Coherent signature of warming-induced extreme sub-continental boreal wildfire activity 4800 and 1100 years BP

Climate changes are expected to progressively increase extreme wildfire frequency in forests. Finding past analogs for periods of extreme biomass burning would provide valuable insights regarding what the effects of warming might be for tree species distribution, ecosystem integrity, atmospheric greenhouse gas balance, and human safety. Here, we used a network of 42 lake-sediment charcoal records across a ~2000 km transect in eastern boreal North America to infer widespread periods of wildfire activity in association with past climate conditions. The reconstructed fluctuations in biomass burning are broadly consistent with variations in ethane concentration in Greenland polar ice cores. Biomass burning fluctuations also significantly co-varied with Greenland temperatures estimated from ice cores, at least for the past 6000 years. Our retrospective analysis of past fire activity allowed us to identify two fire periods centered around 4800 and 1100 BP, coinciding with large-scale warming in northern latitudes and having respectively affected an estimated ~71% and ~57% of the study area. These two periods co-occurred with widespread decreases in mean fire-return intervals. The two periods are likely the best analogs for what could be anticipated in terms of impacts of fire on ecosystem services provided by these forests in coming decades

A Biomarker-Based Diagnostic Model for Cardiac Dysfunction in Childhood Cancer Survivors

Background: Childhood cancer survivors at risk for heart failure undergo lifelong echocardiographic surveillance. Previous studies reported the limited diagnostic accuracy of N-terminal pro–B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) in detecting left ventricular (LV) dysfunction. However, potential enhanced diagnostic accuracy through the combination of biomarkers and clinical characteristics has been suggested. Objectives: The aim of this study was to develop and internally validate a diagnostic model that combines cardiac biomarkers with clinical characteristics for effectively ruling in or ruling out LV dysfunction in childhood cancer survivors. Methods: A multicenter cross-sectional study included 1,334 survivors (median age 34.2 years) and 278 siblings (median age 36.8 years). Logistic regression models were developed and validated through bootstrapping, combining biomarkers with clinical characteristics. Results: Abnormal NT-proBNP levels were observed in 22.1% of survivors compared with 5.4% of siblings, whereas hs-cTnT levels exceeding 10 ng/L were uncommon in both survivors (5.9%) and siblings (5.0%). The diagnostic models demonstrated improvement upon the addition of NT-proBNP and hs-cTnT to clinical characteristics, resulting in an increased C statistic from 0.69 to 0.73 for LV ejection fraction (LVEF) &lt;50% and a more accurate prediction of more severe LV dysfunction, with the C statistic increasing from 0.80 to 0.86 for LVEF &lt;45%. For LVEF &lt;50% (prevalence 10.9%), 16.9% of survivors could be effectively ruled out with high sensitivity (95.4%; 95% CI: 90.4%-99.3%) and negative predictive value (97.5%; 95% CI: 94.6%-99.7%). Similarly, for LVEF &lt;45% (prevalence 3.4%), 53.0% of survivors could be ruled out with moderate to high sensitivity (91.1%; 95% CI: 79.2%-100%) and high negative predictive value (99.4%; 95% CI: 98.7%-100%). Conclusions: The biomarker-based diagnostic model proves effective in ruling out LV dysfunction, offering the potential to minimize unnecessary surveillance echocardiography in childhood cancer survivors. External validation is essential to confirm these findings. (Early Detection of Cardiac Dysfunction in Childhood Cancer Survivors; A DCOG LATER Study; https://onderzoekmetmensen.nl/nl/trial/23641)</p

A Biomarker-Based Diagnostic Model for Cardiac Dysfunction in Childhood Cancer Survivors

Background: Childhood cancer survivors at risk for heart failure undergo lifelong echocardiographic surveillance. Previous studies reported the limited diagnostic accuracy of N-terminal pro–B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) in detecting left ventricular (LV) dysfunction. However, potential enhanced diagnostic accuracy through the combination of biomarkers and clinical characteristics has been suggested. Objectives: The aim of this study was to develop and internally validate a diagnostic model that combines cardiac biomarkers with clinical characteristics for effectively ruling in or ruling out LV dysfunction in childhood cancer survivors. Methods: A multicenter cross-sectional study included 1,334 survivors (median age 34.2 years) and 278 siblings (median age 36.8 years). Logistic regression models were developed and validated through bootstrapping, combining biomarkers with clinical characteristics. Results: Abnormal NT-proBNP levels were observed in 22.1% of survivors compared with 5.4% of siblings, whereas hs-cTnT levels exceeding 10 ng/L were uncommon in both survivors (5.9%) and siblings (5.0%). The diagnostic models demonstrated improvement upon the addition of NT-proBNP and hs-cTnT to clinical characteristics, resulting in an increased C statistic from 0.69 to 0.73 for LV ejection fraction (LVEF) &lt;50% and a more accurate prediction of more severe LV dysfunction, with the C statistic increasing from 0.80 to 0.86 for LVEF &lt;45%. For LVEF &lt;50% (prevalence 10.9%), 16.9% of survivors could be effectively ruled out with high sensitivity (95.4%; 95% CI: 90.4%-99.3%) and negative predictive value (97.5%; 95% CI: 94.6%-99.7%). Similarly, for LVEF &lt;45% (prevalence 3.4%), 53.0% of survivors could be ruled out with moderate to high sensitivity (91.1%; 95% CI: 79.2%-100%) and high negative predictive value (99.4%; 95% CI: 98.7%-100%). Conclusions: The biomarker-based diagnostic model proves effective in ruling out LV dysfunction, offering the potential to minimize unnecessary surveillance echocardiography in childhood cancer survivors. External validation is essential to confirm these findings. (Early Detection of Cardiac Dysfunction in Childhood Cancer Survivors; A DCOG LATER Study; https://onderzoekmetmensen.nl/nl/trial/23641)</p

