What are early warning systems and why do they matter for climate action?

How do early warning systems work?

Early warning systems function through interconnected processes that ensure accurate, timely and actionable alerts.

Employing ground-based sensors, satellites, weather and hydrological stations, and ocean buoys, meteorologists and climate scientists gather climate and environmental data such as temperature, precipitation, wind patterns and sea levels. They then analyze this data using advanced forecasting models to assess the likelihood and severity of extreme weather events and climate-related hazards.

Once a potential hazard is identified, warnings are disseminated through multiple channels, including TV, radio, mobile services, social media and community networks. Using the appropriate channels in each specific context is vital to ensuring that people and communities at risk receive timely and comprehensible alerts.

This knowledge also informs governments and emergency responders to activate preparedness and response measures, enabling timely evacuations, infrastructure reinforcement, or resource conservation efforts. These response measures need to take into account where and when people and assets are most vulnerable and identify the best available options for responding.

Overall, the effectiveness of an early warning system depends on its ability to translate scientific, environmental and socio-economic information into practical, accessible warnings that reach at-risk populations in time.

Why are early warning systems important for climate action?

Global warming and climate change fuel more frequent and more intense extreme weather events and hazards. Each fraction of a degree of warming increases the risks that communities across the world face and leaves many more people vulnerable and exposed.

Early warning systems are among the most effective tools for reducing climate-related risks. A well-functioning early warning system is multi-hazard in nature, meaning it accounts for multiple hazard risks and how they might interact. This aspect is crucial in the context of climate change impacts as communities can experience hazards they have never faced before or the compounding effects of multiple hazards at the same time. For example, storms can trigger both floods and landslides while droughts, high winds and high temperatures can trigger or increase the severity of wildfires.

Investing in climate information and early warning systems is not only a humanitarian imperative but also a sound economic investment. These systems are one of the most cost-effective climate change adaptation measures, providing up to a tenfold return on investment. Is it estimated that a 24-hours advance warning of an incoming hazard, like a storm or a heatwave, can reduce the ensuing damage by up to 30 percent. Countries with effective early warning systems experience significantly lower disaster-related losses. Strengthening these systems is therefore a priority for climate adaptation worldwide, particularly in least developed countries and fragile and conflict-affected settings where access to information is limited and people, communities and infrastructure are most vulnerable.

What are the benefits of early warning systems?

Early warning systems benefit a wide range of stakeholders. Governments use early warnings to coordinate disaster response and protect public infrastructure. Businesses and farmers leverage climate information to manage risks to supply chains, agriculture and operations. Vulnerable communities, particularly in developing countries, rely on these systems to prepare for and respond to climate shocks.

The key benefits of early warning systems include:

• Reduced loss of life and injury: Early warnings allow people to evacuate or take protective measures before hazards hit, reducing fatalities and injuries.
• Reduced economic losses: Forecasting extreme weather helps businesses, farmers and governments mitigate financial risks by protecting assets and infrastructure.
• Protecting critical infrastructure: Early warnings can allow authorities to take measures to safeguard bridges, roads and energy and healthcare infrastructure which are critical to ensuring people receive the help they need when a hazard hits or during its aftermath.
• Enhanced climate resilience: By raising awareness of risks and promoting preparedness measures, early warning systems contribute to building long-term resilience to climate change impacts.

What are the challenges and the gaps in implementing early warning systems?

Despite significant progress on advancing early warning systems across the world, several challenges remain in ensuring their full effectiveness, particularly in least developed countries and fragile and conflict-affected settings. These include:

• Limited financial resources: Many countries lack the necessary resources to invest in and maintain robust infrastructure and capacities for early warning systems.
• Limited technical capacity: Many countries face shortages of skilled personnel, tools and technologies needed to analyze and interpret climate data.
• Data gaps and uncertainties: In some regions, there are significant gaps in climate and weather data, which can limit the accuracy of forecasts and warnings.
• Communication barriers: Ensuring that warnings reach and are understood by all at-risk communities, particularly marginalized and vulnerable groups and those in remote areas, can be challenging.
• Weak institutional capacities: Many countries need further support in strengthening their institutional frameworks and coordination mechanisms for the effective implementation of early warning systems.
• Complex and evolving climate risks: Climate change is creating conditions which compound risks and challenge traditional forecasting models. Under these new conditions, hazards such as storms and wildfires can rapidly intensify in ways which are difficult to predict, sometimes with devastating effects.

