Paris, France - Coastal cities are not doing enough to adapt to climate change, taking too long and implementing insufficient measures, according to a major scientific study published this week.

While flood barriers and pumping systems are a step in the right direction, "across all regions and income groups, scientifically reported adaptation in coastal cities remains at rather low depth, scope and speed," said the study published in Nature Cities, which looked at 199 cities worldwide.

Given the high exposure and vulnerability of many coastal cities, "this finding is alarming as an adaptation to future climate change will require many cities to go beyond business as usual risk management," it said.

Short- and mid-term solutions, as many cities are implementing, could even have an adverse effect, the study warned, leading to a "lock-in and maladaptive path dependency in the long-term."

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Instead, adaptation must aim at the "transformation" of cities – a change both in infrastructure and at the institutional level.

Positive models cited in the report include Singapore, Hong Kong, and several Swedish cities.

But in the majority, the study found that coastal cities focus primarily on combating sea level rise, various types of flooding, and to a lesser extent the risks posed by erosion and storms.

And for scientists such a scope is too narrow – cities need to address other problems linked to climate change, such as heatwaves.

By comparing data from 199 cities, listed in 683 scientific articles, the researchers found that the actors driving adaptation changed according to the country and income category.

The richest coastal areas take a technological approach to dealing with climate change and the major players are institutions.

Meanwhile, lower-income cities located mainly in Africa, Asia, and South and Central America, have no other choice but to rely on a "behavioral and cultural" effort for populations to adapt.

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In lower-income coastal cities, there is a lack of institutional and/or technological support, making it "more likely individuals/households are reported as prime adaptation actors."

The poorest economies remain under-represented in the scientific literature, which complicates their adaptation.

"A considerable gap in research that needs to be addressed urgently," the study warned.