A high level discussion involving top scientists discussing what is a 'scientifically defensible, sustainable human population size for the long term' as called for in the World Scientists Warning to Humanity - A Second Notice issued in 2017 by over 15,000 scientists. Once we know the correct population size then how should we get there and when? The 2017 warning also called for 'rallying nations and leaders to support that vital goal’ in terms of population size.

July 11th is World Population Day. Population is also included as one of the 6 stressors in the World Scientists Warning of Climate Emergency issued on 5 November 2019 .Connected with this Scientists Warning Europe believe the United Nations should include a scientifically determined population goal into its SDGs. This would seem to be currently a worrying weakness in the current list of SDGs as so many of them are, in any case, dependent on or effected by global population levels and connected consumption.

Panel discussion will be chaired by Ed Gemmell, Managing Director of Scientists Warning Europe and the panellists will include the following eminent scientists:

Dr Bill Rees

Prof Phoebe Barnard

Dr Jane O'Sullivan

Dr Christopher Tucker

Speaker Bios

Dr William Rees is a population ecologist, ecological economist, Professor Emeritus and former Director of the University of British Columbia’s School of Community and Regional Planning. Prof Rees is a founding member and former President of the Canadian Society for Ecological Economics; a Fellow of the Post-Carbon Institute; a founding Director of the OneEarth Initiative; and a Director of The Real Green New Deal. Prof Rees’ research focuses on the biophysical prerequisites for sustainability. He is best known as the originator and co-developer (with his graduate students) of ‘ecological footprint analysis,’ a quantitative tool that shows definitively that the human enterprise is in dysfunctional overshoot—we would need five Earth-like planets to support just the present world population sustainably with existing technologies at North American material standards. Such findings led to a special interest in cities as inherently unsustainable and particularly vulnerable components of the human ecosystem. Concerned about societal unresponsiveness to worsening indicators, Dr Rees also studies the biological and psycho-cognitive barriers to rational political behavior. He has authored hundreds of peer reviewed articles on the above topics. Dr Rees was elected to Royal Society of Canada in 2006; his international awards include the Boulding Memorial Award in Ecological Economics, the Herman Daly Award in Ecological Economics and a Blue Planet Prize (jointly with his former student Dr Mathis Wackernagel)

Prof Phoebe Barnard. Phoebe is a passionate global citizen with a fire in her belly about accelerating transformative and sustainable change in society. A behavioral and evolutionary ecologist by background, she is now a biodiversity and climate change strategic planner, sustainability strategist, conservation and global change ecologist, policy analyst and teacher. She is chief science and policy officer at the Conservation Biology Institute, and affiliate full professor at the University of Washington. Phoebe has 26 years of deep experience on three continents, mainly in Africa, North America and Europe - founding and running national and bioregional programs, and helping to steer global ones. She works in academia, government, nonprofits and with community science groups at global, ecoregional and local scales on the existential problems of our time: biodiversity loss, ecological connectivity, climate risk and adaptation, green economic recovery, and sustainability tipping points. Her climate risk and adaptation work draws on existential threats to (and opportunities for) civilization including climate migration and managed coastal retreat. She is fueled by her core co-authorship of the World Scientists’ Warning of a Climate Emergency and her work to implement its six recommendations. Phoebe and her filmmaker husband John Bowey also work through film, immersive media, and prose to tell compelling and powerful stories about ecosystem health, biodiversity, climate and society, among other big issues (https://www.phoebebarnard.com/conservation-writing-filmmaking and https://www.tmvusa.net/). She holds a PhD from Uppsala University in Sweden, a MSc with distinction from University of the Witwatersrand in South Africa, and a BSc Hons from Acadia University in Canada.

Dr Jane O’Sullivan is an Honorary Senior Research Fellow at the University of Queensland. She researches the environmental and economic impacts of demographic change, challenging the many myths that are used to dismiss concerns about population growth. In particular, she researchers the environmental, social and economic impacts of population growth, and the efficacy of policy and program options addressing it.

Dr. Christopher Tucker has spent the last two decades at the intersection of technology, strategy, geography and national security as an innovator, investor, social entrepreneur, author, and strategic advisor to the US national security community. As Chairman of the American Geographical Society, he launched a multi-year strategic dialog known as Geography2050, focused on the vital trends that will reshape the geography of our planet over the coming decades. He has served on a wide variety of public sector, corporate, and non-profit boards including the Defense Science Board Intelligence Task Force, the Director of National Intelligence's Strategic Studies Group, the Secretary of Interior’s National Geospatial Advisory Committee, the United States Geospatial Intelligence Foundation, and the Open Geospatial Consortium. He holds a BA, MA, and PhD from Columbia University. His passion for geography and the fate of future generations animates his work. Chris Tucker is also the author of A Planet of 3 Billion (www.Planet3Billion.com).