The summer cooling effect under the projected restoration of Aral Sea in Central AsiaHe, Huili; Hamdi, Rafiq; Luo, Geping; Cai, Peng; Yuan, Xiuliang; Zhang, Miao; Termonia, Piet; De Maeyer, Philippe; Kurban, Alishir
doi: 10.1007/s10584-022-03434-8pmid: N/A
The Aral Sea once covered 68 × 103 km2, but lost 90% of its area during the last decades due to unreasonable water resources utilization. Fortunately, some measures to save the Aral Sea have been proposed. Regional climate model ALARO-SURFEX was applied in dynamic downscaling simulations to quantify the climatic effects generated by increasing greenhousegas (GHG) emissions and the Aral Sea restoration. The results show that performance of CNRM-CM5 dynamically downscaled by ALARO-SURFEX in reproducing 2-m temperature is reliable and better than outputs of 17 global climate models. If the Aral Sea kept the almost dry-up state (8.6 × 103 km2) in the future (2021–2050), the Aral Sea region will suffer a warmer summer than in historical period. Daily maximum (T2max), mean (T2avg), and minimum (T2min) temperature will rise by 0.91 °C, 1.06 °C, and 1.22 °C, respectively, and reduce diurnal temperature range (DTR) by 0.31 °C. If the Aral Sea could recover to twice its current area (17.2 × 103 km2), the T2max and T2avg (T2min) over the ambient region of Aral Sea (350 km) will reduce (increase) by 1.54 and 1.10 °C (1.16 °C), respectively, which can dampen the DTR by 2.4 °C. The cooling effect induced by the projected Aral Sea restoration is mainly contributed by enhanced latent heat. While the warming effect caused by GHG emissions increase is primarily attributed to increased incoming longwave radiation. This study quantified the summer cooling effect under the projected restoration of Aral Sea, which could provide scientific reference in working out the sustainable development strategies under the warming threat in Central Asia.
If a tree grows no ring and no one is around: how scientists deal with missing tree ringsLi, Dan
doi: 10.1007/s10584-022-03424-wpmid: N/A
Responding to a discrepancy between dendro-reconstruction and climate model during large volcano eruptions, scientists have been debating a missing tree ring (MTR) hypothesis—trees missing an annual ring at a large scale due to extreme cooling. Although both parties claim victory, their arguments are shown to be compromised in our analysis. On the one hand, one party’s argument based on the rarity of missing rings in current data cannot serve as evidence against the MTR because data collection methods already assume the MTR to be impossible; on the other, the other party’s hypothesis testing cannot support the MTR because it merely shows that data in volcanic years are less certain, which is known. Lastly, our analysis highlights a current knowledge gap in tree growth in extreme conditions and thus we urge scientists to perform natural and interventional experiments to understand tree growth limitations. Filling this gap will enhance dendro-reconstructions.
A case for ensuring reductions in CO2 emissions are given priority over reductions in CH4 emissions in the near termMcKeough, Paterson
doi: 10.1007/s10584-022-03428-6pmid: N/A
For several base scenarios, the impacts, on the global mean temperature, of the time of instigation of reductions in emissions of carbon dioxide (CO2) and methane (CH4) were estimated using standard methods. It was confirmed that the necessary bending over of the global temperature curve is crucially dependent on the rapid phaseout of CO2 emissions. Reductions in CH4 emissions could be delayed till the period 2050–2080 without appreciably affecting the global temperature in 2100. For pathways consistent with the Paris Agreement, the analysis highlighted the dependence of the abatement costs associated with a temperature overshoot on whether the overshoot is primarily due to a delay in reducing CO2 emissions or primarily due to a delay in reducing CH4 emissions. A delay in reducing CO2 emissions increases both the overshoot and the abatement costs accrued over the century, whereas although it also increases the overshoot, a delay in reducing CH4 emissions until the period from 2050 to 2080 actually lowers overall abatement costs. To minimize the risk of the enabling resources being inadequate for the essential near-term reductions in CO2 emissions, a new instrument is needed to ensure that if the rate of reduction of CO2 emissions is deemed to be insufficient for achieving a 1.5 °C consistent pathway with limited overshoot, near-term reductions in CO2 emissions are given priority over near-term reductions in CH4 emissions. The replacement of the default GWP100 metric for CH4 by the time-dependent GTP metric, with the year 2100 as the endpoint, is proposed as the basis of the new instrument.
Being green or being nice? People are more likely to share nicer but potentially less impactful green messagesLiu, Syalie; Altay, Sacha; Mercier, Hugo
doi: 10.1007/s10584-022-03429-5pmid: N/A
Citizens can play an important role in disseminating scientific information about climate change, if motivated to do so. However, expressing green positions has the potential to negatively affect people’s reputation, by making them look judgmental for instance. In three experiments among US and UK participants (N = 1197), we investigate the reputational costs of sharing statements about climate change that vary in accuracy and in potential impact. In experiment 1, we show that participants judge more negatively someone sharing a bleak (but arguably more accurate) statement about climate change (e.g., calling it “climate breakdown”), compared to a control statement. Experiment 2 replicates this finding with control statements (e.g., “The richest 1% in the world is responsible for most of the greenhouse gas emissions”) compared to accusatorial statements (adding “because most citizens in countries like the United States consume too much energy”). Experiment 3 shows that participants are less willing to share more accusatorial statements—even though they are thought to exert a greater effect on their audience. Our results further show that the fear of appearing judgmental and unfriendly might make people less likely to share bleaker or more accusatorial—even if more accurate or potentially effective—statements about climate change.
