Arquivo da tag: El Niño

In Brazil’s Amazon, rivers rise to record levels (Associated Press)


June 1st, 2021

MANAUS, Brazil (AP) — Rivers around the biggest city in Brazil’s Amazon rainforest have swelled to levels unseen in over a century of record-keeping, according to data published Tuesday by Manaus’ port authorities, straining a society that has grown weary of increasingly frequent flooding.

The Rio Negro was at its highest level since records began in 1902, with a depth of 29.98 meters (98 feet) at the port’s measuring station. The nearby Solimoes and Amazon rivers were also nearing all-time highs, flooding streets and houses in dozens of municipalities and affecting some 450,000 people in the region.

Higher-than-usual precipitation is associated with the La Nina phenomenon, when currents in the central and eastern Pacific Ocean affect global climate patterns. Environmental experts and organizations including the U.S. Environmental Protection Agency and the National Oceanic and Atmospheric Administration say there is strong evidence that human activity and global warming are altering the frequency and intensity of extreme weather events, including La Nina.

Seven of the 10 biggest floods in the Amazon basin have occurred in the past 13 years, data from Brazil’s state-owned Geological Survey shows.

“If we continue to destroy the Amazon the way we do, the climatic anomalies will become more and more accentuated,” said Virgílio Viana, director of the Sustainable Amazon Foundation, a nonprofit. ” Greater floods on the one hand, greater droughts on the other.”

Large swaths of Brazil are currently drying up in a severe drought, with a possible shortfall in power generation from the nation’s hydroelectric plants and increased electricity prices, government authorities have warned.

But in Manaus, 66-year-old Julia Simas has water ankle-deep in her home. Simas has lived in the working-class neighborhood of Sao Jorge since 1974 and is used to seeing the river rise and fall with the seasons. Simas likes her neighborhood because it is safe and clean. But the quickening pace of the floods in the last decade has her worried.

“From 1974 until recently, many years passed and we wouldn’t see any water. It was a normal place,” she said.

Aerial view of streets flooded by the Negro River, in downtown Manaus, Amazonas state, Brazil, Tuesday, June 1, 2021. Rivers around Brazil's biggest city in the Amazon rain forest have swelled to levels unseen in over a century of record-keeping, according to data published Tuesday by Manaus' port authorities. (AP Photos/Nelson Antoine)
Aerial view of streets flooded by the Negro River in downtown Manaus. (AP Photos/Nelson Antoine)
A man pushes a shopping cart loaded with bananas on a street flooded by the Negro River, in downtown Manaus, Amazonas state, Brazil, Tuesday, June 1, 2021. Rivers around Brazil's biggest city in the Amazon rain forest have swelled to levels unseen in over a century of record-keeping, according to data published Tuesday by Manaus' port authorities. (AP Photo/Edmar Barros)
A man pushes a shopping cart loaded with bananas on a street flooded by the Negro River, in downtown Manaus. (AP Photo/Edmar Barros)

When the river does overflow its banks and flood her street, she and other residents use boards and beams to build rudimentary scaffolding within their homes to raise their floors above the water.

“I think human beings have contributed a lot (to this situation,” she said. “Nature doesn’t forgive. She comes and doesn’t want to know whether you’re ready to face her or not.”

Flooding also has a significant impact on local industries such as farming and cattle ranching. Many family-run operations have seen their production vanish under water. Others have been unable to reach their shops, offices and market stalls or clients.

“With these floods, we’re out of work,” said Elias Gomes, a 38-year-old electrician in Cacau Pirera, on the other side of the Rio Negro, though noted he’s been able to earn a bit by transporting neighbors in his small wooden boat.

Gomes is now looking to move to a more densely populated area where floods won’t threaten his livelihood.

A man rides his motorcycle through a street flooded by the Negro River, in downtown Manaus, Amazonas state, Brazil, Tuesday, June 1, 2021. Rivers around Brazil's biggest city in the Amazon rain forest have swelled to levels unseen in over a century of record-keeping, according to data published Tuesday by Manaus' port authorities. (AP Photo/Edmar Barros)
A man rides his motorcycle through a street in downtown Manaus. (AP Photo/Edmar Barros)

Limited access to banking in remote parts of the Amazon can make things worse for residents, who are often unable to get loans or financial compensation for lost production, said Viana, of the Sustainable Amazon Foundation. “This is a clear case of climate injustice: Those who least contributed to global warming and climate change are the most affected.”

Meteorologists say Amazon water levels could continue to rise slightly until late June or July, when floods usually peak.

People walk on a wooden footbridge set up over a street flooded by the Negro River, in downtown Manaus, Amazonas state, Brazil, Tuesday, June 1, 2021. Rivers around Brazil's biggest city in the Amazon rain forest have swelled to levels unseen in over a century of record-keeping, according to data published Tuesday by Manaus' port authorities. (AP Photo/Edmar Barros)
People walk on a wooden footbridge set up over a street in downtown Manaus. (AP Photo/Edmar Barros)


Diana Jeantet reported from Rio de Janeiro.

New study ties solar variability to the onset of decadal La Nina events (Science Daily)

[Linking solar activity to the onset of droughts in places like Northeast Brazil has historically been treated as something that did not deserve attention by mainstream meteorology. The El Niño Southern Oscillation – of which La Niña is part – was always presented as the main causal factor for droughts. This new study connects solar activity with the La Niña. The interesting thing here is that many local farmers seen as knowledgeable about rains and drought in NE Brazil mention a 10 years period for the repetition of climate events. -RT]

Date: April 5, 2021

Source: National Center for Atmospheric Research/University Corporation for Atmospheric Research

Summary: A new study shows a correlation between the end of solar cycles and a switch from El Nino to La Nina conditions in the Pacific Ocean, suggesting that solar variability can drive seasonal weather variability on Earth.

A new study shows a correlation between the end of solar cycles and a switch from El Nino to La Nina conditions in the Pacific Ocean, suggesting that solar variability can drive seasonal weather variability on Earth.

If the connection outlined in the journal Earth and Space Science holds up, it could significantly improve the predictability of the largest El Nino and La Nina events, which have a number of seasonal climate effects over land. For example, the southern United States tends to be warmer and drier during a La Nina, while the northern U.S. tends to be colder and wetter.

“Energy from the Sun is the major driver of our entire Earth system and makes life on Earth possible,” said Scott McIntosh, a scientist at the National Center for Atmospheric Research (NCAR) and co-author of the paper. “Even so, the scientific community has been unclear on the role that solar variability plays in influencing weather and climate events here on Earth. This study shows there’s reason to believe it absolutely does and why the connection may have been missed in the past.”

The study was led by Robert Leamon at the University of Maryland-Baltimore County, and it is also co-authored by Daniel Marsh at NCAR. The research was funded by the National Science Foundation, which is NCAR’s sponsor, and the NASA Living With a Star program.

