Climate Analytics

Crop yield and the availability of arable land are impacted by climate change, leading to effects on global patterns of production and trading. To gain more precise insights in how future climate change might lead to redistributing productive crop areas, we developed a new method to assess climatic crop suitability, which combines temperature and precipitation suitability through water balance calculations. We applied the method to evaluate the effects of climate change under two climatic scenarios (SSP2-4.5 and SSP5-8.5), using an ensemble of five general circulation models, for nine crops (Arabica coffee, cassava, common beans, common wheat, maize, plantain, rice, sorghum and sugarcane) for four periods of time: past (1995–2014), present day (2015–2034), medium term (2040–2059), long term (2080–2099). We observed that the fraction of area with optimal suitability might be on a downward trajectory for coffee, cassava, beans, wheat and plantain, and could be halved by the end of the century. The tropics and sub-tropics are negatively affected for all crops, while mid-latitudes see large decreases in suitability for beans, wheat and maize. Global patterns show that suitability decreases at local levels (in about 30% of the global area for bean and wheat) are not compensated by increases in suitability elsewhere (in about 19% of the area for bean and wheat). As relocation and expansion of production areas are constrained by available arable land, other strategies might be considered to improve suitability, such as irrigation, which would increase the area of optimal suitability from 5%–25% to 40%–50% of total arable land for the nine crops. Drainage could improve the optimal suitability area fivefold for maize and sorghum, while shading increases suitability for coffee (by up to 20% in both cases). The increased risk of food supply shortages led by climatic suitability loss may trigger increased deforestation if adaptation measures are not implemented.

Since its emergence in the 1990s, the science of attributing observed phenomena to human-induced and natural climate drivers has made remarkable progress. To ensure the relevance and uptake of climate impact attribution studies, scientists must effectively engage with stakeholders. This engagement allows stakeholders to pose key questions, which scientists can then substantiate with evidence evaluating the existence of causal links. Although significant advancements have been made in climate impact attribution science, much work remains to understand the varied requirements of different stakeholders for impact attribution findings. This perspective explores the usefulness of stakeholder engagement in climate impact attribution, the challenges it presents, and how it can be made more relevant for addressing societal questions. It advocates for prioritizing stakeholder involvement to achieve greater transparency, legitimacy, and practical application of findings. Such involvement can enhance the societal impact of attribution studies and support informed decision-making in the face of climate change.

To achieve the 1.5°C target of the Paris agreement, rapid, sustained, and deep emission reductions are required, which often includes negative emissions through land‐based mitigation. However, the effects of future land‐use change on climate are often not considered when quantifying the climate‐induced impacts on human heat stress and labor capacity. By conducting simulations with three fully coupled Earth System Models, we project the effects of land‐use change on heat stress and outdoor labor capacity for two contrasting future land‐use scenarios under high‐ambition mitigation. Achieving a sustainable land‐use scenario with increasing global forest cover instead of an inequality scenario with decreasing forest cover in the Global South causes a global cooling ranging between 0.09°C and 0.35°C across the Earth System Models. However, the effects on human heat stress are less strong, especially over the regions of intense land‐use change such as the tropics, where biogeophysical effects on near‐surface specific humidity and wind speed counteract the cooling effect under warm extremes. The corresponding influence on outdoor labor capacity is small and inconsistent across the three Earth System Models. These results clearly highlight the importance of land‐use change scenarios for achieving global temperature targets while questioning the adaptation potential for reduction in heat stress.

