CSHOR ENSO Science Symposium 29 to 31 January 2019
CSHOR gathered El Niño Southern Oscillation (ENSO) experts and students in Hobart over a 3-day symposium to address important scientific questions. How reliable are our modelling and observational tools used to monitor, predict, and study ENSO? What advances do we need to improve projections of ENSO in a changing climate?
The field of ENSO research is rapidly progressing and it is necessary to re-assess the state of ENSO science. ENSO significantly impacts our climate, ecosystems, economy and society on a global scale. An improved understanding of its dynamics, evolution, predictability, teleconnection and impact in a climate that is undergoing change is critical to manage risks and resources. The character of ENSO and the frequency of extreme events may change on a warming planet. Just a couple of years ago an extreme El Niño with major global climatic consequences occurred and one may wonder when the next big one will arrive.
The Symposium was followed by a 2 day writing session for ENSO book authors on 1-2 February at CSIRO Marine Laboratories.
Professor John Church wins top climate change award
Congratulations to John Church on winning the BBVA Foundation Frontiers of Knowledge Award in the Climate Change category.
Anny Cazenave (France) and Jonathan Gregory (UK) joined John in receiving the award for their outstanding contributions, the BBVA committee states, “to detecting, understanding and projecting the response of global and regional sea level to anthropogenic climate change.” Over the past 30 years John has worked with Anny Cazenave and Jonathan Gregory as joint authors on academic papers and on reports for the Intergovernmental Panel on Climate Change (IPCC), an intergovernmental body of the United Nations.
The international award, now in its 11th year, recognises significant contributions in the areas of scientific research and cultural creation. The award will be presented at a ceremony in Madrid in June 2019.
John Church is an important collaborator working with Xuebin Zhang on the CSHOR Southern Ocean role in sea level change project.
CSHOR’s Annie Foppert wins award at QNLM Annual Meeting
Congratulations to Dr Annie Foppert on winning second prize for her presentation at the Qingdao National Laboratory for Marine Science and
Technology (QNLM) Academic Annual Meeting Young Scholars’ Forum held in Qingdao, China last week. Annie’s talk was titled, ‘Hot spots of eddy-driven transport across the East Antarctic slope’. The prize is 6,000 YUAN (~AU$1,200). The Annual Meeting was held on 10 and 11 January 2019.
QNLM invited many young scientists from QNLM partner organisations both in China and internationally to submit a presentation to the Forum. The presentations were of a high calibre across a broad range of ocean science disciplines.
Our staff also took the opportunity to tour the wonderful facility at QNLM and to attend a banquet in honour of CSHOR’s visit to Qingdao. CSHOR staff received a friendly and gracious reception at QNLM.
Increased variability of eastern Pacific El Niño under greenhouse warming
The El Niño–Southern Oscillation (ENSO) is the dominant and most consequential climate variation on the planet. Answering the question of how ENSO may change under greenhouse warming has been plagued for decades by a persistent lack of inter-model agreement on the response of the associated sea surface temperature variability.
This paper by Cai et al. shows for the first time strong inter-model consensus over sea surface temperature variability of a type of El Niño, eastern Pacific El Niño that is strong in both strength and impact, despite differences in the details of the simulated El Niño across models. The result means that we can expect more occurrences of extreme weather associated with eastern Pacific El Niño events (the strongest and most destructive of the two types of El Niño events), which will have pronounced implications for the twenty-first century climate, extreme weather and ecosystems. Read the full article at the following link. An associated Nature News and Views article is at this link
Understanding El Niño-Southern Oscillation Complexity
El Niño events are characterized by tropical Pacific surface warming and weakening of trade winds occurring every few years. Such conditions are accompanied by changes in atmospheric and oceanic circulation, affecting global climate, marine and terrestrial ecosystems, fisheries and human activities. The alternation of warm El Niño and cold La Niña conditions, referred to as the El Niño-Southern Oscillation (ENSO), represents the strongest year-to-year fluctuation of the global climate system. A Nature review paper published recenlty (Timmermann et al. 2018) provides a synthesis of the current understanding of the spatio-temporal complexity (In terms of amplitude, timing, duration, predictability and global impacts) of this important climate mode and its influence on the earth system. The paper proposes a unifying framework to explain ENSO spatio-temporal complexity, by considering the two most dominant coupled modes of variability on about two-year and four-year time scales. Read the full article at the following link. The CSIRO blog highlighting six reasons you should care about El Niño is also recommended reading.
