In this newsletter:
1) New study cautions against over-interpreting influence of climate on cultural change and catastrophe
University of Main, 17 August 2022
2) Ancient El Niños reveals limits to future climate projections
University of Texas at Austin, 15 March 2022
3) La Niña amplifies weather extremes in first half of 2022: Aon
Reinsurance News, 25 July 2022
4) La Nina: Worsening drought seen as next big threat of economic disruption
Seeking Alpha, 22 August 2022
Reinsurance News, 25 July 2022
4) La Nina: Worsening drought seen as next big threat of economic disruption
Seeking Alpha, 22 August 2022
5) How salmon numbers rise and fall during El Nino and La Nina
Fox Weather, 13 August 2022
Fox Weather, 13 August 2022
6) Spring Rainfall Shortages in Europe: Is La Niña to Blame?
Met Swift, July 2022
Met Swift, July 2022
7) Empirical observations show no sign of ‘climate crisis’
GWPF, 14 April 2022
8) And finally: The changing nature of Earth's reflected sunlight
Proceedings of the Royal Society, 27 July 2022
Proceedings of the Royal Society, 27 July 2022
Full details:
1) New study cautions against over-interpreting influence of climate on cultural change and catastrophe
University of Main, 17 August 2022
El Nino has been a major driver of societal collapse, various catastrophes and cultural change in coastal Peru for millennia, but it isn't the only culprit. In a new study, University of Maine researchers warn against over-interpreting the role climatic change, like an El Nino event, plays in societal and cultural transition.
Dan Sandweiss, a professor in the Anthropology Department and Climate Change Institute, and Kirk Maasch, a professor in the School of Earth and Climate Sciences and the Climate Change Institute, investigated whether climate influenced the abandonment of three sites in the Lambayeque Valley in northern Peru: Pampa Grande not long after 750 A.D., Batán Grande in 1100 A.D. and Túcume, America's largest pyramid center, between 1532 and 1547 A.D. Sandweiss excavated Túcume in collaboration with Norwegian explorer Thor Heyerdahl in the 1990s.
All three sites were major centers of Andean society at their time, and large adobe and fill mounds in each site were burned when they were abandoned. Pampa Grande covered 600 acres and centered around the mound Huaca Fortaleza. Batán Grande had eight large mounds. Túcume spanned 200 hectares with 13 major mounds and several dozen smaller structures, according to researchers.
Sandweiss and Maasch analyzed data from three proxy records for climate change and El Nino activity to determine whether they occurred around the same time as the abandonment of these sites. Those records included an ice core from the Quelccaya ice cap in southern Peru, a marine sediment core from the coast and a lake sediment record from Pallcacocha in highland Ecuador.
The data showed that climate contributed to the abandonment of Pampa Grande and Batán Grande, but not Túcume, which resulted from the Spanish conquest. The new study also revealed associations between the abandonment of Pampa Grande and Batán Grande and El Nino, albeit at different degrees of intensity.
"Our study shows that equifinality—similar outcomes from different causes—likely happened in Peruvian prehistory," says Maasch. "This urges caution in seeing a single process such as climate change as the prime driver of all abrupt change."
Ice core and marine and lake sediment core records showed that the abandonment of Pampa Grande occurred during the onset of the Medieval Warm Period, a time of extreme drought and a strong peak in El Nino intensity, according to researchers. The abandonment of Batán Grande happened at the latter end of the Medieval Warm Period during a drought and when there was a small peak in El Nino intensity. After both sites were abandoned, El Nino intensity diminished and new mound centers were built, researchers say.
Civilizations along the Peruvian Coast experience several different types of El Nino. Researchers theorize that the abandonment of Pampa Grande and Batán Grande occurred during a Central Pacific El Nino, which is known for causing drought in areas of the Andean Highlands like the Lambayeque Valley.
Sandweiss and Maasch previously found connections between climate and cultural change in early Peruvian civilizations, particularly during initial monument construction in 5800 B.P., at the end of the Late Preceramic Period around 3800–3600 B.P., and at the conclusion of the Initial Period temple tradition at 2850 B.P. The climatic pattern has brought extreme weather conditions that decimate agricultural infrastructure, depress fisheries, usher in disease and damage archaeological resources in northern Peru, and it continues to threaten the region's economy and culture.
"When we began working on the Peruvian coast, we saw El Nino events as unmitigated disasters," says Sandweiss. "Thanks to more recent work by many colleagues and studies like this one, we now have a better understanding of the resilience of ancient Peruvians in the face of climatic and other catastrophes. Along with technological responses, ideological changes such as site abandonment were part of the cultural repertoire for dealing with disaster."
Sandweiss has spent decades conducting pioneering research on the origins of El Nino and fluctuations of its frequency and intensity over time. He also is credited with discovering variation in the frequency of El Nino events during the Holocene (the last 11,400 years) and, in the process, demonstrating the value of archaeological remains as records of past climates and early maritime adaptations.
