Disasters from hazards such as cyclones, volcanic eruptions and earthquakes exact an enormous toll on economic and social development. Over the past two decades, 1.35 million lives have been lost and US$2.5 trillion in economic losses absorbed ^[1] as a result of these events. Recent analysis by the World Bank ^[2] suggests that the annual loss from extreme weather alone now exceeds US$500 billion, and 26 million people are forced into poverty from these events each year.

As disturbing as these figures are, they almost certainly underestimate the true costs of disasters. For example, they don’t include the less documented, smaller but frequent disasters such as flash floods, fires and droughts that occur in both urban and rural areas. Some analysts have suggested that incorporating these events would increase the costs by at least 50% ^[3]. It’s telling that each year the global wine industry suffers more than US$10 billion in losses ^[4] from these hazards.

Disasters have a hugely disproportionate impact on less developed countries, where 90% of disaster deaths occur. Although wealthy countries absorb the majority of the total economic losses, the relative economic impact in less developed countries is far greater, equating to over 20% of their average annual social expenditure (in some highly vulnerable countries, the figure exceeds 60%). The destruction wrought by Hurricane Maria on the Caribbean island of Dominica is a tragic recent example: in a matter of hours it wiped out the equivalent of more than 200% of the country’s GDP ^[5].

Improvements in disaster management over the past two decades, in particular the establishment of early warning systems and evacuation planning, have contributed to an overall reduction in mortality from disasters globally (notably in places such as Bangladesh, Chile, India and the Philippines). But far less progress has been made in addressing the economic losses, which are increasing rapidly, in some places outpacing GDP growth.

Two main factors account for the accelerating costs: a failure to incorporate disaster risk in planning and investments (examples would be building hospitals in flood zones or construction that ignores seismic risk) and, increasingly, climate change. Over the next 15 years, an estimated US$80–90 trillion is expected to be invested globally in new infrastructure ^[6] for energy, transport, telecommunications, water supply and sanitation. This new investment will exceed the current value of the entire existing stock. It represents a once-in-a-lifetime opportunity to reverse the increasing economic losses by embedding disaster resilience in the built environment.

Climate change makes this effort all the more essential. More than 80% of major disasters over the past four decades have been from hydro-meteorological hazards (storms, droughts, floods, etc.). They have doubled in frequency and are expected to increase further and intensify.

Arguably, the single most urgent global disaster risk treatment is to reduce greenhouse gas emissions as quickly as possible. The urgency stems from the inertia in the climate system. Even if we could halt all greenhouse gas emissions tomorrow, the climate would continue to warm ^[7] for hundreds of years as a result of the emissions already released and disaster risk would continue to grow. There’s also a significant possibility of reaching ‘tipping points’ that could trigger sudden, non-linear and irreversible changes ^[8] that greatly exacerbate hazards and disaster risk.

These two aspects of the climate system require us to reduce emissions well before the impacts become more visible. And they require infrastructure investors and planners to go beyond relying on the historical record of previous disasters to determine standards for resilient infrastructure. They now need to supplement the historical record with a risk assessment that incorporates climate change risk.

Because around 70% of the trillions of new investment will be made by the private sector, this is fundamentally a task for businesses, but with key roles as well for governments. Governments have a responsibility to create the enabling environment (hazard information, climate modelling tools, regulations, etc.) for private sector and community action in these areas. They also need to incorporate climate risk and disaster risk more generally in managing public goods and assets.

Globally, most governments are just beginning to integrate their climate change and disaster risk reduction work and investments. National climate change adaptation plans are usually developed through whole-of-government processes led by environment ministries. National disaster risk reduction strategies are developed through similar whole-of-government processes led by the disaster management agencies. Given the enormous overlap between these two topics, they need to be brought together and embedded in planning and investments with the active engagement and shared ownership of finance ministries and treasuries.

Achieving the global targets to reduce disaster risk that Australia and other countries have endorsed in the Sendai Framework for Disaster Risk Reduction ^[9], the international agreement reached in 2015 at the Third UN World Conference on Disaster Risk Reduction, will be impossible without greatly increased global ambition to reduce greenhouse gas emissions.