Summer heat extremes increasingly co‐occur worldwide, posing disastrous impacts on our society and the environment. However, the spatial pattern and underlying mechanisms of concurrent heat extremes remain unclear. We used a statistical framework to estimate the spatial concurrence strength of heat extremes in the Northern Hemisphere and identified their relationships to global warming, atmospheric circulation, and land‐atmosphere feedbacks. Concurrent heat extremes over different regions have significantly increased in the Northern Hemisphere from 1950 to 2023. Moreover, heat extremes show strong spatial concurrence strength, and the driving factors vary geographically. Global warming is responsible for long‐term increases in the frequency and strength of concurrent heat extremes, with most pronounced impact in tropical regions. In the absence of warming trends, the temporal and spatial variations in concurrent heat extremes are mainly caused by simultaneous high atmospheric pressure controlled by large‐scale circulations, particularly in mid‐latitude regions. While low soil moisture enhances regional heat extremes through land‐atmosphere feedbacks, it plays a minor role in driving concurrent heat extremes alone but can contribute in combination with high‐pressure anomalies. Given the ever‐increasing risks of heat extremes, our study underscores the importance of identifying the mechanisms of spatially concurrent heat extremes to improve prediction and mitigation of widespread heatwaves and their adverse impacts on socio‐economic sustainability and human well‐being.

We describe the latest version of the NASA Earth eXchange Downscaled Climate Projections 30 arcseconds (NEX-DCP30-CMIP6). The archive contains downscaled historical and future projections for 1950–2100 based on output from Phase 6 of the Climate Model Intercomparison Project (CMIP6). The downscaled products were produced using a daily variant of the monthly bias correction/spatial disaggregation (BCSD) method and are at 30-arcsecond horizontal resolution. Four variables (maximum temperature, minimum temperature, precipitation, and vapour pressure) from five CMIP6 experiments (historical, and the four Tier 1 scenarios: SSP1.2-6, SSP2.4-5, SSP3.7-0, and SSP5.8-5) are provided as available from thirty global climate models. The downscaled data cover the coterminous United States (CONUS), extending from approximately 24-50 degrees North and 235–294 degrees East.

Due to insufficient climate action over the past decade, it is increasingly likely that 1.5 °C of global warming will be exceeded – at least temporarily – in the 21st century. Such a temporary temperature overshoot carries additional climate risks which are poorly understood. Earth System Model climate projections are only available for a very limited number of overshoot pathways, thereby preventing comprehensive analysis of their impacts. Here, we address this issue by presenting a novel dataset of spatially resolved emulated annual temperature projections for different overshoot pathways. The dataset was created using the FaIR and MESMER emulators. First, FaIR was employed to translate ten different emission scenarios, including seven that are characterised by overshoot, into a large ensemble of forced global mean temperatures. These global mean temperatures were then converted into stochastic ensembles of local annual temperature fields using MESMER. To ensure an optimal tradeoff between accurate characterization of the ensemble spread and storage requirements for large ensembles, this procedure was accompanied by testing the sensitivity of sample quantiles to different ensemble sizes. The resulting dataset offers the unique opportunity to study local and regional climate change impacts of a range of overshoot scenarios, including the timing and magnitude of temperature thresholds exceedance.

Achieving net-zero global emissions of carbon dioxide (CO2), with declining emissions of other greenhouse gases, is widely expected to halt global warming. CO2 emissions will continue to drive warming until fully balanced by active anthropogenic CO2 removals. For practical reasons, however, many greenhouse gas accounting systems allow some 'passive' CO2 uptake, such as enhanced vegetation growth owing to CO2 fertilization, to be included as removals in the definition of net anthropogenic emissions. By including passive CO2 uptake, nominal net-zero emissions would not halt global warming, undermining the Paris Agreement. Here we discuss measures to address this problem, to ensure residual fossil fuel use does not cause further global warming: land management categories should be disaggregated in emissions reporting and targets to better separate the role of passive CO2 uptake; where possible, claimed removals should be additional to passive uptake; and targets should acknowledge the need for Geological Net Zero, meaning one tonne of CO2 permanently restored to the solid Earth for every tonne still generated from fossil sources. We also argue that scientific understanding of Net Zero provides a basis for allocating responsibility for the protection of passive carbon sinks during and after the transition to Geological Net Zero.

