Changing Weather – Hinchinbrook

People in the Hinchinbrook Local Landscape know that rainfall, temperature and cyclones vary from year to year, but that our ability to live in and manage the landscape is based on long experience of general seasonal patterns. However, knowledge based on past experience is becoming less reliable as temperatures and sea levels rise and extreme weather events become more common.

• Less predictable weather: With less reliability and predictability in future weather patterns, it will become increasingly difficult to rely on our past experience to make decisions about where to build houses and infrastructure, which crops to grow, which pests and diseases to target, and how to manage fire.
• Climate change and industries: Making sure we are informed about possible impacts of a changing climate will make it easier to plan ahead and develop strategies to ensure we maintain healthy and diverse industries in our local landscape.
• Climate change and communities: Coastal communities are particularly vulnerable to impacts of climate change, with rises in sea level already being observed.  By accessing reliable information to support good decision making, we can increase Hinchinbrook’s resilience and ability to adapt to a changing climate.
• Climate change and natural systems: Natural systems will also be faced with increased disturbances, more intense weather events, hotter temperatures and rising sea levels.  The implications of managing for climate change impacts on our natural systems will be complex, but we have access to good scientific data to support decision making.

There are opportunities for everyone to get involved in shaping a resilient and sustainable future for the Hinchinbrook region. For more information on climate change, including links to more detailed climate change modelling for our region, go to the Climate Futures page.

Less predictable weather

Long-term temperature records from Ingham show reasonable variability over much of the previous 50 years, with some years hotter than average and some cooler.  More recent years, from around 2014 onwards, appear to show an increasing trend in maximum temperatures compared to the long term average, with 2016 recording the highest variation from the long term temperature average in Ingham (Figure 1).

Long-term rainfall data from Ingham’s Victoria Mill show that rainfall continues to vary dramatically between years, and that there is no obvious increasing or decreasing trend in annual rainfall at this stage (Figure 2).

As time goes on, higher temperatures will be reached more frequently. For example, maximum daily temperatures during January are projected to increase from the current average of 32.4°C to 33.9°C by 2030, 33.4°C by 2070 and 34.7°C by 2090 (Figure 3). Furthermore, there will be a longer season of high temperatures, with the average daily maximum temperature well above 30°C from October to April.

While we are likely to see an increasing trend in temperatures as a result of climate change, one of the most concerning predictions coming from climate scientists is the impact of greater variability and less predictability in our weather patterns, making it harder to plan.

Climate change and industries

Sugar cane production and grazing will be directly affected by increasing average temperatures, evapotranspiration, heat waves, extreme rainfall events and increasing atmospheric carbon dioxide. For example:

• The sucrose content of sugarcane can decline if temperatures are high and/or there is high rainfall during the ripening and harvest season.
• Areas of cultivation and ponded pasture in low-lying coastal areas will obviously be vulnerable to sea level rise, either through sea water inundation, increased tidal reach or salt-water contamination of coastal aquifers.
• Heavy rainfall events associated with cyclones or other systems can prevent planting or harvest, with serious economic implications for cropping and horticulture industries.
• Climate change may also bring new diseases and pests, which we know potentially pose enormous threats to our agricultural industries.
• Flooding associated with extreme rainfall will also affect waterways and floodplains, potentially increasing erosion in these areas.

Regional primary industries may also be impacted by increasing bottlenecks in processing or distribution networks. For example, heat waves, cyclones and floods all have the potential to result in shut down of industrial operations such as the Victoria and Macknade sugar mills, either through workplace health and safety concerns, power failure, flooding or damage. Operation of facilities such as the Cairns, Townsville or Lucinda sea ports will also be affected by storm surge, cyclones, flooding during heavy rainfall, and extreme heat. Considering the importance of ports to both the import of fuel, food and other supplies, as well as to the export of regional produce, more frequent closures are likely to have significant economic implications for the region.

Climate change will also impact the commercial fishing industry. People in the Hinchinbrook area have experienced the impacts of intense cyclones, with several months of lost operations due to large amounts of debris or sediment in the water, as well as damage to boats, marinas, ramps and other infrastructure. Commercial fishing operations will also be affected as certain types of fish move south due to increasing water temperatures, as coral bleaching becomes more widespread and as conditions decline in fish breeding and nursery areas.

