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On behalf of the journal, AGU, and the scientific community, the editors of Geophysical Research Letters would like to sincerely thank those who reviewed manuscripts for us in 2023. The hours reading and commenting on manuscripts not only improve the manuscripts, but also increase the scientific rigor of future research in the field. With the advent of AGU's data policy, many reviewers have also helped immensely to evaluate the accessibility and availability of data, and many have provided insightful comments that helped to improve the data presentation and quality. We greatly appreciate the assistance of the reviewers in advancing open science, which is a key objective of AGU's data policy. We particularly appreciate the timely reviews in light of the demands imposed by the rapid review process at Geophysical Research Letters. We received 4,512 submissions in 2023 and 5,112 reviewers contributed to their evaluation by providing 8,587 reviews in total. We deeply appreciate their contributions. Individuals in italics provided three or more reviews for GRL in 2023. The editors thank the 2023 peer‐reviewers The editors thank the 2023 peer‐reviewers

Exertional dyspnoea among children and adolescents is a common presenting complaint to general practitioners. Exertional dyspnoea is most commonly attributed to exercise-induced bronchoconstriction (EIB), but there are several other causes including hyperventilation syndrome, breathlessness associated with normal exercise limitation and exercise-induced laryngeal obstruction (EILO). The symptoms of EILO include stridor, throat tightness and difficulty on inspiration. If these are mistaken for EIB, children will receive asthma therapy. The underlying mechanism of EILO includes closure of the larynx during high-intensity exercise, which causes a reduction in airflow and breathlessness. This phenomenon is often associated with a background of psychological stress. Historically, a diagnosis of EILO has been considered ‘rare’ though this may be a reflection of under-recognition. Direct visual observation via laryngoscopy is the gold standard for diagnosis of EILO; however, this is rarely available even in specialised centres. Nevertheless, the diagnosis can usually be made by recognising the characteristic clinical pattern. Here we provide recommendations for appropriate investigations for the determination of EILO, together with suggested treatment.

On behalf of the journal, AGU, and the scientific community, the Editors would like to sincerely thank those who reviewed manuscripts for Geophysical Research Lettersin 2018. The hours reading and commenting on manuscripts not only improves the manuscripts but also increases the scientific rigor of future research in the field. We particularly appreciate the timely reviews, in light of the demands imposed by the rapid review process at Geophysical Research Letters. With the revival of the “major revisions” decisions, we appreciate the reviewers' efforts on multiple versions of some manuscripts. Many of those listed below went beyond and reviewed three or more manuscripts for our journal, and those are indicated in italics. In total, 4,484 referees contributed to 7,557 individual reviews in journal. Thank you again. We look forward to the coming year of exciting advances in the field and communicating those advances to our community and to the broader public. In total, 4,484 referees contributed to 7,557 individual reviews in journal

We propose a dynamical interpretation of model projections for an end‐of‐century wetting in equatorial East Africa. In the current generation of global climate models, increased atmospheric moisture content associated with warming is not the dominant process explaining the increase in rainfall, as the regional circulation is only weakly convergent even during the rainy seasons. Instead, projected wetter future conditions are generally consistent with the El Niño‐like trend in tropical Pacific sea surface temperatures in climate models. In addition, a weakening in moisture convergence over the adjacent Congo Basin and Maritime Continent cores of convection results in the weakening of near‐surface winds, which increases moisture advection from the Congo Basin core toward the East African margin. Overall confidence in the projections is limited by the significant biases in simulation of the regional climatology and disagreement between observed and modeled tropical Pacific sea surface temperature trends to date. Moisture budget decomposition indicates that CMIP5 end of 21st century projections for wetter conditions in equatorial East Africa are primarily due to a weakening of the zonal overturning circulationUncertainties are associated with our limited understanding of the response of sea surface temperatures, El Niño, and monsoons to warming, as well as the realism of East African orography in the models

Given the uncertainties in climate model projections of Sahel precipitation, at the northern edge of the West African Monsoon, understanding the factors governing projected precipitation changes in this semiarid region is crucial. This study investigates how long‐term soil moisture changes projected under climate change may feedback on projected changes of Sahel rainfall, using simulations with and without soil moisture change from five climate models participating in the Global Land Atmosphere Coupling Experiment‐Coupled Model Intercomparison Project phase 5 experiment. In four out of five models analyzed, soil moisture feedbacks significantly influence the projected West African precipitation response to warming; however, the sign of these feedbacks differs across the models. These results demonstrate that reducing uncertainties across model projections of the West African Monsoon requires, among other factors, improved mechanistic understanding and constraint of simulated land‐atmosphere feedbacks, even at the large spatial scales considered here. Climate model projections of Sahel rainfall remain notoriously uncertain; understanding the physical processes responsible for this uncertainty is thus crucial. Our study focuses on analyzing the feedbacks of soil moisture changes on model projections of the West African Monsoon under global warming. Soil moisture‐atmosphere interactions have been shown in prior studies to play an important role in this region, but the potential feedbacks of long‐term soil moisture changes on projected precipitation changes have not been investigated specifically. To isolate these feedbacks, we use targeted simulations from five climate models, with and without soil moisture change. Importantly, we find that climate models exhibit soil moisture‐precipitation feedbacks of different sign in this region: in some models soil moisture changes amplify precipitation changes (positive feedback), in others they dampen them (negative feedback). The impact of those feedbacks is in some cases of comparable amplitude to the projected precipitation changes themselves. In other words, we show, over a subset of climate models, how land‐atmosphere interactions may be a cause of uncertainty in model projections of precipitation; we emphasize the need to evaluate these processes carefully in current and next‐generation climate model simulations. Feedbacks on projected Sahel rainfall from long‐term soil moisture changes significantly impact precipitation projections in climate modelsFeedbacks on climate model projections of Sahel rainfall from long‐term soil moisture changes vary in sign across modelsThese results call for further assessment and evaluation of soil moisture‐atmosphere interactions across current‐generation climate models