His work on El Nino has provided seminal contributions to the field and provided a scientific foundation for exploring the impact of climatic disasters on cultural change in the Andes.
2) Ancient El Niños reveals limits to future climate projections
University of Texas at Austin, 15 March 2022
The climate pattern El Niño varies over time to such a degree that scientists will have difficulty detecting signs that it is getting stronger with global warming.
University of Main, 17 August 2022
El Nino has been a major driver of societal collapse, various catastrophes and cultural change in coastal Peru for millennia, but it isn't the only culprit. In a new study, University of Maine researchers warn against over-interpreting the role climatic change, like an El Nino event, plays in societal and cultural transition.
Dan Sandweiss, a professor in the Anthropology Department and Climate Change Institute, and Kirk Maasch, a professor in the School of Earth and Climate Sciences and the Climate Change Institute, investigated whether climate influenced the abandonment of three sites in the Lambayeque Valley in northern Peru: Pampa Grande not long after 750 A.D., Batán Grande in 1100 A.D. and Túcume, America's largest pyramid center, between 1532 and 1547 A.D. Sandweiss excavated Túcume in collaboration with Norwegian explorer Thor Heyerdahl in the 1990s.
All three sites were major centers of Andean society at their time, and large adobe and fill mounds in each site were burned when they were abandoned. Pampa Grande covered 600 acres and centered around the mound Huaca Fortaleza. Batán Grande had eight large mounds. Túcume spanned 200 hectares with 13 major mounds and several dozen smaller structures, according to researchers.
Sandweiss and Maasch analyzed data from three proxy records for climate change and El Nino activity to determine whether they occurred around the same time as the abandonment of these sites. Those records included an ice core from the Quelccaya ice cap in southern Peru, a marine sediment core from the coast and a lake sediment record from Pallcacocha in highland Ecuador.
The data showed that climate contributed to the abandonment of Pampa Grande and Batán Grande, but not Túcume, which resulted from the Spanish conquest. The new study also revealed associations between the abandonment of Pampa Grande and Batán Grande and El Nino, albeit at different degrees of intensity.
"Our study shows that equifinality—similar outcomes from different causes—likely happened in Peruvian prehistory," says Maasch. "This urges caution in seeing a single process such as climate change as the prime driver of all abrupt change."
Ice core and marine and lake sediment core records showed that the abandonment of Pampa Grande occurred during the onset of the Medieval Warm Period, a time of extreme drought and a strong peak in El Nino intensity, according to researchers. The abandonment of Batán Grande happened at the latter end of the Medieval Warm Period during a drought and when there was a small peak in El Nino intensity. After both sites were abandoned, El Nino intensity diminished and new mound centers were built, researchers say.
Civilizations along the Peruvian Coast experience several different types of El Nino. Researchers theorize that the abandonment of Pampa Grande and Batán Grande occurred during a Central Pacific El Nino, which is known for causing drought in areas of the Andean Highlands like the Lambayeque Valley.
Sandweiss and Maasch previously found connections between climate and cultural change in early Peruvian civilizations, particularly during initial monument construction in 5800 B.P., at the end of the Late Preceramic Period around 3800–3600 B.P., and at the conclusion of the Initial Period temple tradition at 2850 B.P. The climatic pattern has brought extreme weather conditions that decimate agricultural infrastructure, depress fisheries, usher in disease and damage archaeological resources in northern Peru, and it continues to threaten the region's economy and culture.
"When we began working on the Peruvian coast, we saw El Nino events as unmitigated disasters," says Sandweiss. "Thanks to more recent work by many colleagues and studies like this one, we now have a better understanding of the resilience of ancient Peruvians in the face of climatic and other catastrophes. Along with technological responses, ideological changes such as site abandonment were part of the cultural repertoire for dealing with disaster."
Sandweiss has spent decades conducting pioneering research on the origins of El Nino and fluctuations of its frequency and intensity over time. He also is credited with discovering variation in the frequency of El Nino events during the Holocene (the last 11,400 years) and, in the process, demonstrating the value of archaeological remains as records of past climates and early maritime adaptations.
His work on El Nino has provided seminal contributions to the field and provided a scientific foundation for exploring the impact of climatic disasters on cultural change in the Andes.
2) Ancient El Niños reveals limits to future climate projections
University of Texas at Austin, 15 March 2022
The climate pattern El Niño varies over time to such a degree that scientists will have difficulty detecting signs that it is getting stronger with global warming.
A map of the strongest El Niño on record in 2016, showing sea surface temperature. Red is higher and blue lower than normal. Credit: NOAA.
That's the conclusion of a study led by scientists at The University of Texas at Austin that analyzed 9,000 years of Earth's history. The scientists drew on climate data contained within ancient corals and used one of the world's most powerful supercomputers to conduct their research.