Tourism in the area is underpinned by the natural values of the Hinchinbrook region. Climate-induced changes in the health and composition of natural systems, including the potential loss of iconic species (see below), will potentially have major impacts on tourism in the area. Islands such as Hinchinbrook Is are particularly vulnerable to impacts from sea level rise and more intense cyclones. Since tourism is already very seasonal, prolonged hot weather and less predictable rainfall is likely to affect visitation patterns to the region, while more extreme weather may influence tourists’ perception of their safety in the region.

Changing climatic conditions will challenge our established ways of doing things, but may also present new agricultural and commercial opportunities. For example, it may be necessary to diversify or switch crops or breeds to suit new climatic conditions, or to change practices. In order to adapt to new and changing climatic conditions, we may need to shift farming and other commercial enterprises to different parts of the landscape. This could create opportunities for the restoration of wildlife habitat on former agricultural land, but could also create conflict between the need to protect existing habitat and also maintain production.

Climate change and communities

Doing things the way they’ve been done for generations won’t necessarily keep working as climate conditions continue to change, meaning that traditions and local wisdom will be challenged. Everyone will be affected in one way or another by climate change: some types of farms may not remain viable, certain areas along the coastline may become unsafe to live, and some of our iconic species may not survive in the new conditions. While change can be unsettling, new opportunities may come out of new ways of doing things, especially by working together across sectors and industries. Importantly, being informed about the types of changes we can reasonably expect means that we can develop plans and strategies to adapt to these, rather than being taken by surprise by unusual climate events.

Although people in the Hinchinbrook area are used to living with high temperatures, we can expect that periods of extreme heat will become more common and even hotter. For example, the number of days hotter than 35°C in Ingham is projected to increase from the current average of six to 21 by 2030 (and to 30 by 2050) under the ‘business as usual’ emissions scenario (Figure 4). More people will be vulnerable to heat-related illnesses and stress, especially sick, elderly and very young people, and people living without air-conditioning.

In the same way that maximum temperatures are increasing (Figure 3), minimum temperatures are also rising. This means that overnight temperatures will remain above 20°C for more months of the year, potentially affecting sleep quality, especially for households without air conditioning, and increasing the use of air conditioning in households with it.

Sea levels are already rising and models project that sea levels in this region will increase by an average of 0.14 m by the year 2030, and by an average of 0.65 m by 2090 under a business as usual emissions scenario. By 2030, homes and other assets along the Southern Cassowary coastline would need to be 0.14 m higher (and by 0.79 m in 2090) to maintain their current level of exposure to flooding from the ocean (Figure 5). Low elevation areas of the coastline will be most vulnerable.

Rising sea levels will increase the tidal extent of coastal rivers and streams, meaning that the tidal reach in the Herbert and Seymour Rivers and coastal creeks may push further upstream, potentially affecting homes, businesses and crops on adjacent floodplains, as well as roads and other infrastructure.  Even a modest increase in sea level height will mean that there are many more high tides and storm surges, increasing coastal erosion, flooding and contaminating freshwater systems with salt water.

The impacts of sea level rise will be compounded by more frequent and intense heavy rainfall events in the region, as well as more intense (though probably less frequent) tropical cyclones. There will be an increased threat to homes, businesses and roads in the extensive low-lying areas along the Hinchinbrook coastline from river flooding and storm surge and cyclonic winds. People living in buildings that can’t withstand severe cyclones will be very vulnerable during cyclonic winds. Local planning for development, stormwater drains, roads and bridges will be affected. We can expect more frequent interruptions to grid-based electricity supply as well as to fuel and other supplies due to shut down of the region’s rail lines, sea and air ports during extreme weather events. Working together to address back-up power and supply issues will help build Hinchinbrook’s resilience in the face of these changes.

Climate change and natural systems

Natural systems have coped with changing climatic conditions in the past but current changes are happening so fast that some species may not be able to adapt. Because climatic factors such as temperature and rainfall play such an important role in determining the suitability of different areas for plants and animals, we can expect that changes in temperature and rainfall will change the suitability of the landscape for certain species and systems. The result of climate change will be new combinations of plants and animals, sometimes in new locations, challenging our concept of what is ‘natural’. Even fairly small changes, such as the increased recruitment of colonising (or pioneer) rainforest plant species can have a substantial effect on the suitability of an area for other plants and for some animals.  It’s also likely that this region will become more attractive to people moving from other areas that become less liveable. Increasing pressure for housing and more infrastructure to support growing populations will potentially lead a push for more clearing of native vegetation.

