Unique Opportunities of Island States to Transition to a Low-Carbon Mobility System

Small islands developing states (SIDS) contribute minuscule proportions to global greenhouse gas (GHG) emissions and energy consumption, but are highly exposed to climate change impacts, in particular to extreme weather events and sea-level rise. However, there is little research on potential decarbonization trajectories unique to SIDS. Here, we argue that insular topology, scale, and economy are distinctive characteristics of SIDS that facilitate overcoming carbon lock-in. We investigate these dimensions for the three islands of Barbados, Fiji, and Mauritius. We find that insular topologies and small scale offer an opportunity for both public transit corridors and rapid electrification of car fleets. The tourism sector enables local decision-makers and investors to experiment with shared mobility and to induce spillover effects by educating tourists about new mobility options. Limited network effects, and the particular economy thus enables to overcome carbon lock-in. We call for targeted investments into SIDS to transition insular mobility systems towards zero carbon in 2040. The decarbonization of SIDS is not only needed as a mitigation effort, but also as a strong signal to the global community underlining that a zero-carbon future is possible.DFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli

Avoiding Carbon Lock-In: Policy Options for Advancing Structural Change

A major obstacle for the transformation to a low-carbon economy is the risk of a carbon lock-in: fossil fuel-based ('dirty') technologies dominate the market although their carbon-free ('clean') alternatives are dynamically more efficient. We study the interaction of learning-by-doing spillovers and the substitution elasticity between the clean and the dirty sector in an intertemporal general equilibrium model. We find that the substitution possibilities between the two sectors have an ambivalent effect: although a high substitution elasticity requires less aggressive mitigation policies than a low one, it creates a greater lock-in in the absence of regulation. The optimal policy response consists of a permanent carbon tax as well as a learning subsidy for clean technologies. A single policy instrument can also avoid high welfare losses, but a more stringent mitigation target can only be achieved at painful costs. We demonstrate that the policy implication of [Acemoglu et al. 2012] is limited in scope. Our numerical results also highlight that infrastructure provision is crucial to facilitate the low-carbon transformation.structural change, low-carbon economy, carbon lock-in, mitigation policies, learning-by-doing

Spatially contextualized analysis of energy use for commuting in India

India's land transport GHG emissions are small in international comparison, but growing exponentially. Understanding of geographically-specific determinants of GHG emissions is crucial to devise low-carbon sustainable development strategies. However, previous studies on transport patterns have been limited to socio-economic context in linear and stationary settings, and with limited spatial scope. Here, we develop a nested typology that categorizes all 640 Indian districts according to the econometrically identified drivers of their commuting emissions. Results reveal that per capita commuting emissions significantly vary over space, after controlling for socioeconomic characteristics, and are strongly influenced by built environment (e.g., urbanization, and road density), and mobility-related variables (e.g., travel distance and travel modes). The commuting emissions of districts are characterized by unique, place-specific combinations of drivers. We find that income and urbanization are dominant classifiers of commuting emissions, while we explain more fine-grained patterns with mode choice and travel distance. Surprisingly the most urbanized areas with highest population density are also associated with the highest transport GHG emissions, a result that is explained by high car ownership. This result contrasts with insights from OECD countries, where commuting emissions are associated with low-density urban sprawl. Our findings demonstrate that low-carbon commuting in India is best advanced with spatially differentiated strategies

Climate policies for road transport revisited (II): Closing the policy gap with cap-and-trade

Current policies in the road transport sector fail to deliver consistent and efficient incentives for greenhouse gas abatement (see companion article by Creutzig et al., 2010a). Market-based instruments such as cap-and-trade systems close this policy gap and are complementary to traditional policies which are required where specific market failures arise. Even in presence of strong existing non-market policies, cap-and-trade delivers additional abatement and efficiency by incentivizing demand side abatement options. This paper analyzes generic design options and economic impacts of including the European road transport sector to the EU ETS. The point of regulation in a road transport cap-and-trade system should be upstream in the fuel chain to ensure effectiveness (cover all life-cycle emissions and avoid double-counting), efficiency (incentivize all abatement options) and low transaction costs. Based on year 2020 marginal abatement cost curves from different models and current EU climate policy objectives we show that in contrast to conventional wisdom road transport inclusion would not change the EU ETS allowance price. This puts concerns over industrial carbon leakage as a consequence of adding road transport to the EU ETS into perspective.Climate Policy, Road Transport, Cap-and-trade

Reducing urban heat wave risk in the 21st century

Global warming increases the frequency, intensity and duration of heat waves, particularly endangering urban populations. However, the health risks of heat waves are distributed unequally between people because of intrinsic person-specific characteristics and extrinsic factors. The confluence of forecasted urbanisation and projected heat wave increase necessitates the identification of strategies that both lower the overall health impact and narrow the gap in risk distribution within urban populations. Here, we review the literature on vulnerability to heat, highlighting the factors that affect such distribution. As a key lesson we find that the literature strands on public health, risk reduction and urban planning all contribute to the identification of alleviation options for urban heat wave health impacts, but that they are rarely jointly evaluated. On the basis of the literature review, we suggest a common framework. We also evaluate response measures in addressing total and distributed risks. We find that person-specific risk is effectively addressed by public health and risk reduction intervention, while intra-urban variations of extrinsic factors can be efficiently tackled with urban planning, both in scale and scope

