Month: August 2024

Enora CARIOU’s final year internship

National School of Meteorology

February – August 2023

Supervisors: Alexandre Peltier (Météo-France), Christophe Menkes (IRD)

Enora Cariou completed a 6-month internship, which included three presentations (at the start, mid-term and end of the internship) to the CLIPSSA supervisory team and the community of researchers from the IRD, IFREMER, Météo-France, etc.

She defended her end-of-internship thesis on 24 August 2023 in front of the Ecole Nationale de Météorologie, IRD and Météo-France teams.

Main objective of the study

The aim of this study was to take stock of the heat waves that have affected New Caledonia over the last 40 years. The research is based on the Excess Heat Factor (EHF) index, which characterises the intensity of heat waves and is generated from in-situ temperature data from eight Météo-France stations and ERA5 Land reanalyses.

Context, issues and specific objectives

10 years ago, Météo-France and the New Caledonian government set up a heatwave monitoring and forecasting tool to guard against any health risks associated with hyperthermia. The population of New Caledonia has a number of co-morbidities – diabetes, severe hypertension, heart failure, obesity – which make it particularly vulnerable to heatstroke that lasts through the night. The hot weather monitoring and forecasting tool developed by Météo-France has enabled the government to take measures to limit the risk of hyperthermia during the hot season. Although the health authorities have expressed their satisfaction with the quality of the forecasts, scientific knowledge of heat waves has not improved. The aim of the course was therefore to answer the following questions :

• What are the characteristics of heat waves in New Caledonia (duration, intensity, number)?
• What are the trends?
• What atmospheric mechanisms are involved?
• Were the most significant episodes localised or synoptic in scale?

The work plan focused on the following points:

• Temporal characteristics of localized heat waves in New Caledonia : definition of the Excess Heat Factor (EHF) index to describe heat waves (data, methods and behaviour of the index).
• Spatial and temporal characteristics of heat waves on a regional scale (swSPCZ): climatologies, trends, teleconnections with ENSO and weather patterns.
• Study of the most intense episodes: application of archetypal analysis to EHF data.

Main results

Studies of annual and seasonal climatologies and long-term trends have revealed an average of 4 to 5 heat waves across the region, lasting an average of 4.5 to 5 days. There are more heatwaves on the south-east coast of Grande Terre and on the Loyalty Islands, but they are more intense on the relief and the west coast. The cool season (April to October) also sees more intense and longer episodes. There has been a significant increase in the number of heat waves over most of the country, but the signal is less clear for average intensities and durations. The study of the impact of different atmospheric phenomena on the number of heat waves across the three types of weather (Tropical Weather, Unstable Trade Winds and Southern Disturbance) favoured the number of heat wave days. In addition, La Nina also appears to significantly favour the number of heatwaves. Finally, the test carried out on the Madden-Julian Oscillation revealed two phases with a significant but opposite effect on the occurrence of heatwaves.

The study of teleconnections and the analysis of the most intense events, using the Archetypal Analysis method, demonstrate a significant influence of ENSO on the number and intensity of heat waves. Weather patterns in the region also influence the occurrence of heat waves. Finally, the Archetypal analysis reveals geographical patterns during the most intense heat waves. In order to improve this analysis, statistical tests should be set up to confirm these findings. In New Caledonia, the intense heat wave in the summer of 2015-2016 caused massive coral bleaching, which was not expected. In fact, during a Niño, temperatures are normally cooler. Here, we are seeing a teleconnection with El Niño, which creates intense heat waves. This link has yet to be proven.

It would also be interesting to apply the analysis over the whole year and not just the warm season (not done due to lack of time). In fact, by running the algorithm several times over the warm season alone to deduce the optimum number of archetypes, the calculation time was around 48 hours. However, it is possible to reduce the size of the dataset by applying a principal component analysis beforehand.

Perspectives 

To continue this work, statistical tests will have to be carried out to verify the impact of El Niño on the intensity of heat waves. In addition, the ERA5 Land re-analyses show non-negligible biases in relation to observations, particularly in terms of temperature values and the number of heat waves detected. Further work is required using other models. As part of CLIPSSA’s high-resolution numerical simulations over New Caledonia, it would therefore be interesting, in future work, to calculate the HFE on these data. Here, we have applied the archetypal analysis only to the warm season. Applying it over the whole year would make it possible to compare patterns in different seasons.

Finally, coral reefs are threatened by bleaching, particularly as a result of marine heat waves. We could therefore consider developing a line of research linking atmospheric and marine heat waves.

Read her thesis, presentation and article here!

A poster summarising his work was presented by Alexandre Peltier at the 30th Conference of the Australian Meteorological and Oceanographic Society (AMOS) – 3 to 9 February 2024 in Canberra.

The “Fête de la Science” 2023, which ran from 10 to 27 November under the theme ‘Sport and Science’, took a unique twist in New Caledonia thanks to a series of events co-organised by the IRD, Météo-France, Studio 4×4 and Canal+ Calédonie. These events, combining documentary screenings and debates, explored the links between sport and climate, focusing on the impact of climate change on local sporting practices.