Applying a new solar clock

The appearance (and disappearance) of spots on the Sun — the outwardly visible signs of solar variability — have been observed by humans for hundreds of years. The waxing and waning of the number of sunspots takes place over approximately 11-year cycles, but these cycles do not have distinct beginnings and endings. This fuzziness in the length of any particular cycle has made it challenging for scientists to match up the 11-year cycle with changes happening on Earth.

In the new study, the researchers rely on a more precise 22-year “clock” for solar activity derived from the Sun’s magnetic polarity cycle, which they outlined as a more regular alternative to the 11-year solar cycle in several companion studies published recently in peer-reviewed journals.

The 22-year cycle begins when oppositely charged magnetic bands that wrap the Sun appear near the star’s polar latitudes, according to their recent studies. Over the cycle, these bands migrate toward the equator — causing sunspots to appear as they travel across the mid-latitudes. The cycle ends when the bands meet in the middle, mutually annihilating one another in what the research team calls a terminator event. These terminators provide precise guideposts for the end of one cycle and the beginning of the next.

The researchers imposed these terminator events over sea surface temperatures in the tropical Pacific stretching back to 1960. They found that the five terminator events that occurred between that time and 2010-11 all coincided with a flip from an El Nino (when sea surface temperatures are warmer than average) to a La Nina (when the sea surface temperatures are cooler than average). The end of the most recent solar cycle — which is unfolding now — is also coinciding with the beginning of a La Nina event.

“We are not the first scientists to study how solar variability may drive changes to the Earth system,” Leamon said. “But we are the first to apply the 22-year solar clock. The result — five consecutive terminators lining up with a switch in the El Nino oscillation — is not likely to be a coincidence.”

In fact, the researchers did a number of statistical analyses to determine the likelihood that the correlation was just a fluke. They found there was only a 1 in 5,000 chance or less (depending on the statistical test) that all five terminator events included in the study would randomly coincide with the flip in ocean temperatures. Now that a sixth terminator event — and the corresponding start of a new solar cycle in 2020 — has also coincided with an La Nina event, the chance of a random occurrence is even more remote, the authors said.

The paper does not delve into what physical connection between the Sun and Earth could be responsible for the correlation, but the authors note that there are several possibilities that warrant further study, including the influence of the Sun’s magnetic field on the amount of cosmic rays that escape into the solar system and ultimately bombard Earth. However, a robust physical link between cosmic rays variations and climate has yet to be determined.

“If further research can establish that there is a physical connection and that changes on the Sun are truly causing variability in the oceans, then we may be able to improve our ability to predict El Nino and La Nina events,” McIntosh said.

Story Source:

Materials provided by National Center for Atmospheric Research/University Corporation for Atmospheric Research. Original written by Laura Snider. Note: Content may be edited for style and length.

Journal Reference:

  1. Robert J. Leamon, Scott W. McIntosh, Daniel R. Marsh. Termination of Solar Cycles and Correlated Tropospheric Variability. Earth and Space Science, 2021; 8 (4) DOI: 10.1029/2020EA001223

Com 516 milímetros de chuva em 5 anos, Ceará tem pior seca desde 1910 (G1)

09/09/2016 09h20 – Atualizado em 09/09/2016 11h57

Previsão para 2017 ainda é indefinida devido ao “Oceano Pacífico Neutro”.
Águas do Açude Orós estão sendo transferidas para o Castanhão.

Do G1 CE com informações da TV Verdes Mares


Levantamento feito pela Fundação Cearense de Meteorologia e Recursos Hídricos (Funceme) nesta quinta-feira (8) mostra que nos últimos cinco anos, de 2012 a 2016, foram apenas 516 milímetros de chuva, em média, no Ceará. O índice é o menor desde 1910.

De acordo com o meteorologista Davi Ferran, vai ser preciso conviver com a incerteza pelos próximos meses, já que ainda é cedo pra afirmar se 2017 vai trazer chuva ou não.

Ano Chuva (mm)
2012 388
2013 552
2014 565
2015 524
2016 550
Média 516
Fonte: Funceme

“No período chuvoso do ano que vem, ou seja, março, abril e maio, que é o período chuvoso principal, a maior probabilidade é que o Oceano Pacífico não tenha El Niño nem La Niña. Vamos ter o Oceano Pacífico neutro. Em anos de Oceano Pacífico neutro, a probabilidade de chuvas no Ceará depende mais fortemente do Atlântico. Então a previsão vai ser divulgada somente em janeiro”, explica.

Enquanto isso, segundo a Companhia de Gestão de Recursos Hídricos (Cogerh), os reservatórios secam cada vez mais. No momento, o nível médio dos 153 açudes monitorados pela Cogerh é de apenas 9,4% do volume total.O “Gigante” Castanhão, responsável por abastecer toda a Região Metropolitana de Fortaleza, está praticamente sem água. Há apenas sete anos, ele chegou a inundar a cidade de Jaguaribara com a enorme vazão das comportas.

Hoje, a Cogerh diz que o maior açude do Ceará está com apenas 6% da capacidade. Bem perto dele, o Açude Orós, também na Região Jaguaribana, sangrou em 2004 e 2008. Na época, virou até atração turística no Centro Sul do Estado.

Agora em 2016, o Orós aparece nesse cenário de seca em forma de ajuda. Desde julho, as águas do açude estão sendo transferidas para o Castanhão. Segundo a Cogerh, essa água deve chegar às residências da Região Metropolitana de Fortaleza em setembro, e garantir o abastecimento pelo menos durante esse período  de crise hídrica.

“Nossa programação é até o final de janeiro. Ou seja, até janeiro vamos estar operando de forma integrada os dois reservatórios. O caso da Região Metropolitana, ela está totalmente integrada à Região do Jaguaribe por dois grandes canais: o do Trabalhador e Eixão das Águas. Então é o caso de uma bacia hoje tem uma maior dependência de outra região, de outra bacia hidrográfica, mas elas estão integradas. Esse é o caso que eu diria mais emblemática no Estado”, explica o presidente da Cogerh, João Lúcio Farias.

saiba mais

2016 é um dos anos mais secos do Ceará e o pior começa agora (O Povo)

CHUVA 14/06/2016

Os meteorologistas afirmam que não há previsão de precipitações para os últimos seis meses do ano 

Igor Cavalcante

Os próximos meses serão de mais escassez hídrica para o Ceará. Quando o assunto é chuva, o segundo semestre é o mais crítico para o Estado. As precipitações que ainda acontecem são causadas por instabilidades meteorológicas e não devem impactar no cenário de estiagem.

Em coletiva de imprensa ontem, a Fundação Cearense de Meteorologia e Recursos Hídricos (Funceme) informou que, de 2012 para cá, a estiagem deste ano é a segunda pior. Em algumas regiões não choveu nem metade do esperado. O cenário faz de 2016 um dos dez anos mais secos da história.