Climate change alters aging patterns of reservoir aquatic habitatsMiranda, Leandro E.; Faucheux, Nicky M.
doi: 10.1007/s10584-022-03432-wpmid: N/A
Two slow-moving developments are threatening reservoir aquatic habitats globally: aging and climate change. These events are projected to transform reservoir aquatic habitats in various and often unpredictable ways. Aging affects in-lake habitats directly, whereas climate change affects both in-lake and off-lake conditions. Climate change is expected to accelerate and, in some instances, possibly decelerate aging. Aging can be indexed as functional age, an index that signals the position of a reservoir along its lifespan relying on in-lake descriptors of aquatic habitat. Using existing habitat datasets and climate projections, we developed semi-quantitative predictions about the effect of climate change on reservoir functional age in the USA. Driven by increased warming, functional age was predicted to increase latitudinally from south to north with no obvious longitudinal gradient. Functional age also changed with precipitation, increasing latitudinally from south to north and longitudinally in the east and west but decreasing in the central USA. Our projections are tentative because of the uncertain nature of reservoir aging and climate change sciences, as well as the inexactness of available data and models. We review general strategies suitable for systematically dealing with the unpredictable and constantly changing conditions expected to occur this century as reservoirs certainly continue to get older, within the scope of uncertain climate change projections.
Fear emotion reduces reported mitigation behavior in adolescents subject to climate change educationWang, Xueqi; Chen, Jin
doi: 10.1007/s10584-022-03419-7pmid: N/A
Emotion has been recognized as a significant factor affecting climate engagement behavior. However, empirical experiments testing emotions influencing behavioral changes, climate change education (CCE) in particular, are rare. In this study, we conducted a 2-week CCE program with the support of video clips to induce emotions such as fear and/or hope through the manipulated treatments and were then compared between emotion plus lecture group and lecture-only group for adolescents to explore how emotions affect self-reported mitigation behavior toward climate change. The study involved 1730 students from nine middle schools in three coastal cities (Xiamen, Shenzhen, and Ningbo) in China. The results demonstrated that emotional video clips were the successful stimulus for target emotions. There was a significant improvement in both knowledge-gaining and self-reported mitigation behavior in the lecture-only group, and climate change concern and involvement mediated the effect on mitigation behavior. Compared to the lecture-only group, the hope treatment group showed decreased knowledge gain but no significant effect on self-reported mitigation behavior. In contrast, emotion significantly reduced students’ self-reported mitigation behavior in the fear treatment group, which was mostly pinpointed to the behavioral change of emission reduction activities. Thus, the study highlighted the importance of knowledge with appropriate emotions in adolescents to safeguard educational outcomes.
Prosets: a new financing instrument to deliver a durable net zero transitionMitchell-Larson, Eli; Allen, Myles
doi: 10.1007/s10584-022-03423-xpmid: 36185778
Interest in carbon offsetting is resurging among companies and institutions, but the vast majority of existing offerings fail to enable a credible transition to a durable net zero emission state. A clear definition of what makes an offsetting product “net zero compliant” is needed. We introduce the “proset”, a new form of composite carbon credit in which the fraction of carbon allocated to geological-timescale storage options increases progressively, reaching 100% by the target net zero date, generating predictable demand for effectively permanent CO2 storage while making the most of the near-term opportunities provided by nature-based climate solutions, all at an affordable cost to the purchaser.
Spatiotemporal variability in exposure to excessive heat at the sub-urban scaleShafran-Nathan, Rakefet; Broday, David M.
doi: 10.1007/s10584-022-03425-9pmid: N/A
Exposure to excessive heat can lead to adverse health outcomes in both healthy and vulnerable individuals. This study examines the spatiotemporal variability of exposure to severe heat at the sub-neighborhood scale using temperature and relative humidity measurements of a wireless distributed sensor network (WDSN). First, we demonstrate a multi-sensor calibration scheme for the temperature and the relative humidity sensors. Next, exposure to heat was calculated using the heat index (HI) scale, which enables linking exposure to HI and heat-related health risks. We noticed repeated exposures to excessive heat above the safe threshold for about 8 h per day throughout July–August, 2015, in Haifa, Israel. Persistent exposure to such conditions is unhealthy. The areas that experienced high HI were scattered across the study area, with the HI showing spatiotemporal variability. In general, in some microenvironments, the HI peaked earlier during the day than in other microenvironments. This was attributed to variability in urban physical drivers, which were found to be good predictors of the morning HI variability buildup but less so of the HI variability in the afternoon. Our results are consistent with summer HI occurrence in the study area in the past 20 years. Since exposure to excessive heat in the east Mediterranean is expected to increase in the future due to climate changes, it may result in a grave health toll.Graphical abstract[graphic not available: see fulltext]