Urban densification as a strategy for sustainability

Sprawl vs. density

• 10-20 persons/ha• Public transport is NOT viable• Walking and bicycle are not

attractive• Requires MUCH land and

energy

• 360 persons/ha• Public transport is viable• Encourages walking• Requires less land and

energy

Atlanta BarcelonaSimilar population size

Similar length of metro system

Share of population within 600m of metro station:Atlanta: 4 % Barcelona: 60 %

TransportUN-Habitat recommends: at least 150 persons/ha– Typical for

European inner city areas

– Main reason: Makes public transport feasible (shorter distances are of less importance)

Source: UNEP, 2008

Transport

• USA’s 125 largest cities: Doubling density

• Household travel CO2 emissions down by 48%• Residential energy consumption down by

35%• Household travel and residential energy

account for 42% of total U.S. CO2 emissions…

Source: Lee and Lee, 2014

Transport

Density alone is not enough!

Source: IPCC, 2013

Transport

Space for car parking

• Each spot: ~20 m2

• That’s a small apartment!• Encourage car pools!

What do people want?

• Access to restaurants, commerce, culture, etc.– Depends on

density of residents and work places (land use mix!)

What do people want?

• Closed structures– People like

courtyards– Suitable for

urban values

What do people want?

• Parks – Qualitative green

space, playgrounds and sports facilities

– Not just any green space

What do people want?

How many residents experience a lack of parks or nature?Area: Örby (Stockholm)

Floor area ratio: 0.2

40%

Source: Temo, 2001

How many residents experience a lack of parks or nature?Area: Högdalen (Stockholm)

Floor area ratio: 0.5

33%Source: Temo, 2001

How many residents experience a lack of parks or nature?

Area: Östermalm (Stockholm)

Floor area ratio: 2.0

4%Source: Temo, 2001

Other social and economic aspects

• People in denser areas walk more and are less overweight

• Density means lower costs for infrastructure• Density counteracts social segregation

– Proximity– Mix

Stormwater

Stormwater

How to densify?

How to densify?

How to densify?

How to densify?

THANK YOU