The study of the past, which was recently published in Science Advances, was motivated by the need to get a clearer picture of how climate change may affect El Niño in the future.
El Niño is the warm phase of the El Niño Southern Oscillation, a climate phenomenon that sets the stage every few years for weather patterns worldwide. Strong El Niño events, such as the ones in 1997 and 2015 that brought wildfires to the rainforests of Borneo in Asia and caused widespread bleaching to the world's coral reefs, happened about once a decade.
Computer models, however, are unclear about whether El Niño events will become weaker or stronger as the world warms due to climate change.
"Much of the world's temperature and rainfall are influenced by what happens in the tropical Pacific Ocean where El Niño starts," said the study's lead author, Allison Lawman, who began the research as a Ph.D. project at the UT Jackson School of Geosciences and is now a postdoctoral researcher at the University of Colorado Boulder. "The difference in rainfall between greater or fewer strong El Niño events is going to be a critical question for infrastructure and resource planners."
That's the conclusion of a study led by scientists at The University of Texas at Austin that analyzed 9,000 years of Earth's history. The scientists drew on climate data contained within ancient corals and used one of the world's most powerful supercomputers to conduct their research.
The study of the past, which was recently published in Science Advances, was motivated by the need to get a clearer picture of how climate change may affect El Niño in the future.
El Niño is the warm phase of the El Niño Southern Oscillation, a climate phenomenon that sets the stage every few years for weather patterns worldwide. Strong El Niño events, such as the ones in 1997 and 2015 that brought wildfires to the rainforests of Borneo in Asia and caused widespread bleaching to the world's coral reefs, happened about once a decade.
Computer models, however, are unclear about whether El Niño events will become weaker or stronger as the world warms due to climate change.
"Much of the world's temperature and rainfall are influenced by what happens in the tropical Pacific Ocean where El Niño starts," said the study's lead author, Allison Lawman, who began the research as a Ph.D. project at the UT Jackson School of Geosciences and is now a postdoctoral researcher at the University of Colorado Boulder. "The difference in rainfall between greater or fewer strong El Niño events is going to be a critical question for infrastructure and resource planners."
A 500-year simulation of El Niño intensity from the study period. Although the data appears chaotic, finding how these patterns change during periods of past climate change could hold the key to future climate projections, according to climate researchers at University of Texas Institute for Geophysics. Credit: Allison Lawman
Lawman and her collaborators used the Lonestar5 supercomputer at UT's Texas Advanced Computing Center to run a series of climate simulations of a period in Earth's history before human influences, when the main source of climate change came from a tilt in the planet's orbit. The simulations were verified using a coral emulator Lawman had previously developed to compare them with climate records from ancient corals.
They found that although the occurrence of strong El Niño events intensified over time, the change was small compared with El Niño's highly variable nature.
"It's like trying to listen to soft music next to a jackhammer," said study co-author Jud Partin, a research scientist at the University of Texas Institute for Geophysics.
To achieve this, Partin, Lawman and the study's other authors call for further investigations into even earlier times in Earth's history, such as the last ice age, to see how El Niño responded to more intense changes in climate forces.
"Scientists need to keep pushing the limits of models and look at geological intervals deeper in time that could offer clues on how sensitive El Niño is to changes in climate," said co-author Pedro DiNezio, an associate professor at University of Colorado Boulder. "Because if there's another big El Niño, it's going to be very hard to attribute it to a warming climate or to El Niño's own internal variations."
3) La Niña amplifies weather extremes in first half of 2022: Aon
Reinsurance News, 25 July 2022
The persistence of La Niña conditions across the central and eastern Pacific Ocean has been one of the most prominent reasons for elevated weather extremes since 2020, reports re/insurance broker Aon.
These conditions have global implications on weather patterns and other atmospheric or oceanic phenomena that can often bring amplified extremes of temperature and rain.
The broker notes that during the first six months of 2022, there were several examples of considerable and record-setting heatwaves and prolific rainfall. Such occurrences drove intense drought and floods in many areas.
Climate change has continued to influence these temperature and precipitation extremes during the past several decades. Data has indicated the growing intensity and frequency of “tail” (or low probability) events that are affecting a greater number of people.
While heatwaves and floods are not new, the behaviour change of these events are growing more evident. In the case of temperature extremes alone, scientists are discovering that climate change is making these events longer, more extreme, and more frequent with an earlier onset.
The toll of heatwaves on human health and the energy market is expected to increase as average global temperatures continue to rise.
According to the National Oceanic and Atmospheric Administration (NOAA), preliminary global ocean and land temperatures during 1H 2022 were 1.53°F (0.85°C) above the 20th century average. This marked the 6th warmest 1H period since records began in 1880.
