The future of climate change is here

Aslan Shand

The smoke has been settling in the valley like mist in the mornings as fires burn throughout NSW and Queensland.

Icons such as Binna Burra Lodge in the Border Ranges have burnt to the ground as the cry from scientists builds, saying that we need to both reduce our global emissions as quickly as possible and start preparing for the serious impacts of climate change.

But what are those likely impacts?

Several are happening at the moment, specifically the increased risk of drought and fires. ‘We’ve always had drought and fires’ is often the retort and you’re right, we have – but it is now happening against the background of a rapidly warming climate.

This means the risks of drought, fires, and extreme flooding are increasing – that is, they are going to happen more often.
‘We are the driest inhabited continent on Earth, with around 77 per cent of the country classified as arid or semi-arid,’ Dr Joelle Gergis told Byron Shire councillors, staff, and members of the public last Friday in Mullumbimby.

Dr Gergis, who is one of the Australian scientists contributing to the sixth IPCC (Intergovernmental Panel on Climate Change ) report due out in 2021, describes herself as fairly centre-of-the-road when it comes to her approach to climate change but even she is saying, ‘We need to be talking about putting the brakes on as quickly as possible. Global emissions need to peak as soon as possible.’

Acting on the emergency climate declaration passed last year, Byron councillors and staff had their first workshop on Friday to look at how to develop a climate emergency response strategy, Cr Cate Coorey told The Echo.

Time to prepare

If we continue to move forward on a high greenhouse gas emissions trajectory, then it is predicted that on the NSW north coast we will experience an average increase in temperature of between 2.8 and 5 degrees by 2090.

‘That means that the number of warm days [on average in Brisbane] will increase from the current 12 days above 35 degrees a year to 55 days (possible range of 37–80 days) above 35 degrees by 2090,’ explained Dr Gergis.

‘This will lead to increasing heatwaves, increasing extreme rainfall events like ex-cyclone Debbie, and increasing droughts. Extreme heat and humidity are likely to make one of Australia’s largest population centres dangerously hot by the end of the century.’

Less predictable rainfall combined with longer droughts (those lovely sunny days) will have significant effects on food production because farmers’ crops will die without water and when it rains the deluges will also destroy crops. So the call to help drought- and flood-affected Australians is likely to become the norm rather than the exception.

It will also affect the reliability and quality of the water supply because a warming climate will lead to less predictable rain patterns and more extreme weather events – think ex-cyclone Debbie. This will be compounded by the fact that, according to CSIRO projections, tropical cyclones will become less frequent but more intense and drift further south.

‘This increases the cyclone risk of areas like northern NSW and SE Queensland,’ said Dr Gergis.

‘A warmer and wetter atmosphere leads to more intense rainfall, particularly when it is being fuelled by a warmer ocean surface.’

Dr Gergis, who lives in Byron Shire, pointed out that almost all of the water that fell during ex-cyclone Debbie fell in 24 hours, making this an unusual weather event for the north coast. ‘This made me think that this is a glimpse of the future. Think about ex-cyclone Debbie and think of that as the new average,’ she said.

Byron Shire vulnerable

‘Byron Shire has significant vulnerability and exposure to climate change. We are currently on track for the highest scenario of climate warming and in the absence of global action Byron Shire needs to address climate-change mitigation.

‘Under current predictions there will be a 23–40cm ocean rise by 2050. Sea-level rise (SLR) will make things worse, so planned retreat of vulnerable areas, flood risks, and the impact of droughts need to be planned for.
‘A combination of higher rainfall intensity and sea levels will amplify the distressing impacts of storm surges, resulting in coastal inundation and beach erosion on a scale that hasn’t been witnessed by modern Australian society,’ she said.

‘An increase in sea level means that low-lying areas become more prone to inundation during high-tide or storm-surge events. As the planet continues to warm and the sea level rises, our coastlines and low-lying areas become more exposed to inundation.

‘So events that used to be considered floods in our present climate will just be the new high tides in the future.’

Currently the approach to sea-level rise is based on the ‘bathtub’ approach; that is, the sea level rises by 1m and that is added to the current known flood level, says local hydrologist and former councillor Duncan Dey.

‘The shape of the river opening and to a small extent of the coast near it enables more energy to enter the estuary when ocean levels at the opening are 1m higher than now.’ That means that as the sea level rises there will be increasing amounts of water at the opening and a bigger amount of storm energy transferring into the estuary.

‘When the ocean rises 1m, the surge height won’t add 1.5m at that location, it will add more, because more ocean energy reaches the location,’ explained Mr Dey.

‘When ocean levels rise high enough to top delicate coastal dunes and break into an estuary, the transfer of ocean energy into the estuary will likely raise flood levels far more than the simple SLR.’

But what does that mean for you?

One way to get a basic understanding of what the effects might be on you is to consider what happens at a high tide or during a flood. Take that as the new normal and think about how you can adapt. Perhaps a house on stilts is the answer?

In areas such as Belongil where Council has had a longstanding policy of coastal retreat it is time to make sure you house can be picked up by a crane and moved – or enjoy it while you can and prepare yourself for the fact that there will be a time when you say goodbye to it.

The websites Coast Adapt www.coastadapt.com.au and Coastal Risk www.coastalrisk.com.au are good places to start to get an indication of what the impacts might be in your location.

Remember that you need to look at the very high greenhouse-gas scenarios (RCP8.5) because unless there is significant, fast change to the levels of greenhouse gas being emitted then that is the outcome everyone needs to prepare for.
You can look for sea-level rise, inundation, temperature, and rainfall information by entering your postcode or local government area (eg Byron).

Areas that may be inundated with water at high tide by 2100 include the West Byron site, areas behind New City Road and Ann Street in Mullumbimby, The Fishermen’s Co-op in Brunswick Heads, and increasingly more areas of New Brighton and South Golden Beach.