A map showing "artificial sky brightness" around the world. Light pollution from cities and industry is one of the most visible footprints of the Anthropocene, the newest geologic epoch in the history of the planet. Graphic: Falchi et al. 2016
Owen Gaffney traces the major events and scientific findings that shaped thinking and action on global sustainability over the past year – from good news about the ozone hole to concerns that we are living in a “post truth” society.
2016 could be described as the year of the Anthropocene. Certainly, month by month the footprint of industrialised societies became more evident across the planet. But let’s start with the good news, and there has been a surprising amount of it.
In November, the Global Carbon Project announced that for the third year running, the growth of emissions from fossil fuels has hovered around zero, even during strong economic growth globally. In the same month, the Paris Agreement came into force ahead of schedule after more than 55 nations representing over 55% of total global greenhouse gas emissions had ratified or otherwise approved the agreement in their countries.
More good news: Five months previously, in July, Susan Solomon and colleagues announced in Science the “Antarctic ozone hole is finally showing signs of disappearing, nearly 30 years after the Montreal Protocol came into effect.” The research was the 36th “most-discussed” journal article in 2016, according to the Altimetric top 100, which tracked 17 million mentions in the media of 2.7 million different research outputs. (For 96 more examples of how things got better in 2016 see here.)
The world, it seemed, entered 2016 on a wave of optimism following events in Paris at the tail end of 2015 when France’s Foreign Minister Laurent Fabius brought down the gavel on the climate summit sealing a historic deal. For many, that optimism was short-lived.
In the same month as the Paris Climate Conference, the Met Office predicted 2016 would likely be the warmest year on record. It is unusual for a meteorological office to make such a strong statement, but 2015 had broken the old record – set in 2014 – and now the planet was dealing with an epic El Nino.
It was a safe bet. Indeed, records kept crashing. First in January, then February, then March, right through to August – the 16th straight warmest respective month on record on Earth since records began in 1880. By November the World Meteorlogical Organisation declared: “Preliminary data shows that 2016’s global temperatures are approximately 1.2° Celsius above pre-industrial levels.” The Paris agreement aims to keep global temperatures “well below 2°C.” Earlier in the year, carbon dioxide crossed the 400 parts per million milestone. It is unlikely anyone will see carbon dioxide fall below this threshold in our lifetimes.
On 8 January, the full scale of the impact of industrialised societies on the planet came in to sharp relief with the publication of a major paper (#84 in the Altimetric top 100) from members of the Anthropocene Working Group of the International Commission on Stratigraphy. Colin Waters and colleagues argued forcefully that the Anthropocene was stratigraphically distinct from the Holocene – the geologic epoch that began 11,700 years back. The authors discussed the appearance of “technofossils," fossil traces of our technologies. Mining, construction and urbanisation are responsible for the greatest “expansion of new minerals since the Great Oxygenation Event,” which occurred 2.4 billion years ago, the group reported. The impact goes beyond just these future artifacts in the rock, however, and the authors also documented the scale of how the planet’s biology and chemistry have changed, too.
It is looking increasingly likely that the effects of the Anthropocene could have a destabilising impact on Antarctica. Robert DeConto and David Pollard warned in Nature that the rapidly melting Antarctic ice sheet may contribute more than a metre of sea-level rise by 2100 and more than 15 metres by 2500 if emissions continue unabated – and that doesn’t include sea level rise from Greenland or other glaciers (#15 in top 100).
Elesewhere, Jiafu Mao and colleagues described how humans were responsible for “greening” Earth’s northern hemisphere in Nature Climate Change. The authors provided evidence that carbon dioxide as a result of human emissions has led to increased plant growth rather than natural variability in the tundra and forests of places like Siberia.
Beyond climate, James Watson and colleagues reported in Current Biology “catastrophic declines in wilderness areas” (#59 in top 100). The authors uncovered “alarming losses comprising one-tenth (3.3 million km2) of global wilderness areas over the last two decades, particularly in the Amazon (30%) and central Africa (14%).”
Of course, much of this loss is due to the spread of agriculture, which affects climate change and biodiversity. Marco Springmann and colleagues looked at what would happen to people’s health and the climate if people made major changes to their diets (#55 in top 100). They found that lowering meat consumption to remain within health guidelines could reduce greenhouse gas emissions from food by nearly one-third by 2050. Going vegetarian would slash emissions from the food system by 63%. There would be other benefits from such choices, too: Reducing meat consumption could prevent five million premature deaths worldwide by 2050 – rising to seven million if vegetarian diets are followed, reducing global healthcare costs by up to 1 billion USD.
But in 2016, another trend stood out. Of all the papers in the top Altimetric 100, Springmann’s was the only one to offer meaningful options to deal with the challenges facing global sustainability. Perhaps it is the nature of high-impact research that it is less likely to have obvious, immediate applications – take the discovery of gravitational waves (#3). But it is clear that wherever the discussion is happening on solutions for global sustainability, it is not happening within the “most discussed” peer-reviewed papers. So, perhaps one of the biggest tasks ahead for sustainability researchers in 2017 is to examine how they can frame their work to ensure that it is central to public discourse of science.
Indeed, in a year when global datasets provided an alarming picture of the trajectory of the Earth system, the public discourse on science became a defining feature of the last 12 months for all the wrong reasons. Repeatedly, the integrity and value of science came under attack. In the United Kingdom, Brexit campaigner and politician Michael Gove pronounced that the public had enough of “experts” (without providing supporting evidence). The U.S. presidential election was largely devoid of discussion on climate change and the global environment. When these topics were discussed, established facts and the scientific consensus were often dismissed without thought or challenge, leading some to declare we live in a “post truth” society. Despite the important scientific discoveries of 2016 – from gravitational waves to ozone holes – it’s this declaration that might be the most profound takeaway for science this year.
We don’t live in a “post truth” society. But increasingly, we are building societies where lies go unchallenged and even reinforced within tribal groups through social media echo chambers. However, the scientific community remains one of the most trusted sectors in society. If we are to navigate the Anthropocene successfully, the defining question for 2017, will be how the research community responds.