Full story
4) La Nina: Worsening drought seen as next big threat of economic disruption
Seeking Alpha, 22 August 2022
7) Empirical observations show no sign of ‘climate crisis’
Global Warming Policy Foundation, 14 April 2022
Lawman and her collaborators used the Lonestar5 supercomputer at UT's Texas Advanced Computing Center to run a series of climate simulations of a period in Earth's history before human influences, when the main source of climate change came from a tilt in the planet's orbit. The simulations were verified using a coral emulator Lawman had previously developed to compare them with climate records from ancient corals.
They found that although the occurrence of strong El Niño events intensified over time, the change was small compared with El Niño's highly variable nature.
"It's like trying to listen to soft music next to a jackhammer," said study co-author Jud Partin, a research scientist at the University of Texas Institute for Geophysics.
To achieve this, Partin, Lawman and the study's other authors call for further investigations into even earlier times in Earth's history, such as the last ice age, to see how El Niño responded to more intense changes in climate forces.
"Scientists need to keep pushing the limits of models and look at geological intervals deeper in time that could offer clues on how sensitive El Niño is to changes in climate," said co-author Pedro DiNezio, an associate professor at University of Colorado Boulder. "Because if there's another big El Niño, it's going to be very hard to attribute it to a warming climate or to El Niño's own internal variations."
3) La Niña amplifies weather extremes in first half of 2022: Aon
Reinsurance News, 25 July 2022
The persistence of La Niña conditions across the central and eastern Pacific Ocean has been one of the most prominent reasons for elevated weather extremes since 2020, reports re/insurance broker Aon.
These conditions have global implications on weather patterns and other atmospheric or oceanic phenomena that can often bring amplified extremes of temperature and rain.
The broker notes that during the first six months of 2022, there were several examples of considerable and record-setting heatwaves and prolific rainfall. Such occurrences drove intense drought and floods in many areas.
Climate change has continued to influence these temperature and precipitation extremes during the past several decades. Data has indicated the growing intensity and frequency of “tail” (or low probability) events that are affecting a greater number of people.
While heatwaves and floods are not new, the behaviour change of these events are growing more evident. In the case of temperature extremes alone, scientists are discovering that climate change is making these events longer, more extreme, and more frequent with an earlier onset.
The toll of heatwaves on human health and the energy market is expected to increase as average global temperatures continue to rise.
According to the National Oceanic and Atmospheric Administration (NOAA), preliminary global ocean and land temperatures during 1H 2022 were 1.53°F (0.85°C) above the 20th century average. This marked the 6th warmest 1H period since records began in 1880.
Full story
4) La Nina: Worsening drought seen as next big threat of economic disruption
Seeking Alpha, 22 August 2022
What do factory shutdowns in China, shipping delays in Europe and reduced agricultural output in the U.S. have to do with each other? They are all being caused by severe droughts impacting the world's largest economies.
Researchers say the dry spells are partly because of seasonal weather patterns like La Niña, but are also related to consequences of land degradation and climate change.
Snapshot: The Chinese province of Sichuan just announced it would extend industrial power cuts and activate its highest emergency response, impacting a number of global manufacturers like Apple, Foxconn, Toyota and Volkswagen. The vital Yangtze, the longest river in Asia, has reached its lowest level on record for August, effecting supply of hydropower and causing widespread shortages. Tesla has even asked the government to help ensure its suppliers have a sufficient amount of electricity, with over a dozen of them currently not able to manufacture at full capacity.
Over in Europe, cargo ships have had to reduce their loads due to critically low levels of the Rhine. The waterway is usually occupied with vessels transporting raw materials to power plants and factories, and Italy has even declared a state of emergency along its important Po River.
Separately, agricultural forecasters in the U.S. now expect farmers to lose more than 40% of the cotton crop, while many acres of farmland are being left unplanted because of water shortages. In fact, the U.S. Bureau of Reclamation has announced that states like Arizona and Nevada will have to cut their water allocations by up to 21% next year because of the increasing megadrought in the Southwest.
Go deeper: The situation could drive up energy prices as hydro and nuclear power are reduced given the lower levels of water (that cannot sufficiently cool reactors). Higher transport costs and supply chain snarls could also raise food prices, adding to inflationary forces and squeezing a global trade system that was already under pressure from the coronavirus pandemic.
Researchers say the dry spells are partly because of seasonal weather patterns like La Niña, but are also related to consequences of land degradation and climate change.
Snapshot: The Chinese province of Sichuan just announced it would extend industrial power cuts and activate its highest emergency response, impacting a number of global manufacturers like Apple, Foxconn, Toyota and Volkswagen. The vital Yangtze, the longest river in Asia, has reached its lowest level on record for August, effecting supply of hydropower and causing widespread shortages. Tesla has even asked the government to help ensure its suppliers have a sufficient amount of electricity, with over a dozen of them currently not able to manufacture at full capacity.