Extensive Cardiac Function Analyses Using Contemporary Echocardiography in Childhood Cancer Survivors:A DCCSS LATER Study

Background: Childhood cancer survivors (CCS) are at risk for cardiotoxicity. Objectives: We sought to assess how cardiac dysfunction measurements in CCS overlap and are differentially influenced by risk factors. Methods: This cross-sectional Dutch Childhood Cancer Survivor Study evaluated echocardiograms of 1,397 ≥5-year CCS and 277 siblings. Of CCS, n = 1,254 received cardiotoxic (anthracyclines/mitoxantrone/radiotherapy involving the heart region [RTheart]) and n = 143 received potentially cardiotoxic (cyclophosphamide, ifosfamide, or vincristine) therapy. We assessed demographic, treatment-related, and traditional cardiovascular risk factors for cardiac dysfunction using multivariable logistic regression. Results: CCS were a median of 26.7 years after diagnosis; 49% were women. Abnormal left ventricular ejection fraction (LVEF) (defined as &lt;52% in men, &lt;54% in women) occurred most commonly in CCS treated with anthracyclines and RTheart combined (38%). Age/sex-specific abnormal global longitudinal strain (GLS) occurred most commonly in CCS treated with RTheart, either with (41%) or without (38%) anthracyclines. Of CCS with normal LVEF, 20.2% showed abnormal GLS. Diastolic dysfunction grade ≥II was rare. Abnormal LVEF was mainly associated with female sex, anthracycline dose, and only in women, RTheart dose. Abnormal GLS was associated with female sex, RTheart dose, diastolic blood pressure, and only in women, anthracycline dose. Cyclophosphamide, ifosfamide, and vincristine were not associated with LVEF or GLS. Compared with siblings, CCS showed higher risk of abnormal LVEF (OR: 2.9; 95% CI: 1.4-6.6) and GLS (OR: 2.1; 95% CI: 1.2-3.7), independent of (potentially) cardiotoxic treatment-related and cardiovascular risk factors. Conclusions: Abnormal LVEF and GLS constitute complementary measures of systolic dysfunction among long-term CCS. Their diagnostic value may differ according to cardiotoxic exposures. Also, CCS have residual, unexplained risk of cardiac dysfunction.</p

Extensive Cardiac Function Analyses Using Contemporary Echocardiography in Childhood Cancer Survivors:A DCCSS LATER Study

Background: Childhood cancer survivors (CCS) are at risk for cardiotoxicity.Objectives: We sought to assess how cardiac dysfunction measurements in CCS overlap and are differentially influenced by risk factors.Methods: This cross-sectional Dutch Childhood Cancer Survivor Study evaluated echocardiograms of 1,397 ≥5-year CCS and 277 siblings. Of CCS, n = 1,254 received cardiotoxic (anthracyclines/mitoxantrone/radiotherapy involving the heart region [RTheart]) and n = 143 received potentially cardiotoxic (cyclophosphamide, ifosfamide, or vincristine) therapy. We assessed demographic, treatment-related, and traditional cardiovascular risk factors for cardiac dysfunction using multivariable logistic regression.Results: CCS were a median of 26.7 years after diagnosis; 49% were women. Abnormal left ventricular ejection fraction (LVEF) (defined as &lt;52% in men, &lt;54% in women) occurred most commonly in CCS treated with anthracyclines and RTheart combined (38%). Age/sex-specific abnormal global longitudinal strain (GLS) occurred most commonly in CCS treated with RTheart, either with (41%) or without (38%) anthracyclines. Of CCS with normal LVEF, 20.2% showed abnormal GLS. Diastolic dysfunction grade ≥II was rare. Abnormal LVEF was mainly associated with female sex, anthracycline dose, and only in women, RTheart dose. Abnormal GLS was associated with female sex, RTheart dose, diastolic blood pressure, and only in women, anthracycline dose. Cyclophosphamide, ifosfamide, and vincristine were not associated with LVEF or GLS. Compared with siblings, CCS showed higher risk of abnormal LVEF (OR: 2.9; 95% CI: 1.4-6.6) and GLS (OR: 2.1; 95% CI: 1.2-3.7), independent of (potentially) cardiotoxic treatment-related and cardiovascular risk factors.Conclusions: Abnormal LVEF and GLS constitute complementary measures of systolic dysfunction among long-term CCS. Their diagnostic value may differ according to cardiotoxic exposures. Also, CCS have residual, unexplained risk of cardiac dysfunction.</p