On behalf of the journal, AGU, and the scientific community, the editors of Geophysical Research Letters would like to sincerely thank those who reviewed manuscripts for us in 2022. The hours reading and commenting on manuscripts not only improve the manuscripts, but also increase the scientific rigor of future research in the field. With the advent of AGU's data policy, many reviewers have also helped immensely to evaluate the accessibility and availability of data, and many have provided insightful comments that helped to improve the data presentation and quality. We greatly appreciate the assistance of the reviewers in advancing open science, which is a key objective of AGU's data policy. We particularly appreciate the timely reviews in light of the demands imposed by the rapid review process at Geophysical Research Letters. We received 6,687 submissions in 2022 and 5,247 reviewers contributed to their evaluation by providing 8,720 reviews in total. We deeply appreciate their contributions in these challenging times. Individuals in italics provided three or more reviews for GRL in 2022. The editors thank the 2022 peer reviewers The editors thank the 2022 peer reviewers

The response of the terrestrial water cycle to global warming is central to issues including water resources, agriculture and ecosystem health. Recent studies indicate that aridity, defined in terms of atmospheric supply (precipitation, P) and demand (potential evapotranspiration, Ep) of water at the land surface, will increase globally in a warmer world. Recently proposed mechanisms for this response emphasize the driving role of oceanic warming and associated atmospheric processes. Here we show that the aridity response is substantially amplified by land–atmosphere feedbacks associated with the land surface’s response to climate and CO2change. Using simulations from the Global Land Atmosphere Coupling Experiment (GLACE)-CMIP5 experiment, we show that global aridity is enhanced by the feedbacks of projected soil moisture decrease on land surface temperature, relative humidity and precipitation. The physiological impact of increasing atmospheric CO2on vegetation exerts a qualitatively similar control on aridity. We reconcile these findings with previously proposed mechanisms by showing that the moist enthalpy change over land is unaffected by the land hydrological response. Thus, although oceanic warming constrains the combined moisture and temperature changes over land, land hydrology modulates the partitioning of this enthalpy increase towards increased aridity.

Regional information on climate change is urgently needed but often deemed unreliable. To achieve credible regional climate projections, it is essential to understand underlying physical processes, reduce model biases and evaluate their impact on projections, and adequately account for internal variability. In the tropics, where atmospheric internal variability is small compared with the forced change, advancing our understanding of the coupling between long-term changes in upper-ocean temperature and the atmospheric circulation will help most to narrow the uncertainty. In the extratropics, relatively large internal variability introduces substantial uncertainty, while exacerbating risks associated with extreme events. Large ensemble simulations are essential to estimate the probabilistic distribution of climate change on regional scales. Regional models inherit atmospheric circulation uncertainty from global models and do not automatically solve the problem of regional climate change. We conclude that the current priority is to understand and reduce uncertainties on scales greater than 100 km to aid assessments at finer scales.

The unusual severity and return time of the 2005 and 2010 dry‐season droughts in western Amazon is attributed partly to decadal climate fluctuations and a modest drying trend. Decadal variability of western Amazon hydroclimate is highly correlated to the Atlantic sea surface temperature (SST) north‐south gradient (NSG). Shifts of dry and wet events frequencies are also related to the NSG phase, with a 66% chance of 3+ years of dry events per decade when NSG > 0 and 19% when NSG < 0. The western Amazon and NSG decadal covariability is well reproduced in general circulation models (GCMs) historical (HIST) and preindustrial control (PIC) experiments of the Coupled Model Intercomparison Project Phase 5 (CMIP5). The HIST and PIC also reproduce the shifts in dry and wet events probabilities, indicating potential for decadal predictability based on GCMs. Persistence of the current NSG positive phase favors above normal frequency of western Amazon dry events in coming decades. Decadal variability of western Amazon dry‐season hydroclimate is quantifiedAtlantic and Amazon decadal covariability is well reproduced in CMIP5 modelsCurrent Atlantic decadal phase favors drier dry seasons in western Amazon

Much scientific discussion has focused on rising greenhouse gas emissions and changing rainfall patterns in an increasingly warmer world. In fact, preventing the worst impacts of climate change on future human well-being will mean dealing with heightened flood and drought risks. The authors explain why the complex science of the shifting rainfall patterns and intensities caused by global warming is made even more complex by increasingly extreme air pollution. The article describes how scientists now think that the so-called “atmospheric brown cloud” over India affects the summer monsoon more than global warming does. In India, agriculture, industrial productivity, and life in general depend on monsoonal downpours that bring huge amounts of water to the subcontinent, feeding rivers and aquifers and cooling the land between June and September. As bad as it sounds, the scenario in which air pollution plays a major role in climate is actually good news for developing nations such as India. Pollution control is a regional and local problem that developing nations need to address in any case because of the huge human health costs related to it. The authors also warn that once pollution is brought under control, the full extent of global warming caused by developed nations’ greenhouse gas emissions from decades ago will become more prevalent and its impacts on the Indian monsoon will be unmasked.