Over in Europe, cargo ships have had to reduce their loads due to critically low levels of the Rhine. The waterway is usually occupied with vessels transporting raw materials to power plants and factories, and Italy has even declared a state of emergency along its important Po River.
Separately, agricultural forecasters in the U.S. now expect farmers to lose more than 40% of the cotton crop, while many acres of farmland are being left unplanted because of water shortages. In fact, the U.S. Bureau of Reclamation has announced that states like Arizona and Nevada will have to cut their water allocations by up to 21% next year because of the increasing megadrought in the Southwest.
Go deeper: The situation could drive up energy prices as hydro and nuclear power are reduced given the lower levels of water (that cannot sufficiently cool reactors). Higher transport costs and supply chain snarls could also raise food prices, adding to inflationary forces and squeezing a global trade system that was already under pressure from the coronavirus pandemic.
5) How salmon numbers rise and fall during El Nino and La Nina
Fox Weather, 13 August 2022
Salmon numbers rise and fall during El Nino and La Nina.
It’s one of the most iconic shots in nature documentaries: salmon, in slow-motion, leaping above rushing river rapids and dodging the open jowls of hungry bears, all for the sake of reaching their nesting grounds.
Their treacherous journey is a tale as old as time. But outside of a bear’s voracious appetite, another factor can impact the salmon’s journey and the survivability of the fish they spawn: the weather.
In the United States, salmon are primarily found in the waters of Alaska and the Pacific Northwest. Given the coastal nature of these regions, the weather they experience is largely dictated by the conditions of the Pacific Ocean.
Oceanic temperature changes, in particular, create certain weather conditions that can have a significant effect on the amount and quality of cold water in salmon habitats. This, in turn, affects the health and numbers of salmon.
The role of El Niño and La Niña
Oceanic temperatures and weather changes are driven by extreme weather cycles known as El Nino and La Nina.
El Nino is a cyclical climate pattern that sees the warming of ocean waters around the tropics. In contrast, La Niña is a cyclical climate pattern that sees a cooling of tropical ocean waters.
These cooling and warming events cause ripple effects throughout the Pacific Ocean and around the world.
"This is a phenomenon that's totally natural — it's been happening for hundreds of thousands of years," said Nate Mantua, a research scientist in NOAA's Southwest Fisheries Science Center.
"It's something that scientists got excited about decades ago because it affects so much of the earth's climate and it also affects the oceans and marine life and fisheries in sometimes unpredictable ways."
One of those ways involves the size of salmon populations in Alaska and the Pacific Northwest.
According to Mantua, in Alaska, El Nino typically brings a milder and wetter winter with more snowmelt and rain-fed runoff. This runoff feeds the waterways with plenty of cold water, creating prime habitat for breeding in freshwater and improved ocean conditions for salmon once they go to sea.
But further south in the Pacific Northwest, Mantua said this same El Nino event brings a warmer and drier winter, along with a warmer ocean.
This means that less snow falls, creating a smaller snowpack in the mountains during winter; and because of the small snowpack during an El Nino winter, when spring arrives, there is less snow for the warmer temperatures to melt. This creates less cold water flowing into the watersheds, which leads to a degradation in the freshwater habitat for salmon.
During a La Nina year, the effects on each location are reversed.
According to Mantua, the colder ocean currents disfavor Alaska salmon by bringing in a drier winter, while benefiting salmon in the Pacific Northwest by bringing in colder storms and heavier snowpacks to the region’s mountains.
"The ocean currents and ocean temperatures tend to change in ways that also make it more productive and more of a cold water subarctic ocean food web, where salmon grow faster and survive at higher rates and come back in bigger numbers," Mantua said.
Full story
Fox Weather, 13 August 2022
Salmon numbers rise and fall during El Nino and La Nina.
It’s one of the most iconic shots in nature documentaries: salmon, in slow-motion, leaping above rushing river rapids and dodging the open jowls of hungry bears, all for the sake of reaching their nesting grounds.
Their treacherous journey is a tale as old as time. But outside of a bear’s voracious appetite, another factor can impact the salmon’s journey and the survivability of the fish they spawn: the weather.
In the United States, salmon are primarily found in the waters of Alaska and the Pacific Northwest. Given the coastal nature of these regions, the weather they experience is largely dictated by the conditions of the Pacific Ocean.
Oceanic temperature changes, in particular, create certain weather conditions that can have a significant effect on the amount and quality of cold water in salmon habitats. This, in turn, affects the health and numbers of salmon.
The role of El Niño and La Niña
Oceanic temperatures and weather changes are driven by extreme weather cycles known as El Nino and La Nina.
El Nino is a cyclical climate pattern that sees the warming of ocean waters around the tropics. In contrast, La Niña is a cyclical climate pattern that sees a cooling of tropical ocean waters.
These cooling and warming events cause ripple effects throughout the Pacific Ocean and around the world.