The Reading Palaeofire Database : an expanded global resource to document changes in fire regimes from sedimentary charcoal records

Sedimentary charcoal records are widely used to reconstruct regional changes in fire regimes through time in the geological past. Existing global compilations are not geographically comprehensive and do not provide consistent metadata for all sites. Furthermore, the age models provided for these records are not harmonised and many are based on older calibrations of the radiocarbon ages. These issues limit the use of existing compilations for research into past fire regimes. Here, we present an expanded database of charcoal records, accompanied by new age models based on recalibration of radiocarbon ages using IntCal20 and Bayesian age-modelling software. We document the structure and contents of the database, the construction of the age models, and the quality control measures applied. We also record the expansion of geographical coverage relative to previous charcoal compilations and the expansion of metadata that can be used to inform analyses. This first version of the Reading Palaeofire Database contains 1676 records (entities) from 1480 sites worldwide. The database (RPDv1b - Harrison et al., 2021) is available at https://doi.org/10.17864/1947.000345.Peer reviewe

Assessing changes in global fire regimes

PAGES, Past Global Changes, is funded by the Swiss Academy of Sciences and the Chinese Academy of Sciences and supported in kind by the University of Bern, Switzerland. Financial support was provided by the U.S. National Science Foundation award numbers 1916565, EAR-2011439, and EAR-2012123. Additional support was provided by the Utah Department of Natural Resources Watershed Restoration Initiative. SSS was supported by Brigham Young University Graduate Studies. MS was supported by National Science Centre, Poland (grant no. 2018/31/B/ST10/02498 and 2021/41/B/ST10/00060). JCA was supported by the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 101026211. PF contributed within the framework of the FCT-funded project no. UIDB/04033/2020. SGAF acknowledges support from Trond Mohn Stiftelse (TMS) and University of Bergen for the startup grant ‘TMS2022STG03’. JMP participation in this research was supported by the Forest Research Centre, a research unit funded by Fundação para a Ciência e a Tecnologia I.P. (FCT), Portugal (UIDB/00239/2020). A.-LD acknowledge PAGES, PICS CNRS 06484 project, CNRS-INSU, Région Nouvelle-Aquitaine, University of Bordeaux DRI and INQUA for workshop support.Background The global human footprint has fundamentally altered wildfire regimes, creating serious consequences for human health, biodiversity, and climate. However, it remains difficult to project how long-term interactions among land use, management, and climate change will affect fire behavior, representing a key knowledge gap for sustainable management. We used expert assessment to combine opinions about past and future fire regimes from 99 wildfire researchers. We asked for quantitative and qualitative assessments of the frequency, type, and implications of fire regime change from the beginning of the Holocene through the year 2300. Results Respondents indicated some direct human influence on wildfire since at least ~ 12,000 years BP, though natural climate variability remained the dominant driver of fire regime change until around 5,000 years BP, for most study regions. Responses suggested a ten-fold increase in the frequency of fire regime change during the last 250 years compared with the rest of the Holocene, corresponding first with the intensification and extensification of land use and later with anthropogenic climate change. Looking to the future, fire regimes were predicted to intensify, with increases in frequency, severity, and size in all biomes except grassland ecosystems. Fire regimes showed different climate sensitivities across biomes, but the likelihood of fire regime change increased with higher warming scenarios for all biomes. Biodiversity, carbon storage, and other ecosystem services were predicted to decrease for most biomes under higher emission scenarios. We present recommendations for adaptation and mitigation under emerging fire regimes, while recognizing that management options are constrained under higher emission scenarios. Conclusion The influence of humans on wildfire regimes has increased over the last two centuries. The perspective gained from past fires should be considered in land and fire management strategies, but novel fire behavior is likely given the unprecedented human disruption of plant communities, climate, and other factors. Future fire regimes are likely to degrade key ecosystem services, unless climate change is aggressively mitigated. Expert assessment complements empirical data and modeling, providing a broader perspective of fire science to inform decision making and future research priorities.Peer reviewe

The Reading Palaeofire Database: an expanded global resource to document changes in fire regimes from sedimentary charcoal records

Sedimentary charcoal records are widely used to reconstruct regional changes in fire regimes through time in the geological past. Existing global compilations are not geographically comprehensive and do not provide consistent metadata for all sites. Furthermore, the age models provided for these records are not harmonised and many are based on older calibrations of the radiocarbon ages. These issues limit the use of existing compilations for research into past fire regimes. Here, we present an expanded database of charcoal records, accompanied by new age models based on recalibration of radiocarbon ages using IntCal20 and Bayesian age-modelling software. We document the structure and contents of the database, the construction of the age models, and the quality control measures applied. We also record the expansion of geographical coverage relative to previous charcoal compilations and the expansion of metadata that can be used to inform analyses. This first version of the Reading Palaeofire Database contains 1676 records (entities) from 1480 sites worldwide. The database (RPDv1b – Harrison et al., 2021) is available at https://doi.org/10.17864/1947.000345