Reflection through film

The central point of the crossroads between sport and climate was the broadcast of the sports documentary series ‘Sans limites’, which highlights the surpassing of self by New Caledonian athletes. The series served as the basis for discussions on a highly topical subject : the evolution of sporting practices in a world increasingly subject to the effects of climate change.

The screenings and debates took place in two stages and in two different venues, each dealing with a specific aspect of land and water sports.

First stage : Le Rex cinema

On 10 November, land-based sporting activities took centre stage at Le Rex cinema. In the morning, two screenings and debates were organised for schoolchildren, enabling around forty secondary school pupils to watch the episode devoted to mountain biking.

This was followed by a lively discussion with Alexandre Peltier, head of the climate division at Météo-France’s New Caledonia and Wallis and Futuna Interregional Office, mountain bike champion David Esposito and Fleur Vallet, coordinator of the CLIPSSA project, to give young people a better understanding of the environmental challenges they will have to face in the future.

Presentation of the mountain bike episode to schoolchildren

In the evening of the same day, the Fête de la Science in New Caledonia was inaugurated with the screening of the Ultra-Trail episode. In front of an audience of 75 people, moderated by host and facilitator Soizic Fleury, a debate took place with the participation of 4 speakers from the sporting, academic and scientific fields :

• Angélique Plaire, a New Caledonian athlete who won the Ultratour des 4 massifs (UT4M) in 2017, the Ultra Trail de Nouvelle Calédonie in 2017, 2018 and 2019 and finished on the podium of the Ultra World Tour in the Pacific in 2019, in February on the Tarawera Ultramarathon in New Zealand.
• Olivier Galy, lecturer and doctor in Sciences and Techniques of Physical and Sports Activities (STAPS), and director of the Education Research Laboratory at the University of New Caledonia.
• Alexandre Peltier, head of the climate division at the New Caledonia and Wallis and Futuna Interregional Office of Météo-France.
• Fleur Vallet, environmental geographer and coordinator of the CLIPSSA project.

These discussions provided an opportunity to explore in greater depth the challenges that climate change poses for top-level athletes.

Discussions with the speakers after the Trail episode

Second stage : Origin Cinéma

On 16 November, the spotlight moved to the Origin cinema, where water sports took centre stage. The evening was centred on the Va’a episode of the ‘Sans limite’ series. The discussion that followed, in the presence of oceanographer Alexandre Ganachaud from the IRD and Phoebe Roger, French junior freestyle kite-surfing champion, was attended by around thirty people. The debate focused on the impact of climate change on the oceans and, consequently, on water sports, offering an enlightened scientific perspective on future challenges.

An open and essential dialogue

Under the moderation of moderator and facilitator Soizic Fleury, these events provided a platform for exchange around essential questions : how will our sporting practices evolve in the face of rising temperatures, heat waves and extreme climatic events? What challenges will tomorrow’s athletes face?

These screenings and debates were also an opportunity to highlight the results of Enora Cariou’s research course on heat waves in New Caledonia, providing a bridge between scientific research and the concerns of the general public.

In this way, the Fête de la Science 2023 in New Caledonia did more than just celebrate science; it also provided an opportunity for in-depth reflection on the future of sport in a world undergoing climate change, while raising awareness of these crucial issues among the younger generations and the general public.

To find out more, watch the making-off video for the Fête de la Science 2023 :

Participation in international scientific events

In 2023, CLIPSSA continued its involvement in various high-level scientific and institutional events, thanks to various participations and presentations by the project’s researchers and experts (Catherine Sabinot, Alexandre Peltier, Victoire Laurent) and post-doctoral student (Vishnu Sasidharan Nair). Here are a few examples : EGU-23 international scientific symposium in Vienna in April, the VIII Wallace Scientific Conference in Costa Rica in May, the ICRC-CORDEX workshop in Italy in September and the Pacific Island Climate Outlook Forum in Suva (Fiji) in October.

Awareness-raising and outreach activities

The project has continued to raise awareness at local level, notably at the seminar on climate change organised by the Bourail municipality in September at the municipal cinema.

During the Fête de la Science 2023 in November, CLIPSSA organised screenings and debates on the link between sport and climate, including the broadcast of the New Caledonian documentary series ‘Sans limites’ (Studio 4×4, Canal+ Calédonie), and discussions on the impact of climate change on sporting practices were held with the general public.

Media presence

CLIPSSA raised its profile with a number of media appearances, including articles in New Caledonia’s legal and political journal and radio broadcasts on NC1ère. The project was also mentioned at an IRD international press conference, highlighting its role in climate change research efforts in the Pacific.

Participation in international scientific events

The year 2022 was marked by the CLIPSSA project’s active participation in a number of international scientific and institutional events. At the start of the year, the project team produced a poster for the 13th International Conference on Southern Hemisphere Meteorology and Oceanography (ICSHMO) in February. In April, the Météo-France Interregional Office in New Caledonia and Wallis and Futuna gave a brief presentation on the project at the 10th session of the Pacific Islands Climate Outlook Forum (PICOF-10).

