Earth's vital signs worsen amid 'business as usual' climate policy

Twenty months after more than 11,000 scientists declared a global climate emergency, establishing a set of benchmarks for the planet’s health, an international coalition says its update on those vital signs “largely reflect the consequences of an unrelenting ‘business as usual’ approach to climate change policy”.

Dr Thomas Newsome from the University of Sydney said: “Especially troubling is the increase in climate-related disasters, including the 2019-20 Australian megafires, and the fact that three main greenhouse gases – carbon dioxide, methane and nitrous oxide – set records for atmospheric concentrations in 2020 and again in 2021. This was despite shifts during the COVID-19 pandemic.”

Dr Newsome and co-authors, led by Professor William Ripple and Dr Christopher Wolf from Oregon State University, lay out their climate update in a paper published today in BioScience.

The research team calls for a “three-pronged near-term policy approach”, including:

• a globally implemented carbon price;
• a phase-out and eventual ban of fossil fuels; and
• strategic environmental reserves to safeguard and restore natural carbon sinks and biodiversity.

Dr Newsome said: “The COVID pandemic has shown dips in human activity are not enough to avoid climate disaster: we need structural transformation of the economy.”

The authors say the introduction of a global price for carbon needs to be high enough to induce “decarbonisation” across the industrial and consumption spectrum.

Dr Newsome said: “We suggest an urgent need for transformative change to reduce greenhouse gas emissions and, more broadly, human overexploitation of the planet.

“Opportunities still exist to shift pandemic related monetary support measures into climate friendly activities; it is encouraging to see fossil-fuel divestment and fossil-fuel subsidies improving in record setting ways.”

The scientists note an unprecedented surge in climate-related disasters since 2019, including devastating floods, record heatwaves, and extraordinary storms and fires.

“There is growing evidence we are getting close to or have already gone beyond tipping points associated with important parts of the Earth system, including warm-water coral reefs, the Amazon rainforest and the West Antarctic and Greenland ice sheets,” said Professor Ripple, distinguished professor of ecology in the Oregon State University College of Forestry.

Last year was the second hottest year in recorded history, with the five hottest years on record all occurring since 2015. And in April this year, carbon dioxide concentration reached 416 parts per million, the highest monthly global average concentration ever recorded.

“Priorities need to shift toward immediate, drastic reductions in greenhouse gases, especially methane,” said Dr Wolf, a postdoctoral scholar at Oregon State.

With its myriad economic interruptions, the COVID-19 pandemic had the side effect of providing some climate relief but only of the ephemeral variety, the scientists say.

“Global gross domestic product dropped by 3.6 percent in 2020 but is projected to rebound to an all-time high,” Professor Ripple said. “Likely because of the pandemic, fossil-fuel consumption has gone down since 2019, as have carbon dioxide emissions and airline travel levels. All of these are expected to significantly rise with the opening of the economy.”

A major lesson of the pandemic, the authors say, is that even sharply decreased transportation and consumption are insufficient to tackle climate change and instead transformational system changes are required, even if politically unpopular.

Despite pledging to “build back better” by globally directing COVID-19 recovery investments toward environmental policies, only 17 percent of such funds had been allocated that way as of early March 2021.

“As long as humanity’s pressure on the Earth system continues, attempted remedies will only redistribute the pressure,” Dr Wolf said. “But by halting the unsustainable exploitation of natural habitats, we can reduce zoonotic disease transmission risks, protect carbon stocks and conserve biodiversity, all at the same time.”

Other vital signs the authors highlight:

• Ruminant livestock now number more than 4 billion, and their total mass is more than that of all humans and wild mammals combined.
• Brazilian Amazon annual forest loss rates increased in both 2019 and 2020, reaching a 12-year high of 1.11 million hectares deforested in 2020.
• Ocean acidification, together with thermal stress, threatens the coral reefs that more than half a billion people depend on for food, tourism dollars and storm surge protection.

The paper comes out as the Intergovernmental Panel on Climate Change prepares to release its report, on the physical science of climate change, on 9 August. The IPCC says the report will include an assessment of scientific knowledge about the warming of the planet and projections for future warming.

Joining Dr Newsome and Oregon State University researchers Ripple and Wolf are: Jillian Gregg and Beverley Law, both from Oregon State University; Timothy Lenton of the University of Exeter; Ignacio Palomo of the University of Grenoble Alps; Jasper Eikelboom of Wageningen University and Research; Saleemul Huq of Independent University Bangladesh; Philip Duffy of the Woodwell Climate Research Center; and Johan Rockström of the Potsdam Institute for Climate Impact Research.

The 2019 climate emergency paper, also published in BioScience, at the time had more than 11,000 scientist signatories from 153 countries. The signatories now total nearly 14,000 from 158 countries.

The 31 benchmarks are: human population; fertility rate; ruminant livestock; per capita meat production; GDP; tree cover loss; Amazon rainforest loss; coal consumption; oil consumption; gas consumption; solar/wind power consumption; air transport; fossil-fuel divestment; carbon dioxide emissions; per capita CO2 emissions; greenhouse gases covered by carbon pricing; carbon price; fossil-fuel subsidies; national declarations of climate emergency; CO2 parts per million; methane parts per billion; nitrous oxide parts per billion; surface temperature; Arctic sea ice; Greenland ice mass; Antarctica ice mass; glacier thickness; ocean heat change; ocean acidity; sea-level change; area burned in the US.

Declaration

Dr Thomas Newsome received no additional funding for this publication.