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.

 
 
 
 

Here’s how we plant 2 billion more trees in the UK

A tree in Northallerton, North Yorkshire. Image: Getty.

The UK’s official climate advisor, the Committee on Climate Change (CCC), recently published a report outlining how to reduce the 12 per cent of greenhouse gas emissions that come from land use by two thirds by 2050. Alongside recommending cutting meat and dairy consumption by 20 per cent, the report calls for the annual creation of up to 50,000 hectares of broadleaf and conifer woodland for the next three decades. This would increase forest cover from 13 per cent to at least 17 per cent – a level not seen in Britain since before the Norman invasion.

Reforestation at that rate would mean creating roughly the area of the city of Leeds every year for the next three decades. At typical stocking densities of 1,500 stems per hectare, the ambition is to establish some 2.25 billion additional trees. Given that the UK, as with most of Europe, is in the grip of ash dieback, a disease likely to prove fatal for many millions of native ash trees, the scale of the challenge is massive.

On a crowded and intensively farmed island like Britain, unlocking a million and a half hectares of land will be no mean feat. But it’s not impossible – and is an unprecedented opportunity not only to tackle the climate crisis but also the biodiversity crisis that is every bit as detrimental to our wellbeing.

Trees and farms

One million and a half hectares is just 6 per cent of the mainland UK’s land area. To give some sense of perspective on this, 696,000 hectares of “temporary grassland” were registered in 2019. So if land supply is not the problem, what is? Often it’s cultural inertia. Farmers are firmly rooted to the land and perhaps understandably reluctant to stop producing food and instead become foresters. But the choice need not be so binary.

The intensification of agriculture has caused catastrophic declines in many species throughout the UK by reducing vast wooded areas and thousands of miles of hedgerows to small pockets of vegetation, isolating populations and making them more vulnerable to extinction.

Integrating trees with the farmed landscape delivers multiple benefits for farms and the environment. Reforestation doesn’t have to mean a return to the ecologically and culturally inappropriate single-species blocks of non-native conifers, which were planted en masse in the 1970s and 1980s. Incentivised under tax breaks to secure a domestic timber supply, many of the resulting plantations were located in places difficult or in some cases impossible to actually harvest.

Productive farmland needn’t be converted to woodland. Instead, that 4 per cent of land could be found by scattering trees more widely. After all, more trees on farmland is good for business. They prevent soil erosion and the run-off of pollutants, provide shade and shelter for livestock, a useful source of renewable fuel and year-round forage for pollinating insects.

The first tranche of tree planting could involve new hedgerows full of large trees, preferably with wide headlands of permanently untilled soils, providing further wildlife refuge.


Natural regeneration

Where appropriate, new woody habitats can be created simply by stopping how the land is currently used, such as by removing livestock. This process can be helped by scattering seeds in areas where seed sources are low. But patience is a virtue. If people can learn to tolerate less clipped and manicured landscapes, nature can run its own course.

A focus on deliberate tree planting also raises uncomfortable truths. Most trees are planted with an accompanying stake to keep them upright and a plastic shelter that protects the sapling from grazing damage. All too often, these shelters aren’t retrieved. Left to the elements, they break down into ever smaller pieces, and can be swept into rivers and eventually the ocean, where they threaten marine wildlife. Two billion tree shelters is a lot of plastic.

The main reason for using tree shelters at all is because the deer population in the UK is so high that in many places, it is all but impossible to establish new trees. This also has serious implications for existing woodland, which is prevented from naturally regenerating. In time, these trees will age and die, threatening the loss of the woodland itself. Climate change, pests and pathogens and the lack of a coordinated, centrally supported approach to deer management means the outlook for the UK’s existing treescape is uncertain at best.

An ecologically joined-up solution would be to reintroduce the natural predators of deer, such as lynx, wolves, and bears. Whether rewilding should get that far in the UK is still the subject of debate. Before that, perhaps the focus should be on providing the necessary habitat, rich in native trees.

A positive response would be to implement the balanced recommendations, made almost a decade ago in a government review, of creating more new habitat, improving what’s already there, and finding ways to link it together. Bigger, better, and more connected habitats.

But the UK is losing trees at increasing rates and not just through diseases. The recent removal of Victorian-era street trees in Sheffield and many other towns and cities is another issue to contend with. As the climate warms, increasing urban temperatures will mean cities need shade from street trees more than ever.

Trees aren’t the environmental panacea that the politicians might have people believe – even if they do make for great photo opportunities – but we do need more of them. Efforts to expand tree cover are underway across the world and the UK will benefit from contributing its share. Hitting the right balance – some commercial forestry, lots of new native woodland and millions of scattered trees – will be key to maximising the benefits they bring.

Nick Atkinson, Senior Lecturer in Ecology & Conservation, Nottingham Trent University.

This article is republished from The Conversation under a Creative Commons license. Read the original article.