As exceeding the 1.5°C level of global warming is likely to happen in the near future, understanding the response of the ocean‐climate system to temporarily overshooting this warming level is of critical importance. Here, we apply the Adaptive Emissions Reduction Approach to the Earth System Model GFDL‐ESM2M to conduct novel overshoot scenarios that reach 2.0, 2.5 and 3.0°C of global warming before returning to 1.5°C over the time period of 1861–2500. We also perform a complementary scenario that stabilizes global temperature at 1.5°C, allowing to isolate impacts caused by the temperature overshoots alone, both during their peaks and after their reversals. The simulations indicate that substantial residual ocean surface warming persists in the high latitudes after the overshoots, with most notable regional anomalies occurring in the North Atlantic (up to +3.1°C in the 3°C overshoot scenario compared to the 1.5°C stabilization scenario) and the Southern Ocean (+1.2°C). The residual warming is primarily driven by the recoveries of the Atlantic and Southern Ocean meridional overturning circulation and associated increases in ocean heat transport. Excess subsurface heat storage in low and mid‐latitudes prevents steric sea level rise (SLR) from reverting to 1.5°C stabilization levels in any overshoot scenario, with steric sea level remaining up to 32% higher in the 3°C overshoot scenario on centennial time scales. Both peak impacts and persistent changes after overshoot reversal bear significant implications for future assessments of coastlines, regional climates, marine ecosystems, and ice sheets.

Background Land-use and land-cover change (LULCC) can substantially affect climate through biogeochemical and biogeophysical effects. Here, we examine the future temperature–mortality impact for two contrasting LULCC scenarios in a background climate of low greenhouse gas concentrations. The first LULCC scenario implies a globally sustainable land use and socioeconomic development (sustainability). In the second LULCC scenario, sustainability is implemented only in the Organisation for Economic Cooperation and Development countries (inequality). Methods Using the Multi-Country Multi-City (MCC) dataset on mortality from 823 locations in 52 countries and territories, we estimated the temperature–mortality exposure–response functions (ERFs). The LULCC and noLULCC scenarios were implemented in three fully coupled Earth system models (ESMs): Community Earth System Model, Max Planck Institute Earth System Model, and European Consortium Earth System Model. Next, using temperature from the ESMs’ simulations and the estimated location-specific ERFs, we assessed the temperature-related impact on mortality for the LULCC and noLULCC scenarios around the mid and end century. Results Under sustainability, the multimodel mean changes in excess mortality range from −1.1 to +0.6 percentage points by 2050–2059 across all locations and from −1.4 to +0.5 percentage points by 2090–2099. Under inequality, these vary from −0.7 to +0.9 percentage points by 2050–2059 and from −1.3 to +2 percentage points by 2090–2099. Conclusions While an unequal socioeconomic development and unsustainable land use could increase the burden of heat-related mortality in most regions, globally sustainable land use has the potential to reduce it in some locations. However, the total (cold and heat) impact on mortality is very location specific and strongly depends on the underlying climate change scenario due to nonlinearity in the temperature–mortality relationship.

Global emission reduction efforts continue to be insufficient to meet the temperature goal of the Paris Agreement¹. This makes the systematic exploration of so-called overshoot pathways that temporarily exceed a targeted global warming limit before drawing temperatures back down to safer levels a priority for science and policy2–5. Here we show that global and regional climate change and associated risks after an overshoot are different from a world that avoids it. We find that achieving declining global temperatures can limit long-term climate risks compared with a mere stabilization of global warming, including for sea-level rise and cryosphere changes. However, the possibility that global warming could be reversed many decades into the future might be of limited relevance for adaptation planning today. Temperature reversal could be undercut by strong Earth-system feedbacks resulting in high near-term and continuous long-term warming6,7. To hedge and protect against high-risk outcomes, we identify the geophysical need for a preventive carbon dioxide removal capacity of several hundred gigatonnes. Yet, technical, economic and sustainability considerations may limit the realization of carbon dioxide removal deployment at such scales8,9. Therefore, we cannot be confident that temperature decline after overshoot is achievable within the timescales expected today. Only rapid near-term emission reductions are effective in reducing climate risks.

