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Various fire emission estimates for southern Africa during 2019, derived with multiple burned area data sets with resolutions ranging from 500 to 20 m, are evaluated using satellite carbon monoxide (CO) observations. Southern African emissions derived from burned area generated by 20 m Sentinel‐2 satellite imagery are up to 120% higher than other estimates because small fires are better detected with a higher‐resolution satellite instrument. A comprehensive comparison between simulated and observed atmospheric CO indicates that the Sentinel‐2 burned area data significantly improves emission estimates, with up to 15% reduction in CO concentration biases in comparison to emissions based on coarser resolution burned area data. We also found that the temporal lag between emissions and atmospheric CO concentrations during the peak fire month was related to atmospheric transport. These findings emphasize the importance of utilizing higher‐resolution satellite instruments in accurately estimating emissions and understanding the impact of small fires on global climate. Plain Language Summary: We studied how much carbon monoxide (CO) was released into the air in southern Africa due to fires. To derive CO emissions we used different remotely sensed data of area burned, with varying levels of detail, from 500 to 20 m, and used these emissions in a model to mimic atmospheric transport and chemistry of CO. We found that emissions derived from the very detailed 20‐m satellite images from Sentinel‐2 produced a similar large amount of CO in the atmosphere over southern Africa as seen by CO satellite observations. This is because the smaller fires, which are harder to spot, were detected with the 20‐m burned area satellite observations. We also found that the air movement and inflow of polluted air from outside Africa impacted the peak of air pollution. Key Points: Sentinel‐2 burned area detects small fires, resulting in up to 120% higher fire emissions compared to conventional resolution estimatesImproved fuel load modeling and new emission factors yield more trustworthy fire emissions that can be evaluated with top‐down constraintsAtmospheric modeling and TROPOMI CO observations indicate a 15% bias reduction using Sentinel‐2 burned area compared with coarser fire data [ABSTRACT FROM AUTHOR]

Objectives: To determine associations between the banning of sex work during the COVID-19 pandemic, and work, financial problems, mental well-being and HIV/sexually transmittable infection (STI) testing among sex workers in the Netherlands., Design: Two cross-sectional online surveys. The first survey covered two time-periods: pre-COVID-19 (1 January 2019 to 31 December 2019) and period 1 (15 March 2020 to 1 July 2020). The second survey covered period 2 (1 January 2021 to 31 December 2021)., Setting: The Netherlands PARTICIPANTS: In total, 106 (first survey) and 196 (second survey) sex workers participated. Most of the participants in the first and second survey were cisgender women (respectively, 76.4% and 66.5%), followed by cisgender men (respectively, 12.3% and 15.7%) and the combination of transgender men, transgender women, non-binary or other (respectively, 11.3% and 17.6%). Most participants were born in the Netherlands (respectively, 61.4% and 69.7%)., Primary and Secondary Outcome Measures: We provide descriptive statistics of self-reported work during and prior to COVID-19 measures, financial problems due to COVID-19 measures and HIV/STI testing and mental well-being during the COVID-19 pandemic. We also performed logistic and linear regression analyses to identify risk factors associated with reporting financial problems due to COVID-19 measures, not testing for HIV/STIs and lower mental well-being during the COVID-19 pandemic., Results: In periods 1 and 2, respectively, 69.6% and 62.0% reported financial problems due to the COVID-19 measures. Among those who reported to have had sex with clients, the percentage not HIV/STI testing was: 4.5% (95% CI: 0.9; 12.5) pre-COVID-19, 28.2% (95% CI: 15.0; 44.9) in period 1, and 15.2% (95% CI: 9.7; 22.3) in period 2. In the multivariate analysis, reported financial problems due to the COVID-19 pandemic was associated with not HIV/STI testing (OR: 12.1, p<0.001) and lower mental well-being (B: -2.7, p<0.001)., Conclusion: The COVID-19 pandemic control measures in the Netherlands were associated with major financial problems, low mental well-being and reduced HIV/STI testing among sex workers., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Climate change increases fire-favorable weather in forests, but fire trends are also affected by multiple other controlling factors that are difficult to untangle. We use machine learning to systematically group forest ecoregions into 12 global forest pyromes, with each showing distinct sensitivities to climatic, human, and vegetation controls. This delineation revealed that rapidly increasing forest fire emissions in extratropical pyromes, linked to climate change, offset declining emissions in tropical pyromes during 2001 to 2023. Annual emissions tripled in one extratropical pyrome due to increases in fire-favorable weather, compounded by increased forest cover and productivity. This contributed to a 60% increase in forest fire carbon emissions from forest ecoregions globally. Our results highlight the increasing vulnerability of forests and their carbon stocks to fire disturbance under climate change.

