A decade on from the destruction of the World Trade Center, New York is busy rebuilding – and tall buildings have got stronger

The shocking human scale of the disaster that destroyed the twin towers of the World Trade Center in New York on 11 September 2001, 10 years ago this month, appalls the imagination as much today as it did then. And in the weeks that followed the attack in which 2,753 people were killed, that shock was inevitably joined by grave concerns over how to guard against the risk of such a tragedy happening again.

In 2001, the then head of the GLA’s planning committee firmly asserted: ‘This will put developers off tall buildings’

Amid the alarm around national security and international relations, questions were raised over the very idea of constructing iconic towers whose scale and grandeur made them attractive to governments and high-profile corporations, but also marked them out as potential targets for terrorism. This debate reverberated far beyond New York: Tony Arbour, the then head of the Greater London Authority’s planning committee, firmly asserted in Building: “This will put developers off tall buildings.”

Yet within two months, the New York authorities had established the Lower Manhattan Development Corporation to oversee the site’s renewal - and the following year launched perhaps the most hotly contested architectural competition in history: to design a new generation of towers for the site. The speed with which the authorities moved is testament to their refusal to be cowed by the terrorism threat, and to their recognition of the symbolic importance of replacing the destroyed structures. But elsewhere, too, the doubts raised over the viability of tall buildings have been all but silenced by strong arguments in favour. As well as the appeal of status - nowhere more apparent than in the Middle East - there is the need to build upwards to cope with the demands of a burgeoning global urban population. And in spite of the delays and litigation, not to mention a change of designer, the WTC site is thriving.

Of course, the concerns raised by the 9/11 attacks were not simply passed over: in New York in particular, regulation of structural stability and fireproofing has been strengthened considerably. But a point of note has been that, since 2001, once clients made up their mind of the need for building tall, they and their supply chains drove these improvements rather than waiting for legislation to catch up. Within days of the attacks, structural engineer WSP was revising designs for the Barclays building in Canary Wharf, and although there have been no 9/11-related changes to fire regulations in the UK, fire engineering has advanced to offer protection far above regulatory standards in high-risk parts of buildings, without adding to the overall cost.

These positive actions teach a lesson that - away from the drama of the WTC site - the industry would do well to remember. Whether in response to disasters or to concerns such as sustainability, the construction industry at its best, working alongside responsible clients, is capable of driving improvement of its own accord. In an era when governments and clients are under pressure to come up with innovative solutions to a growing list of problems that affect the built environment, with minimal financial outlay, that’s something that is as relevant now as it was in the aftermath of the tragedy 10 years ago.

Sarah Richardson, deputy editor