Non-technical summaryLoss and damage is treated as comprising separate ‘economic’ and ‘non-economic’ dimensions in research and policy. While this has contributed to greater awareness and visibility of non-economic values, our empirical insights show that the two are inextricably linked and that research aimed at informing policy must be better attuned to the multifaceted and cascading nature of loss and damage. Technical summaryIn research and policy, climate-related loss and damage is commonly categorized as either ‘economic’ or ‘non-economic’. One clear benefit of this dichotomy is that it has raised people's awareness of the often under-discussed intangible loss and damage. However, empirical research shows that these two categories are inextricably linked. Indeed, ‘economic’ and ‘non-economic’ loss and damage often overlap, with items that are valued in monetary terms also having non-monetary significance. For example, the loss of a home due to flooding is not only a financial loss but can also have a profound impact on identity and well-being. Moreover, ‘economic’ loss and damage can cascade into ‘non-economic’ loss and damage, and vice versa. For example, when a household incurs economic losses due to drought, this may prevent their children from attending school, which has long-term financial consequences. We argue that rather than dichotomizing loss and damage, recognizing that it is multidimensional, interwoven, and evolving over time will open up new avenues for research that better reflect reality and can therefore better inform policies to address loss and damage. Social mediaThis comment shows how economic and non-economic loss and damage are linked, which has important policy implications.

In seasonal weather forecasting, the exact location within a study area determines the relationship between local predicted variables and global predictors. Both dynamic models and machine learning approaches that define models for single grid points can determine these relationships with high spatial granularity, but at high computational cost. To avoid the latter, clustering of predicted variables is often used in machine learning approaches, which however sacrifices geographical resolution. In this paper, we present a machine learning approach that is a hybrid between gridpoint and cluster-based approaches (finres_S2S). This approach preserves geographical resolution, but at low computational cost, and is tested for monthly 2-m temperature (2T) and precipitation (TP) in Tanzania and for a lead time of up to 6 months. The finres_S2S approach has a number of advantages over both the cluster and point approaches, including that of obtaining good results compared to a dynamic model. We find that the dominant predictors for the application area are associated with El Niño–Southern Oscillation, the Madden–Julian oscillation, and the Indian Ocean dipole. Significance Statement Seasonal forecasting of atmospheric parameters is important in various fields including agriculture. Machine learning makes it possible to forecast at lower computational costs than dynamic models. This advantage is even more important in certain regions of the world. The hybrid model developed here (finres_S2S) allows seasonal forecasting with a spatial resolution equal to that of ERA5 data and a low cost in calculation time. The model is tested over Tanzania, and the seasonal forecast scores outperform those of ECMWF. The development of the use of machine learning in seasonal forecasting seems to provide a complementary response to dynamic models, and research efforts in this direction should be pursued.

Under current emission trajectories, temporarily overshooting the Paris global warming limit of 1.5 °C is a distinct possibility. Permanently exceeding this limit would substantially increase the probability of triggering climate tipping elements. Here, we investigate the tipping risks associated with several policy-relevant future emission scenarios, using a stylised Earth system model of four interconnected climate tipping elements. We show that following current policies this century would commit to a 45% tipping risk by 2300 (median, 10–90% range: 23–71%), even if temperatures are brought back to below 1.5 °C. We find that tipping risk by 2300 increases with every additional 0.1 °C of overshoot above 1.5 °C and strongly accelerates for peak warming above 2.0 °C. Achieving and maintaining at least net zero greenhouse gas emissions by 2100 is paramount to minimise tipping risk in the long term. Our results underscore that stringent emission reductions in the current decade are critical for planetary stability.

Changing climatic conditions threaten forest ecosystems. Drought, disease and infestation, are leading to forest die-offs which cause substantial economic and ecological losses. In central Europe, this is especially relevant for commercially important coniferous tree species. This study uses climate envelope exceedance (CEE) to approximate species risk under different future climate scenarios. To achieve this, we used current species presence-absence and historical climate data, coupled with future climate scenarios from various Earth System Models. Climate scenarios tended towards drier and warmer conditions, causing strong CEEs especially for spruce. However, we show that annual averages of temperature and precipitation obscure climate extremes. Including climate extremes reveals a broader increase in CEEs across all tree species. Our study shows that the consideration of climate extremes, which cannot be adequately reflected in annual averages, leads to a different assessment of the risk of forests and thus the options for adapting to climate change.

