Netherlands Environmental Assessment Agency,Ministry of Infrastructure and the Environment,Government of Netherlands

Future population growth is expected to concentrate in urban agglomerations that overlap with various natural hazard zones. However, quantifying the resulting risks remains challenging, as hazard areas tend to be bounded locally while population forecasts are produced at much coarser scales. Addressing this gap, the high-resolution 2UP model disaggregates national-level, scenario-based population projections to a 30 arc-seconds grid, simultaneously simulating urban expansion and the distribution of urban and rural populations through 2100. By overlaying these projections with comparably detailed fluvial flood and landslide hazard data, this study demonstrates that, at a global scale, rapid urbanization will disproportionately increase population growth in hazard-prone zones compared to safer areas. This trend is particularly pronounced in sub-Saharan Africa and South Asia, where both the extent of exposed urban land and the magnitude of exposed populations are projected to rise sharply. In contrast, slower growth in North America and Europe leads to more moderate increases in hazard exposure, with smaller differences between hazardous and non-hazardous sites. Notably, while urban areas in many countries continue expanding into high-risk regions, the fraction of the total population exposed to these hazards may stabilize or even decline after 2050. The 2UP model's fine-grained outputs are especially valuable in regions with fragmented urban landscapes, large rural populations, and rapid demographic shifts, providing decision-makers and researchers with critical insights for integrated risk management and sustainable development planning.

Excessive and inefficient nitrogen (N) use in agriculture poses pervasive environmental threats for Water quality, Air quality, Greenhouse gas emissions, Ecosystems and biodiversity, and Soil (WAGES). However, it is unclear whether the global distribution of research corresponds to the severity of these threats. Here we provide a global assessment linking research outputs across WAGES with cropland N surplus, a proxy for the severity of N threats. We show that N surplus correlates well with the number of publications addressing WAGES threats, although marked regional disparities exist. Higher income countries distribute research more evenly across threats associated with high fertiliser inputs, while lower income countries prioritise soil research, particularly soil fertility. Publications from lower income countries account for only 8 % of the total and focus largely on food security rather than on N pollution. Since these countries are responsible for half of global N losses, they represent important "low hanging fruits" where targeted research can simultaneously improve food security and reduce N pollution. Our study highlights the need to strengthen research capacity, support locally led priorities, and better align research investments with the severity of N threats to advance toward more equitable and effective N management.

In 2025, almost 130 countries submitted new national climate plans, known as nationally determined contributions (NDCs), outlining mitigation targets for 2035. This study evaluates their impact on emissions for all countries and assesses their ambition levels, with a main focus on the G20 economies. Full implementation of unconditional and conditional NDCs would reduce projected median global greenhouse gas emissions in 2035 by approximately 7% and 11% respectively, compared to 2019 levels—still falling short of the reductions needed to align with below 2°C and 1.5°C pathways. Among the G20, four economies—Australia, the EU, Japan, and the United Kingdom—have set new NDC targets on a linear path to net-zero emissions. In contrast, Brazil, Canada, the Russian Federation, and South Africa have NDCs misaligned with their net-zero targets. For the remaining G20 economies that have yet to peak—China, Indonesia, Mexico, the Republic of Korea, and Türkiye—transitioning to net-zero emissions must occur within 15 to 35 years, a timeline significantly shorter than the 37 to over 60 years required by those that have already peaked, underscoring the urgency for rapid decarbonization after 2035. Lastly, the majority of G20 economies do not meet 2035 reduction targets derived from Paris-aligned equity-based effort-sharing approaches.

This study presents a novel integrated methodology that combines harmonized simulation and optimization models to evaluate the effectiveness and efficiency of low-carbon policy instruments. We introduce IESA-Sim, a simulation model that uses agent-based modeling to represent heterogeneous investment behavior and a broad range of policy tools, including CO2 taxes, subsidies, and technology portfolio standards. IESA-Sim is harmonized with IESA-Opt, a cost-optimization model that shares the same energy system architecture, database, and temporal resolution. This alignment enables direct comparison between behavior-driven and cost-optimal decarbonization pathways, which is a novelty in the field; the IESA framework enables a structured evaluation of how policy instruments interact with behavioral diversity, system architecture, and economic constraints. It provides a transparent and modular tool to explore the implications of different policy mixes, agent behaviors, and technology assumptions. The framework is applied to the Netherlands, assessing four scenarios that combine different policy portfolios and agent preference structures. Results show that renewable technologies are adopted even under weak policies, but full decarbonization requires targeted interventions, especially in harder-to-abate sectors. Heterogeneous agents accelerate adoption under weak policies but increase inefficiency under strong ones. Comparing scenarios against a Pareto front from IESA-Opt reveals transition inefficiencies of 2.6-5.7 billion euros per year, or 28 to 48 euros per mitigated ton of CO2. Our analysis concludes that a fully decarbonized system is more affordable by 2050 than a fossil-based alternative (considering a very conservative development of EUA prices), but reaching that point requires high upfront investments and an accelerated turnover of technologies. These costs are concentrated between 2035 and 2045, driven by early adoption, immature supply chains, and the premature replacement of fossil-based assets. Nonetheless, once installed, the clean energy system benefits from low operating costs and a reduced fuel dependence.

Over the past 15 years, the planetary boundaries (PB) framework has advanced as a scientific approach to define limits for Earth’s system processes, including boundaries for nitrogen (N) and phosphorus (P). These boundaries have been conceptualized and quantified using various approaches, leading to varying estimates and interpretations. In this paper, we review existing control variables and methods used to define and quantify ‘safe’ N and P boundaries for environmental impacts and ‘just’ N and P boundaries for food production. Based on our analysis, we propose that ‘N losses’ (N delivery to surface water, N leaching to groundwater, and NH 3 emissions to air) and ‘P delivery to surface water’ are the most suitable control variables for defining ‘safe’ boundaries for biogeochemical flows of these elements. We present quantitative estimates for both ‘safe’ planetary N and P boundaries, for N based on previous studies and for P based on new calculations. We then assess the contribution of the food system (including agricultural production, aquaculture, and human wastewater streams) to N and P losses. We propose to define ‘just’ boundaries for N and P based on the required input of these nutrients to meet the dietary needs of the population. We indicate possible values for such ‘just’ N and P boundaries and provide options to attain those boundaries while staying with ‘safe’ N and P boundaries.