With architects changing their ways in response to global warming, Phineas Harper asks: what does radical architecture look like in the era of climate change?

A whole host of Stirling Prize-winning architecture practices have declared an emergency in response to accelerating climate change. Calling for a "paradigm shift", they unveiled 11 pledges to bring architectural practice in line with planetary limits and called on other UK designers to sign up.

And not before time. The British government estimates that the built environment accounts for almost 47 per cent of greenhouse gas emissions. Architecture's potential to lead the fight against global heating, to date, has been matched only by its failure to do so.

Many commentators have spun Architects Declare as mere virtue signalling, pointing to some of the founding firms' poor track record on ecological construction. Yet just two weeks later, over 400 practices have signed up, while architecture students have launched a parallel declaration. We're seeing an unprecedented mobilisation of architects in the fight against climate change.

Pledges and sexy websites are one thing, but channelling the momentum behind these strident words into meaningful change is another. The 11 pledges are solid first steps and amount to a significantly reformed vision of urban practice, but ultimately fall short of the comprehensive paradigm shift their authors insist is needed.

The aesthetic and material possibilities of a new ecological architecture could be exceptionally rich

What could go further? What would a more radical architectural response to an era of climate emergency look like? What would it mean for the designers, builders, commissioners and users of buildings to rise to such an emergency with holistic cultural and economic, as well as technical ambitions?

These are the most compelling questions facing urban practitioners today.

The aesthetic and material possibilities of a new ecological architecture could be exceptionally rich, driving an international artistic and political renaissance no less profound than the advent of modernism.

Exploring that potential will mean upending the conventions of the contemporary construction industry and challenging received wisdom, from urban morphology to material choices. In the past for example, architects have often justified specifying materials with high embodied carbon by averaging out a new building's construction-related emissions over its entire lifetime – a formula which, like many others may need reinventing.

The argument goes that high emissions on day one are a worthwhile investment if the project is so robust that it can stand for decades. Buildings that employ thousands of tons of concrete can, therefore, be described as "sustainable" on the grounds that they might be specced to last for a hundred years or more. This logic seems reasonable at face value but in fact it is a perilous fantasy.

As has become clear in the IPCC's recent report, hitting an ecological tipping point in the next 12 years could trigger a series of multiplier effects meaning the absolute priority for emissions-heavy economies has to be curbing greenhouse gas emissions now.

We can no longer think of gases emitted during construction as spread over a building's use life – there just enough isn't enough time.

What would it mean to embrace thatch and other plant-based and natural materials with vigour?

The implications of this for construction are profound. Durable walls can no longer come at the cost of high embodied carbon no matter how resilient they are. Longevity, hardwearingness, solidity – the seductive values we've traditionally invoked with so many material strategies, may need to be abandoned as we explore a radically different tactic of far less durable buildings that require far more repair.

This would require a seismic cultural shift in the commissioning of buildings.

Many clients have a pathological fear of exposure to ongoing repair commitments. Material specifications are regularly made solely to reduce maintenance needs – green spaces are paved, vinyl is laid over timber floors, tarmac is poured on cobbles, etc.

To actively embrace maintenance, rather than avoid it, would mean a sea change in the material culture of construction, and a revaluation of janitorial labour.

Thatching, for example, was once a widespread roofing technique with good thermal performance, hyper-low environmental impact and seductive sculptural qualities. Yet today, thatch is not just rarely specified, but actively replaced as its need for occasional repair makes it unattractive in the eyes of our durability-obsessed culture.

What would it mean to rethink this stance, to embrace thatch, and other plant-based and natural materials with vigour, not despite of their need for maintenance, but because of it?

To repair the biosphere, we may need to rethink the repair of architecture first

One possibility is to think at the civic scale. The walls of Mali's Great Mosque of Djenné (main image), rebuilt in 1907, are peppered with toron, protruding bundles of rodier palm sticks. These decorative posts are in fact also permanent scaffolding which are used annually for repairing the mud facade. The toron's duality – both ornament and expression of repair – is a rich seam which can be found elsewhere in wider design history also.

In Japan, the boro technique is a way of repairing garments in perpetuity. During the Edo period, boro became common among peasants who carefully mended their garments with spare fabric scraps, handing them down over generations until they resemble a dense patchwork. Another Japanese precedent is kintsugi, the art of repairing broken pottery with lacquer dusted with gold.

Thatch, Djenné, kintsugi and boro celebrate the constantness of repair and ongoing history of materials. The garment is never finished. The building is always in flux.

What would it mean to apply these philosophies to contemporary building maintenance so that acts of repair are valued and expressed formally?

There is, perhaps, a lesson to draw surprisingly from high-tech. The glass facades specified in gleaming towers across the world don't need replacing often but they do require regular cleaning. In the hands of the best high-tech architects, window cleaning infrastructure became exuberant architectural features such as the deep blue cranes perched on the Lloyds Building by Richard Rogers. If high-tech can articulate cleaning as architecture, what new forms and architectural devices could embody an architecture of maintenance?

The bottom line is simple. The studios that have joined Architects Declare are right. This is an emergency, and the transformation of contemporary urban practice is an urgent, as it is an exciting project. The opportunity to radically reduce emissions while exploring new architectural forms and philosophies is immense and tantalising.

Making modest efficiency gains alone will not be enough. A merely more optimised, less reckless version of late capitalist modernity still overshoots planetary limits and squanders the opportunity to discover architectural languages that nourish the planet and enrich our experience of it.

Challenging contemporary material culture and our compulsion for durability is one avenue to explore. An architecture of repair could not just reduce emissions but facilitate a culturally infused urbanism of constant process, even civic festivity.

To repair the biosphere, we may need to rethink the repair of architecture first.