Publications by authors named "J L Lamarque"
Article Synopsis
- * This reduction is due to the movement of ozone-poor and halogen-rich air from the Arctic, which impacts ozone levels further south by decreasing the overall tropospheric ozone column by around 4%.
- * Comparatively, the current effect of Arctic halogens on ozone reduction is less significant than it was in preindustrial times, highlighting a complex relationship between human pollution and natural halogen contributions that should be better represented in global climate models.
Tropospheric ozone (O) is a strong greenhouse gas, particularly in the upper troposphere (UT). Limited observations point to a continuous increase in UT O in recent decades, but the attribution of UT O changes is complicated by large internal climate variability. We show that the anthropogenic signal ("fingerprint") in the patterns of UT O increases is distinguishable from the background noise of internal variability.
View Article and Find Full Text PDFShort-term exposure to ground-level ozone in cities is associated with increased mortality and is expected to worsen with climate and emission changes. However, no study has yet comprehensively assessed future ozone-related acute mortality across diverse geographic areas, various climate scenarios, and using CMIP6 multi-model ensembles, limiting our knowledge on future changes in global ozone-related acute mortality and our ability to design targeted health policies. Here, we combine CMIP6 simulations and epidemiological data from 406 cities in 20 countries or regions.
View Article and Find Full Text PDFBackground: Morbidity burdens from ambient air pollution are associated with market and non-market costs and are therefore important for policymaking. The estimation of morbidity burdens is based on concentration-response functions (CRFs). Most existing CRFs for short-term exposures to PM assume a fixed risk estimate as a log-linear function over an extrapolated exposure range, based on evidence primarily from Europe and North America.
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- Atmospheric methane is a significant greenhouse gas with both natural and human-made sources, and adding chlorine to the atmosphere has been suggested as a way to reduce methane's impact on global warming.
- Research indicates that to effectively lower methane levels by specific targets (20%, 45%, or 70% by 2050), a substantial increase in chlorine emissions (from 630 to 1880 Tg Cl/year) is required due to the non-linear nature of atmospheric chemistry.
- The proposed increase in chlorine emissions could lead to a decrease in surface temperature by up to 0.6 °C by 2050, but careful consideration of the environmental implications, including air quality and ocean acidity, is essential before proceeding with this approach.