Circular construction could be positive tipping point according to climate research

In a report released this week, Dr Steven Smith, an Impact Fellow at Tipping Points, argues that material reuse and cutting waste in construction — the largest single waste stream — could help push planet onto new climate trajectory, highlighting built environment professionals as agents of change.

 

The research, produced by the University of Exeter with the Earthshot Prize, identifies "positive tipping points" in five areas or ’Earthshots’ that are capable of triggering transformative change to alter the carbon trajectory – opposing the usual story of tipping points as irreversible negative thresholds, such as the collapse of ice sheets.

 

The five Earthshots include: Protect and restore nature, clean our air, revive our oceans, build a waste-free world, and fix our climate.

 

The research positions architects, engineers, planners and developers as ’tipping agents’ who can trigger and accelerate cascades of progress.

 

The report highlights how agents of change provide solutions that unlock feedback loops by inspiring others, making new “behaviours socially normal and structurally easy.” If these behaviours are then embedded into policy on material usage and design, the expectation is set for others to reach the “desired future state” and change becomes inevitable – a positive tipping point.

 

Smith identifies decarbonising the grid as the most powerful tipping point that could unlock change over the next two to eight years. “The single most important cross-cutting finding from the five chapters is that clean electricity is the enabling cascade for transitions across most other Earthshot domains,” writes Smith.

 

For the built environment, this means electrified buildings, mobility (EV-ready streets and homes) and decarbonising buildings through heat pump adoption, retrofit and net-zero construction.

 

With construction and demolition as the largest single waste stream globally, currently sitting at 3.5bn tonnes/year, professional turning to circular, low-carbon alternatives is key to reaching net-zero construction.

 

While quality variability and fragmented standards create a barrier at this time, the report sets a target of 70% of construction and demolition waste being recycled into high-value applications as the desired future state. This could trigger reuse markets and create new streams of circularity.

 

Built environment professionals shape the enabling conditions needed to reach the tipping point. Cycling accelerates when safe routes reach critical mass, circular materials accelerate when reuse hubs and deconstruction infrastructure exist, and reuse of materials happens when architects and engineers help standardise it.

 

Smith writes that progress cannot be made without changes to the urban form. Smith notes that “public transport investment lags in many car dependant cities,” which limits the opportunity to progress street design and increase mixed-use density. This paves the way for infrastructure investment for EVs, public transport and low emission zones.

 

Alongside clean electricity unlocking Electric Vehicles and low-emission zones (LEZ), it is hoped that by 2030 there will be over 500 LEZ in European cities, an increase from the current 320. 

 

“The Avoid-Shift-Improve framework recognises that the deepest decarbonisation requires reducing travel demand, shifting to lower-carbon modes, and improving the efficiency of remaining vehicle travel,” Smith writes.

 

One challenge is keeping cities and buildings cool from rising temperatures. Two billion air conditioning units are used globally at this time, a figure expected to grow with temperatures increasing.  “The cooling–emissions doom loop – hotter conditions drive cooling demand, which drives electricity demand, which drives emissions, which drives warming – is measurable and accelerating,” writes Smith.

 

An increased consideration of shading, building orientation and ventilation for homes are suggested to reduce the 10% global energy demand of cooling – indeed, Smith suggests a Passive-first and retrofit-first strategies to cut energy demand for buildings in general.

 

Buildings account for around 21% of global energy use and 8-9 GtCO2 emissions annually. Heat pumps and other energy efficient measures can make home more efficiency by a multiple of 3-5. Yet only 10% of European homes rely on heat pumps. 

 

Smith acknowledges that barriers to implementation include “split-incentives between landlords and tenants, electricity-to-gas price ratios, workforce training capacity and building codes.”

 

Smith names building regulators, public procurers, architects, engineering firms, construction industry, material producers, developers and real estate investors as key to shifting behaviour norms among key actors – essential to trigger demand-side tipping points.

 

Smith argues that behaviour change is not just about reversing damage limitation or mitigating climate impacts and disasters – anticipatory action must be made “replacing reactive, post-disaster spending with pre-agreed finance”.

 

Acting on a forecast before impact strikes prevents funds from being mobilised after disaster, saving money, homes and lives.

 

Smith says climate-resilient infrastructure must be outlined and implemented on a case-by-case basis despite funding constraints. As each programme is successful, political support for anticipatory action begins to cascade and builds an investor confidence loop.

 

The report makes one thing clear: Key actors need to design the conditions for self-propelling change by choice, not as a response to policy or guidelines. The built environment has the opportunity to lead change towards positive tipping points.

 

Smith concludes that there’s three enablers to change — Governance, Finance and Monitoring.

 

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Read the report: Positive Tipping Points: Accelerating system change to repair our planet, furthers Professor Tim Lenton’s pioneering research, expanding positive tipping point science to five Earthshots: Protect and Restore Nature, Clean Our Air, Revive Our Oceans, Build a Waste-Free World, and Fix Our Climate.

 

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