Contudo, monitoramento do Oceano Pacífico indica que águas estão resfriando. É um sinal de que precipitações podem aumentar no próximo ano. O aquecimento oceânico, fenômeno conhecido como El Niño, impacta na formação da Zona de Convergência Intertropical, principal responsável pelas chuvas na costa cearense. Quando parte do Pacífico está aquecida, as nuvens tendem a se formar e precipitar no mar.

De acordo com Eduardo Sávio Martins, presidente da Funceme, ainda é cedo para garantir boa quadra chuvosa para 2017. “É um aspecto positivo, mas temos de aguardar como vai ser o padrão desse resfriamento”, pondera.

O meteorologista Raul Fritz também é cauteloso quanto às previsões. Segundo ele, mesmo num cenário em que não haja El Niño, bom inverno é incerto.

A preocupação dos meteorologistas é com os meses até a próxima quadra chuvosa.. “A gente tem certeza da chuva no primeiro semestre e certeza de que não chove no segundo semestre”, cita o presidente da Funceme. Historicamente, mais de 90% do volume anual de chuva no Estado acontece no primeiro semestre.

Abaixo do esperado

Também foram as temperaturas elevadas das águas do Pacífico que contribuíram para as poucas precipitações no Estado. Conforme O POVO havia adiantado na edição do último dia 1°, a quadra chuvosa deste ano terminou como a segunda pior desde 2012, quando começou a sequência de cinco anos de estiagem.

Entre fevereiro e maio deste ano, as chuvas ficaram 45,2% abaixo do esperado. Fevereiro foi o período mais crítico, quando o volume no Estado ficou 55,3% abaixo da expectativa. Os meses de março e abril — historicamente de mais chuva — também tiveram precipitações inferiores à média.

As regiões Jaguaribana e do Sertão dos Inhamuns foram as de maior escassez. Nos municípios, as chuvas sequer atingiram metade do esperado, ficando 54,5% e 52,3% abaixo da média, respectivamente.

Segundo o presidente da Funceme, desde o início do ano, o Estado trabalha com o cenário da seca e promove ações para garantir licitações de poços e adutoras emergenciais na tentativa de suprir a necessidade hídrica do Interior.

Saiba mais 

Uma das alternativas para amenizar a escassez hídrica, o Projeto de Integração do rio São Francisco será concluído em dezembro, com previsão de abastecer os reservatórios em janeiro do próximo ano.

No último fim de semana, comitiva do Ministério da Integração vistoriou os eixos Norte e Leste do Projeto. Além do Ceará, Pernambuco e Paraíba devem ser beneficiados a partir de 2017.

Amid Climate-Fueled Food Crisis, Filipino Forces Open Fire on Starving Farmers (Common Dreams)

Published on Monday, April 04, 2016 by Common Dreams

Police and army forces in the Philippines unleashed bullets on a starving crowd, killing 10, for demonstrating for drought relief

by Nika Knight, staff writer

A wounded farmer is assisted by other demonstrators after Friday’s mass shooting by security forces in the Philippines. (Photo: Kilab Multimedia)

Police and army forces shot at about 6,000 starving farmers and Lumad Indigenous people demonstrating for drought relief in the Philippines on Friday, ultimately killing 10. Observers characterized the security forces’ action as “a strafing.”

“The government’s response to hunger is violence,” said Zeph Repollo, Southeast Asia campaign coordinator for, in an email to Common Dreams.

Three protesters were immediately killed, and by Monday the death toll had risen to 10 as more demonstrators succumbed to injuries.

“We don’t have anything to eat or harvest. Our plants wilted. Even our water has dried up.”
—Noralyn Laus, demonstrating farmer

The farmers and Indigenous people had been blockading a highway in the Cotabato province for four days in a desperate plea for government aid, after this winter’s record-breaking temperatures produced a three-months-long drought that has destroyed their crops and now threatens their lives.

The demonstrators were asking the government to provide 15,000 sacks of rice to ease the hunger crisis. Provincial governor Emmylou Mendoza has refused to engage the protesters.

“The government’s policy of  systematic land grabbing combined with the intensified El Nino pushed our farmers and indigenous peoples to heighten their struggles with sweat and blood in defense of their right to land and life,” wrote Repollo in a statement.

After an especially intense El Nino created a months-long drought and the local government ignored their plight, farmers and Indigenous people blockaded a highway to publicize their need for relief. (Photo: Pinoy Weekly)

After an especially intense El Nino created a months-long drought and the local government ignored their plight, farmers and Indigenous people blockaded a highway to publicize their need for relief. (Photo: Pinoy Weekly)

On Monday, local farmer Noralyn Laus gave Democracy Now! a firsthand account of the disaster:

“Why we came down here is not to make trouble. We just want to demand for rice, because of the situation of El Niño is leaving our tribes hungry. What happened yesterday, we didn’t start it. They started it by beating us. We wouldn’t be angry if we weren’t beaten up or attacked. We’re having a crisis. We don’t have anything to eat or harvest. Our plants wilted. Even our water has dried up.”

“Our farmers—the country’s food producers—are battered the hardest and are left in poverty and hunger,” Rapollo said. “Civil disobedience will continue to escalate until the government stops playing deaf and blind to the genuine cry of the people.”

Seventy-eight people were still under arrest on Monday, Rapollo said, and a local Methodist Church is sheltering many protesters who escaped the bullets. Rapollo also reported that no members of the armed forces have been relieved of duty or investigated for Friday’s shooting.

The state-sponsored violence in the Philippines portends what turmoil may come as the planet continues to warm, creating more disastrous, extreme weather events worldwide, environmental activists note.

“The conditions that prompted the 3-day blockade gives us a glimpse of what’s ahead if decisive and just actions in addressing climate change remain in the periphery,” said Repollo.

“This is not a distant reality to anywhere in the world,” Repollo wrote to Common Dreams, “unless we change the system that feeds [on] hunger, injustices, and climate catastrophe.”

Drought and rising temperatures ‘leaves 36m people across Africa facing hunger’ (The Guardian)

Unusually strong El Niño, coupled with record-high temperatures, has had a catastrophic effect on crops and rainfall across southern and eastern Africa

A maize plant among other dried maize in a field

A maize plant among other dried maize in a field in Hoopstad in the Free State province, South Africa. The country suffered its driest year on record in 2015. Photograph: Siphiwe Sibeko/Reuters 

The immediate cause of the drought which has crippled countries from Ethiopia to Zimbabwe is one of the strongest El Niño events ever recorded. It has turned normal weather patterns upside down around the globe, climate scientists say. 

But with the world still reeling from record-high temperatures in February, there are fears that the long-term impacts of climate change are also undermining the region’s ability to endure extremes in weather, leaving huge numbers of people vulnerable to hunger and disease.

The worst hit country in the current crisis is Ethiopia, where rains vital to four-fifths of the country’s crops have failed. Unicef has said it is making plans to treat more than 2 million children for malnutrition, and says more than 10 million people will need food aid.

