New ECMWF Experiments Prove Weather Investments in Poor Nations Improve Forecasts

A pioneering set of impact experiments by the European Centre for Medium-Range Weather Forecasts (ECMWF), commissioned by the World Meteorological Organization (WMO), has provided the most compelling scientific evidence to date that investing in basic weather and climate observations in under-resourced regions significantly improves the accuracy of global weather forecasts.

The experiments, which were developed in the context of the Systematic Observations Financing Facility (SOFF), confirm that closing observational gaps—especially in Least Developed Countries (LDCs) and Small Island Developing States (SIDS)—not only strengthens local early warning systems but also enhances the performance of global forecasting models, potentially saving lives and bolstering economic and climate resilience worldwide.

"Without Data, There Is No Forecast" – Why the Gaps Matter

Despite technological advances in forecasting, large parts of the world remain blind spots in the global observing system, particularly in Africa, the Pacific, and the Caribbean. In these areas, surface and upper-air observations, such as radiosonde (weather balloon) data, are either sparse or non-existent. The result is reduced reliability of forecasts, both regionally and globally.

“Without data, there is no forecast,” stressed Celeste Saulo, Secretary-General of the WMO. “The ECMWF impact experiments provide the strongest scientific evidence to date that SOFF investments to close these blind spots dramatically improve forecast accuracy.”

The Experiments: How Simulated Observations Transformed Accuracy

The ECMWF team designed eight SOFF investment scenarios that simulated the effect of adding new surface, upper-air, and marine observations in countries with major observational gaps. These simulated datasets were then fed into ECMWF’s operational forecasting model using advanced data assimilation techniques.

The results revealed significant forecast improvements:

• Over Africa: Forecast uncertainty decreased by over 30%, showing the greatest potential gains.

• In the Pacific: Uncertainty dropped by up to 20%, especially benefiting island nations highly exposed to tropical storms and rising sea levels.

• Globally: Even though the data came from local upgrades, the benefits extended worldwide, reducing forecast errors across hemispheres.

One of the most critical findings is the outsized impact of upper-air observations, such as radiosonde data, particularly in the tropics, where weather systems rapidly evolve and data scarcity has long limited forecast reliability.

Local Investment, Global Benefits

The experiments not only demonstrated local improvements in 12-hour weather forecast windows, but also found that forecasting accuracy propagated across borders, benefiting countries far removed from the original data source.

“These experiments show how better observations in some of the world’s most vulnerable countries not only improve local early warning systems but also enhance global climate models,” said Florian Pappenberger, ECMWF Director of Forecasts and Deputy Director-General.

SOFF: Funding the Future of Observational Equity

The Systematic Observations Financing Facility (SOFF) is a United Nations multi-agency fund managed by WMO, the UN Development Programme (UNDP), and the UN Environment Programme (UNEP). It provides grant-based financing and technical assistance to help eligible countries generate and share weather observations aligned with the Global Basic Observing Network (GBON) requirements.

The initiative particularly targets LDCs and SIDS—regions on the frontlines of climate change and disasters—supporting the installation, maintenance, and international data exchange of modern weather stations and upper-air sensors.

SOFF is designed to be country-led, with long-term capacity-building and sustainability at its core. It bridges the long-standing gap between weather observation infrastructure funding and data delivery, ensuring investments lead to measurable forecast improvements.

Forecasts Save Lives, Economies, and Ecosystems

Accurate weather forecasts are essential across every sector:

• Farmers depend on forecasts to protect crops from droughts or floods.

• Energy providers use forecasts to balance supply and demand.

• Emergency services rely on accurate data to plan evacuations.

• Logistics and aviation companies depend on forecasts to manage global supply chains.

• Communities need warnings to evacuate or prepare for disasters.

Yet until now, the global forecasting community lacked a clear, quantified basis for where and how new observational investments yield the greatest benefit.

A Turning Point for Global Forecasting Equity

The findings from ECMWF’s impact experiments represent a scientific turning point—providing a robust, evidence-based justification for continued and expanded investments in under-observed regions.

WMO and ECMWF are calling on governments, climate finance institutions, and private-sector partners to scale up contributions to SOFF, thereby ensuring that forecasting equity becomes a reality, not a luxury, for vulnerable countries.

In doing so, the world can collectively enhance resilience to climate extremes, improve economic planning, and protect lives and livelihoods, regardless of where people live.