The climate crisis has arrived, leaving fate of humanity in the balance — thousands of top scientists

Sounding the clarion call in high-impact journal BioScience, the peer-reviewed declaration affirms the science community’s “moral obligation to clearly warn humanity of any catastrophic threat” and to “tell it like it is”.

“On the basis of this obligation and the graphical indicators presented,” the declaration’s lead authors state, “we declare, with more than 11,000 scientist signatories from around the world, clearly and unequivocally that planet Earth is facing a climate emergency.”

The scientists represent top-tier institutions in 153 countries, from Albania to Zimbabwe. They specialise in a dizzying array of disciplines, including environmental sciences, mathematics, neuroscience and astrophysics.

Through a glass darkly

Released this week, the declaration embodies a historical moment in science communication — this is the first time that scientists from around the world have joined forces to declare an “unequivocal climate emergency” on a global scale. Compared with previous climate publications, studies and reports, such as the IPCC Special Report on Global Warming of 1.5°C, this declaration uses dramatic wording that creates a disturbing portrait of “profoundly troubling signs from human activities”.

“We are all extremely aware that the expectations of normal scientific communication — couched in neutral, dry, dusty, dispassionate language — have had far too little effect on policymakers and captains of industry,” Dr Phoebe Barnard, chief science and policy officer at Washington’s Conservation Biology Institute, told Our Burning Planet. A lead co-author on the landmark paper, Barnard is also a researcher with South African academic institutions, including the African Climate and Development Initiative at the University of Cape Town.

“Our purpose is to show denialists and recalcitrant politicians — and you’ll know who I mean — they have absolutely zero wiggle room left,” she told Our Burning Planet. “They’re asleep at the wheel, or worse, cutting the brake cables to make a quick personal buck as hitmen. Their actions (and inactions) will be remembered darkly by the public and future generations.”

Barnard’s co-authors are affiliates of Oregon State and Tufts universities in the US, and the University of Sydney in Australia. As for assembling thousands of scientist signatures, Barnard said “we don’t have to persuade people to sign this, or ‘sell’ them something. They are angry, frustrated and deeply fearful for their children and grandchildren”.

She added, “Nobody trained in science who has been alive with their eyes open, reading the news and watching the horizon can fail to see what is happening. The voices of scientists still have strong currency with many people. So we opened up the letter to all scientists.”



Four decades of global climate negotiations have ticked by since the first World Climate Conference in Geneva, in 1979, according to the paper attached to the declaration. It was this gathering of 50 governments who agreed unsettling climate trends made it “urgently necessary to act”. Since then, nations have met at the 1992 Rio Earth Summit, locked heads of state over the 1997 Kyoto Protocol and, in 2015, concluded the widely criticised, non-committal Paris climate goals. There’ve been “scores of other global assemblies and scientists’ explicit warnings”, the paper points out.

Massive South African push

Explaining why he added his signature, Cape Town-based Professor Nicholas King told Our Burning Planet: “The magnitude of the environmental changes coming our way are immense, far beyond anything humanity has ever experienced.”

An independent environmental futurist, King was a review editor for the Intergovernmental Panel on Climate Change’s fifth assessment report, a global diagnosis of the climate crisis. King is among more than 200 scientist signatories affiliated with South Africa, whose total signatures noticeably outweigh average contributions by scientists from other countries — some indication of concern about South Africa’s role as the continent’s top carbon emitter.

“All scientific reporting speaks of the urgent need for ‘transformative change’ in everything we do, from industrial agriculture… to our consumerist lifestyles. These are drivers of the crisis, and will be collapsed by the crisis, if we do not change direction,” said King.

Dr Jock Currie, who studies the impact of trawling on seafloor habitats along the South African coast, told Our Burning Planet he added his name because he was “frustrated by the apathy shown by governments and societies. By supporting efforts to change our climate trajectory, I can hopefully face future generations with a healthy conscience and tell them I did try.”

“An immense increase” in “endeavours to conserve our biosphere is needed to avoid untold suffering due to the climate crisis”, according to the paper.

Yet, it warns that “most public discussions on climate change are based on global surface temperature only”. As a new response to typically “inadequate” measures to “capture the breadth of human activities” and the “real dangers stemming from a warming planet”, the paper offers a suite of graphs denoting the planet’s waning “vital signs”. These include graphs on human-induced climate impacts spanning 40 years.

“We use only relevant data sets that are clear, understandable, systematically collected… and updated at least annually,” the paper explains. Aimed at groups as diverse as business, policymakers and the public, the ambitious paper also targets “those working to implement the Paris climate agreement, the United Nations’ Sustainable Development Goals and the Aichi Biodiversity Targets”.

Huge tracts of Earth could become ‘uninhabitable’

The collective effort paints in damning detail the existential fork in the road our species has reached.

“Potential irreversible climate tipping points and nature’s reinforcing feedbacks”, the authors say, “could lead to a catastrophic ‘hothouse Earth’, well beyond the control of humans.”

“The climate crisis has arrived and is accelerating faster than most scientists expected… threatening natural ecosystems and the fate of humanity,” the paper cautions. “These climate chain reactions could cause significant disruptions… potentially making large areas of Earth uninhabitable.”

The paper also cites the thorny issue of population growth as being “among the most important drivers of increases in CO₂ emissions from fossil fuel combustion”. All people of the world should be given access to family-planning services, it urges.

There are reassuring signs. Some encouraging trends include decreases in global fertility rates; reduced forest loss in the Brazilian Amazon; fossil-fuel divestment of more than US$7-trillion; and climate-heating emissions covered by carbon pricing.