In November, at COP27 in Egypt, Christophe Menkès was an expert panellist at the French Pavilion during the side event ‘Managing and measuring adaptation in a context of climate emergency’ organised by AFD, Expertise France, IDDRI and FERDI. The project and its main objectives were presented at the round table.

Round table at the Pavillon France, 11 November 2022

Other noteworthy events involving the CLIPSSA team took place in New Caledonia, including the Loyalty Islands Province Economic Forum (September and October), the Tech&Bio trade fair and the disaster risk prevention and management day (October).

Presentation and debates on disaster risk management and reduction at the launch of the disaster risk policy in Nouméa, Château Royal hotel, 13 October 2022

Awareness-raising and outreach activities

In parallel with these commitments, CLIPSSA has carried out a number of awareness-raising and popularisation activities, notably through film debates in New Caledonia, such as the film-debate on the Empreinte programme on the theme of climate change in March. The project was also highlighted in the documentary ‘Un paradis en péril’, produced in collaboration with JADA Productions and the IRD.

Extract from the Empreinte programme, available for replay on youtube

CLIPSSA took part in a project combining art and science based on the works of Myazaki, entitled ‘The Forces of Nature – A Musical and Scientific Journey through the Works of Hayao Miyazaki’, which took place in October at the Auditorium of the Conservatoire de Musique in Nouméa. The main theme was climate change and its impact, with scientific and university presentations (IRD, UNC, Institut Pasteur, Météo-France) in film/concert/lecture format. To find out more, see the specific article here !

The Fête de la Science 2022, organised in November, saw CLIPSSA make an active contribution, in partnership with the Caledonian Energy Agency, through the Fresque du Climat workshops and mini-conferences on climate change at the University of New Caledonia in Nouméa and Bako (Koné). In French Polynesia, Victoire Laurent, head of the climate division at the DIRPF-MF, has been chosen as Ambassador. Some of the Météo-France teams worked on a number of issues, and a number of activities took place, including a review of climate change and its impacts (extremes, cyclones, rainfall, temperature, etc.) in French Polynesia. CLIPSSA was presented at a public conference in Tahiti and Moorea and through an educational video.

Media presence

Finally, the project received significant media coverage in New Caledonia, with appearances on NC1ère and a mention in DEMAIN magazine (natural disasters, anticipating and adapting to climate change) in October, addressing the climate challenges of the future.

As part of the “Fête de la science”, a major event held every year in mainland France and the French overseas territories, Victoire Laurent, meteorologist and tropical climatology expert, delivers a hard-hitting analysis of the impact of climate change on French Polynesia. In her article published on The Conversation, she sheds light on the already visible effects of climate disruption on this archipelago, revealing data that is both alarming and instructive.

Historical climate data

Laurent highlights the importance of analysing long series of climate data in order to grasp the trends in climate change. In French Polynesia, the first rainfall measurements date back to 1853, and local meteorological archives are an invaluable treasure trove for research. By homogenising these data series, researchers can detect and quantify the signs of climate change, an essential step in anticipating future challenges.

Signs of global warming in French Polynesia

Made up of 120 islands divided into five archipelagos, French Polynesia is far from immune to global climate upheaval. Research shows that the Polynesian climate has warmed significantly in recent decades, with temperatures rising by between +0.6°C and +1.55°C depending on the archipelago. This warming is particularly marked at night. In Tahiti, for example, night-time temperatures have risen by +2°C over the last 58 years, almost twice as fast as daytime temperatures.

Cyclones down, but risks up

Although annual rainfall appears to be little affected by climate change, the article reveals a significant drop in cyclone activity over the last two decades. However, this decline does not mean the end of risks for local residents. Climate projections point to an increase in heatwaves and greater risk of drought, particularly on the high islands, by 2050. These changes could increase the vulnerability of water resources and the risk of vegetation fires. In the ocean, rising sea levels and the salinisation of freshwater lenses pose serious threats, particularly for the atolls.

The CLIPSSA project: towards local adaptation

In light of these worrying findings, Victoire Laurent has been actively involved in the CLIPSSA (CLImat du Pacifique Savoirs locaux et Stratégie d’Adaptation) project. The aim of this project is to provide very high-resolution climate simulations to help local populations develop adaptation strategies tailored to the specific cultural and geographical characteristics of French Polynesia.

Understanding the climate challenges

This article by Victoire Laurent is a powerful reminder of the urgent need to act to protect these particularly vulnerable territories in the face of climate change. It is essential reading for anyone interested in the future of island regions facing major environmental upheaval.

To find out more, read the full article here : L’impact du changement climatique sur la Polynésie française.

Pacific Climate, Local Knowledge and Adaptation Strategies Project (CLIPSSA) : Adaptation solutions for the Pacific Islands

Discover the CLIPSSA regional project, which contributes to the effort to respond to the specific climate challenges of the Pacific islands.

CLIPSSA aims to develop unprecedented scientific data on the future climate of the South Pacific (by 2100), to analyze the sectoral impacts on agricultural systems and water resources, and to produce and transmit new knowledge already existing in each territory. These new data are essential foundations for the formulation of adaptation strategies and the development of action and adaptation plans in the face of climate change in Wallis and Futuna, French Polynesia, New Caledonia and Vanuatu.