Daily rainfall records of 39 stations spanning the different agro—climatic zones of Burkina Faso were analyzed to describe the evolution of five seasonal rainfall descriptors over time. The period from1941 to 2000, including the two most contrasted periods in the recent history of the Sahelian climate, i.e. the wet decades (1941–1970) and the dry decades (1971–2000), were considered. It was found that certain seasonal descriptors—namely total seasonal rainfall, number of rain-days and cessation dates of the rainy season—when aggregated into annual and national means manifested almost the same evolution pattern; while others, notably average rainfall per rain-day and onset date of the growing period, showed different patterns of evolution. It was concluded that the recent reduction in seasonal precipitation amount was related to a reduced number of rain-days in August and September, with precocious cessation of the rainy season as a consequence. However, all the seasonal descriptors showed recovery trends since the end of the 1980s, with the mean rainfall per rain-day, exhibiting the steadiest trend. But, the descriptors were more volatile during that recovery time according to the upward trends in their interannual variability. Importantly, the links between the seasonal descriptors and two sea surface temperature indexes were discussed in light of climate change impacts on rain-fed agriculture, the main source of food for the population of Burkina Faso. The results should be incorporated in alleviation strategies of climate change impacts in the Sahel region.

In the Sahel of West Africa, food security is a top development priority. Climate shocks threaten communities that rely on a single rainy season to grow crops and raise livestock. We exploit repeat surveys collected by the World Food Programme to quantitatively assess the year-to-year dynamics of household food security. Our methodology singles out the impact of climate shock on food access. We combine three variables, namely the Food Consumption Score, the Food Expenditure Share and the Reduced Coping Strategies Index to explore the access dimension of food security. Cluster analysis on the three variables leads us to 1) classify into categories, and spatially locate less and more food secure households; and 2) discuss the response of each category of household to seasonality and variability in climate. First, we find that in a drought year, some rural households – with average food security status – that normally do not use coping strategies actually have to use them. Second, we notice that food expenditure share increases in all categories of households, except one. Based on the different ways in which categories of households respond to (climatic) shock we recommend the design of targeted and more efficient interventions. We focus on Senegal because of the unprecedented opportunity to access repeat surveys, including an unusual one, taken during a “crisis” year. However, our methodology and recommendations can inform interventions in other Sahelian countries.

On behalf of the journal, AGU, and the scientific community, the editors would like to sincerely thank those who reviewed the manuscripts for Geophysical Research Lettersin 2019. The hours reading and commenting on manuscripts not only improve the manuscripts but also increase the scientific rigor of future research in the field. We particularly appreciate the timely reviews in light of the demands imposed by the rapid review process at Geophysical Research Letters. With the revival of the “major revisions” decisions, we appreciate the reviewers' efforts on multiple versions of some manuscripts. With the advent of AGU's data policy, many reviewers have helped immensely to evaluate the accessibility and availability of data associated with the papers they have reviewed, and many have provided insightful comments that helped to improve the data presentation and quality. We greatly appreciate the assistance of the reviewers in advancing open science, which is a key objective of AGU's data policy. Many of those listed below went beyond and reviewed three or more manuscripts for our journal, and those are indicated in italics. The editors thank the 2019 peer reviewers

Letters to the editor are presented in response to articles including "Reversal of Fortune," by Patrick Radden Keefe about a lawsuit against Chevron in the January 9, 2012 issue, "Drug Test" by Ariel Levy about Indian philanthropist Kiran Mazumdar-Shaw in the January 2, 2012 issue, and "The Great Oasis" by Burkhard Bilger on desert reforestation in the December 19 and 26, 2011 issues.

The African Sahel experienced severe drying between the 1950s and the 1980s, with partial recovery since. We compare Sahel rainfall in the 20th century, pre‐industrial, and increased greenhouse gases (GHG) simulations produced for the Intergovernmental Panel on Climate Change (IPCC). The simulations forced by 20th century concentrations of aerosol and GHG reproduce (i) a global change in SST akin to that associated with Sahel drought and (ii) a correspondent drying of the Sahel. We conclude that late 20th century Sahel climate was significantly dryer than pre‐industrial, and at least 30% of the drying was externally forced. Comparison between 20th century runs and runs forced by GHG alone reveals the key role of reflective aerosols: they force a gradient in SST that excites robust drying in the northern edge of the Atlantic Inter‐Tropical Convergence Zone (ITCZ) and in the Sahel.