May 30, 2022 03:18 PM
Weather’s unwanted guest: Nasty La Nina keeps popping up
https://apnews.com/article/what-is-la-ni...dca0c45dcf
INTRO: Something weird is up with La Nina, the natural but potent weather event linked to more drought and wildfires in the western United States and more Atlantic hurricanes. It’s becoming the nation’s unwanted weather guest and meteorologists said the West’s megadrought won’t go away until La Nina does.
The current double-dip La Nina set a record for strength last month and is forecast to likely be around for a rare but not quite unprecedented third straight winter. And it’s not just this one. Scientists are noticing that 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 their best computer model simulations say should be happening with human-caused climate change.
“They (La Ninas) don’t know when to leave,” said Michelle L’Heureux, head of the National Oceanic and Atmospheric Administration forecast office for La Nina and its more famous flip side, El Nino.
An Associated Press statistical analysis of winter La Ninas show that they used to happen about 28% of the time from 1950 to 1999, but in the past 25 winters, they’ve been brewing nearly half the time. There’s a small chance that this effect could be random, but if the La Nina sticks around this winter, as forecast, that would push the trend over the statistically significant line, which is key in science, said L’Heureux. Her own analysis shows that La Nina-like conditions are occurring more often in the last 40 years. Other new studies are showing similar patterns.
What’s bothering many scientists is that their go-to climate simulation models that tend to get conditions right over the rest of the globe predict more El Ninos, not La Ninas, and that’s causing contention in the climate community about what to believe, according to Columbia University climate scientist Richard Seager and MIT hurricane scientist Kerry Emanuel... (MORE - missing details)
‘Flash droughts’ are Midwest’s next big climate threat
https://grist.org/agriculture/flash-drou...te-threat/
EXCERPTS: . . . Fast-moving droughts like this one are developing more and more quickly as climate change pushes temperatures to new extremes, recent research indicates — adding a new threat to the dangers of pests, flooding, and more long-term drought that farmers in the U.S. already face. Known as “flash droughts,” these dry periods can materialize in as quickly as five days, often devastating agricultural areas that aren’t prepared for them.
[...] The threshold for drought conditions differs by location, with the U.S. Drought Monitor using data on soil moisture, streamflow, and precipitation to categorize droughts by their severity. While typical droughts develop over months as precipitation gradually declines, flash droughts are characterized by a steep drop in rainfall, particularly during a season that normally receives plenty, along with high temperatures and fast winds that quickly dry out the soil. They can wither crops or prevent seeds from sprouting, delaying or diminishing the harvest.
Now, flash droughts are coming on faster and faster — making them more difficult to predict and more damaging, according to a recent study published in Nature Communications. The research, from scientists at the University of Texas and Hong Kong Polytechnic University, found that in the last 20 years, the percentage of flash droughts developing in under a week increased by more than 20 percent in the Central United States.
“There should be more attention paid to this phenomenon,” said Zong-Liang Yang, a geosciences professor at the University of Texas and one of the study’s co-authors, as well as “how to actually implement [these findings] into agricultural management.”
[,,,] Flash droughts are also a global problem, with Brazil, India, and multiple countries in Africa facing the worst impacts. In 2010, a flash drought followed by a heatwave in Russia temporarily halted wheat exports, a major disruption for communities across the Middle East that depend on the country’s grain... (MORE - missing details)
https://apnews.com/article/what-is-la-ni...dca0c45dcf
INTRO: Something weird is up with La Nina, the natural but potent weather event linked to more drought and wildfires in the western United States and more Atlantic hurricanes. It’s becoming the nation’s unwanted weather guest and meteorologists said the West’s megadrought won’t go away until La Nina does.
The current double-dip La Nina set a record for strength last month and is forecast to likely be around for a rare but not quite unprecedented third straight winter. And it’s not just this one. Scientists are noticing that 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 their best computer model simulations say should be happening with human-caused climate change.
“They (La Ninas) don’t know when to leave,” said Michelle L’Heureux, head of the National Oceanic and Atmospheric Administration forecast office for La Nina and its more famous flip side, El Nino.
An Associated Press statistical analysis of winter La Ninas show that they used to happen about 28% of the time from 1950 to 1999, but in the past 25 winters, they’ve been brewing nearly half the time. There’s a small chance that this effect could be random, but if the La Nina sticks around this winter, as forecast, that would push the trend over the statistically significant line, which is key in science, said L’Heureux. Her own analysis shows that La Nina-like conditions are occurring more often in the last 40 years. Other new studies are showing similar patterns.
What’s bothering many scientists is that their go-to climate simulation models that tend to get conditions right over the rest of the globe predict more El Ninos, not La Ninas, and that’s causing contention in the climate community about what to believe, according to Columbia University climate scientist Richard Seager and MIT hurricane scientist Kerry Emanuel... (MORE - missing details)
‘Flash droughts’ are Midwest’s next big climate threat
https://grist.org/agriculture/flash-drou...te-threat/
EXCERPTS: . . . Fast-moving droughts like this one are developing more and more quickly as climate change pushes temperatures to new extremes, recent research indicates — adding a new threat to the dangers of pests, flooding, and more long-term drought that farmers in the U.S. already face. Known as “flash droughts,” these dry periods can materialize in as quickly as five days, often devastating agricultural areas that aren’t prepared for them.
[...] The threshold for drought conditions differs by location, with the U.S. Drought Monitor using data on soil moisture, streamflow, and precipitation to categorize droughts by their severity. While typical droughts develop over months as precipitation gradually declines, flash droughts are characterized by a steep drop in rainfall, particularly during a season that normally receives plenty, along with high temperatures and fast winds that quickly dry out the soil. They can wither crops or prevent seeds from sprouting, delaying or diminishing the harvest.
Now, flash droughts are coming on faster and faster — making them more difficult to predict and more damaging, according to a recent study published in Nature Communications. The research, from scientists at the University of Texas and Hong Kong Polytechnic University, found that in the last 20 years, the percentage of flash droughts developing in under a week increased by more than 20 percent in the Central United States.
“There should be more attention paid to this phenomenon,” said Zong-Liang Yang, a geosciences professor at the University of Texas and one of the study’s co-authors, as well as “how to actually implement [these findings] into agricultural management.”
[,,,] Flash droughts are also a global problem, with Brazil, India, and multiple countries in Africa facing the worst impacts. In 2010, a flash drought followed by a heatwave in Russia temporarily halted wheat exports, a major disruption for communities across the Middle East that depend on the country’s grain... (MORE - missing details)