Incidences of Harmful Algal Blooms (HABs) are becoming more frequent, their scale is growing and so are their impacts on food and water security. HABs are being fed by increases in water temperature, dissolved CO2 concentration and nutrient availability in our oceans and freshwater bodies. Algal blooms act as a sink for atmospheric CO2, but they can also harm biodiversity and disrupt ecosystems and food chains in sea-food based economies.