"This is a phenomenon that's totally natural — it's been happening for hundreds of thousands of years," said Nate Mantua, a research scientist in NOAA's Southwest Fisheries Science Center.
"It's something that scientists got excited about decades ago because it affects so much of the earth's climate and it also affects the oceans and marine life and fisheries in sometimes unpredictable ways."
One of those ways involves the size of salmon populations in Alaska and the Pacific Northwest.
According to Mantua, in Alaska, El Nino typically brings a milder and wetter winter with more snowmelt and rain-fed runoff. This runoff feeds the waterways with plenty of cold water, creating prime habitat for breeding in freshwater and improved ocean conditions for salmon once they go to sea.
But further south in the Pacific Northwest, Mantua said this same El Nino event brings a warmer and drier winter, along with a warmer ocean.
This means that less snow falls, creating a smaller snowpack in the mountains during winter; and because of the small snowpack during an El Nino winter, when spring arrives, there is less snow for the warmer temperatures to melt. This creates less cold water flowing into the watersheds, which leads to a degradation in the freshwater habitat for salmon.
During a La Nina year, the effects on each location are reversed.
According to Mantua, the colder ocean currents disfavor Alaska salmon by bringing in a drier winter, while benefiting salmon in the Pacific Northwest by bringing in colder storms and heavier snowpacks to the region’s mountains.
"The ocean currents and ocean temperatures tend to change in ways that also make it more productive and more of a cold water subarctic ocean food web, where salmon grow faster and survive at higher rates and come back in bigger numbers," Mantua said.
Full story
6) Spring Rainfall Shortages in Europe: Is La Niña to Blame?
Met Swift, July 2022
Europe is currently heading into what are typically the peak weeks of the summer heat on the back of widespread rainfall deficits. As shown below, only the south-western quarter has seen above normal amounts, while most of the south-eastern quarter has been exceptionally dry.
Met Swift, July 2022
Europe is currently heading into what are typically the peak weeks of the summer heat on the back of widespread rainfall deficits. As shown below, only the south-western quarter has seen above normal amounts, while most of the south-eastern quarter has been exceptionally dry.
Rainfall anomalies for Mar-Jun 2022 based on NCEP/NCAR Reanalysis II. The red lines show the division into quadrants (NW, NE, SE, SW where upward is north, rightward is east).
What’s more, these shortfalls are part of a longer-term drought, which is well captured by the European Drought Observatory’s Standardised Precipitation Index (SPI). As you can see on the map to the right, the 6-monthly deficit includes areas that have been wetter in the past four months.
That tells us that the winter shortfall in those areas was so large that a relatively rainy spring hasn’t been able to restore the balance. In fact, a true balance requires a positive SPI across the past 6 months, because water loss to evaporation and plant uptake is much higher in Mar-Jun compared to Jan-Feb.
Why So Dry?
For this blog, I have looked at one plausible culprit for the rainfall shortages: An ongoing La Niña event, which was strong during March-May, then become weak during June.
A La Niña is characterised by persistent anomalously cool ocean temperatures within the central and eastern tropical Pacific. These cause changes in an atmospheric circulation system known as the Walker Cell, which then have knock-on effects on weather patterns as far afield as Europe.
While the effects here are relatively small compared to North America for example, they can still be significant, especially during strong La Niña events such as we saw last spring.
Now, this is far from the only important influence on our weather patterns -a complete causal study requires consideration of many contributing factors - but to avoid a bloated blog, I will stick with just the one here.
La Niña & European Rainfall: A Dipolar Relationship
The plot below illustrates, for each quadrant of Europe, how the distribution of Mar-Jun precipitation (includes rain, hail, snow etc.) varies when there are La Niña events (‘Nina’), El Niño events (‘Nino’ – opposite of La Niña), or neither (‘Nada’), and how that compares to simply grouping all historical years together (‘All’).
Precipitation data was taken from weather stations meeting World Meteorological Organisation standards and rigorously quality assessed to ensure reliable results. The Niño Southern Oscillation was classified using the Oceanic Niño Index (ONI).
The results can be summarised as follows:
- Northwest Europe tends to be driest during a La Niña and wettest during al El Niño, but this is not dependable. On a few occasions it’s been unusually wet during a La Niña or dry during an El Niño.
- There’s a slight tendency for a wetter than usual month in Northeast Europe during an El Niño.
- A drier than usual month is slightly favoured in Southeast Europe during a La Niña.
- Southwest Europe is typically wettest during a La Niña, while a drier than usual month is slightly favoured during an El Niño.
If we put aside the slight tendencies, which aren’t enough to reasonably base expectations on, then we have a precipitation connection to La Niña with two ‘poles’ (dipolar): A negative one over Northwest Europe (i.e. drier during La Niña) and a positive one over Southwest Europe.