The Hinchinbrook area is likely to retain climate conditions that suit many of the species that are currently found here. However, some animals and plants may no longer be able to survive or reproduce in the area. For example, analysis of climate suitability for the mahogany glider shows substantial changes for this region. Modelling shows (http://climas.hpc.jcu.edu.au/maps/) that the area around Lucinda will rapidly become less suitable for the mahogany glider over the next decade. In these models, suitable climatic conditions for the mahogany glider will continue to decline and will be lost from much of this landscape by the year 2085. In reality, changes may not unfold exactly as these models predict, but these projections have complex implications for how we manage landscapes to protect our plants and animals; we have to protect areas that are currently important so that threatened species survive, but also consider where important habitat will likely be in the future, together with whether and how plants and animals would be able to move there and establish. These considerations affect our decisions about which areas to protect and restore, as well as how to manage factors such as fire in these areas.

Coastal species are at particular risk from sea level rise, for example as beaches are inundated and freshwater wetlands and coastal scrub transition to salt-tolerant vegetation communities.  The impacts of climate change on natural areas in coastal locations will be far reaching, including:

• Critically endangered littoral rainforest systems are under extreme threat from climate change. These natural systems protect a diversity of threatened plants and animals, as well as protecting coastal settlements.
• Sea level rise will mean that there will be fewer nesting beaches for sea turtles.
• A range of birds and mammals will be affected by the loss of freshwater wetlands as beaches and dune systems are inundated or eroded.
• Freshwater wetlands and coastal floodplains, together with the abundant wildlife they support, are also under threat from more intense flooding during heavy rainfall events and salt water contamination due to sea level rise and storm surge.
• We can expect widespread dieback of sea grasses and mangroves in lower intertidal zones, due to sea level rise, more intense cyclones and storm surges. These impacts will have a range of flow-on consequences for fish, dugong and other estuarine and marine life.

Strategies such as the planned retreat of human settlements and infrastructure from coastal areas may reduce the risk to humans and also create opportunities for natural systems to shift landward.

In addition to the direct effects of increased temperatures and changed rainfall, climate change will have a range of indirect effects on other factors that drive natural systems. A major impact of climate change for natural systems will be more frequent and/or more intense disturbances, such as floods, heatwaves and cyclones. For example, increased intensity and frequency of river flooding, together with increased water temperatures, will change aquatic systems, as well as those fringing waterways or on floodplains. Narrow riparian vegetation will be particularly vulnerable. More extreme rainfall events will also increase the frequency of intense disturbance to in-stream invertebrates, animals and plants, and exacerbate the issue of soil and pollutant runoff entering the region’s wetlands and the Great Barrier Reef lagoon.

Fire conditions are likely to alter in unpredictable ways, depending on how rainfall patterns change, how grasses and other plants respond to increasing carbon dioxide in the atmosphere, and how these things interact with increased temperatures and more frequent heat waves. It is likely that managers will need to change practices to implement fires that benefit a range of species and maintain grasses in open forest and woodland systems.

Prospects are bleak for the Great Barrier Reef under a business as usual scenario of climate change. Bleaching of coral reefs will continue to be more widespread as average temperatures increase and heatwaves become hotter and more common. As hot spells occur more frequently, reefs won’t have time to recover from previous bleaching episodes and will eventually collapse. Reef systems will also be affected by more acidic sea water (caused by higher CO₂), more intense cyclones and freshwater pulses associated with heavy rainfall events.

Managers of biodiversity are already working to minimise or reverse impacts of land clearing, pollution, introduced plants, animals and diseases on natural systems. Climate change is an additional impact that interacts with these existing pressures. The resilience of natural systems to cyclones and other disturbances is improved by having a large and well-managed network of protected areas. It’s not possible to predict the exact consequences of climate change for plants, animals and their habitats, but sharing observations, trying new management practices and monitoring their outcomes will help build the new knowledge required to promote adaptation of natural systems to climate change.