Pre-exposure prophylaxis (PrEP) use prevents HIV transmission, and may lead to changes in sexual behavior. We aimed to explore sexual behavior over time, and identify predictors of behavior change in men who have sex with men (MSM) using PrEP at sexual health centers (SHC) in the Netherlands. We used longitudinal data from the national STI surveillance database (January 2018-June 2021) of HIV-negative MSM who first initiated PrEP in the national PrEP pilot. We modelled behavior change after PrEP initiation, and identified predictors of behavior change using multi-state Markov models. The probability of stopping group sex, chemsex, use of poppers or erection stimulants, and having ≥ 10 partners in the past 6 months among included MSM (n = 4,349, n SHC visits = 21,820) was higher compared to the probability of starting with these behaviors after PrEP initiation. However, MSM who used condoms consistently during anal sex had a high probability of changing to inconsistent condom use (0.8) at the next visit, and inconsistent condom users mostly remained inconsistent (0.8). First visit, visiting the SHC more often (vs. regular), and STI diagnosis were predictors of starting or continuing with most of the behaviors associated with increased risk. Behavior change was less likely among older participants (> 34 compared to ≤ 34 years), and during COVID-19 lockdown and post-lockdown periods compared to pre-COVID-19. Although condom use decreased over time, transitions towards stopping with other behaviors associated with increased likelihood of acquiring an STI after PrEP initiation were common. This may suggest increased sexual empowerment, especially among younger MSM. Predictors of behavior change may help to identify MSM who are likely to start with or continue to engage in these behaviors in the near future and to provide suitable and timely counselling about behavior and PrEP adherence., (© 2024. The Author(s).)

This study identified subgroups of sexual behaviors associated with increased STI/HIV risk among those eligible for but not using pre-exposure prophylaxis (PrEP) in order to improve PrEP uptake and prioritization in the context of restricted capacity. We used data from sexual health centers (SHCs) in the Netherlands, including all visits of eligible but non-PrEP using men who have sex with men (MSM), men who have sex with men and women (MSMW) and transgender persons between July 2019 (start of the Dutch national PrEP pilot (NPP)) and June 2021. Using latent class analysis (LCA), we identified classes of sexual behaviors (number of partners, chemsex, group sex and sex work) and explored whether these classes were associated with STI diagnosis and sociodemographics. Across 45,582 visits of 14,588 eligible non-PrEP using individuals, the best fitting LCA model contained three classes of sexual behaviors. Classes were distinguished by seldomly reported sexual behaviors (class 1; 53.5%, n = 24,383), the highest proportions of ≥6 partners and group sex (class 2; 29.8%, n = 13,596), and the highest proportions of chemsex and sex work (class 3; 16.7% of visits, n = 7,603). Visits in classes 2 and 3 (vs. class 1) were significantly more often with individuals who were diagnosed with an STI, older (≥36 vs. ≤35 years), MSMW (vs. MSM), and visiting an urban (vs. non-urban) SHC; while these visits were significantly less often with individuals from an STI/HIV endemic area. The percentage of visits at which an STI was diagnosed was 17.07% (n = 4,163) in class 1, 19.53% (n = 2,655) in class 2 and 25.25% (n = 1,920) in class 3. The highest risk of STI, and thereby HIV, was in those engaging in specific subgroups of sexual behavior characterized by frequently reporting multiple partners, group sex, sex work or chemsex. PrEP uptake should be encouraged and prioritized for these individuals., Competing Interests: MP obtained unrestricted research grants and speaker/ advisory fees from Gilead Sciences, Abbvie and MSD; all of which were paid to her institute and were unrelated to the current work. EH obtained unrestricted research grants from Gilead Sciences, which were paid to her institute and were unrelated to the current work. This does not alter our adherence to PLOS ONE policies on sharing data and materials. The other authors report no conflicts of interest., (Copyright: © 2023 de la Court et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

