Jianhua Zhang1
1Institute for Sustainable Industries and Liveable Cities, Victoria University, Melbourne, VIC, Australia
Correspondence: Jianhua Zhang Jianhua.zhang@vu.edu.au
The temperature of our planet has increased by 1.2 ± 0.1°C, compared to its preindustrial values, three quarters of which takes place in the past 40 years. Anthropogenic emissions of greenhouse gases (GHGs) have been considered as a main trigger of current climate change. Lowering emission of GHGs and capturing GHGs are two major approaches to slow down the global warming trend. Human activities transfer carbon fixed in the fossil fuel to carbon oxide into the air. Hence, the carbon oxide could be reduced by refixing into biomass. Marine algae transform nearly 50 Gt of carbon dioxide each year from the atmosphere and convert it into biomass. The seaweed ecosystem acts as a carbon sink, and carbon retained by seaweeds could be buried in sediments or migrate to the deep sea. Furthermore, since carbohydrates present 30 – 80% of the overall carbon content in algal biomass as storage of carbon and energy, seaweeds can be used as a carbon buffer to lower carbon dioxide in the atmosphere. The total global seaweed production (wet weight) are approximately 36 million ton annually, in which 97.38% from Asia and 97.0% are farmed seaweeds. China is the largest seaweed producer, and produced 56.75% of the overall seaweeds worldwide and 58.02% of farmed seaweeds. These farmed seaweeds can be consumed as foods and used for industrial purposes, which will prolong carbon in solids and supress the rate of atmospheric carbon dioxide increase. The length of the Australian coastline is similar to that of the Chinese coastline. Australia’s pristine and isolated coastal environment provides a massive opportunity for seaweed farming. Assuming the productivity of Australia increases to 10% of the productivity of China, 0.2 million ton (wet weight) seaweeds will harvest 0.22 million ton of carbon dioxide annually, based on equivalent 10% dry weight and 30% carbon content. Based on prices of carbon credits, $37/ton CO2 in Australia, an additional $8 million could be added to industry annually.