Addressing these challenges requires sustained efforts and collaboration among governments, international organizations, civil society and the private sector.

How can we ensure early warning systems are inclusive and accessible?

Ensuring that early warning systems reach all people, including marginalized groups, requires a combination of community engagement, local knowledge and technological innovation. Local leaders and organizations must be actively involved in designing and disseminating warnings to ensure that alerts are culturally appropriate and accessible. Moreover, Indigenous knowledge and community-based observations can complement scientific forecasting, enhancing accuracy and relevance for at-risk populations.

Advancements in mobile alerts, social media and AI-driven forecasting have improved the reach and precision of warnings. However, these efforts must be complemented by multi-channel communication strategies, such as radio broadcasts, mobile phone notifications, visual signals and door-to-door alerts, to ensure broad coverage, particularly in areas with limited digital access.notifications, visual signals and door-to-door alerts, to ensure broad coverage, particularly in areas with limited digital access.

An inclusive approach ensures that vulnerable populations, including persons with disabilities, women and rural communities, receive timely warnings that they can act upon effectively.

What role does UNDP play in advancing climate information and early warning systems?

Alongside international and local partners, UNDP is a key player in strengthening early warning systems worldwide, supporting governments with funding, capacity building and technology deployment. By working together with governments, the private sector and local communities, UNDP is helping ensure that climate information and early warnings are accessible, actionable and lifesaving for all.

In Malawi, with financing from the Green Climate Fund (GCF), UNDP has helped establish participatory climate services, solar-powered weather stations and advanced lightning detection. In addition to protecting the lives and assets of up to 5 million people including smallholder farmers, fisher folk and lakeshore communities, early action alerts have enhanced agricultural productivity, with an annual estimated benefit of US$3.8 million.

In Bhutan, Nepal and Pakistan, with financing from the Least Developed Countries Fund and the Adaptation Fund, UNDP helped reduce climate change-induced risks and vulnerabilities from glacial lake outburst floods (GLOFs). Based on lessons and good practices from these initiatives, UNDP is currently scaling up climate information and GLOF early warning systems in Northern Pakistan and supporting the design of a GLOF early warning system in Nepal, with financial support from the GCF.

In Georgia, through a GCF-financed project, UNDP is scaling up a multi-hazard early warning system and implementing community-based risk reduction measures to directly protect 1.7 million people from climate-induced hazards such as floods.

In Tuvalu, with support from the GCF, UNDP developed and launched a state-of-the-art online hazard and risk dashboard, which, for the first time, allows the atoll nation to clearly identify, plan for and reduce risks associated with sea level rise and more frequent intense storms driven by climate change. The free, publicly available platform enables public authorities, businesses and communities to make sound, risk-informed development decisions including where to build new structures and how to plan climate change adaptation into the future.

In addition to supporting governments in designing and delivering projects on climate information and early warning systems, UNDP also plays a leading role in several global initiatives aimed at accelerating the development and implementation of early warning systems, including the Systematic Observations Financing Facility (SOFF) which supports least developed countries and small island developing states in generating and using essential climate and weather observations data, and the UN Secretary-General's Early Warnings for All initiative, a global effort led by the World Meteorological Organization (WMO) to ensure that everyone on Earth is protected by early warning systems by 2027. Under this global initiative, UNDP is leading a multi-agency effort to advance multi-hazard early warning systems benefiting 26 million people in seven of the world’s most climate-vulnerable countries: Antigua and Barbuda, Cambodia, Chad, Ecuador, Ethiopia, Fiji and Somalia, with more than $100 million in financing from the GCF.

UNDP is also a key partner in the Risk-informed Early Action Partnership (REAP), an initiative bringing together stakeholders from across the climate, humanitarian and development communities with the aim of making 1 billion people safer from disaster by 2025, and the Alliance for Hydromet Development which brings together major international development, humanitarian and climate finance institutions to scale up and unite efforts to close the hydromet capacity gap by 2030.