Last year was the joint-hottest year on record and disasters struck every continent. Smoke-belching wildfires burned through communities from Australia to the Arctic. Extreme storms battered coastal cities from the Philippines to Nicaragua, while floods put a third of Bangladesh underwater and covered entire villages in Nigeria.

Extreme weather and climate-related disasters have killed more than 410,000 people in the past 10 years, almost all of them in poorer countries, according to the International Federation of the Red Cross and Crescent.

"The hard truth is that climate change is upon us," said UNEP Executive Director Inger Andersen, in the foreword to the report. "Its impacts will intensify, even if we limit global warming. We cannot afford to lose the race to adaptation."

Adaptation Has a Long Way to Go

The Adaptation Gap Report, now in its 5th year, finds "huge gaps" between what world leaders agreed to do under the 2015 Paris Agreement and what they need to do to keep their citizens safe from climate change.

A review by the Global Adaptation Mapping Initiative of almost 1,700 examples of climate adaptation found that a third were in the early stages of implementation — and only 3% had reached the point of reducing risks.

Disasters like storms and droughts have grown stronger than they should be because people have warmed the planet by burning fossil fuels and chopping down rainforests. The world has heated by more than 1.1 degrees Celsius since the Industrial Revolution and is on track to warm by about 3°C by the end of the century.

If world leaders deliver on recent pledges to bring emissions to net-zero by the middle of the century, they could almost limit warming to 2°C. The target of the Paris Agreement, however, is to reach a target well below that — ideally 1.5°C.

There are two ways, scientists say, to lessen the pain that warming will bring: mitigating climate change by cutting carbon pollution and adapting to the hotter, less stable world it brings.

The Cost of Climate Adaptation

About three-quarters of the world's countries have national plans to adapt to climate change, according to the report, but most lack the regulations, incentives and funding to make them work.

More than a decade ago, rich countries most responsible for climate change pledged to mobilize $100 billion a year by 2020 in climate finance for poorer countries. UNEP says it is "impossible to answer" whether that goal has been met, while an OECD study published in November found that between 2013 and 2018, the target sum had not once been achieved. Even in 2018, which recorded the highest level of contributions, rich countries were still $20 billion short.

The yearly adaptation costs for developing countries alone are estimated at $70 billion. This figure is expected to at least double by the end of the decade as temperatures rise, and will hit $280-500 billion by 2050, according to the report.

But failing to adapt is even more expensive.

When powerful storms like cyclones Fani and Bulbul struck South Asia, early-warning systems allowed governments to move millions of people out of danger at short notice. Storms of similar strength that have hit East Africa, like cyclones Idai and Kenneth, have proved more deadly because fewer people were evacuated before disaster struck.

The Global Commission on Adaptation estimated in 2019 that a $1.8 trillion investment in early warning systems, buildings, agriculture, mangroves and water resources could reap $7.1 trillion in benefits from economic activity and avoided costs when disasters strike.

Exploring Nature-Based Solutions

The report also highlights how restoring nature can protect people from climate change while benefiting local communities and ecology.

Wildfires, for instance, could be made less punishing by restoring grasslands and regularly burning the land in controlled settings. Indigenous communities from Australia to Canada have done this for millennia in a way that encourages plant growth while reducing the risk of uncontrolled wildfires. Reforestation, meanwhile, can stop soil erosion and flooding during heavy rainfall while trapping carbon and protecting wildlife.

In countries like Brazil and Malaysia, governments could better protect coastal homes from floods and storms by restoring mangroves — tangled trees that grow in tropical swamps. As well as anchoring sediments and absorbing the crash of waves, mangroves can store carbon, help fish populations grow and boost local economies through tourism.

While nature-based solutions are often cheaper than building hard infrastructure, their funding makes up a "tiny fraction" of adaptation finance, the report authors wrote. An analysis of four global climate funds that spent $94 billion on adaptation projects found that just $12 billion went to nature-based solutions and little of this was spent implementing projects on the ground.

But little is known about their long-term effectiveness. At higher temperatures, the effects of climate change may be so great that they overwhelm natural defenses like mangroves.

By 2050, coastal floods that used to hit once a century will strike many cities every year, according to a 2019 report on oceans by the Intergovernmental Panel on Climate Change (IPCC), the gold standard on climate science. This could force dense cities on low-lying coasts to build higher sea walls, like in Indonesia and South Korea, or evacuate entire communities from sinking islands, like in Fiji.

It's not a case of replacing infrastructure, said Matthias Garschagen, a geographer at Ludwig Maximilian University in Germany and IPCC author, who was not involved in the UNEP report. "The case for nature-based solutions is often misinterpreted as a battle... but they're part of a toolkit that we've ignored for too long."