Climate Change

The global climate is expected to be increasingly hotter in the coming decades due to greenhouse gas emissions. Climate projections developed by the Intergovernmental Panel on Climate Change (IPCC) suggest these likely increases in average global temperature:

• near term (2021–40) 1.5°C
• mid-term (2041–60) 2.0°C
• long-term (2081–2100) 2.7 °C

These increases are relative to the 1850–1900 average climate and are based on an emissions scenario called ‘SSP2–4.5: Regional Rivalry — A Rocky Road. This intermediate emissions pathway assumes that resistance to mitigation and adaptation will lead to emissions only declining slowly. Even scenarios that assume a rapid reduction in emissions suggest that average temperatures will increase due to greenhouse gases already in the atmosphere.

The climate models that the IPCC uses to make temperature projections also make projections for climate variables such as sea level and rainfall. The global climate and the models that represent it are complex systems and the degree of confidence in the projections for different climate variables varies widely.

For the Tablelands Regional Council (TRC) region the climate projections are for:

• substantial increases in average, maximum and minimum air temperatures; and rising ocean temperatures to the east of the TRC region (very high confidence)
• substantial increases in the temperature, frequency and duration of hot days (very high confidence)
• average sea level and height of extreme sea-level events will continue to rise, with indirect effects on the TRC region though its high dependence on Cairns for goods and services (very high confidence)
• increases in evapotranspiration in all seasons (high confidence)
• increased intensity of extreme daily rainfall events (high confidence)
• drought will continue to be a feature of the regional climate variability, but projected changes are uncertain (low confidence)
• less frequent but more intense tropical cyclones (medium confidence)
• slowing of the forward speed (motion) of tropical cyclones (low confidence)
• changes in annual rainfall are possible but unclear (low confidence)
• potential summer and autumn rainfall changes are approximately -15 to +10% for the intermediate emissions scenario (SSP2–4.5).

Potential Impacts of Climate Change in the TRC Region

The climate will change in different ways across the globe. In each region, the impacts will be influenced by the exposure and vulnerability of people and the environment. In the TRC region, some of the potential impacts include:

Agriculture & Land

• Increasingly variable rainfall may reduce water security.
• Increasing temperatures and more frequent drought reduce soil carbon.
• Tropical fruit crops like mangoes are exposed to increasing temperatures, reducing the number of inductive days for flowering. Heat-sensitive crops and livestock may be forced to relocate elsewhere.
• Existing weeds, pests and diseases may have increased impact. New invasive species may be introduced.
• Heat stress in cattle reduces their growth rate and milk yield by 10 to 30% and affects reproduction, while extreme heat waves can lead to mortality
• The TRC region may benefit in the medium-term as lowland agriculture relocates to the TRC region, taking advantage of its elevation and lower exposure to tropical cyclones. In the short term, increasing temperatures and carbon dioxide levels may increase the growing season and yield of sugarcane.

Biodiversity & Related Tourism Impacts

• Loss of rainforest in response to more severe tropical cyclones and El Niño droughts. Decline in cool-adapted species in higher elevation rainforests and increased risk of extinction e.g. Lemuroid Ringtail Possums.
• Rising cloud base will reduce the ‘cloud stripping’ mechanism for upland forests during the dry season, reducing base flow in perennial streams.
• Declining health of the Great Barrier Reef due to more frequent mass bleaching will bring knock-on effects for tourism in the broader region.

Human Health & Wellbeing

• An ageing population increases the public health impacts, as older people generally cannot tolerate extreme heat events like younger groups. Low-income earners, people with disabilities, remote settlements and Indigenous communities are also vulnerable.
• The productivity of outdoor workers may decline due to increased heatwaves. Accidents may become more frequent due to fatigue, concentration lapses and poor decision-making.
• Riverine and flash flood events are Australia’s most expensive extreme weather events and may increase.
• Floods and storms in vulnerable areas can cause injuries, depression, anxiety and poor physical health. Flow-on effects include business closures and loss of work productivity through absenteeism and reduced agricultural productivity.

Critical Infrastructure & Built Environments

• Increases in storms, floods and heatwaves are likely to disrupt critical infrastructure. Electricity outages can happen when coal-fired generators fail during extreme heat and demand for air-conditioning is high.
• Increased flooding and cyclone risk mean that some locations may become uninsurable. Variable insurance costs will especially impact disadvantaged communities that cannot afford rising premiums.
• Water scarcity in some years will increase competition for freshwater among urban and agricultural users and environmental needs.
• More intense and slower-moving tropical cyclones create a greater risk of wind damage and prolonged rain events.

Aboriginal Cultural Values

• Bio-cultural diversity and totemic species may be impacted.
• Traditional bush tucker foods may become less available and force dietary changes.
•  Inequitable power structures undermine Aboriginal communities’ ability to build adaptive capacity, respond to climate challenges, and care for Country.

References

Lawrence J et al. (2022) Australasia. Intergovernmental Panel on Climate Change, 6th Assessment Report, Working Group 2, Impacts, Adaptation and Vulnerability. Cambridge University Press: Cambridge UK.

Turton SM (2022) Surviving the Climate Crisis: Australian Perspectives and Solutions. Taylor & Francis: London, UK.