Flannery has long spoken out about the impacts of climate change in Australia and internationally. In 2019 Flannery said, "Sadly, I've been aware of urgency to act for a long time. We have to reduce emissions as hard and fast as possible... The speed and scale of impacts have been something that is really shocking." He contined to warn people that, "People are shocked, but they should be angry...The consequences will grow year by year, and stuff we were warning people about 20 years ago is now coming to fruition and is impossible to deny, unless you are wilfully blind."