About half of the anthropogenic CO 2 emissions remain in the atmosphere and half are taken up by the land and ocean 1 . If the carbon uptake by land and ocean sinks becomes less efficient, for example, owing to warming oceans 2 or thawing permafrost 3 , a larger fraction of anthropogenic emissions will remain in the atmosphere, accelerating climate change. Changes in the efficiency of the carbon sinks can be estimated indirectly by analysing trends in the airborne fraction, that is, the ratio between the atmospheric growth rate and anthropogenic emissions of CO 2 (refs.  4-10 ). However, current studies yield conflicting results about trends in the airborne fraction, with emissions related to land use and land cover change (LULCC) contributing the largest source of uncertainty 7,11,12 . Here we construct a LULCC emissions dataset using visibility data in key deforestation zones. These visibility observations are a proxy for fire emissions 13,14 , which are - in turn - related to LULCC 15,16 . Although indirect, this provides a long-term consistent dataset of LULCC emissions, showing that tropical deforestation emissions increased substantially (0.16 Pg C decade -1 ) since the start of CO 2 concentration measurements in 1958. So far, these emissions were thought to be relatively stable, leading to an increasing airborne fraction 4,5 . Our results, however, indicate that the CO 2 airborne fraction has decreased by 0.014 ± 0.010 decade -1 since 1959. This suggests that the combined land-ocean sink has been able to grow at least as fast as anthropogenic emissions., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Fires, among other forms of natural and anthropogenic disturbance, play a central role in regulating the location, composition and biomass of forests. Understanding the role of fire in global forest loss is crucial in constraining land-use change emissions and the global carbon cycle. We analysed the relationship between forest loss and fire at 500 m resolution based on satellite-derived data for the 2003-2018 period. Satellite fire data included burned area and active fire detections, to best account for large and small fires, respectively. We found that, on average, 38 ± 9% (± range) of global forest loss was associated with fire, and this fraction remained relatively stable throughout the study period. However, the fraction of fire-related forest loss varied substantially on a regional basis, and showed statistically significant trends in key tropical forest areas. Decreases in the fraction of fire-related forest loss were found where deforestation peaked early in our study period, including the Amazon and Indonesia while increases were found for tropical forests in Africa. The inclusion of active fire detections accounted for 41%, on average, of the total fire-related forest loss, with larger contributions in small clearings in interior tropical forests and human-dominated landscapes. Comparison to higher-resolution fire data with resolutions of 375 and 20 m indicated that commission errors due to coarse resolution fire data largely balanced out omission errors due to missed small fire detections for regional to continental-scale estimates of fire-related forest loss. Besides an improved understanding of forest dynamics, these findings may help to refine and separate fire-related and non-fire-related land-use change emissions in forested ecosystems., (© 2021 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

Fires are a major contributor to atmospheric budgets of greenhouse gases and aerosols, affect soils and vegetation properties, and are a key driver of land use change. Since the 1990s, global burned area (BA) estimates based on satellite observations have provided critical insights into patterns and trends of fire occurrence. However, these global BA products are based on coarse spatial-resolution sensors, which are unsuitable for detecting small fires that burn only a fraction of a satellite pixel. We estimated the relevance of those small fires by comparing a BA product generated from Sentinel-2 MSI (Multispectral Instrument) images (20-m spatial resolution) with a widely used global BA product based on Moderate Resolution Imaging Spectroradiometer (MODIS) images (500 m) focusing on sub-Saharan Africa. For the year 2016, we detected 80% more BA with Sentinel-2 images than with the MODIS product. This difference was predominately related to small fires: we observed that 2.02 Mkm 2 (out of a total of 4.89 Mkm 2 ) was burned by fires smaller than 100 ha, whereas the MODIS product only detected 0.13 million km 2 BA in that fire-size class. This increase in BA subsequently resulted in increased estimates of fire emissions; we computed 31 to 101% more fire carbon emissions than current estimates based on MODIS products. We conclude that small fires are a critical driver of BA in sub-Saharan Africa and that including those small fires in emission estimates raises the contribution of biomass burning to global burdens of (greenhouse) gases and aerosols., Competing Interests: The authors declare no competing interest., (Copyright © 2021 the Author(s). Published by PNAS.)