Climate policies for road transport revisited (I): Evaluation of the current framework

The global rise of greenhouse gas (GHG) emissions and its potentially devastating consequences require a comprehensive regulatory framework for reducing emissions, including those from the transport sector. Alternative fuels and technologies have been promoted as means for reducing the carbon intensity of the transport sector. However, the overall transport policy framework in major world economies is geared towards the use of conventional fossil fuels. This paper evaluates the effectiveness and efficiency of current climate policies for road transport that (1) target fuel producers and/or car manufacturers, and (2) influence use of alternative fuels and technologies. With diversifying fuel supply chains, carbon intensity of fuels and energy efficiency of vehicles cannot be regulated by a single instrument. We demonstrate that vehicles are best regulated across all fuels in terms of energy per distance. We conclude that price-based policies and a cap on total emissions are essential for alleviating rebound effects and perverse incentives of fuel efficiency standards and low carbon fuel standards. In tandem with existing policy tools, cap and price signal policies incentivize all emissions reduction options. Design and effects of cap and trade in the transport sector are investigated in the companion article (Flachsland et al., 2010).Fuel efficiency standards, low carbon fuel standards, climate change

Participatory design in transit-oriented development uncovers social benefits

Transit-oriented development (TOD) tackles multiple challenges simultaneously and fosters sustainable urban development. Low-carbon intensity transport modes help mitigating climate change, enhance the quality of local ecosystems and offer monetary savings. While less well studied, TOD also positively affects citizen’s social interactions. The social sustainability that can be drawn from TOD interventions may multiply when designed through participatory planning processes. To investigate this hypothesis, we evaluate TOD and participatory intervention for Medellin (Colombia). We find that designing TOD together with participatory measures results not only in the decrease of motorized transport modes, but also in positive changes in socioeconomic variables, people´s perception of public interventions and in social capital especially of disadvantaged groups. Making citizens feeling part of the projects that shape their communities fosters transparency, trust, social inclusion, collective action and social networks. Participatory measures can catalyse urban sustainability

CITIES: Car Industry, Road Transport and an International Emission Trading Scheme – Policy Options

This report evaluates existing regulations for climate change mitigation in the transport sector and investigates the effects of including transportation in emission trading schemes.

Predicting building age from urban form at large scale

To stay within 1.5 °C of global warming, reducing energy-related emissions in the building sector is essential. Rather than generic climate recommendations, this requires tailored, low-carbon urban planning solutions and spatially explicit methods that can inform policy measures at urban, street and building scale. Here, we propose a scalable method that is able to predict building age information in different European countries using only open urban morphology data. We find that spatially cross-validated regression models are sufficiently robust to generalize and predict building age in unseen cities with a mean absolute error (MAE) between 15.3 years (Netherlands) and 19.9 years (Spain). Our experiments show that large-scale models improve generalization for predicting across cities, but are not needed to infer missing data within known cities. Filling data gaps within known cities is possible with a MAE between 9.6 years (Netherlands) and 16.7 years (Spain). Overall, our results demonstrate the feasibility of generating missing age data in different contexts across Europe and informing climate mitigation policies such as large-scale energy retrofits. For the French residential building stock, we find that using age predictions to target retrofit efforts can increase energy savings by more than 50% compared to missing age data. Finally, we highlight challenges posed by data inconsistencies and urban form differences between countries that need to be addressed for an actual roll-out of such methods

Timescale-invariant representation of acoustic communication signals by a bursting neuron

Acoustic communication often involves complex sound motifs in which the relative durations of individual elements, but not their absolute durations, convey meaning. Decoding such signals requires an explicit or implicit calculation of the ratios between time intervals. Using grasshopper communication as a model, we demonstrate how this seemingly difficult computation can be solved in real time by a small set of auditory neurons. One of these cells, an ascending interneuron, generates bursts of action potentials in response to the rhythmic syllable-pause structure of grasshopper calls. Our data show that these bursts are preferentially triggered at syllable onset; the number of spikes within the burst is linearly correlated with the duration of the preceding pause. Integrating the number of spikes over a fixed time window therefore leads to a total spike count that reflects the characteristic syllable-to-pause ratio of the species while being invariant to playing back the call faster or slower. Such a timescale-invariant recognition is essential under natural conditions, because grasshoppers do not thermoregulate; the call of a sender sitting in the shade will be slower than that of a grasshopper in the sun. Our results show that timescale-invariant stimulus recognition can be implemented at the single-cell level without directly calculating the ratio between pulse and interpulse durations