“Ethiopia has been hit by a double blow, both from a change to the rainy seasons that have been linked to long-term climate change and now from El Niño, which has potentially led the country to one of the worst droughts in decades,” said Gillian Mellsop, Unicef representative to Ethiopia.

The crisis has been damaging even to Ethiopians not at immediate risk of going hungry. It has truncated the education of 3.9 million children and teenagers, who “are unable to access quality education opportunities because of the drought”, she said.

An boy walks through failed crops and farmland in Ethiopia.

An boy walks through failed crops and farmland in Afar, Ethiopia. Four-fifths of crops in the country have failed. Photograph: Mulugeta Ayene/AP

Neighbouring countries grappling with hunger after crops failed include Somalia, Sudan and Kenya, and altogether the failed rains have left more than 20 million people “food insecure” in the region.

The drought caught many officials by surprise, because although El Niño was forecast, the weather event normally brings more rain to the region, not less.

“The typical pattern that you would expect with El Niño is very dry weather in southern Africa, but slightly wetter than normal in eastern Africa,” said Dr Linda Hirons, a research scientist at the National Centre for Atmospheric Science.

“So the fact that we have had parts of eastern Africa experiencing drought is unusual … but every single El Niño event manifests itself differently.”

In southern Africa, the drought caused by El Niño was expected, but it has been even more severe than feared, with rains failing two years in a row.

Overall nearly 16 million people in southern Africa are already going hungry, and that number could rise fast. “More than 40 million rural and 9 million poor urban people are at risk due to the impacts of El Niño’s related drought and erratic rainfall,” the World Food Programme has warned.

Zimbabwe, once the region’s bread basket, is one of the worst hit countries. In February, the country’s president Robert Mugabe declared a state of disaster due to the drought, and in less than a month official estimates of people needing food aid has risen from 3 million to 4 million.

Neighbouring countries are also scrambling to find food aid, including South Africa, whose ports are the main entry point for relief across the region.

“We are seeing this as a regional crisis, a cross-country humanitarian crisis,” said Victor Chinyama. “In each country maybe the numbers [of hungry people] are nowhere near as much as Ethiopia, but if you put these numbers together as a whole region, you get a sense of how large a crisis this is.”

More than a third of households are now going hungry, he said. Families that used to eat two meals a day are cutting back to one, and those who could once provide a single meal for their dependents are now entirely reliant on food aid, he said.

Beyond the immediate scramble to get food to those who need it, aid workers in the region say the drought has served as reminder that communities vulnerable to changing weather patterns need longer-term help adapting.

“It’s becoming common knowledge now that we will experience droughts much more,” said Beatrice Mwangi, resilience and livelihoods director, southern Africa region, World Vision, who said she is focused on medium- and long-term responses.

“In the past it was one big drought every 10 years, then it came to one drought every five years, and now the trends are showing that it will be one every three to five years. So we are in a crisis alright, that is true.

“But it’s going to be the new norm. So our responses need to appreciate that … there is climate change, and it’s going to affect the people that we work with, the communities we serve.”

This article was amended on 17 March 2016 to remove a picture because it was an inaccurate illustration of the theme of the article and contained ambiguities in the caption.

El Niño is causing global food crisis, UN warns (The Guardian)

Severe droughts and floods have ruined harvests, and left nearly 100 million people in southern Africa, Asia and Latin America facing food and water shortages

A farmer surveys her maize fields in Dowa near the Malawi capital of Lilongwe, 3 February 2016.

A farmer surveys her maize fields in Dowa, near the Malawi capital of Lilongwe, earlier this month. The country is experiencing its first maize shortage in a decade, causing prices to soar. Photograph: Mike Hutchings/Reuters

Wednesday 17 February 2016 00.01 GMT / Last modified on Wednesday 17 February 2016 14.48 GMT

Severe droughts and floods triggered by one of the strongest El Niño weather events ever recorded have left nearly 100 million people in southern Africa, Asia and Latin America facing food and water shortages and vulnerable to diseases including Zika, UN bodies, international aid agencies and governments have said.

New figures from the UN’s World Food Programme say 40 million people in rural areas and 9 million in urban centres who live in the drought-affected parts of Zimbabwe, Mozambique, South Africa, Zambia, Malawi and Swaziland will need food assistance in the next year.

In addition, 10 million people are said by the UN’s Office for the Coordination of Humanitarian Affairs (Ocha) to need food in Ethiopia (pdf), and 2.8 million need assistance in Guatemala and Honduras.

Millions more people in Asia and the Pacific regions have already been affected by heatwaves, water shortages and forest fires since El Niño conditions started in mid-2015, says Ocha in a new briefing paper, which forecasts that harvests will continue to be affected worldwide throughout 2016.

“Almost 1 million children are in need of treatment for severe acute malnutrition in eastern and southern Africa. Two years of erratic rain and drought have combined with one of the most powerful El Niño events in 50 years to wreak havoc on the lives of the most vulnerable children,” said Leila Gharagozloo-Pakkala, southern Africa regional director of the UN children’s agency, Unicef.

“Governments are responding with available resources, but this is an unprecedented situation. The situation is aggravated by rising food prices, forcing families to implement drastic coping mechanisms such as skipping meals and selling off assets.”

In a joint statement, the UN’s Food and Agriculture Organisation (FAO) and the Famine Early Warning Systems Network said: “El Niño will have a devastating effect on southern Africa’s harvests and food security in 2016. The current rainfall season has so far been the driest in the last 35 years.”

Britain’s Department for International Development (DfID) said in a briefing paper: “Even if it were to start raining today, the planting window for cereals has already closed in the southern part of the region [Africa] and is fast closing elsewhere. There has been a steep rise in market prices of imported staple goods. This is restricting access to food for the most vulnerable.”

According to the World Health Organisation, the heavy rains expected from El Niño in Peru, Ecuador, Paraguay and southern Brazil could increase the spread of the Zika virus. “The Aedes aegypti mosquito breeds in standing water. We could expect more mosquito vectors which can spread Zika virus because of expanding and favourable breeding sites [in El Niño-affected countries],” the organisation said.

El Niño conditions, which stem from a natural warming of Pacific Ocean waters, lead to droughts, floods and more frequent cyclones across the world every few years. This year’s event is said by meteorologists to be the worst in 35 years and is now peaking. Although it is expected to decline in strength over the next six months, its effects on farming, health and livelihoods in developing countries could last two years or more because of failed harvests and prolonged flooding.

“Insufficient rains since March 2015 have resulted in drought conditions. In Central America, El Niño conditions have led to a second consecutive year of drought – one of the region’s most severe in history,” said an Ocha spokesman.

“Mozambique and southern African countries face a disaster if the rains do not come within a few weeks,” said Abdoulaye Balde, WFP country director in Maputo. “South Africa is 6m tonnes short of food this year. But it is the usual provider of food reserves in the region. If they have to import 6m tonnes for themselves, there will be little left for other countries. The price of food will rise dramatically.”

