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Fire regime in the Iberian Peninsula : links with current and future climate

Publication . Menezes, Tomás; Nunes, João Pedro; Silva, João Neves; Pereira, Mário Gonzalez

Iberia has been affected by wildfires in the last decades, in association with fire weather extremes, as observed in recent years. The main objective of this thesis is to investigate the current and future fire regime in Iberia, with three research questions: (i) Were there recent changes in fire regime or in pyro-regions of Iberia?; (ii) What is the relationship between extreme fire weather and Burnt Area (BA) in Portugal?; and (iii) Will future climate modify the Iberian fire regime or pyro-regions? Several fire weather indices, containing the Daily Severity Rating (DSR), were computed using a reanalysis dataset. A cluster analysis was performed on Normalized Burnt Area (NBA), revealing four pyro-regions. The Number of Extreme Days (NED), defined using DSR and Drought Code above the 95th percentile, was computed and related with the NBA. ERA5-Land reanalysis data was used to compute DSR percentiles for an extended summer period and related with large wildfires in Portugal, to identify which percentile is associated to the majority of accumulated BA. A cluster analysis was performed using this relationship and related with land use data, to analyse the spatial variability of this threshold. The strong link between the NED and the NBA intra-annual patterns was used to project the future pyro-regions, using a climate ensemble for two future scenarios. Projected changes in NED suggested different future Iberian pyro-regions mapping. In conclusion, the three research questions were answered: (i) Recent changes in fire regimes were observed, influenced by fire weather alterations; a strong link between the NED and NBA was disclosed; (ii) Extreme DSR days were responsible for the majority of BA; forest or shrublands prevalence has influence in the spatial variability of this extreme threshold; (iii) Iberian pyro-regions may change profoundly in future climate conditions, with an increase of the NED and DSR.

2022-02Doctoral thesis

Open access

Recent evolution of spatial and temporal patterns of burnt areas and fire weather risk in the Iberian Peninsula

Publication . Menezes, Tomás; Nunes, João Pedro; Pereira, Mário Gonzalez

2020-05Journal article

Open access

Assessing impacts of future climate change on extreme fire weather and pyro-regions in Iberian Peninsula

Publication . Menezes, Tomás; Pereira, M.G.; Nunes, João Pedro

Weather conditions play an important role in wildfire activity. In many regions, future climate could lead to different fire weather, with impacts on the ignition, behaviour, and suppression of wildfires, which may, therefore, force new fire regimes. This study aimed to assess the evolution of fire weather indices and the Number of Extreme Days (NED) in the context of climate change. We estimated the impact of these changes on monthly Normalized Burnt Area (NBA) and in the spatial distribution of Pyro-Regions (PR), using a recently identified relationship between NED and NBA intra-annual patterns. The components of the Canadian Forest Fire Weather Index System (CFFWIS) in the Iberian Peninsula were analysed for present-day conditions and future climate scenarios, using daily data from ERA-Interim (1980-2014) and an ensemble of simulations from 11 EURO-CORDEX high spatial resolution models, for two future periods (2041-2070 and 2071-2100) and scenarios (RCP4.5 and RCP8.5). Results suggest a significant increase in future fire weather risk, especially in late spring and early autumn, and also in southern and eastern Iberian Peninsula. NED is expected to strongly increase in summer months in the four PRs, but also to decrease in March and April in the northwestern and southwestern PR. This could change the spatial distribution of PRs, with a general northwards movement: the northern PR is expected to disappear except north of the Cantabrian Mountains, being replaced by the northwestern PR; the southwestern PR is expected to grow and occupy part of the area currently in the northwestern PR; and a new PR could appear in parts of the current eastern PR. These PR changes follow the projected modifications in the major climate regions. Results suggest different fire regimes in the future, with higher fire weather risk, and a longer and harsher fire season.

