The NOW imperative:  Time for personal, professional, social, political action: A letter from 16,000 scientists in 180 countries

World Scientists’ Warning to Humanity: A Second Notice

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by *William J. Ripple, Christopher Wolf, Mauro Galetti, Thomas M Newsome, Mohammed Alamgir, Eileen Crist, Mahmoud I. Mahmoud, William F. Laurance  and nearly 15,000 scientist signatories from 180 countries.  First published in Bioscience.  November 13, 2017

SEE http://scientistswarning.forestry.oregonstate.edu/cosignators

            Twenty-five years ago, the Union of Concerned Scientists and more than 1500 independent scientists, including the majority of living Nobel laureates in the sciences, penned the 1992 “World Scientists’ Warning to Humanity” (see Supplemental File S1). These concerned professionals called on humankind to curtail environmental destruction and cautioned that “a great change in our stewardship of the Earth and the life on it is required, if vast human misery is to be avoided.” In their manifesto, they showed that humans were on a collision course with the natural world. They expressed concern about current, impending, or potential damage on planet Earth involving ozone depletion, freshwater availability, marine fishery collapses, ocean dead zones, forest loss, biodiversity destruction, climate change, and continued human population growth. They proclaimed that fundamental changes were urgently needed to avoid the consequences our present course would bring.

            The authors of the 1992 declaration feared that humanity was pushing Earth’s ecosystems beyond their capacities to support the web of life. They described how we are fast approaching many of the limits of what the planet can tolerate without substantial and irreversible harm. The scientists pleaded that we stabilize the human population, describing how our large numbers— swelled by another 2 billion people since 1992, a 35 percent increase—exert stresses on Earth that can overwhelm other efforts to realize a sustainable future (Crist et al. 2017). They implored that we cut greenhouse gas (GHG) emissions and phase out fossil fuels, reduce deforestation, and reverse the trend of collapsing biodiversity.

On the 25th anniversary of their call, we look back at their warning and evaluate the human response by exploring available time-series data. Since 1992, with the exception of stabilizing the stratospheric ozone layer, humanity has failed to make sufficient progress in generally solving these foreseen environmental challenges, and alarmingly, most of them are getting far worse (figure 1, Supplemental File S1). Especially troubling is the current trajectory of potentially catastrophic climate change due to rising GHGs from burning fossil fuels (Hansen et al. 2013), deforestation (Keenan et al. 2015), and agricultural production—particularly from farming ruminants for meat consumption (Ripple et al. 2014). Moreover, we have unleashed a mass extinction event, the sixth in roughly 540 million years, wherein many current life forms could be annihilated or at least committed to extinction by the end of this century.

            Humanity is now being given a second notice as illustrated by these alarming trends (figure 1). We are jeopardizing our future by not reining in our intense but geographically and demographically uneven material consumption and by not perceiving continued rapid population growth as a primary driver behind many ecological and even societal threats (Crist et al. 2017). By failing to adequately limit population growth, reassess the role of an economy rooted in growth, reduce greenhouse gases, incentivize renewable energy, protect habitat, restore ecosystems, curb pollution, halt defaunation, and constrain invasive alien species, humanity is not taking the urgent steps needed to safeguard our imperilled biosphere.

As most political leaders respond to pressure, scientists, media influencers, and lay citizens must insist that their governments take immediate action, as a moral imperative to current and future generations of human and other life. With a groundswell of organized grassroots efforts, dogged opposition can be overcome and political leaders compelled to do the right thing. It is also time to re-examine and change our individual behaviours, including limiting our own reproduction (ideally to replacement level at most) and drastically diminishing our per- capita consumption of fossil fuels, meat, and other resources.         

            The rapid global decline in ozone-depleting substances shows that we can make positive change when we act decisively. We have also made advancements in reducing extreme poverty and hunger (www.worldbank.org). Other notable progress (which does not yet show up in the global data sets in figure 1) include: the rapid decline in fertility rates in many regions attributable to investments in girls’ and women’s education (www.un.org/esa/population), the promising decline in the rate of deforestation in some regions, and the rapid growth in the renewable-energy sector. We have learned much since 1992, but the advancement of urgently needed changes in environmental policy, human behavior, and global inequities is still far from sufficient.