Zimbabwe, which declared a national emergency this month, has seen harvests devastated and food prices soar, according to the WFP in Harare. It reports that food production has halved compared to last year and maize is 53% more expensive. It expects to need nearly $1.6bn in aid to help pay for grain and other food after the drought.

Malawi is experiencing its first maize deficit in a decade, pushing the price 73% higher than the December 2015 average. In Mozambique, prices were 50% higher than last year. The country depends on food imports from South Africa and Zimbabwe, and faces a disaster if rains do not arrive in the next few weeks, said Balde.

Fears are also growing that international donors have been preoccupied by Syriaand the Ebola crisis, and have not responded to food aid requests from affected countries.

“El Niño began wreaking havoc last year. The government has done its best to tackle the resultant drought on its own, by tapping into the national food reserves and allocating more than $300m [£210m] to buy wheat in the international market,” said Ethiopian foreign minister Tedros Ghebreyesus.

“But the number of people in need of food assistance has risen very quickly, making it difficult for Ethiopia to cope alone. For the 10.2 million people in need of aid, requirements stood at $1.4bn. The Ethiopian government has so far spent $300m and a similar sum has been pledged by donors. The gap is about $800m,” he said.

According to the Famine Early Warning Systems Network, set up by the US international development agency, USAID, in 1985, continued below-average rainfall and high temperatures are likely to persist in southern African well into 2016, with the food crisis lasting into 2017.

El Niño history raises fear of cholera outbreak (SciDev.Net)


María Elena Hurtado


  • El Niño may carry disease-causing Vibrio bacteria across Pacific
  • Previous events linked to cases of diarrhoea and cholera
  • Current El Niño developing similarly to 1977 one when diarrhoea reached Peru


The ongoing El Niño event may be spreading cholera and other diseases caused by Vibrio bacteria from Asia to South America, researchers suggest.

This is because the bacteria, which are typically found in salty water, could ‘piggyback’ on zooplankton that travel to Peru and Chile with the warm easterly and southerly Pacific currents associated with El Niño, according to a comment published in Nature Microbiology last month.

Vibrio bacteria cause severe diarrhoea when people eat raw, contaminated molluscs such as oysters, clams and mussels. Such outbreaks have been linked to previous El Niño episodes.

The ongoing El Niño — dubbed El Niño Godzilla because of its intensity — may be the strongest on record. It is developing similarly to an episode in 1977, during which a diarrhoea epidemic broke out in Peru. In that year, Vibrio parahaemolyticus bacteria caused an estimated 10,000 cases of severe gastroenteritis along the South American coastline.

In 1997, another strong El Niño year, the Vibrio parahaemolyticus strain of the bacteria, which had emerged in India, plagued the South American coast.

“The emergence of cases correlated with southward dissemination of El Niño water during the 1997 event,” says Jaime Martinez-Urtaza, a biologist at the University of Bath in the United Kingdom, and a coauthor of the article.

In terms of cholera, South America had been free of the disease for almost a century — until it reemerged in the early 1990s. Within weeks, cholera spread across South and Central America, going on to cause more than a million cases and 10,000 deaths by 1994.

Martinez-Urtaza says the cholera outbreak “coincided in both time and space with a significant El Niño event in late 1991 and early 1992”.

Ronnie Gavilán, a researcher at Peru’s National Institute of Health, says there is other evidence for El Niño’s influence on Vibrio bacteria in the Americas. He points out that, during warm El Niño events, Vibrioinfections continue to spread in the cold winter months, when they usually only occur in hot summers.

The current El Niño has not yet led to a Vibrio outbreak, but health authorities in Chile and Peru are closely monitoring water quality near the coast.

The delay could be “because the pathogens that may have arrived during the summer season may show up years later”, says Romilio Orellana, a biochemist at the University of Chile.


Jaime Martinez-Urtaza and others Is El Niño a long-distance corridor for waterborne disease? (Nature Microbiology, 24 February 2016)

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Dudas sobre El Niño retrasan preparación ante desastres (SciDev Net)

Dudas sobre El Niño retrasan preparación ante desastres

Crédito de la imagen: Patrick Brown/Panos


Martín De Ambrosio

De un vistazo

  • Efectos del fenómeno aún son confusos a lo largo del continente
  • No hay certeza, pero cruzarse de brazos no es opción, según Organización Panamericana de la Salud
  • Hay consenso científico del 95 por ciento sobre posibilidades de un El Niño fuerte

Los desacuerdos que existen entre los científicos sobre la posibilidad de que Centro y Sudamérica sufran o no un fuerte evento El Niño están generando cierto retraso en las preparaciones, según advierten las principales organizaciones que trabajan en el clima de la región.

Algunos investigadores sudamericanos aún tienen dudas sobre la forma cómo se desarrolla el evento este año. Esta incertidumbre impacta en los funcionarios y los estados, que deberían actuar cuanto antes para prevenir los peores escenarios, incluyendo muertes debido a desastres naturales, reclaman las organizaciones meteorológicas.

Eduardo Zambrano, investigador del Centro de Investigación Internacional sobre el Fenómeno de El Niño (CIIFEN) en Ecuador, y uno de los centros regionales de la Organización Meteorológica Mundial, dice que el problema es que los efectos del fenómeno todavía no han sido claros y evidentes en todo el continente.

“Algunas imágenes de satélite nos muestran un Océano Pacífico muy caliente, una de las características de El Niño”.

Willian Alva León, presidente de la Sociedad Meteorológica del Perú

“De todos modos podemos hablar sobre las extremas sequías en el noreste de Brasil, Venezuela y la zona del Caribe”, dice, y menciona además las inusualmente fuertes lluvias en el desierto de Atacama en Chile desde marzo y las inundaciones en zonas de Argentina, Uruguay y Paraguay.

El Niño alcanza su pico cuando una masa de aguas cálidas para los habituales parámetros del este del Océano Pacífico, se mueve de norte a sur y toca costas peruanas y ecuatorianas. Este movimiento causa efectos en cascada y estragos en todo el sistema de América Central y del Sur, convirtiendo las áridas regiones altas en lluviosas, al tiempo que se presentan sequías en las tierras bajas y tormentas sobre el Caribe.

Pero El Niño continúa siendo de difícil predicción debido a sus muy diferentes impactos. Los científicos, según Zambrano, esperaban al Niño el año pasado “cuando todas las alarmas sonaron, y luego no pasó nada demasiado extraordinario debido a un cambio en la dirección de los vientos”.

Tras ese error, muchas organizaciones prefirieron la cautela para evitar el alarmismo. “Algunas imágenes de satélite nos muestran un Océano Pacífico muy caliente, una de las características de El Niño”, dice Willian Alva León, presidente de la Sociedad Meteorológica del Perú. Pero, agrega, este calor no se mueve al sudeste, hacia las costas peruanas, como sucedería en caso del evento El Niño.

