Australia's eco system sequesters more CO2 every year than Australia emits, therefore we are a carbon neutral country, what we emit is taken up by our land and its eco system.
Here are some crude results from what information is available.
Depending on their state like, tree spacing, humidity, dryness etc etc
Australian grasslands and forests sequester approximately between
0.5 to 2 tonnes of carbon per hectare annually
To convert to CO2 we need to multiply by 3.67, therefore re-writing
Australian grasslands and forests sequester approximately between
1.835 to 7.34 tonnes of carbon dioxide per hectare annually
There are approximately 149 million hectares of Australian forests
There are approximately 440 million hectares of Australia grass lands
Forrest uptake of atmospheric CO2 every year
Lowest: 149 x 1.835 = 273.4 million tonnes of CO2 per annum
Highest: 149 x 7.34 = 1093.66 million tonnes of CO2 per annum
Grasslands uptake of atmospheric CO2 every year
Lowest: 440 x 1.835 = 807.4 million tonnes of CO2 per annum
Highest: 440 x 7.34 = 3229.6 million tonnes of CO2 per annum
Lets combine grasslands and forest uptake of atmospheric CO2 per annum
Lowest: 273.4 + 807.4 = 1080.8 million tonnes of CO2 per annum
Highest: 1093.66 + 3229.6 = 4323.26 million tonnes per annum
Australia emits 560 million tonnes of CO2 per annum
The bottom line is
Lowest: Our grasslands and forests sequester nearly double what we emit.
Highest: Our grass lands and forests sequester nearly eight times more than we emit.
Conclusion:
It would be a rare occasion for the lowest or the highest values to take place therefore more than likely we would hover somewhere in between lowest and highest depending on the sun and weather conditions.
The above doesn't take into account the uptake of the land (Australian soil) itself which would make those values even bigger.
https://www.chiefscientist.gov.au/2009/12/which-plants-store-more-carbon-in-aust...