Wrenching stories of loss and hardship after Hurricanes Harvey and Irma made vivid and upsetting viewing in recent days. The death tolls from the two hurricanes are currently estimated at 70 to 80, and early estimates suggest that the two storms combined could cost between $150-$200 billion. And now, Hurricane Maria is hammering parts of the Caribbean that are still reeling from Irma.

An even greater number of people in India, Bangladesh and Nepal were recently hit by record-setting floods. At least 1,400 are thought to have died from the immediate impacts, with thousands more ill due to subsequent outbreaks of diarrhoea, malaria and dengue.

For the world's poorest people in particular, the extreme weather event is just the beginning, with impacts felt for weeks, months and, in some cases, years after. Research has found that, "Differences in vulnerability and exposure arise from non-climatic factors and from multidimensional inequalities often produced by uneven development processes (very high confidence). These differences shape differential risks from climate change."

This fact has been borne out in New Orleans where, more than ten years later, aspects of the city's economy are still feeling the effects of Hurricane Katrina. Jobs in the hospitality and tourism industry were hit hardest by Katrina, and have had a limited recovery. Layer on top of that the fact that average wages in this industry were already among the lowest in the area, and it's clear that those least able to withstand climate impacts have the highest risk of exposure to them.

The full impact of an extreme weather event like a hurricane is not just about the strength of the storm. It's about who gets hit, where they live, the jobs they do and how mobile they are. But while it may feel a long way off for many victims, recovery also presents an opportunity―which is why New Orleans has experienced a surge in entrepreneurship since Katrina.

The real opportunity for hard-hit cities lies not just in rebuilding, but in a smart recovery. A smart recovery can increase not only climate resilience, but also productivity, efficiency and equitability.

New Climate Economy research makes a strong case for rebuilding cities more compactly. It finds that increasing economic density (the number of people living or working in an area) by 10 percent is worth approximately $71 per capita per year due to higher productivity, $62 due to higher job accessibility, and $49 due to better access to services. The benefits of creating more compact cities also include the preservation of urban green space (worth $41 per person per year), greater energy efficiency (worth $25 per person per year), reduced pollution (worth $14 per person per year), and safer urban environments (worth $8 per person per year).

Designing urban areas with resilience to more frequent and higher magnitude storm events also makes sense, given our already-changing climate. And it creates possibilities for innovative urban design, such as the skate board parks introduced strategically in the Danish city of Roskilde. The parks, installed following an extreme flash rain event in 2011, also help to channel flood waters safely away from housing areas.

Urban planners shouldn't require an extreme weather event to seize opportunities to increase climate resilience. Over the next 15 years, the world is expected to spend around $90 trillion on infrastructure. This investment is needed to replace aging infrastructure in advanced economies and to accommodate rapid urbanization, growth and structural change in emerging markets and developing countries―especially in the global South, which will account for roughly two-thirds of the global infrastructure investment. Whether this new infrastructure helps or hinders countries and cities trying to meet climate targets and become more resilient to climate impacts depends upon decisions made now.

Debris carried towards a temple in Uttarakhand, India in 2013 by floods. Flickr/Diariocritico de Venezuela
Debris carried towards a temple in Uttarakhand, India in 2013 by floods. Flickr/Diariocritico de Venezuela

More than half of the world's population lives in urban areas, and that proportion is expected to rise to 66 percent by 2050. So how we develop urban areas is integral to how we help vulnerable people, who are hit hardest by climate impacts and are least able to fully recover, achieve greater security and prosperity. This year it was people in Mumbai, the Caribbean, Niger and Houston, and many other places. Any one of the 40 million people currently exposed to a 100-year coastal flood event could be next. And that number could triple by the 2070s. By bringing economic opportunity, sustainable infrastructure and basic services to poor people today, we can make the world less vulnerable to disaster in the future.