“Consumption of solar and wind energy has increased 373% per decade,” it says. The authors are also “encouraged by a recent surge of concern. Governmental bodies are making climate emergency declarations. Schoolchildren are striking. Ecocide lawsuits are proceeding… Grassroots citizen movements are demanding change.”

But there’s a dark flipside to these sunshine developments.

The decline in human fertility rates has “substantially slowed”. That means population growth trends are showing less reduction over the recent 20-year period.

The massive increase in solar and wind consumption was still, in 2018, “28 times smaller than fossil fuel” equivalents. Conversely, subsidies for fossil fuels were “greater than US$400-billion in 2018”. These subsidies spiked last year despite climate protests gaining never-before-seen global momentum, and the IPCC special report rerouting climate politics.

As for the Brazilian Amazon, the “pace of forest loss has now started to increase again”, due to factors such as fires and conversion to agricultural land.

Worldwide loss in tree cover, swift global ice melt, worldwide extreme weather and ocean levels, temperature and acidity “have all been trending upward”.

Lifestyle changes — when money doesn’t grow on trees

The paper adds simply: “These issues highlight the urgent need for action… We must change how we live.”

If cited lifestyle factors are anything to go by, the paper’s arrow points at the wealthy classes. Feasting on meat and fossil fuel — often at the same time if one is a carnivorous frequent flyer — hover alongside consumptive capitalist outflows such as gross domestic product.

Incorporating a “critical” rescue plan to change the habits that power the crisis, and resuscitate the biosphere, the paper suggests six interlocking steps.

They call for, among others, leaving remaining fossil fuel stocks in the ground and reducing short-lived climate pollutants like hydrofluorocarbons (this could slash the “short-term warming trend by more than 50% over the next few decades, while saving millions of lives and increasing crop yields due to reduced air pollution”). The steps also emphasise the need to restore natural systems that sequester carbon.

“Although available land may be limiting in places,” it observes encouragingly, “up to a third of emissions reductions needed by 2030 for the Paris agreement (less than 2°C) could be obtained with these natural climate solutions.”

Scientists in the trenches

Of course, these solutions are not all that is “needed” or “even possible” — which dovetails with a debate on how frontline scientists should communicate explosive climate information at their fingertips.

Asked about unintended consequences of pulling climate “emergency” alarms, a prominent South African environmental scientist who spoke to Our Burning Planet anonymously, said: “I worry about the technical political meaning of ‘emergency’ — because that might trigger actions that are not fully thought through, as in ‘state of emergency’ responses. There’s an urgency to implement climate mitigation and adaptation responses, but ‘emergency’ language may cloud clear thinking.”

Said Barnard: “Of course, it’s a risk. But it’s not nearly the same magnitude as the overwhelming risks of continued apathy and denialism… Many of us [scientists] have worked in situations that actively discourage advocacy. But the future of the planet, human civilisation, and millions of human lives — and millions of other species — are at stake. We cannot mince our words — we’re also human beings, parents, siblings, teachers, lovers, poets, filmmakers and writers, as well as scientists. We cannot help but speak up, repeatedly.”

King pointed out that “politicians the world over seem unable, or unwilling to grasp the magnitude of this challenge. So, we must ask, what is the role of science if not to improve decision-making? And if science is not improving decision-making, then science, and scientists, need to change too — to become vociferous advocates for the change our work dictates.”

Currie, affiliated with Nelson Mandela University and the South African National Biodiversity Institute, said: “There’s been a narrative that scientists should stick to doing science and provide knowledge for decision-makers in objective, unemotional language. Most scientists would love to be able to forget about the world’s problems and focus on the fun stuff, namely their research.

“But we’re global citizens — seeing our planet burn, we can’t stick our head in the sand. There’s so much disinformation from interest groups who stand to lose if we rapidly decarbonise our economies, which threatens to drown out the truth. So, many scientists are realising they have to add their voice to reason and help lobby decision-makers to act, besides doing their normal duty of pursuing objective research.”

Barnard and her co-authors’ paper, World Scientists’ Warning of a Climate Emergency, is among thousands of academic and popular publications to chart ecological collapse. How big must Homo sapiens think to repair nature; care about lived experiences beyond our immediate tribes; and evolve towards future societies who are, as Barnard puts it, “simpler; less damaging; healthier and more meaningful”?

She urged people to start with history, dire and redemptive: “Writers like polymath Jared Diamond (Collapse) and historian David Keys (Catastrophe) have shown how relatively modest and temporary climate changes, like those associated with volcanic eruptions” often accompany disease outbreaks, unrest, economic instability, warfare and resource depletion.

“I cannot emphasise enough how close we are to upending all of this.”

A Marshall Plan for Planet Earth

Even so, she said she did not support social media memes like “near-term human extinction” (“NTHE”). Instead, she cited the past 10,000 years since the agricultural revolution as an example of “uncommonly stable and benign climatic conditions”. Though “pockmarked”, these have “allowed us to develop remarkable civilisations and incredible beauty, poetry, architecture, innovation and opportunity”.

Alluding to “the fire in my own belly” — language rarely used in science interviews with the press — Barnard spoke of a vision philosophical and pragmatic: “Have the courage to change what needs to be changed. Have the serenity to accept that some things can’t be changed. Sea-level rise is now unstoppable in a human lifespan; we need to retreat our communities and infrastructure from the coast.”

To achieve drastic action envisaged by the declaration, Barnard called for “uncommon leadership” that could initiate climate recovery through a “Marshall-type” plan, such as the US-funded rescue package that injected billions of dollars to resurrect war-torn Europe.

This far-reaching emergency declaration, then, is not just for a few thousand scientists. It needs “all humanity”, Barnard and her colleagues conclude in their paper, to “sustain life on planet Earth, our only home”. MC