That’s exactly what we’ve seen during Mar-Jun 2022, which suggests that La Niña has been a significant player for Western Europe.
What About the Parched East?
In Eastern Europe there have been even greater rainfall shortages, which the findings above suggest cannot be attributed to La Niña. Instead, this anomaly is probably connected to other key drivers of weather patterns (known as teleconnections), such as temperature anomalies in the North Atlantic or Indian oceans.
Advanced Statistics
A great deal of research has been carried out on those connections, not just in Europe but all across the world. This collective knowledge underpins MetSwift’s Advanced Statistical model, which considers a wide variety of teleconnections to ascertain the most likely conditions weeks, months, even years ahead.
As shown below, it correctly predicted the general distribution of rainfall anomalies in June 2022.
For July, it predicted an abnormally dry month for much of northern Europe and parts of the southeast, and wet month for much of the Southwest along with central-eastern countries. During at least the next 10 days, something close to that is expected, the main exception being unusually wet weather in and around Greece.
So it might well be on for a good result for this month too. A timely demonstration that statistically driven projections can provide useful guidance out to more than a few weeks ahead.
What’s more, these shortfalls are part of a longer-term drought, which is well captured by the European Drought Observatory’s Standardised Precipitation Index (SPI). As you can see on the map to the right, the 6-monthly deficit includes areas that have been wetter in the past four months.
That tells us that the winter shortfall in those areas was so large that a relatively rainy spring hasn’t been able to restore the balance. In fact, a true balance requires a positive SPI across the past 6 months, because water loss to evaporation and plant uptake is much higher in Mar-Jun compared to Jan-Feb.
Why So Dry?
For this blog, I have looked at one plausible culprit for the rainfall shortages: An ongoing La Niña event, which was strong during March-May, then become weak during June.
A La Niña is characterised by persistent anomalously cool ocean temperatures within the central and eastern tropical Pacific. These cause changes in an atmospheric circulation system known as the Walker Cell, which then have knock-on effects on weather patterns as far afield as Europe.
While the effects here are relatively small compared to North America for example, they can still be significant, especially during strong La Niña events such as we saw last spring.
Now, this is far from the only important influence on our weather patterns -a complete causal study requires consideration of many contributing factors - but to avoid a bloated blog, I will stick with just the one here.
La Niña & European Rainfall: A Dipolar Relationship
The plot below illustrates, for each quadrant of Europe, how the distribution of Mar-Jun precipitation (includes rain, hail, snow etc.) varies when there are La Niña events (‘Nina’), El Niño events (‘Nino’ – opposite of La Niña), or neither (‘Nada’), and how that compares to simply grouping all historical years together (‘All’).
Precipitation data was taken from weather stations meeting World Meteorological Organisation standards and rigorously quality assessed to ensure reliable results. The Niño Southern Oscillation was classified using the Oceanic Niño Index (ONI).
The results can be summarised as follows:
- Northwest Europe tends to be driest during a La Niña and wettest during al El Niño, but this is not dependable. On a few occasions it’s been unusually wet during a La Niña or dry during an El Niño.
- There’s a slight tendency for a wetter than usual month in Northeast Europe during an El Niño.
- A drier than usual month is slightly favoured in Southeast Europe during a La Niña.
- Southwest Europe is typically wettest during a La Niña, while a drier than usual month is slightly favoured during an El Niño.
If we put aside the slight tendencies, which aren’t enough to reasonably base expectations on, then we have a precipitation connection to La Niña with two ‘poles’ (dipolar): A negative one over Northwest Europe (i.e. drier during La Niña) and a positive one over Southwest Europe.
That’s exactly what we’ve seen during Mar-Jun 2022, which suggests that La Niña has been a significant player for Western Europe.
What About the Parched East?
In Eastern Europe there have been even greater rainfall shortages, which the findings above suggest cannot be attributed to La Niña. Instead, this anomaly is probably connected to other key drivers of weather patterns (known as teleconnections), such as temperature anomalies in the North Atlantic or Indian oceans.
Advanced Statistics
A great deal of research has been carried out on those connections, not just in Europe but all across the world. This collective knowledge underpins MetSwift’s Advanced Statistical model, which considers a wide variety of teleconnections to ascertain the most likely conditions weeks, months, even years ahead.
As shown below, it correctly predicted the general distribution of rainfall anomalies in June 2022.
For July, it predicted an abnormally dry month for much of northern Europe and parts of the southeast, and wet month for much of the Southwest along with central-eastern countries. During at least the next 10 days, something close to that is expected, the main exception being unusually wet weather in and around Greece.
So it might well be on for a good result for this month too. A timely demonstration that statistically driven projections can provide useful guidance out to more than a few weeks ahead.
7) Empirical observations show no sign of ‘climate crisis’
Global Warming Policy Foundation, 14 April 2022
A systematic review of climate trends and observational data by an eminent climate scientist has found no evidence to support the claim of a climate crisis.
