Driving in London has been falling since 1990. Has the city passed "peak car"?

Which lane is the future? Image: Getty.

Cars are one of the biggest threats to the planet. The transport sector accounts for more than 60 per cent of global oil consumption and about a quarter of energy-related carbon emissions.

It's also seen as harder to decarbonise than other parts of the economy. Typical forecasts of future world vehicle ownership point to substantial increases, particularly in the developing economies.

But the problem of transport-related greenhouse gases may be less than generally thought. There is emerging evidence that individual car use, as measured by the average annual distance travelled, has ceased to grow in most of the developed economies – a phenomenon that started well before the recent recession. In some countries, it may already be declining, a phenomenon known as “peak car”.

A number of factors could could contribute to this trend. Suggestions have included a decline in the number of younger people holding driver’s licences, changes to company car taxation and the technological constraints that stop us travelling faster on roads. It may also be that we have simply sufficient daily travel to meet our needs.

There has also been a shift away from car use in urban areas. This could be particularly important in a world where future population growth will be mainly urban, and where densely populated cities are seen as a driver for economic growth.

For example, over the past 20 years the population of London has been growing and incomes have been rising – yet car use has held steady at about 10m trips a day. This is mainly because the city has not increased road capacity but instead has invested in public transport.

Most importantly, rail offers speedy and reliable travel for work journeys compared with the car on congested roads. This gets business and professional people out of their cars, which makes the city a less congested and more agreeable place to be.

With a growing population but static car use, London has seen a marked decline in the share of journeys by car, from 50 per cent of all trips in 1990 to 37 per cent currently. With continued population growth projected and more investment in rail planned, the share of trips by car could fall to 27 per cent by mid-century. There is every reason to suppose that London will continue to thrive as car use declines – and perhaps because car use declines.

This decrease in car use from 1990 was preceded by a 40-year period of growth from 1950. That was the result of rising incomes, leading to increased car ownership – and, at the same time, a falling population, as people left an overcrowded damaged city for new towns, garden cities and greener surroundings. So we see a marked peak in car use at around 1990, the time when the population of London was at a minimum, which was when attitudes to city living began to change.

Screenshot from David Metz's 2015 paper, "Peak Car in the Big City: Reducing London's transport greenhouse gas emissions".

This phenomenon of peak car in big cities is not unique to London, although this is the city for which we have the best data. There is evidence for something similar happening in Birmingham, Manchester and other British cities, as well as those in other developed countries. The shift in economies from manufacturing to services is an important driver, as is the growth of higher education located in city centres, attracting young people for whom the car is not part of their lifestyle.

If car use has really peaked, both in the sense of national per capita figures and the share of trips in cities, it should help mitigate greenhouse gas emissions from transport. I have estimated that these changes in behaviour, taken together with expected developments of low-emission vehicles, could by 2050 reduce UK surface transport greenhouse gas emissions by 60 per cent of their 1990 level. This falls short of the overall target of an 80 per cent reduction, but it's a good deal better than conventional projections.

Peak car is not just an emerging phenomenon to be investigated. It is a helpful trend to be encouraged, to achieve both successful, sustainable cities and national reduction of transport greenhouse gas emissions. The Conversation

David Metz is a visiting professor in transport studies at University College London.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

What can other cities learn about water shortages from Cape Town’s narrow escape from ‘Day Zero’?

Cape town. Image: Pixabay/creative commons.

Cape Town was set to run dry on 12 April, leaving its 3.7m residents without tap water.

“Day Zero” was narrowly averted through drastic cuts in municipal water consumption and last-minute transfers from the agricultural sector. But the process was painful and inequitable, spurring much controversy.

The city managed to stave off “Day Zero,” but does that mean Cape Town’s water system is resilient?

We think not.

This may well foreshadow trouble beyond Cape Town. Cities across the Northern Hemisphere, including in Canada, are well into another summer season that has already brought record-setting heat, drought and flooding from increased run-off.

Water crises are not just about scarcity

Water scarcity crises are most often a result of mismanagement rather than of absolute declines in physical water supplies.

In Cape Town, lower than average rainfall tipped the scales towards a “crisis,” but the situation was worsened by slow and inadequate governance responses. Setting aside debates around whose responsibility it was to act and when, the bigger issue, in our view, was the persistence of outdated ways of thinking about “uncertainty” in the water system.

As the drought worsened in 2016, the City of Cape Town’s water managers remained confident in the system’s ability to withstand the drought. High-level engineers and managers viewed Cape Town’s water system as uniquely positioned to handle severe drought in part because of the vaunted success of their ongoing Water Demand Management strategies.

They weren’t entirely mistaken — demand management has cut overall daily consumption by 50 per cent since 2016. So what went wrong?


Limits to demand management

First, Cape Town’s approach to water management was not well-equipped to deal with growing uncertainty in rainfall patterns — a key challenge facing cities worldwide. Researchers at the University of Cape Town argued recently that the conventional models long used to forecast supply and demand underestimated the probability of failure in the water system.

Second, Cape Town’s water system neared disaster in part because demand management seemed to have reached its limits. Starting late last year, the city imposed a limit on water consumption of 87 litres per person per day. That ceiling thereafter shrunk to 50 litres per person per day.

Despite these efforts, Cape Town consistently failed to cut demand below the 500m-litre-per-day citywide target needed to ensure that the system would function into the next rainy season.

The mayor accused the city’s residents of wasting water, but her reprimanding rhetoric should not be seen as a sign that the citizens were non-compliant. The continuously shrinking water targets were an untenable long-term management strategy.

Buffers are key to water resilience

In the end, “Day Zero” was avoided primarily by relying on unexpected buffers, including temporary agricultural transfers and the private installation of small-scale, residential grey-water systems and boreholes in the city’s wealthier neighbourhoods. The former increased water supply and the latter lowered demand from the municipal system. These buffers are unlikely to be available next year, however, as the water allocations for the agricultural sector will not be renewed and there is uncertainty in the long-term sustainability of groundwater withdrawals.

For more than a decade, Cape Town has levelled demand, reduced leaks and implemented pressure management and water restrictions. This made Cape Town’s water system highly efficient and therefore less resilient because there were fewer reserves to draw from in times of unusual scarcity.

The UN Water 2015 report found that most cities are not very resilient to water risks. As water managers continue to wait for climate change models to become more certain or more specific, they defer action, paralysing decision-makers.

If we really want our cities to be water-resilient, we must collectively change long-held ideas about water supply and demand. This will require technological and institutional innovation, as well as behavioural change, to create new and more flexible buffers — for example, through water recycling, green infrastructure and other novel measures.

Although Cape Town avoided disaster this year, that does not make it water-resilient. Despite the arrival of the rainy season, Cape Town is still likely to face Day Zero at some point in the future.

The ConversationThere’s a good chance that the city is not alone.

Lucy Rodina, PhD Candidate, University of British Columbia and Kieran M. FindlaterUniversity of British Columbia.

This article was originally published on The Conversation. Read the original article.