the prize, former Prime Minister John Howard said that the scientist "has encouraged Australians into new ways of thinking about our environmental history and future ecological challenges." That said, Howard—who was a climate sceptic at the time—was unconvinced as to some of Flannery's views. Climate change Flannery has long spoken out about the impacts of climate change in Australia and internationally.In May 2004, Flannery said in light of the city's water crisis that "I think there is a fair chance Perth will be the 21st century's first ghost metropolis", a warning reiterated in 2007. In 2005, he issued several warnings about water issues in Australia, saying "water is going to be in short supply across the eastern states". In June 2005 warning that "the ongoing drought could leave Sydney's dams dry in just two years". In October 2006 Flannery quoted a US Navy study stating that, there may be, "no Arctic icecap in Summer in the next five to 15 years. He also quoted NASA's Professor James Hansen, "arguably the world authority on climate change" who said, "we have just a decade to avert a 25-metre rise of the sea". In February 2007, as he explained how increased soil evaporation impacts on runoff, he said "even the [existing amount of] rain that falls isn't actually going to fill our dams and our river systems" and in June 2007, he said that, "Adelaide, Sydney and Brisbane, water supplies are so low they need desalinated water urgently, possibly in as little as 18 months". In May 2008, Flannery suggested that sulphur could be dispersed into the atmosphere to help block the sun leading to global dimming, in order to counteract the effects of global warming. In 2019, Flannery said, "Sadly, I've been aware of [the 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 continued 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." He also said that climate activism during the previous two decades had been a "colossal failure", but praised Greta Thunberg, school strikes for climate and Extinction Rebellion for their impact on