Alva León cree que los peores efectos ya sucedieron este año, lo que significa que el fenómeno está en retirada. “El Niño tiene un límite de energía y creo que ya ha sido alcanzado este año”, dice.

Este desacuerdo entre las instituciones de investigación del clima preocupa a quienes generan políticas, pues necesitan guías claras para iniciar las preparaciones necesarias del caso. Ciro Ugarte, asesor regional del área de Preparativos para Emergencia y Socorro en casos de Desastrede la Organización Panamericana de la Salud, dice que es obligatorio actuar como si El Niño en efecto estuviera en proceso para asegurar que el continente enfrente las posibles consecuencias.

“Estar preparados es importante porque reduce el impacto del fenómeno así como otras enfermedades que hoy son epidémicas”, dice.

Para asegurar el grado de probabilidad de El Niño, algunos científicos usan modelos que abstraen datos de la realidad y generan predicciones. María Teresa Martínez, subdirectora de meteorología del Instituto de Hidrología, Meteorología y Estudios Ambientales de Colombia, señala que los modelos más confiables predijeron en marzo que había entre un 50 y un 60 por ciento de posibilidad de un evento El Niño. “Ahora El Niño se desarrolla con fuerza desde su etapa de formación hacia la etapa de madurez, que será alcanzada en diciembre”, señala.

Ugarte admite que no hay certezas, pero dice que para su organización “no hacer nada no es una opción”.

“Como creadores de políticas de prevención, lo que tenemos que hacer es usar lo que es el consenso entre los científicos, y hoy ese consenso dice que hay un 95% de posibilidades de tener un fuerte o muy fuerte evento El Niño”, dice.

Extending climate predictability beyond El Niño (Science Daily)

Date: April 21, 2015

Source: University of Hawaii – SOEST

Summary: Tropical Pacific climate variations and their global weather impacts may be predicted much further in advance than previously thought, according to research by an international team of climate scientists. The source of this predictability lies in the tight interactions between the ocean and the atmosphere and among the Atlantic, the Pacific and the Indian Oceans. Such long-term tropical climate forecasts are useful to the public and policy makers, researchers say.

This image shows inter-basin coupling as a cause of multi-year tropical Pacific climate predictability: Impact of Atlantic warming on global atmospheric Walker Circulation (arrows). Rising air over the Atlantic subsides over the equatorial Pacific, causing central Pacific sea surface cooling, which in turn reinforces the large-scale wind anomalies. Credit: Yoshimitsu Chikamoto

Tropical Pacific climate variations and their global weather impacts may be predicted much further in advance than previously thought, according to research by an international team of climate scientists from the USA, Australia, and Japan. The source of this predictability lies in the tight interactions between the ocean and the atmosphere and among the Atlantic, the Pacific and the Indian Oceans. Such long-term tropical climate forecasts are useful to the public and policy makers.

At present computer simulations can predict the occurrence of an El Niño event at best three seasons in advance. Climate modeling centers worldwide generate and disseminate these forecasts on an operational basis. Scientists have assumed that the skill and reliability of such tropical climate forecasts drop rapidly for lead times longer than one year.

The new findings of predictable climate variations up to three years in advance are based on a series of hindcast computer modeling experiments, which included observed ocean temperature and salinity data. The results are presented in the April 21, 2015, online issue of Nature Communications.

“We found that, even three to four years after starting the prediction, the model was still tracking the observations well,” says Yoshimitsu Chikamoto at the University of Hawaii at Manoa International Pacific Research Center and lead author of the study. “This implies that central Pacific climate conditions can be predicted over several years ahead.”

“The mechanism is simple,” states co-author Shang-Ping Xie from the University of California San Diego. “Warmer water in the Atlantic heats up the atmosphere. Rising air and increased precipitation drive a large atmospheric circulation cell, which then sinks over the Central Pacific. The relatively dry air feeds surface winds back into the Atlantic and the Indian Ocean. These winds cool the Central Pacific leading to conditions, which are similar to a La Niña Modoki event. The central Pacific cooling then strengthens the global atmospheric circulation anomalies.”

“Our results present a paradigm shift,” explains co-author Axel Timmermann, climate scientist and professor at the University of Hawaii. “Whereas the Pacific was previously considered the main driver of tropical climate variability and the Atlantic and Indian Ocean its slaves, our results document a much more active role for the Atlantic Ocean in determining conditions in the other two ocean basins. The coupling between the oceans is established by a massive reorganization of the atmospheric circulation.”

The impacts of the findings are wide-ranging. “Central Pacific temperature changes have a remote effect on rainfall in California and Australia. Seeing the Atlantic as an important contributor to these rainfall shifts, which happen as far away as Australia, came to us as a great surprise. It highlights the fact that on multi-year timescales we have to view climate variability in a global perspective, rather than through a basin-wide lens,” says Jing-Jia Luo, co-author of the study and climate scientist at the Bureau of Meteorology in Australia.

“Our study fills the gap between the well-established seasonal predictions and internationally ongoing decadal forecasting efforts. We anticipate that the main results will soon be corroborated by other climate computer models,” concludes co-author Masahide Kimoto from the University of Tokyo, Japan.

Journal Reference:

  1. Yoshimitsu Chikamoto, Axel Timmermann, Jing-Jia Luo, Takashi Mochizuki, Masahide Kimoto, Masahiro Watanabe, Masayoshi Ishii, Shang-Ping Xie, Fei-Fei Jin. Skilful multi-year predictions of tropical trans-basin climate variabilityNature Communications, 2015; 6: 6869 DOI: 10.1038/ncomms7869

Modeling the past to understand the future of a stronger El Niño (Science Daily)


November 26, 2014


University of Wisconsin-Madison


El Nino is not a contemporary phenomenon; it’s long been the Earth’s dominant source of year-to-year climate fluctuation. But as the climate warms and the feedbacks that drive the cycle change, researchers want to know how El Nino will respond.


Using state-of-the-art computer models maintained at the National Center for Atmospheric Research, researchers determined that El Niño has intensified over the last 6,000 years. This pier and cafe are in Ocean Beach, California. Credit: Jon Sullivan

It was fishermen off the coast of Peru who first recognized the anomaly, hundreds of years ago. Every so often, their usually cold, nutrient-rich water would turn warm and the fish they depended on would disappear. Then there was the ceaseless rain.

They called it “El Nino,” The Boy — or Christmas Boy — because of its timing near the holiday each time it returned, every three to seven years.

El Nino is not a contemporary phenomenon; it’s long been Earth’s dominant source of year-to-year climate fluctuation. But as the climate warms and the feedbacks that drive the cycle change, researchers want to know how El Nino will respond. A team of researchers led by the University of Wisconsin’s Zhengyu Liu published the latest findings in this quest Nov. 27, 2014 in Nature.

