We can cut emissions in half by 2040 – but only if we build smarter cities

Shanghai's Jinmao Tower, under construction in 2009. Image: Getty.

As a planet, we have some serious climate targets to meet in the coming years. The Paris Agreement, signed by 192 countries, set an aspirational goal of limiting global warming to 1.5ᵒC. The United Nations Sustainable Development Goals, set to be achieved by 2030, commit the world to “take urgent action” on climate change.

All this will require ridding our economies of carbon. If we’re to do so, we need to completely rethink our cities.

The UN’s peak climate body showed in its most recent report that cities are crucial to preventing drastic climate change. Already, cities contribute 71 per cent to 76 per cent to energy-related carbon emissions.

In the Global South, energy consumption and emissions in urban areas tend to be way higher than those in rural areas. Future population growth is expected to take place almost entirely in cities and smaller urban settlements. Unfortunately, those smaller centres generally lack the capacity to properly address climate change.

China’s “New-type Urbanisation Policy” aims to raise its city populations from 54.2 per cent in 2012 to 60 per cent in 2020. This will mean building large urban infrastructure projects, and investing trillions of dollars into new developments. Meanwhile, India’s sheer volume of urbanisation and infrastructure needs are phenomenal.

The problem with infrastructure

Infrastructure contributes to greenhouse gas emissions in two ways: through construction (for example, the energy footprints of cement, steel and aluminium used in the building process) and through the things that go on to use that infrastructure (for example, cars or trains using new roads or tracks).

In a recent study, my colleagues and I have shown that the design of today’s transportation systems, buildings and other infrastructure will largely determine tomorrow’s CO2 emissions.

Less of this, please. Image: Getty.

But by building climate-smart urban infrastructure and buildings, we could cut future emissions in half from 2040 onwards. We could reduce future emissions by ten gigatonnes per year: almost the same quantity currently being emitted by the United States, Europe and India put together (11 gigatonnes).

We assessed cities’ potential to reduce emissions on the basis of three criteria: the emissions savings following upgrades to existing infrastructure; emissions savings from using new, energy-efficient infrastructure; and the additional emissions generated by construction.

In established cities, we found that considerable progress can be made through refurbishment of existing infrastructure. But the highest potential is offered by construction of new, energy-efficient projects from the beginning. The annual reductions that could be achieved by 2040 by using new infrastructure is three to four times higher than that of upgrading existing roads or buildings.

With this in mind, governments worldwide must guide cities towards low-carbon infrastructure development and green investment.


Urbanisation is about more than megacities

Significant opportunities exist to promote high-density living, build urban set-ups that mix residential, work and leisure in single spaces, and create better connectivity within and between cities. The existing window of opportunity to act is narrowing over time, as the Global South develops rapidly. It should not be missed.

Besides global megacities such as Shanghai and Mumbai, smaller cities must also be a focus for lowering emissions. Studies have shown a paradox for these places: the capacity for governance and finance are lower in the smaller cities, despite the fact that the majority of future urban populations will grow there, and they will expand quicker than their larger cousins.

We must give up on our obsession with megacities. Without building proper capacity in mid- and small-sized cities to address climate solutions, we cannot meet our climate goals.

Perhaps most important is raising the level of ambition in the existing climate policies in cities of all sizes, making them far-reaching, inclusive and robust. Despite the rhetoric, the scale of real change on ground from existing cities climate actions are unproven and unclear.

Existing cities’ climate mitigation plans and policies, such as in Tokyo, London, Bangkok, and activities promoted by networks such as ICLEI, C40, Covenant of Mayors for Energy and Environment are a good start; they must be appreciated but further strengthened.

But, to further support these good ideas, the world urgently needs support measures for urban mitigation from local to global levels together with a tracking framework and agreed set of indicators for measuring the extent of progress towards low-carbon future.

Only if we start with cities, big and small, will we manage to limit warming to 1.5°C.The Conversation

Shobhakar Dhakal is associate professor at the Asian Institute of Technology.

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

 
 
 
 

This fun map allows you to see what a nuclear detonation would do to any city on Earth

A 1971 nuclear test at Mururoa atoll. Image: Getty.

In 1984, the BBC broadcast Threads, a documentary-style drama in which a young Sheffield couple rush to get married because of an unplanned pregnancy, but never quite get round to it because half way through the film the Soviets drop a nuclear bomb on Sheffield. Jimmy, we assume, is killed in the blast (he just disappears, never to be seen again); Ruth survives, but dies of old age 10 years later, while still in her early 30s, leaving her daughter to find for herself in a post-apocalyptic wasteland.

It’s horrifying. It’s so horrifying I’ve never seen the whole thing, even though it’s an incredibly good film which is freely available online, because I once watched the 10 minutes from the middle of the film which show the bomb actually going off and it genuinely gave me nightmares for a month.

In my mind, I suppose, I’d always imagined that being nuked would be a reasonably clean way to go – a bright light, a rushing noise and then whatever happened next wasn’t your problem. Threads taught me that maybe I had a rose-tinted view of nuclear holocaust.

Anyway. In the event you’d like to check what a nuke would do to the real Sheffield, the helpful NukeMap website has the answer.

It shows that dropping a bomb of the same size as the one the US used on Hiroshima in 1945 – a relatively diddly 15kt – would probably kill around 76,500 people:

Those within the central yellow and red circles would be likely to die instantly, due to fireball or air pressure. In the green circle, the radiation would kill at least half the population over a period of hours, days or weeks. In the grey, the thing most likely to kill you would be the collapse of your house, thanks to the air blast, while those in the outer, orange circle would most likely to get away with third degree burns.

Other than that, it’d be quite a nice day.

“Little boy”, the bomb dropped on Hiroshima, was tiny, by the standards of the bombs out there in the world today, of course – but don’t worry, because NukeMap lets you try bigger bombs on for size, too.

The largest bomb in the US arsenal at present is the B-83 which, weighing in at 1.2Mt, is about 80 times the size of Little Boy. Detonate that, and the map has to zoom out, quite a lot.

That’s an estimated 303,000 dead, around a quarter of the population of South Yorkshire. Another 400,000 are injured.

The biggest bomb of all in this fictional arsenal is the USSRS’s 100Mt Tsar Bomba, which was designed but never tested. (The smaller 50MT variety was tested in 1951.) Here’s what that would do:

Around 1.5m dead; 4.7m injured. Bloody hell.

We don’t have to stick to Sheffield, of course. Here’s what the same bomb would do to London:

(Near universal fatalities in zones 1 & 2. Widespread death as far as St Albans and Sevenoaks. Third degree burns in Brighton and Milton Keynes. Over 5.9m dead; another 6m injured.)

Everyone in this orange circle is definitely dead.

Or New York:

(More than 8m dead; another 6.7m injured. Fatalities effectively universal in Lower Manhattan, Downtown Brooklyn, Williamsburg, and Hoboken.)

Or, since it’s the biggest city in the world, Tokyo:

(Nearly 14m dead. Another 14.5m injured. By way of comparison, the estimated death toll of the Hiroshima bombing was somewhere between 90,000 and 146,000.)

I’m going to stop there. But if you’re feeling morbid, you can drop a bomb of any size on any area of earth, just to see what happens.


And whatever you do though: do not watch Threads. Just trust me on this.

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and also has a Facebook page now for some reason. 

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