Sustainability transitions come about in diverse ways and all require civil-society pressure and evidence-based advocacy, political leadership, and a solid understanding of policy instruments, markets, and other drivers. Examples of diverse and effective steps humanity can take to transition to sustainability include (not in order of importance or urgency):

• prioritizing the enactment of connected well-funded and well-managed reserves for a significant proportion of the world’s terrestrial, marine, freshwater, and aerial habitats;

• maintaining nature’s ecosystem services by halting the conversion of forests, grasslands, and other native habitats; and restoring native plant communities at large scales, particularly forest landscapes;

• rewilding regions with native species, especially apex predators, to restore ecological processes and dynamics;

• developing and adopting adequate policy instruments to remedy defaunation, the poaching crisis, and the exploitation and trade of threatened species;

• reducing food waste through education and better infrastructure;

• promoting dietary shifts towards mostly plant-based foods;

• further reducing fertility rates by ensuring that women and men have access to education and voluntary family-planning services, especially where such resources are still lacking;

• increasing outdoor nature education for children as well as the overall engagement of society in the appreciation of nature;

• divesting of monetary investments and purchases to encourage positive environmental change;

• devising and promoting new green technologies and massively adopting renewable energy sources, while phasing out subsidies to energy production through fossil fuels;

• revising our economy to reduce wealth inequality and ensure that prices, taxation and

• incentive systems take into account the real costs which consumption patterns impose on our environment; and

• estimating a scientifically defensible, sustainable human population size for the long term while rallying nations and leaders to support that vital goal.

         To prevent widespread misery and catastrophic biodiversity loss, humanity must practice a more environmentally sustainable alternative to business as usual. This prescription was well articulated by the world’s leading scientists 25 years ago, but in most respects, we have not heeded their warning. Soon it will be too late to shift course away from our failing trajectory, and time is running out. We must recognize, in our day-to-day lives and in our governing institutions, that Earth with all its life is our only home.

Epilogue

          We have been overwhelmed with the support for our article and thank the more than 15,000 signatories from all ends of the Earth. As far as we know, this is the most people to ever co-sign and formally support a published journal article. In the paper, we have captured the environmental trends over the last 25 years, showed realistic concern, and suggested a few examples of possible remedies. Now, as an Alliance of World Scientists (scientists.forestry.oregonstate.edu) and with the public at large, it is important to continue this work to document challenges as well as improved situations, and to develop clear, trackable, and practical solutions, while communicating trends and needs to world leaders. Working together, while respecting the diversity of people and opinions, and need for social justice around the world, we can make great progress for the sake of humanity and the planet on which we depend.

Acknowledgments

           Peter Frumhoff and Doug Boucher of the Union of Concerned Scientists, as well as the following individuals, provided thoughtful discussions, comments, or data for this paper: Stuart Pimm, David Johns, David Pengelley, Guillaume Chapron, Steve Montzka, Robert Diaz, Drik Zeller, Gary Gibson, Leslie Green, Nick Houtman, Peter Stoel, Karen Josephson, Robin Comforto, Terralyn Vandetta, Luke Painter, Rodolfo Dirzo, Guy Peer, Peter Haswell, and Robert Johnson.

References cited

Crist E, Mora C, Engelman R. 2017. The interaction of human population, food production, and biodiversity protection. Science 356: 260–264.

Hansen J, et al. 2013. Assessing “dangerous climate change”: Required reduction of carbon emissions to protect young people, future generations and nature. PLOS ONE 8: e81648.

Keenan, RJ, Reams GA, Achard F, de Freitas JV, Grainger A, Lindquist E. 2015. Dynamics of global forest area: results from the FAO Global Forest Resources Assessment 2015. Forest Ecology and Management, 352: 9–20.

Ripple WJ, Smith P, Haberl H, Montzka SA, McAlpine C, Boucher DH. 2014. Ruminants, climate change and climate policy. Nature Climate Change 4: 2–5. doi:10.1038/nclimate2081

William J. Ripple (bill.ripple@oregonstate.edu), Christopher Wolf, and Thomas M. Newsome are affiliated with the Global Trophic Cascades Program, in the Department of Forest Ecosystems and Society, at Oregon State University, in Corvallis. TMN is also affiliated with the Centre for Integrative Ecology, in the School of Life and Environmental Sciences, at Deakin University, in Geelong, Australia. Mauro Galetti is affiliated with the Instituto de Biociências, Universidade Estadual Paulista, Departamento de Ecologia, in São Paulo, Brazil. Mohammed Alamgir is affiliated with the Institute of Forestry and Environmental Sciences, at the University of Chittagong, in Bangladesh. Eileen Crist is affiliated with the Department of Science and Technology in Society, at Virginia Tech, in Blacksburg. Mahmoud I. Mahmoud is affiliated with the ICT/Geographic Information Systems Unit of the National Oil Spill Detection and Response Agency (NOSDRA), in Abuja, Nigeria. William F. Laurance is affiliated with the Centre for Tropical Environmental and Sustainability Science and the College of Science and Engineering, at James Cook University, in Cairns, Queensland, Australia.

SEE http://scientistswarning.forestry.oregonstate.edu/cosignators