2 research outputs found
Association between population distribution and urban GDP scaling
Urban scaling and Zipf's law are two fundamental paradigms for the science of
cities. These laws have mostly been investigated independently and are often
perceived as disassociated matters. Here we present a large scale investigation
about the connection between these two laws using population and GDP data from
almost five thousand consistently-defined cities in 96 countries. We
empirically demonstrate that both laws are tied to each other and derive an
expression relating the urban scaling and Zipf exponents. This expression
captures the average tendency of the empirical relation between both exponents,
and simulations yield very similar results to the real data after accounting
for random variations. We find that while the vast majority of countries
exhibit increasing returns to scale of urban GDP, this effect is less
pronounced in countries with fewer small cities and more metropolises (small
Zipf exponent) than in countries with a more uneven number of small and large
cities (large Zipf exponent). Our research puts forward the idea that urban
scaling does not solely emerge from intra-city processes, as population
distribution and scaling of urban GDP are correlated to each other.Comment: 17 pages, 3 figures, supplementary information; accepted for
publication in PLoS ON
The decarbonisation of Europe powered by lifestyle changes
Decision makers increasingly recognise the importance of lifestyle changes in reaching low emission targets. How the mitigation potential of changes in mobility, dietary, housing or consumption behaviour compare to those of ambitious technological changes in terms of decarbonisation remains a key question. To evaluate the interplay of behaviour and technological changes, we make use of the European Calculator model and show that changes in behaviour may contribute more than 20% of the overall greenhouse gas (GHG) emission reductions required for net-zero by 2050. Behaviour and technology-oriented scenarios are tested individually and in combination for the EU plus the UK and Switzerland. The impacts of behavioural change vary across sectors, with significant GHG emission reduction potential and broader benefits. Changes in travel behaviour limit the rising demand for electricity, natural resources and infrastructure costs from the electrification of passenger transport. Adopting a healthy diet reduces emissions substantially compared to intensifying agricultural practices, while at the same time making cropland available for conservation or bioenergy crops. The trade-offs between energy and food may be substantially alleviated when deploying technological and behavioural changes simultaneously. The results suggest that without behavioural change, the dependency of Europe on carbon removal technologies for its net-zero ambitions increases. Structural changes will be necessary to achieve full decarbonisation by 2050, yet changes in lifestyles are crucial, contributing to achieving climate targets sooner