We are now experiencing the warmest 12 month period ever on record in Australia: the warmest summer ever, followed by a winter like none we have seen since records began. And the interesting thing about this recent spell is that it is not coincident with a major (or even minor) El Nino event. The world is getting warmer, and it is happening now, to us. But a change in average temperatures goes by almost unnoticed. The days are slightly warmer, the nights a little less cool. But when the climate’s natural variability is added to this shift, it’s the extremes that become amplified. And these we do notice. So when the next big El Niño event comes (and it probably will sometime in the next five to ten years), it will almost certainly push temperatures and weather in Australia to extremes that will put severe stresses on society.

Take, for example, the three day heat wave that hit South-eastern Australia in 2009. Over a three day span, 370 people died prematurely from heat-related stress, half a million homes were without power, transport was disrupted (24% of Melbourne trains were cancelled), infrastructure damaged, and millions of dollars worth of fruit and vegetable crops were lost. Overall, the heat wave cost the economy over $800 million. That was one event. By 2070, our research suggests that the frequency of this type of event will more than triple. Across the board, extreme weather of all types is expected to become more frequent and more intense in the future.

But in many ways, the future has already arrived, and it has found us under-prepared. National analysis, for instance, of our existing and future stock of buildings (currently worth over $5 trillion), reveals that about ten per cent of it is exposed to coastal inundation, inland flooding and bush fire right now. As vulnerable areas become more intensely developed, as asset values rise, and as the frequency and severity of these hazards increases, the total national exposure to this troika of extremes could rise to over $ 100 billion by mid-century if we do not change our approach to planning. 

Superstorm Sandy, which hit New York earlier this year, has been a catalyst for action in that part of the world. First hand evidence of the tremendous damage that extreme weather can do to modern cities has galvanised action. New York is working hard to become more resilient, investing billions of dollars, and using the experience of Sandy to understand what works, what doesn’t, and where the biggest benefits are to be had. For instance, researchers are finding that in places where natural coastlines had been retained (such as dune and wetland systems), inland damage to built assets was far lower than in areas where natural systems had been replaced by manmade constructions. These ‘free’ assets, provided by nature, delivered huge benefits.

Much can be done to make our nation more resilient to the extreme weather which is coming our way. Cost effective measures to make buildings more resilient to coastal flooding, for instance, can yield present value benefits of $20 and more for each $1 spent. The longer we wait to take action to protect ourselves, the greater the costs. The sooner we act, the greater the benefits.