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Climate change

Did you know that approximately 80 per cent of green turtles in the northern Great Barrier Reef population are females?

As one of the largest breeding populations in the world, there are over 200,000 breeding females. But why is the population so skewed? 

Unlike humans where sex is determined during conception, sex determination in turtles is temperature-dependent and therefore influenced by the environment around them. During incubation there is a pivotal temperature that theoretically results in a 1:1 ratio of male to female hatchlings. For the northern Great Barrier Reef green turtle population, this temperature is 29.3 degrees. Incubation temperatures above the pivotal temperature produce mostly female hatchlings, while temperatures below produce mostly males. 

As the environment continues to warm, scientists around the world are drawing links between elevated temperatures and the changing sex ratios of marine turtles, particularly in tropical regions like the northern Great Barrier Reef.  

Climate has warmed by an average of 1.47 ± 0.24 °C since national records began in 1910. ~Bureau of Meteorology, State of the Climate 2022 report 


Reef Authority working to protect the northern Great Barrier Reef green turtle population 

Alongside our partners, we are working to protect the northern GBR green turtle population by: 

  • Filling critical information gaps in our understanding of the population dynamics of northern green turtles 
  • Identifying effective management actions to mitigate the effects of climate change on stock sustainability
  • Enhancing the co-management capacity of Traditional Owners within whose sea country these turtles nest and forage 

What can you do to help? 

The amount of greenhouse gases in the environment contributes to climate change which is impacting the health of the Reef. You can reduce your greenhouse footprint by: 

  • Turning your lights and appliances off when not in use 
  • Walk, ride or take public transport instead of driving 

Do you have other ways of reducing your footprint? Share them using #seeloveprotect and #lovethereef

Updated 2 Mar 2023
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