What will the future look like if El Niño is always with us?: El Niño Forever

Weatherwise ◽  
2005 ◽  
Vol 58 (6) ◽  
pp. 48-51
Author(s):  
David Laskin
Keyword(s):  
El Niño ◽  
El Nino ◽  
2020 ◽  
Vol 33 (5) ◽  
pp. 1619-1641 ◽  
Author(s):  
Jie Feng ◽  
Tao Lian ◽  
Jun Ying ◽  
Junde Li ◽  
Gen Li

AbstractWhether the state-of-the-art CMIP5 models have different El Niño types and how the degree of modeled El Niño diversity would be impacted by the future global warming are still heavily debated. In this study, cluster analysis is used to investigate El Niño diversity in 30 CMIP5 models. As the method does not rely on any prior knowledge of the patterns of El Niño seen in observations, it provides a practical way to identify the degree of El Niño diversity in models. Under the historical scenario, most models show a poor degree of El Niño diversity in their own model world, primarily due to the lopsided numbers of events belonging to the two modeled El Niño types and the weak compactness of events in each cluster. Four models are found showing significant El Niño diversity, yet none of them captures the longitudinal distributions of the warming centers of the two El Niño types seen in the observations. Heat budget analysis of the sea surface temperature (SST) anomaly suggests that the degree of modeled El Niño diversity is highly related to the climatological zonal SST gradient over the western-central equatorial Pacific in models. As the gradient is weakened in most models under the future high-emission scenario, the degree of modeled El Niño diversity is further reduced in the future. The results indicate that a better simulation of the SST gradient over the western-central equatorial Pacific might allow a more reliable simulation/projection of El Niño diversity in most CMIP5 models.


2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Guojian Wang ◽  
Wenju Cai

Abstract The 2019/20 Australian black summer bushfires were particularly severe in many respects, including its early commencement, large spatial coverage, and large number of burning days, preceded by record dry and hot anomalies. Determining whether greenhouse warming has played a role is an important issue. Here, we examine known modes of tropical climate variability that contribute to droughts in Australia to provide a gauge. We find that a two-year consecutive concurrence of the 2018 and 2019 positive Indian Ocean Dipole and the 2018 and 2019 Central Pacific El Niño, with the former affecting Southeast Australia, and the latter influencing eastern and northeastern Australia, may explain many characteristics of the fires. Such consecutive events occurred only once in the observations since 1911. Using two generations of state-of-the-art climate models under historical and a business-as-usual emission scenario, we show that the frequency of such consecutive concurrences increases slightly, but rainfall anomalies during such events are stronger in the future climate, and there are drying trends across Australia. The impact of the stronger rainfall anomalies during such events under drying trends is likely to be exacerbated by greenhouse warming-induced rise in temperatures, making such events in the future even more extreme.


Author(s):  
Roger A., Jr. Pielke

El Niño 97-98 will be remembered as one of the strongest ever recorded (Glantz, 1999). For the first time, climate anomalies associated with the event were anticipated by scientists, and this information was communicated to the public and policy makers to prepare for the “meteorological mayhem that climatologists are predicting will beset the entire globe this winter. The source of coming chaos is El Niño . . .” (Brownlee and Tangley, 1997). Congress and government agencies reacted in varying ways, as illustrated by the headlines presented in Figure 7-1. The link between El Niño events and seasonal weather and climate anomalies across the globe are called teleconnections (Glantz and Tarlton, 1991). Typically, during an El Niño cycle hurricane frequencies in the Atlantic are depressed, the southeast United States receives more rain than usual (chapter 2), and parts of Australia, Africa, and South America experience drought. Global attention became focused on the El Niño phenomenon following the 1982-1983 event, which, at that time, had the greatest magnitude of any El Niño observed in more than a century. After El Niño 82-83, many seasonal anomalies that had occurred during its two years were attributed, rightly or wrongly, to its influence on the atmosphere. As a consequence of the event, societies around the world experienced both costs and benefits (Glantz et al., 1987). Another lasting consequence of the 1982-1983 event was an increase in research into the phenomenon. One result of this research in the late 1990s has been the production of forecasts of El Niño (and La Niña) events and the seasonal climate anomalies associated with them. This chapter discusses the use of climate forecasts by policy makers, drawing on experiences from El Niño 97-98, which replaced the 1982-1983 eventas the” climate event of the century.” The purpose of this chapter is to draw lessons from the use of El Niño -based climate forecasts during the 1997-1998 event in order to improve the future production, delivery, and use of climate predictions. This chapter focuses on examples of federal, state, and local responses in California, Florida, and Colorado to illustrate the lessons.


