'Uncharted territory': climate scientists sound alarm over Earth's vital signs

25 October 2023
Data shows 20 of 35 planetary indicators are at record extremes
This year has likely seen the hottest temperatures for 100,000 years. A global team of scientists, including Dr Thomas Newsome from Faculty of Science, has laid out the numbers.
Data from the report shows record extremes for temperature and ice loss.

Data from the report shows record extremes for temperature and ice loss.

A global team of climate scientists has reported that Earth’s vital signs have worsened beyond anything humans have seen, to the point that life on Earth is imperilled.

In a paper published today in Bioscience, the 12 international scientists have shown that 20 of 35 identified planetary vital signs are at record extremes. They also outline policies needed to address the underlying issue of “ecological overshoot”.

Among the key numbers in the report:

  • Fossil fuel subsidies roughly doubled between 2021 and 2022 globally, from $US531 billion to just over $US1 trillion.
  • This year Canadian wildfires have pumped more than 1 gigaton of carbon dioxide into the atmosphere, greater than Canada’s total 2021 greenhouse emissions.
  • In 2023, there have already been 38 days with global average temperatures more than 1.5 degrees Celsius above pre-industrial levels.
  • The highest average Earth surface temperature ever recorded was in July, and there’s reason to believe it was the highest surface temperature the planet has seen in the last 100,000 years.

Dr Thomas Newsome from the Global Ecology Lab in the School of Life and Environmental Sciences at the University of Sydney is the only Australian co-author of the study, “The 2023 State of the Climate Report: Entering uncharted territory”.

He said: “The trends indicate the need to drastically speed and scale up efforts globally to combat climate change while more generally reducing our ecological footprint.”

Dr Thomas Newsome in the Central Desert.

Dr Thomas Newsome in the Central Desert.

Dr Newsome stressed that all climate-related actions must be grounded in equity and social justice.

“Extreme weather and other climate impacts are disproportionately felt by the poorest people, who have contributed the least to climate change,” he said.

The report comes four years after the “World Scientists’ Warning of a Climate Emergency” published by the research team in BioScience, which was co-signed by more than 15,000 scientists in 161 countries.

Co-lead author William Ripple, a distinguished professor in the Oregon State University College of Forestry, said: “Without actions that address the root problem of humanity taking more from the Earth than it can safely give, we’re on our way to the potential partial collapse of natural and socioeconomic systems and a world with unbearable heat and shortages of food and freshwater.”

The authors share data illustrating how many climate records were broken by enormous margins in 2023, particularly those relating to ocean temperature and sea ice.

“Life on our planet is clearly under siege,” Professor Ripple said. “The statistical trends show deeply alarming patterns of climate-related variables and disasters. We also found little progress to report as far as humanity combating climate change.”

Joint lead author Dr Christopher Wolf, now at Terrestrial Ecosystem Research Associates, said: “As scientists, we are hugely troubled by the sudden increases in the frequency and severity of climate-related disasters.

“The frequency and severity of those disasters might be outpacing rising temperatures. By the end of the 21st century, many regions may have severe heat, limited food availability and elevated mortality rates.”

Ilulissat in Greenland. Global sea ice extent is at historic lows.

Ilulissat in Greenland. Global sea ice extent is at historic lows. Image: Adobe stock

The authors say policies are needed that take aim at the underlying issue of “ecological overshoot”. When human demand on the Earth’s resources is too large, the result is an array of environmental crises, including biodiversity decline. If humanity continues to put extreme pressure on the planet, any strategy that focuses only on carbon or climate will simply redistribute the pressure, they said.

“Our goal is to communicate climate facts and make policy recommendations,” Professor Ripple said. “It is a moral duty of scientists and our institutions to alert humanity of any potential existential threat and to show leadership in taking action.”

The authors urge transitioning to a global economy that prioritises human well-being and curtails overconsumption and excessive emissions by the rich. Specific recommendations include phasing out fossil fuel subsidies, transitioning toward plant-based diets, scaling up forest protection efforts and adopting international coal elimination and fossil fuel non-proliferation treaties.


The CO2 Foundation and Roger Worthington (Oregon, USA) provided partial funding for this research.

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