Imagine floating just above the city of York. As you look down, what do you see?

Much of the city centre is a higgledy-piggledy network of ancient streets – and ancient buildings.

One of the big challenges confronting conservationists in York today is how we can maintain and care for those buildings – while at the same time responding to York’s Climate Emergency, and the city’s commitment to reduce its net carbon emissions to zero by 2030. It is not an easy challenge to address.

Fifty years ago York was dominated by smoking chimneys as factories and fireplaces contributed to our current carbon emergency. The texture of the city today is one of a different heritage – where an historic and uncluttered appearance and character appeal to 8.4 million tourists and contribute to a sense of well-being and pride for residents.

Green technologies are used extensively in modern buildings in the city - but rarely are they allowed in historic buildings. Is it not time for York to be a leader in thinking differently about how heritage can contribute to reducing carbon emissions?

Simply replacing old buildings with new ‘energy-efficient’ structures is not the answer. Historic England now stress the role our heritage buildings and landscapes can play in both climate change mitigation and adaptation.

This is especially so through valuing the ‘whole life carbon’ of historic building materials and heritage’s strong sustainability credentials - repairing and reusing historic materials time and time again, rather than routinely ripping them out and replacing them with carbon-costly modern equivalents.

Recent planning applications from York Minster and the Joseph Rowntree Theatre have asked the question whether installing solar panels on south facing roofs of historic buildings is acceptable to the city.

Will such interventions change the look and feel of the city to its detriment or demonstrate a positive contemporary message of responsibility to the future?

Climate change is destroying York’s heritage buildings - shallow pitched roofs unable to cope severe rainfall events, pollution damage to carved stone and timber exacerbated by extreme weather events and flooding along our river corridors.

We cannot exempt large swathes of the city from contributing to our climate change targets otherwise we run the risk of losing that which we are trying to protect.

Historic buildings can be a part of the solution to climate change.

They showcase tried-and-tested materials that stand the test of time: stone, timber frames, lime mortars and renders – all much cleaner and longer lasting than their modern equivalents which have such high environmental costs: concrete, uPVC plastics, aluminum-polyethylene cladding.

The carbon embedded in their structures is not released or wasted when these buildings are adapted to new uses.

But, even with their advantages, historic buildings must adapt, and our views of them must adapt also if they are to continue to survive and evolve.

Green technology is an asset in our heritage buildings, and York, if we are clever, can be a showcase for its use in keeping historic buildings alive.

We need to think holistically over the use of green technology in historic settings: what will be the impact visually, structurally and archaeologically, but also how much will carbon-use be reduced? And what will be the impact if we do not use green technology?

We need to understand what our baseline level of carbon cost is: per building, and for the city as a whole. What level of carbon reduction do we need to achieve for us achieve ‘success’?

Finally, we can’t just drop this challenging task on City of York Council; it is too important, it affects us all, so we all need to be involved in the discussion. Fortunately, the city has an excellent, if overworked, conservation team; we have two leading universities with specialisms in environment subjects; committed heritage bodies, including York Civic Trust; and major custodians of historic buildings – such as York Minster and York Conservation Trust.

York cannot abandon its hundreds of protected Listed Buildings, Scheduled Monuments and Historic Parks and Gardens. Yet York cannot be a heritage city UNLESS it is a sustainable and carbon-neutral city; and this is everyone's responsibility.

Dr Duncan Marks is the Civic Society Manager at York Civic Trust