Extreme event attribution assesses how anthropogenic climate change affected an extreme climate event, but typically focuses on individual events. Here, we systematize this approach, and apply it to 187 historical heatwaves reported over the period 2000-2022. We show that climate change has made all these heatwaves more likely and more intense. In particular, 33% of these heatwaves were virtually impossible without anthropogenic influence. Furthermore, this influence rises over time, both in intensity and in likelihood: climate change made the median heatwaves 24 times more likely over 2000-2009, 293 times more likely over 2010-2019 and 1355 times more likely over 2020-2022. We also extend the attribution to the contribution of emitters, by quantifying how much these heatwaves were affected by the emissions of 122 carbon majors (fossil fuel and cement producers), assessed through their full value chain. Our best estimate shows that, depending on the carbon major, between 28 and 62 heatwaves have been made 10,000 times more likely. Even small carbon majors enable heatwaves with their sole contribution.

The 6th Assessment Report from the Intergovernmental Panel on Climate Change lacked sufficient land-sector scenario information to estimate total carbon dioxide removal deployment. Here, using a dataset of land-based carbon dioxide removal based on the scenarios assessed by the Intergovernmental Panel on Climate Change, we show that removals via afforestation and reforestation play a critical near-term role in mitigation, accounting for around 10% (median) of the net greenhouse gas emission reductions between 2020 and 2030 in scenarios that limit warming to 1.5 °C with limited overshoot. Novel carbon dioxide removal technologies such as direct air carbon capture and storage scale to multi-gigatonne levels by 2050 and beyond to balance residual emissions and draw down warming. We show that reducing fossil fuel and deforestation emissions (gross emissions) accounts for over 80% of net greenhouse gas reductions until global net zero carbon dioxide (CO2) independent of climate objective stringency. We explore the regional distributions of gross emissions and total carbon dioxide removal in cost-effective mitigation pathways and highlight the importance of incorporating fairness and broader sustainability considerations in future assessments of mitigation pathways with carbon dioxide removal.

What: A workshop on Rossby waves, heatwaves and compound extreme events was co-organized by the Institute for Atmospheric Sciences and Climate (ISAC) of the National Research Council of Italy (CNR) and the University of Trento, Italy. The workshop gathered experts from different fields, such as extreme events analysis, atmospheric dynamics, climate modeling, Numerical Weather Prediction, with the aim to discuss state-of-the-art research, open challenges, and stimulate networking across different communities. When: 28-30th November 2023. Where: CNR Research Area, Bologna, Italy.

As the likelihood of temporarily exceeding 1.5 °C of global warming rises, understanding the response of the ocean-climate system to overshooting this warming level is of increasing importance. Here, we apply the Adaptive Emissions Reduction Approach to the Earth System Model GFDL-ESM2M to conduct novel overshoot scenarios which temporarily exceed 1.5 °C of global warming to 2.0, 2.5 and 3.0 °C, alongside a complementary scenario that stabilizes global temperature at 1.5 °C. The simulation framework allows to isolate impacts attributable to the temperature overshoots alone, both during their peaks and after their reversals, in simulation timeframes spanning from 1861 to 2500. Our results reveal that, while global sea surface temperatures eventually retrace to 1.5 °C stabilization levels, substantial residual ocean surface warming persists regionally, particularly in the North Atlantic (regional average of up to +3.1 °C in the 3°C overshoot scenario) and the Southern Ocean (+1.2 °C). The residual warming is primarily attributed to the recoveries of the Atlantic and Southern Ocean meridional overturning circulation, resulting in a reversed pattern of disproportionate surface warming in low-latitude oceans found during the transient peak of the overshoot. Excess subsurface heat storage in low and mid-latitudes furthermore prevents steric sea level rise from reverting to 1.5 °C stabilization levels in any overshoot scenario, with sea level remaining up to 32 % higher in the 3 °C overshoot scenario. Both peak overshoot impacts and persistent changes following overshoot reversal bear significant implications for future assessments of coastlines, regional climates, marine ecosystems, and ice sheets.