Number of days over 35°C in Greenvale
Figure 2. Number of days over 35°C under ‘Business as usual’ emissions scenario (MIROC5 climate model), http://www.climatechangeinaustralia.gov.au/en/climate-projections/explore-data/threshold-calculator/.
People in the Upper Herbert 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. This will bring challenges, as well as new opportunities, to many aspects of our lives in the Upper Herbert. From the science, we know that:
- Less predictable weather: While models predict the weather in the Upper Herbert will become hotter, the likely changes and climate unpredictability mean 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: A narrow range of industries (mainly cattle grazing) is suited to existing climatic conditions in the Upper Herbert landscape. A changing climate will bring further challenges, but having access to good information and working cooperatively will put us in the best position to adapt and maintain a strong economic base.
- Climate change and communities: Being informed about the effects of a changing climate, such as hotter temperatures, increased fire risk and more intense rainfall events, can help communities in the Upper Herbert develop strategies to enable them to continue to thrive.
- Climate change and natural systems: The rate of change in climate conditions being experienced brings challenges to many of our landscape's natural systems. While changes will occur, we can work to build the new knowledge required to support adaptation of our native plants, animals and ecosystems.
There are opportunities for everyone to get involved in shaping a resilient and sustainable future for the Upper Herbert. For more information on climate change across our region, go to the Climate Futures page.
There are no long-term, publically-available temperature records from the Upper Herbert area, but data from most other landscapes show that average temperatures have been on an increasing trend over about the past 20 years. As time goes on, higher temperatures will be reached more frequently, with models projecting increases in the region in average maximum daily temperatures during January of 1.5°C by 2030.
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.
Long-term rainfall data from Mt Garnet show that rainfall continues to vary dramatically between years, and that there is no obvious increasing or decreasing trend (Figure 1).
There is a lack of official long-term temperature records in the Upper Herbert local landscape. Sharing reliable information collected by residents of the Upper Herbert would help people keep track of how the local climate is changing. This could be a way of recording and sharing observations about the survival, growth, reproduction, health and so on of native and pest plants and animals. Having access to this local information will make it easier to discuss changes and try possible management responses.
The Upper Herbert grazing and other agricultural industries depend on natural resources, and will be substantially affected by increasing average temperatures, evaporation, heat waves, extreme rainfall events and increasing atmospheric carbon dioxide. 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, potentially increasing erosion in these areas.
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.
In order to develop industries that are adapted to the new climate conditions, it will be critical to base decisions on current information about local climate patterns – including rainfall – together with data on the responses of crops and stock to these changes.
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 Upper Herbert are used to living with high temperatures, we can expect that periods of extreme heat will become more common and even hotter. Although outside the Upper Herbert region, the projections for Greenvale give an idea of what can be expected. By the year 2030, the number of days hotter than 35°C in Greenvale is projected to increase from the current annual average of 18 to 54 (and to 69 by 2050) under the ‘business as usual’ emissions scenario (Figure 2). 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, 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.
Fire weather is likely to increase in the Upper Herbert landscape due to the combination of increased evaporation, higher average temperatures, and more frequent and hotter heatwaves. For example, evaporation is projected to increase on average by around 4% annually in north Queensland. Increases in some months are expected to be higher (e.g. 7% increase in January, projections from climate model Had GEM2-ES). While fire is already a familiar part of this area, these conditions would be likely to promote more intense, frequent, and extensive bushfires. If elevated levels of CO2 promote the growth of native C4 grasses such as blady grass Imperata cylindrica, this will exacerbate the risk of large, hot fires in the region.
We can also expect that heavy rainfall events will become more frequent and intense, potentially increasing the occurrence and severity of flooding in the Upper Herbert. This is likely to exacerbate problems associated with access to this already remote region. The impacts of sea level rise in coastal parts of the region will be compounded by more frequent and intense heavy rainfall events, as well as more intense tropical cyclones. While this will not directly impact the Upper Herbert, we can expect more frequent interruptions 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, access and supply issues will help build resilience in the Upper Herbert in the face of these changes.
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’.
The Upper Herbert is likely to retain climate conditions that suit many of the species that are currently found here. On a national scale, the Upper Herbert River is among a small number of watercourses identified as being priorities for conservation of freshwater biodiversity under climate change. However, some animals and plants may no longer be able to survive or reproduce in the area. For example, changing climate conditions and fire patterns are likely to impact whole groups of plants and animals, such as seed-eating birds and grasses. Even fairly common species such as the pretty-faced (whiptail) wallaby Macropus parryi may be affected by declining habitat. Modelling shows (http://climas.hpc.jcu.edu.au/maps/) that climate conditions in the region will become less suitable for the pretty-faced wallaby, with a substantial reduction in the area supporting suitable climate by the year 2085. In reality, changes may not unfold exactly as these models project, 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.
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, fire, 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. More extreme rainfall events will increase the frequency of intense disturbance to in-stream invertebrates, animals and plants, and exacerbate the issue of soil and pollutant runoff entering the Great Barrier Reef lagoon. Fire conditions are also 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.
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.