At left, Santiago Mercadé, chief executive officer of Spanish real estate developer Layetana, speaks about density at a panel at the ULI Europe Trends Conference 2015 in London.

Launching ULI Europe’s report on density, ULI senior fellow Greg Clark drew attention to the “long memory” for failed density projects across the globe. But “political resistance” to this mode of urban planning, which he said is based on a fear of concrete jungles and slums, is now undermining cities’ attempts to support population growth with new housing, schools, amenities, and parks.

“If Europe is to retain economic strength, it is necessary to unlock these issues,” he warned at ULI Europe’s Real Estate Trends Conference 2015 in London.

Related: Walkable Downtowns Drawing Companies and Talent

“Unless we agree that density is a key part of the answer, we can’t move forward. It produces the best returns and social and environmental outcomes. How we deliver good density is a critical issue. But we now have a clearer understanding of what good and bad density looks like,” he said.

Among some of the myths about density that need to be challenged, argued Clark, is that this form of urban design attracts crime and involves a loss of privacy and that low- and high-density buildings cannot be combined successfully.

The report Density: Drivers, Dividends, and Debates is the first of a three-part ULI program that seeks to offer an agenda for advocacy, demonstration, and public education on density issues, since the Institute aims to increase knowledge of density and address the social, economic, and environmental benefits of investing in it.

Its authors—Greg Clark, ULI Europe senior fellow, and Emily Moir, director of the Business of Cities—argue that well-managed and well-serviced densification is the “best strategy” for contending with growing city populations.

The report reveals that the issue is becoming more prominent in the real estate industry. Eighty-nine percent of global ULI members surveyed said that the issue of density has become very important or critical in the last five years.

Clark said that dense cities minimize energy consumption and environmental impact while fostering productivity, innovation, and livability through better connectivity.

But he added that much work needs to be done on developing future models: “What we’ve uncovered is a fundamental need for a public education program. There are different definitions of it and there’s no agreement of how organizations measure it. We need to create a density benchmark.”

He said that retaining green space in urban areas is one issue that needs to be “got right” in an effort to combine high population growth with enhanced livability.

Echoing the report’s sentiments, panelist Isabel Dedring, deputy mayor for transport, GLA, said there is an “urgent need” for a better narrative on density. “We should ban the word density and clarify the facts. If I lived in a 30-story tower block, I am sure I’d know my neighbors. We’re not being armed with good information to tell this story.

“It is the responsibility of [the] public and private sectors to show why density is attractive.”

Also responding to Clark’s report, Santiago Mercadé, chief executive officer of Spanish real estate developer Layetana, said that developers “need to support density” as a matter of corporate citizenship.

He added that denser areas decrease commercial risk: “The product is easier to sell, the neighborhoods are livelier, and our customers are happier. Mixed-use places make life easier on everyone [because] they have better proximity and there is less time lost on unproductive activities like commuting,” he said.

Katrin Stjernfeldt Jammeh and Alice Breheny at the ULI Europe Trends Conference 2015.

Katrin Stjernfeldt Jammeh, mayor of Malmö, Sweden, and Alice Breheny (right), global cohead of research at TIAA Henderson Real Estate, speaking at the ULI Europe Trends Conference 2015.

Fellow panelist Alice Breheny, global cohead of research at TIAA Henderson Real Estate, said the issue is becoming increasing crucial for the investment and development community because occupiers are increasingly turning their attention to cities.

“We’re investing in density [since] cities are where it is at. All of our strategies are based around cities and not countries. Bright young graduates don’t say they want a job in the U.K., but they want a job in London. Investing wisely is about investing in places that can attract people. That is about scale, but it is also about density,” she said.

Malmö, Sweden, is one city where density does not appear to be a dirty word, as Katrin Stjernfeldt Jammeh, the city’s mayor, revealed that development underway there seeks to “preserve it as a compact city” as Malmö experiences rapid population growth. “This is the way to meet the needs of our inhabitants,” she said.

But she emphasized that green spaces also are a factor across all of the city’s urban planning: “We want to make the city denser, but also green. As we have some of Europe’s best farming fields around us, we try to plan everything to grow inward,” she said.

The mayor said the city is looking to grow around preexisting infrastructure while improving green transport routes, adding: “We have a high degree of satisfaction. I am sure that public space is very important in providing a livable city in a fast-growing place.”