In his annual State of the Climate report, Ole Humlum, emeritus professor at the University of Oslo, examined detailed patterns in temperature changes in the atmosphere and oceans together with trends in climate impacts. Many of these show no significant trends and suggest that poorly understood natural cycles are involved.
And while the report finds gentle warming, there is no evidence of dramatic changes, with snow cover stable, sea ice levels recovering, and no change in storm activity.
Professor Humlum said:
“A year ago, I warned that there was great risk in using computer modelling and immature science to make extraordinary claims. The empirical observations I have reviewed show very gentle warming and no evidence of a climate crisis.”
GWPF director, Dr Benny Peiser said:
“It’s extraordinary that anyone should think there is a climate crisis. Year after year our annual assessment of climate trends document just how little has been changing in the last 30 years.
The habitual climate alarmism is mainly driven by scientists’ computer modelling rather than observational evidence.”
Ole Humlum: State of the Climate 2021 (pdf)
In his annual State of the Climate report, Ole Humlum, emeritus professor at the University of Oslo, examined detailed patterns in temperature changes in the atmosphere and oceans together with trends in climate impacts. Many of these show no significant trends and suggest that poorly understood natural cycles are involved.
And while the report finds gentle warming, there is no evidence of dramatic changes, with snow cover stable, sea ice levels recovering, and no change in storm activity.
Professor Humlum said:
“A year ago, I warned that there was great risk in using computer modelling and immature science to make extraordinary claims. The empirical observations I have reviewed show very gentle warming and no evidence of a climate crisis.”
GWPF director, Dr Benny Peiser said:
“It’s extraordinary that anyone should think there is a climate crisis. Year after year our annual assessment of climate trends document just how little has been changing in the last 30 years.
The habitual climate alarmism is mainly driven by scientists’ computer modelling rather than observational evidence.”
Ole Humlum: State of the Climate 2021 (pdf)
8) And finally: The changing nature of Earth's reflected sunlight
Proceedings of the Royal Society, 27 July 2022
Graeme L. Stephens, Maria Z. Hakuba, Seiji Kato, Andrew Gettleman, Jean-Louis Dufresne, Timothy Andrews, Jason N. S. Cole, Ulrika Willen and Thorsten Mauritsen
Abstract
The increased rate of sea-level rise suggests that Earth's energy imbalance is also increasing over time. This study assesses whether 20 years of direct observations of this energy imbalance from Earth-orbiting satellites support the existence of a real trend in this imbalance and the components of it and finds. Changes to the imbalance observed are found to be consistent across multiple sources of observations. The majority of recent studies now clearly point to this energy imbalance being positive, while forced by increasing greenhouse gas concentrations in the atmosphere, being amplified significantly by decreases to the amount of sunlight reflected by Earth to space. Here, we show that the global changes observed appear largely from reductions in the amount of sunlight scattered by Earth's atmosphere. These reductions, in turn, are found to be almost equally split between reduced reflection from the cloudy and clear regions of the atmosphere, with the latter being suggestive of reduced scattering by aerosol particles over the observational period. Climate models, however, show an almost exclusive response from clouds, and a slightly exaggerated darkening of the surface. Thus, models that match the global shortwave change do so for the wrong reasons.
Full paper ££
Proceedings of the Royal Society, 27 July 2022
Graeme L. Stephens, Maria Z. Hakuba, Seiji Kato, Andrew Gettleman, Jean-Louis Dufresne, Timothy Andrews, Jason N. S. Cole, Ulrika Willen and Thorsten Mauritsen
Abstract
The increased rate of sea-level rise suggests that Earth's energy imbalance is also increasing over time. This study assesses whether 20 years of direct observations of this energy imbalance from Earth-orbiting satellites support the existence of a real trend in this imbalance and the components of it and finds. Changes to the imbalance observed are found to be consistent across multiple sources of observations. The majority of recent studies now clearly point to this energy imbalance being positive, while forced by increasing greenhouse gas concentrations in the atmosphere, being amplified significantly by decreases to the amount of sunlight reflected by Earth to space. Here, we show that the global changes observed appear largely from reductions in the amount of sunlight scattered by Earth's atmosphere. These reductions, in turn, are found to be almost equally split between reduced reflection from the cloudy and clear regions of the atmosphere, with the latter being suggestive of reduced scattering by aerosol particles over the observational period. Climate models, however, show an almost exclusive response from clouds, and a slightly exaggerated darkening of the surface. Thus, models that match the global shortwave change do so for the wrong reasons.
Full paper ££
The London-based Net Zero Watch is a campaign group set up to highlight and discuss the serious implications of expensive and poorly considered climate change policies. The Net Zero Watch newsletter is prepared by Director Dr Benny Peiser - for more information, please visit the website at www.netzerowatch.com.
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