“We can’t see the future; the only thing we can do is examine the past,” says Liu, a professor in the Department of Atmospheric and Oceanic Sciences. “The question people are interested in now is whether it’s going to be stronger or weaker, and this requires us to first check if our model can simulate its past history.”

The study examines what has influenced El Nino over the last 21,000 years in order to understand its future and to prepare for the consequences. It is valuable knowledge for scientists, land managers, policymakers and many others, as people across the globe focus on adapting to a changing climate.

Using state-of-the-art computer models maintained at the National Center for Atmospheric Research in Colorado, the researchers — also from Peking University in China, the University of Hawaii at Manoa, and Georgia Institute of Technology — determined that El Nino has intensified over the last 6,000 years.

The findings corroborate data from previous studies, which relied on observations like historical sediments off the Central American coast and changes in fossilized coral. During warm, rainy El Nino years, the coastal sediments consist of larger mixed deposits of lighter color, and the coral provides a unique signature, akin to rings on a tree.

“There have been some observations that El Nino has been changing,” says Liu, also a professor in the Nelson Institute for Environmental Studies Center for Climatic Research. “Previous studies seem to indicate El Nino has increased over the last 5,000 to 7,000 years.”

But unlike previous studies, the new model provides a continuous look at the long history of El Nino, rather than a snapshot in time.

It examines the large-scale influences that have impacted the strength of El Nino over the last 21,000 years, such as atmospheric carbon dioxide, ice sheet melting and changes to Earth’s orbit.

El Nino is driven by an intricate tango between the ocean and Earth’s atmosphere. In non-El Nino years, trade winds over the tropical Pacific Ocean drive the seas westward, from the coast of Central America toward Indonesia, adding a thick, warm layer to the surface of the western part of the ocean while cooler water rises to the surface in the east. This brings rain to the west and dry conditions to the east.

During El Nino, the trade winds relax and the sea surface temperature differences between the Western and Eastern Pacific Ocean are diminished. This alters the heat distribution in both the water and the air in each region, forcing a cascade of global climate-related changes.

“It has an impact on Madison winter temperatures — when Peru is warm, it’s warm here,” says Liu. “It has global impact. If there are changes in the future, will it change the pattern?”

Before the start of the Holocene — which began roughly 12,000 years ago — pulses of melting water during deglaciation most strongly influenced El Nino, the study found. But since that time, changes in Earth’s orbit have played the greatest role in intensifying it.

Like an uptick in tempo, the feedbacks between ocean and atmosphere — such as how wind and seas interact — have grown stronger.

However, even with the best data available, some features of the simulated El Nino — especially prior to 6,000 years ago — can’t be tested unambiguously, Liu says. The current observational data feeding the model is sparse and the resolution too low to pick up subtle shifts in El Nino over the millennia.

The study findings indicate better observational data is needed to refine the science, like more coral samples and sediment measurements from different locations in the Central Pacific. Like all science, better understanding what drives El Nino and how it might change is a process, and one that will continue to evolve over time.

“It’s really an open door; we need more data to get a more significant model,” he says. “With this study, we are providing the first benchmark for the next five, 10, 20 years into the future.”

Story Source:

The above story is based on materials provided by University of Wisconsin-Madison. The original article was written by Kelly April Tyrrell. Note: Materials may be edited for content and length.

Journal Reference:

  1. Zhengyu Liu, Zhengyao Lu, Xinyu Wen, B. L. Otto-Bliesner, A. Timmermann, K. M. Cobb. Evolution and forcing mechanisms of El Niño over the past 21,000 years. Nature, 2014; 515 (7528): 550 DOI: 10.1038/nature13963

Temperaturas do verão vão superar as de 2014, diz instituto (O Globo)

JC, 5070, 24 de novembro de 2014

Aumento seria de até 2 graus Celsius; fenômeno El Niño pode provocar mais chuvas

Daqui a um mês começa a estação mais popular do Rio. E o verão de 2015 não deve dar trégua para quem detesta calor. De acordo com o Instituto Climatempo, o primeiro bimestre do ano que vem terá temperaturas ainda mais elevadas do que as registradas no ano passado. Em janeiro, a média será de 32ºC. Em fevereiro, 36ºC. Em 2014, a média não superou os 34ºC.

Leia mais sobre esse assunto em:

(Renato Grandelle, com Agências Internacionais / O Globo)

Seca em SP deve continuar em 2015, diz cientista (OESP)

Organização Mundial de Meteorologia prevê influência do El Niño ainda neste ano, que já é considerado o mais quente desde 2004

A seca em São Paulo deve continuar em 2015, desta vez associada também ao desenvolvimento do fenômeno El Niño, afirmou ao Estado o secretário-geral adjunto da Organização Mundial de Meteorologia (OMM), Jeremiah Lengoasa.

O aquecimento das águas equatoriais do Oceano Pacífico, na altura do Peru e do Equador, provocará a formação de nuvens que tendem a ser arrastadas pelos ventos na direção oeste.

O conteúdo na íntegra está disponível em:,seca-em-sp-deve-continuar-em-2015-diz-cientista,1584016

(Denise Chrispim Marin / O Estado de São Paulo)

Seca em SP deve continuar em 2015, diz cientista

28/10/14 – A seca em São Paulo deve continuar em 2015, desta vez associada também ao desenvolvimento do fenômeno El Niño, afirmou ao Estado o secretário-geral adjunto da Organização Mundial de Meteorologia (OMM), Jeremiah Lengoasa.

O aquecimento das águas equatoriais do Oceano Pacífico, na altura do Peru e do Equador, provocará a formação de nuvens que tendem a ser arrastadas pelos ventos na direção oeste. Mas não para a América do Sul, explicou o cientista sul-africano, que participou ontem da abertura da 40.ª Sessão do Painel Intergovernamental sobre Mudança Climática (IPCC, em inglês), em Copenhague (mais informações abaixo).

“É a natureza tentando se modelar para atingir seu normal”, declarou, em entrevista ao Estado. “Se entendermos melhor os padrões de oscilação do fenômeno El Niño, poderemos prever de forma mais precisa e tornar disponível essa informação para os governos e as populações a serem atingidas. Mas a mudança do clima está tornando essa tarefa muito difícil.”

Lengoasa explicou que o fenômeno El Niño foi mais agressivo entre 1997-98, quando provocou o aumento médio de 0,5 grau Celsius na temperatura média mundial e levou a uma mudança severa na distribuição das chuvas. Em 2010, voltou a apresentar-se de maneira intensa, mas não tão forte como antes. “Já há 70% de chances de o El Niño surgir muito cedo, ainda no final deste ano. Se tiver o mesmo efeito de 97-98, isso será caracterizado por uma imensa seca no mundo”, disse. “Mas ainda há possibilidade de ele não se desenvolver de maneira tão forte.”