2010 ◽  
Vol 31 (10) ◽  
pp. 1567-1572 ◽  
Author(s):  
Jong-Seong Kug ◽  
K. P. Sooraj ◽  
Fei-Fei Jin ◽  
Yoo-Geun Ham ◽  
Daehyun Kim

2017 ◽  
Vol 30 (3) ◽  
pp. 849-864 ◽  
Author(s):  
Kang Xu ◽  
Chi-Yung Tam ◽  
Congwen Zhu ◽  
Boqi Liu ◽  
Weiqiang Wang

Abstract Future projections of the eastern-Pacific (EP) and central-Pacific (CP) types of El Niño in the twenty-first century, as well as their associated tropical circulation and precipitation variability, are investigated using historical runs and representative concentration pathway 8.5 (RCP8.5) simulations from 31 coupled models in phase 5 of the Coupled Model Intercomparison Project (CMIP5). As inferred from CMIP5 models that best capture both El Niño flavors, EP El Niño sea surface temperature (SST) variability will become weaker in the future climate, while no robust change of CP El Niño SST is found. Models also reach no consensus on the future change of relative frequency from CP to EP El Niño. However, there are robust changes in the tropical overturning circulation and precipitation associated with both types of El Niño. Under a warmer climate, magnitudes of precipitation anomalies during EP El Niño are projected to increase, presenting significant enhancement of the dry (wet) signal over the western (central–eastern) Pacific. This is consistent with an accelerated hydrological cycle in the deep tropics; hence, a “wet get wetter” picture appears under global warming, accompanied by a weakened anomalous Walker circulation. For CP El Niño, drier-than-normal conditions will be intensified over the tropical central–eastern Pacific in the future climate, with stronger anomalous sinking related to the strengthened North Pacific local Hadley cell. These results suggest that, besides the enhanced basic-state hydrological cycle over the tropics, other elements, such as the anomalous overturning circulation, might also play a role in determining the ENSO precipitation response to a warmer background climate.


Science ◽  
2005 ◽  
Vol 309 (5735) ◽  
pp. 687-687 ◽  
Author(s):  
R. A. Kerr
Keyword(s):  
El Niño ◽  
El Nino ◽  
La Niña ◽  
The Past ◽  
La Nina ◽  

2020 ◽  
Author(s):  
Qing He ◽  
Kwok Pan Chun ◽  
Xicai Pan ◽  
Liang Chen ◽  
Pinyu Fan

<p>Vegetation is an integrated regional indicator of environmental changes related to soil, water and climate. For investigating climate change impacts on ecosystems, the transition zones of vegetations are natural hotspots of historical variations. As a transition zone between humid and arid climates in the northwest region of China, the terrestrial ecosystems of Gansu vary from dense vegetation landscapes in southeast to deserts in northwest. Exploring spatiotemporal vegetation responses to climate variations over Gansu has a great significance to project shifting northwest China vegetation patterns which affect regional water and food security. In this study, the spatiotemporal variations of vegetation were characterised by using the Normalized Difference Vegetation Index (NDVI). Between 2001 and 2019, there was a significant increase of the vegetation cover in almost the whole Gansu, and the increasing trend (around 0.015) was more predominant in the southeast part. Over the whole Gansu, especially at the southeast region, the Webster and Yang Monsoon (WYM) and the North Pacific El Nino oscillation (NP) had significant positive relationships with the extent of vegetation coverage at intra-annual and decadal scales respectively. Although the Central Pacific El Nino oscillation (CP) is only a statistically significant variable for some spotty locations of Gansu, it is negatively related to the vegetation variation over the northwest Gansu at an interannual scale. Based on the above relationships between vegetation and climate variables at different temporal scales, the future vegetation conditions of Gansu were projected based on the Beijing Normal University Earth System Model (BNU-ESM) outputs for the RCP4.5 and RCP8.5 scenarios. In a short term (the 2020s), vegetations in Gansu would increase because of the warmer temperatures along with possible increasing snowmelt water. However, for longer terms (the 2050s and the 2080s), the regional vegetation would significantly decline for both RCP4.5 and RCP8.5 scenarios, due to the depletion of snowmelt water sources resulted from the continuously increasing temperature and less snow accumulation in the region. The vegetation projections revealed the future desertification risk in Gansu. These results have important implications to water and food security in the vegetation transition zones of northwest China, which is a key region of the One Belt One Road initiative, connecting semi-arid regions of central Asian nations.</p>


Nature ◽  
10.1038/37499 ◽  
1997 ◽  
Vol 390 (6660) ◽  
pp. 562-564 ◽  
Author(s):  
Peter J. Webster ◽  
Timothy N. Palmer
Keyword(s):  
El Niño ◽  
El Nino ◽  
The Past ◽  

2011 ◽  
Vol 47 (3) ◽  
pp. 223-233 ◽  
Author(s):  
Hanna Na ◽  
Bong-Geun Jang ◽  
Won-Moon Choi ◽  
Kwang-Yul Kim
Keyword(s):  
El Niño ◽  
El Nino ◽  

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