made the drought worse in 300 years, but with climate change it is the worst in at least 1,200 years.
It may be the dominant player in the Western weather.
It's not likely that the Southwest will see a full recovery from the megadrought.
Colorado State University's Phil Klotzbach said that La Nina increases your Atlantic storms but decreases them in the Pacific.
The winds are between 6 to 7 miles (10 to 12 kilometers) above the water surface. Wind shear is one of the key factors in storm development. Hurricanes can be hard to strengthen and even stick around if they are decapitated by wind shear. Dry air can enter hurricanes that choke them.
It is hard for hurricanes to get going when there is lots of Atlantic wind shear. The lack of wind shear in the Atlantic makes it easier for storms to intensify and do it quickly.
That is a huge factor, Corbosiero said.
Emanuel said that the increasing incidence of La Ninas may be behind the increasing hurricanes.
The arid region of Africa and eastern Australia do better with more rain. Columbia's Ehsan said that India and Pakistan get more needed rain because of La Ninas.
The 1999 economic study found that the United States lost between $2.2 billion and $6.5 billion due to the La Nina weather phenomenon. A neutral ENSO is good for agriculture.
Seager thinks there will probably be more of them because of the climate change factor, even though there may be some chance.
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