Summary

Cities are highly vulnerable to climate change. Essential Climate Variables (ECVs) from Earth Observation (EO) data provide valuable insights, but the coarse resolution limits their applicability for intracity-scale assessments. The MOMO-NBS project aims to assess how climate change affects cities with different structures and to evaluate the effectiveness of Nature-Based Solutions for resilience. This is achieved by means of two studies: a global study to correlate existing ECVs to urban morphologies at the city scale; a local study for selected cities integrating information about 2D/3D urban morphology and green/grey infrastructure with ECVs. By linking ECVs with urban spatial patterns, MOMO-NBS advances knowledge relevant to the 2027 IPCC Special Report on Climate Change and Cities and contributes to WMO/GCOS priorities on urban climate monitoring and sustainable urban planning.

From a scientific perspective, several key challenges motivate this project. First, while ECVs are essential for assessing climate trends, their coarse spatial resolution limits their use for urban climate services. Downscaling and integrating ECVs with high-resolution EO products are critical to enable neighborhood-scale assessments relevant to city planning. Second, there is a lack of systematic analysis linking 2D/3D urban morphology to climate impacts and NBS effectiveness. Compact city structures can intensify heat and air pollution but also interact in complex ways with NBS measures such as green roofs or urban vegetation. Current studies remain localized, and a standardized global methodology is missing. Third, there is a persistent mismatch between the scale of available ECVs, and the granularity required by urban stakeholders for effective adaptation planning. This gap undermines the potential for cities to evaluate the effectiveness of NBS and report progress towards climate targets. Finally, knowledge gaps also exist in aligning international adaptation policies with local implementation needs, highlighting the importance of stakeholder-informed approaches.

By addressing these scientific and policy challenges, MOMO-NBS will enhance the usability of ECVs for urban applications, provide recommendations to update GCOS requirements, and deliver evidence directly relevant to the upcoming IPCC Special Report on Cities, thus supporting both global climate science and local decision-making.

This report requires robust evidence on urban climate processes and adaptation measures, including the role of Earth Observation (EO) and Essential Climate Variables (ECVs). MOMO-NBS directly contributes to these policy agendas by generating knowledge and methods to bridge current gaps between global datasets and local urban needs.

Aims and Objectives

The aim of MOMO-NBS is to improve understanding of how climate change impacts cities with different morphologies and how Nature-Based Solutions (NBS) contribute to resilience. The project directly supports the ESA Climate Change Initiative: climate and cities activity by addressing the gap between coarse-scale Essential Climate Variables (ECVs) and urban morphology and explore how to downscale current ECVs to obtain the detailed information required for urban climate services.The project pursues three main objectives:

1. Assess climate impacts at the city scale by analyzing time series of ECVs in combination with Earth Observation (EO) data, across a diverse set of cities representing different sizes, regions, and climates.
2. Evaluate the role of NBS in reducing climate risks by integrating ECVs with EO-derived 2D/3D morphological information on green and grey infrastructure.
3. Identify knowledge and data gaps limiting the urban application of current ECVs and provide recommendations to enhance their usability for monitoring climate impacts and adaptation responses.

MOMO-NBS will conduct proof-of-concept studies co-developed with stakeholders to demonstrate the added value of EO for city-level climate services. The outcomes will inform the upcoming IPCC Special Report on Climate Change and Cities, while equipping local decision-makers with tools to plan and monitor sustainable, climate-resilient urban development.

WP2: Development of method
Building on WP1, methods will be developed and tested to integrate Essential Climate Variables (ECVs) with Earth Observation (EO) data and 2D/3D urban morphology. This includes harmonization of datasets, quality filtering, and feasibility assessments, as well as defining workflows to ensure uncertainties are considered and EO contributions are maximized.

WP3: Core scientific activities and uncertainty characterization
This work package conducts the main analyses at global and local scales. At the global level, statistical relationships between city morphology and ECV trends will be examined across representative cities worldwide. At the local level, intra-city analyses will quantify the effectiveness of NBS using downscaled ECVs and EO-derived morphological data. Uncertainty will be explicitly assessed to ensure robustness of findings, and results will be disseminated through scientific publications.

WP4: Scientific roadmap and data/code archival
Outputs from WP2 and WP3 will be consolidated into a scientific roadmap, identifying key research priorities and recommendations for future ECV development. Reusable code and tailored data products will be made openly available through GitHub, the CCI Open Data Portal, and other repositories, ensuring transparency and enabling follow-on research.

WP5: Management, outreach and communication
Project management ensures timely delivery, quality control, and close collaboration with ESA climate staff and Technical Officer. Outreach activities will include conference contributions, engagement with the CCI Knowledge Exchange, and regular updates on a project website.