Choosing the future of Antarctica
In a recent Nature article, Rintoul et al. present two narratives on the future of Antarctica and the Southern Ocean, from the perspective of an observer looking back from 2070. Read the CSHOR post, which includes a link to the full article, at this link.
The global influence of localised dynamics in the Southern Ocean
This Nature review by Dr Steve Rintoul evaluates the published research on Southern Ocean change: including changes in circulation, stronger winds, and increased freshwater input. The Southern Ocean exerts a disproportionate and profound influence on global ocean currents, climate, biogeochemical cycles, and sea level rise. The paper shows that substantial progress has been made in recent years in understanding the dynamics and global influence of the Southern Ocean. It is becoming clear that local scale processes play a fundamental part in shaping large-scale circulation. This is driven by the local topography which, of course, doesn’t change to a significant degree. Read the full article at this link.
CSHOR Science Seminar and Committee Meeting at CSIRO Hobart
The CSHOR office recently hosted a CSHOR Science Seminar and a joint CSHOR Steering and International Advisory Committee Meeting at CSIRO, Hobart. Over 40 guests attended the seminar on Thursday 3 May, including the CSHOR Steering and Advisory Committees. Advisory Committee Members commented that, ‘CSHOR is an excellent team and the science seminar is a great display. The presentations addressed important key questions and highlighted collaboration with other institutions’. Read more at this link.
Global warming is melting Antarctic ice from below
The results from a study published in Science Advances, and reported in a recent Guardian article, suggest that increased glacial meltwater input in a warming climate will both reduce Antarctic Bottom Water formation and trigger increased mass loss from the Antarctic Ice Sheet, with consequences for the global overturning circulation and sea level rise. The latest CSHOR post provides more detail and links to the paper and The Guardian article.
A new wave of southern hemisphere ocean researchers joins CSHOR
After a flood of applications and hours spent trawling through CVs, the Centre for Southern Hemisphere Oceans Research (CSHOR) welcomes six new Postdoctoral Fellows aboard. Read more about the new recruits here.
Recent progress in climate change research
In a paper published in Nature Communication (Cai et al. 2018a) we show that the extreme pIOD frequency is projected to increase linearly with the GMT but approaches a maximum as the GMT stabilises, in stark contrast to a continuous increase in the extreme El Niño frequency long after the GMT stabilisation. Further detail can be found at this link.
CSHOR wins award in China
CSHOR wins an award at the 16th China’s International Talents Exchange Meeting in Shenzhen. Read more about the award at this link.
Changes in the Southern Ocean revealed by researchers aboard the RV Investigator
Southern Ocean researchers aboard the RV Investigator find a shift in a decades-long trend towards fresher, less dense water off Antarctica. Read the SMH article by Peter Hannam at this link.
Understanding the ultimate risk of extreme El Niño associated with a 1.5˚C warming target
In a paper published in Nature Climate Change (Wang et al., 2017a) we demonstrate that extreme El Niño frequency increases linearly with the GMT towards a doubling at 1.5 °C warming. This increasing frequency of extreme El Niño events continues for up to a century after GMT has stabilized, underpinned by an oceanic thermocline deepening that sustains faster warming in the eastern equatorial Pacific than the off-equatorial region. Ultimately, this implies a higher risk of extreme El Niño to future generations after GMT rise has halted. On the other hand, whereas previous research suggests extreme La Niña events may double in frequency under the 4.5 °C warming scenario8, the results presented here indicate little to no change under 1.5 °C or 2 °C warming.
The Paris Agreement aims to constrain global mean temperature (GMT) increases to 2 °C above pre-industrial levels, with an aspirational target of 1.5 °C. However, the pathway to these targets1,2,3,4,5,6 and the impacts of a 1.5 °C and 2 °C warming on extreme El Niño and La Niña events—which severely influence weather patterns, agriculture, ecosystems, public health and economies7,8,9,10,11,12,13,14,15,16—is little known. Here, by analysing climate models participating in the Climate Model Intercomparison Project’s Phase 5 (CMIP5; ref. 17) under a most likely emission scenario1,2.
Explaining the large increase in ocean heat content in the southern hemisphere oceans
A study based on previous Argo float deployments, published in Nature Climate Change (Gao et al., 2017), shows that wind-driven changes in formation and subduction of Subantarctic Mode Water in the Southern Ocean can explain the large increase in ocean heat content in the southern hemisphere oceans. Further details at: https://doi.org/10.1038/s41558-017-0022-8.
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