Will Steffen fought passionately for our planet. To honour him we must follow his lead | Penny Sackett

I am filled with grief at losing my friend at a time when we need his calm, direct voice more than everThis week science lost one of its greatest Earth system experts, Australia lost a skilled, passionate communicator of climate science and the world lost a humble soul of the highest humanity, kindness and integrity. As did scores of others, I lost a colleague and friend when Will Steffen left us on Sunday after a battle with pancreatic cancer.It is impossible to overstate Will's impact on science. The many tributes to his work can only scratch the surface of his legacy. He led the effort to map the Great Acceleration of human impact on the physical and biological systems of our planet, culminating in consideration of the geological age of humans - the Anthropocene, first proposed by Nobel prize winner Paul Crutzen.As the climate system continues to spiral towards a potentially uncontrollable state, I am struck with an increasing sense of both anger and apprehension. I'm angry because the lack of effective action on climate change, despite the wealth not of only scientific information but also of solutions to reduce emissions, has now created a climate emergency. The students are right. Their future is now being threatened by the greed of the wealthy fossil fuel elite, the lies of the Murdoch press, and the weakness of our political leaders. These people have no right to destroy my daughter's future and that of her generation.I'm apprehensive because the more we learn about climate change, the riskier it looks. Even at a 1 degree C rise in global temperature, extreme weather events are becoming more violent and dangerous than models have predicted. Over the last 5 years, our knowledge of tipping points in the Earth System has advanced rapidly, with many already showing signs of instability. Worse yet, they can interact like a row of dominoes to set off a tipping cascade, driving the Earth to hotter and more unstable conditions. That is my worst fear - that we may reach a 'point of no return' where we commit our children to a future of hell on Earth. Continue reading...