2021-02Journal article

Open access

Drivers of extreme burnt area in Portugal: fire weather and vegetation

Publication . Menezes, Tomás; Benali, Akli; Pereira, Mário Gonzalez; Silva, João M. N.; Nunes, João Pedro

Fire weather indices are used to assess the effect of weather on wildfire behaviour and to support fire management. Previous studies identified the high daily severity rating percentile (DSRp) as being strongly related to the total burnt area (BA) in Portugal, but it is still poorly understood how this knowledge can support fire management at a smaller spatial scale. The aims of this study were to (1) assess whether the 90th DSRp (DSR90p) threshold is adequate for estimating most of the BA in mainland Portugal; (2) analyse the spatial variability of the DSRp threshold that explains a large part of BA, at higher resolution; and, (3) analyse whether vegetation cover can justify the DSRp spatial variability. We used weather reanalysis data from ERA5-Land, wildfire and land use data from Portuguese land management departments for an extended summer period (15 May to 31 October) from 2001 to 2019. We computed and related DSRp to large wildfires (BA > 100 ha) and land use to clarify the effectiveness of the DSRp for estimating BA in Portugal and assess how vegetation influences it. Results revealed that the DSR90p is an adequate indicator of extreme fire weather days and BA in Portugal. In addition, the spatial pattern of the DSRp associated with most of the total BA shows variability at the municipality scale. Municipalities where large wildfires occur with more extreme weather conditions have most of the BAs in forests and are in coastal areas. By contrast, municipalities where large wild fires occur with less extreme weather conditions are predominantly covered by shrublands and are situated in eastern and inland regions. These findings are a novelty for fire science in Portugal and should be considered by fire managers and fire risk assessors.

2022-12Journal article

Open access

A climate change integrated assessment of whale watching in Macaronesia

Publication . G. Sousa, Andreia; Santos, Catarina Frazão da Fonseca Ribeiro dos; Azevedo, José Manuel Viegas de Oliveira Neto

As alterações climáticas estão a decorrer de forma rápida, generalizada e intensa, com impactos graves, interligados e irreversíveis nos sistemas naturais e humanos. No oceano, os efeitos das alterações climáticas estão a afetar fortemente os ecossistemas marinhos, principalmente através do aumento da temperatura, da acidificação, e da desoxigenação. Os ecossistemas marinhos proporcionam um conjunto de serviços de aprovisionamento, de regulação, culturais e de suporte. Estes serviços são particularmente relevantes em estados costeiros e insulares, onde se prevê que os impactos das alterações climáticas tenham maiores consequências, como a subida do nível do mar, a erosão costeira ou o aumento da frequência e intensidade de eventos climáticos extremos. O turismo é uma das principais atividades socioeconómicas desenvolvida em estados insulares a nível mundial, nomeadamente na bioregião da Macaronésia, onde a observação de cetáceos é uma das principais atividades. No entanto, os impactos das alterações climáticas na observação de cetáceos são largamente desconhecidos, ao mesmo tempo que faltam estudos que integrem os impactos socioeconómicos e ecológicos das alterações climáticas na atividade. Por outro lado, há a necessidade de apoiar os decisores na conservação da biodiversidade, identificando os esforços de gestão necessários e as lacunas de conhecimento a preencher. O principal objetivo da presente dissertação é, assim, realizar uma avaliação integrada da vulnerabilidade biológica e socioeconómica da atividade de observação de cetáceos às alterações climáticas, por forma a apoiar a sua sustentabilidade a longo prazo na bioregião da Macaronésia. As três principais perguntas de investigação definidas para responder a este objetivo são: (i) Qual a vulnerabilidade ecológica das espécies de cetáceos às alterações climáticas? (ii) Qual a vulnerabilidade socioeconómica da observação de cetáceos às alterações climáticas? (iii) Como é que a gestão da atividade de observação de cetáceos pode ser apoiada face às alterações climáticas?

2023-01Doctoral thesis

Open access