A OMM apresentará, nas próximas semanas, um relatório preliminar sobre o comportamento meteorológico de 2014. O ano é considerado o mais quente desde 2004, segundo análise dos dez primeiros meses, mesmo com os efeitos em curso do fenômeno de resfriamento conhecido como La Niña. Durante conferência neste mês, a organização estudará particularmente os dois fenômenos, El Niño e La Niña, com especial atenção para o efeito do primeiro no aquecimento das camadas mais profundas do Oceano Pacífico, abaixo de 2 mil metros. Esses dados serão acrescentados aos modelos atuais de previsão do clima. Em especial, para a melhor detecção de eventos extremos.


Para países que enfrentam eventos climáticos extremos, como o Brasil, Lengoasa faz algumas recomendações. Primeiro, fortalecer os serviços hidrometeorológicos, que oferecem as informações sobre o clima. Segundo, de acordo com ele, os países devem intensificar o diálogo entre diferentes ministérios sobre a mudança climática. O apoio aos esforços mundiais, como o da 21.ª Conferência das Partes sobre Mudança Climática (COP21), é sua terceira sugestão. A expectativa é de um acordo sobre compromissos de redução de emissões de gases de efeito estufa na COP21, em maio, em Paris.

*   *   *

OMM prevê possível episódio climático do El Niño em meados de 2014 (AFP)

JC e-mail 4885, de 31 de janeiro de 2014

Hoje as condições são “neutras”, isto é, não se observa a chegada nem de um episódio de El Niño, nem de La Niña, segundo a OMM

O oceano Pacífico pode viver o fenômeno climático conhecido como El Niño no terceiro trimestre deste ano, anunciou nesta quinta-feira, em Genebra, a Organização Meteorológica Mundial (OMM), uma agência da ONU.

Segundo a OMM, há dois possíveis cenários dentro de seis meses: ou “a persistência de condições neutras” ou “um episódio de El Niño de baixa intensidade durante o terceiro trimestre de 2014″.

Os dois cenários “são quase tão plausíveis, tanto um quanto o outro”.

Atualmente, as condições são “neutras”, isto é, não se observa a chegada nem de um episódio de El Niño, nem de La Niña, segundo a OMM.

Estas condições “persistirão provavelmente até o segundo trimestre de 2014″, acrescentou a organização.

Os episódios climáticos El Niño e La Niña têm grande influência no clima da Terra.

O El Niño acontece a cada dois e sete anos, quando os ventos tropicais sobre o oceano Pacífico perdem força, o que provoca fortes chuvas, com inundações e deslizamentos de terra a oeste da América do Sul, seca no Pacífico ocidental e mudanças de correntes ricas em alimentos para os peixes.

O último episódio ocorreu entre junho de 2009 e maio de 2010.

Ao El Niño se segue geralmente um episódio do La Niña, que supõe temperaturas mais baixas das águas superficiais do Pacífico central e tropical.

O último episódio terminou em abril de 2012.

(AFP, via portal UOL)

Global Warming May Worsen Effects of El Niño, La Niña Events (Climate Central)

Published: October 12th, 2011

By Michael D. Lemonick

Does this mean Texas is toast?

As just about everyone knows, El Niño is a periodic unusual warming of the surface water in the eastern and central tropical Pacific Ocean. Actually, that’s pretty much a lie. Most people don’t know the definition of El Niño or its mirror image, La Niña, and truthfully, most people don’t much care.

What you do care about if you’re a Texan suffering through the worst one-year drought on record, or a New Yorker who had to dig out from massive snowstorms last winter (tied in part to La Niña), or a Californian who has ever had to deal with the torrential rains that trigger catastrophic mudslides (linked to El Niño), is that these natural climate cycles can elevate the odds of natural disasters where you live.

At the moment, we’re now entering the second year of the La Niña part of the cycle. La Niña is one key reason why the Southwest was so dry last winter and through the spring and summer, and since La Niña is projected to continue through the coming winter, Texas and nearby states aren’t likely to get much relief.

Precipitation outlook for winter 2011-12, showing the likelihood of below average precipitation in Texas and other drought-stricken states.

But Niñas and Niños (the broader cycle, for you weather/climate geeks, is known as the “El Niño-Southern Oscillation,” or “ENSO”) don’t just operate in isolation. They’re part of the broader climate system, which means that climate change could theoretically change how they operate — make them develop more frequently, for example, or less frequently, or be more or less pronounced. Climate change could also intensify the effects of El Niño and La Niña events.

Climate scientists have been wrestling with the first question for a while now, and they still don’t really have a definitive answer. Some climate models have suggested that global warming has already begun to cause subtle changes in ENSO cycles, and that the changes will become more pronounced later this century. But a new study, published in the Journal of Climate, doesn’t find much evidence for that.

But on the second question, the new study is a lot more definitive. “Due to a warmer and moister atmosphere,” said co-author Baylor Fox-Kemper, of the University of Colorado in a press release, “the impacts of El Niño are changing even though El Niño itself doesn’t change.”

That’s because global warming has begun to change the playing field on which El Niño and La Niña operate, just as it’s changing the background conditions that give rise to our everyday weather. The Texas drought is a prime example. Its most likely cause is reduced rainfall from La Niña-related weather patterns. But however dry Texas and Oklahoma might have been otherwise, the killer heat wave that plagued the region this past summer — the sort of heat wave global warming is already making more commonplace — baked much of the remaining moisture out of both the soil and vegetation. No wonder large parts of the Lone Star State have gone up in smoke.

A map of sea surface temperature anomalies, showing a swath of cooler than average waters in the central and eastern tropical Pacific Ocean – a telltale sign La Niña conditions.

When the next El Niño occurs in a year or two, it will probably bring heavy rains to places like Southern California, whose unstable hillsides tend to slide when soggy. Except now, thanks to global warming, the typical El Niño-related storms that roll in off the Pacific may well be turbocharged, since a warmer atmosphere can hold more water. This is the reason, say many climate scientists, that downpours have become heavier in recent decades across broad geographical areas.

La Niña, plus the added moisture in the air from global warming, have also been partially implicated in the massive snowstorms that struck the Northeast and Mid-Atlantic states during the last two winters. Those could get worse as well, suggests the new analysis. “What we see,” says Fox-Kemper, “is that certain atmospheric patterns, such as the blocking high pressure south of Alaska typical of La Niña winters, strengthen…so, the cooling of North America expected in a La Niña winter would be stronger in future climates.” So to pre-answer the question that will inevitably be asked next winter: no, more snow does NOT contradict the idea that the planet is warming. Quite the contrary.

Finally, for those who really do want to know what El Niño and La Niña actually are, as opposed to what they do, you can go to NOAA’s El Niño page. But be warned: there will be a quiz, and the word “thermocline” will appear.


By Kirk Petersen (Maplewood, NJ 07040)
on October 13th, 2011

Seventh paragraph, third sentence should begin “Its most likely cause”—not “it’s”.