Potential for environmental crisis to end humanity ‘dangerously underexplored’

Destroyed street after an earthquake in Haiti.

Destroyed street after an earthquake in Haiti. “Pathways to disaster are not limited to the effects of high temperatures,” the team warned (Getty)

Despite decades of warnings from the world’s top scientists that skyrocketing greenhouse gas emissions are driving the planet ever closer to disaster, the scale of the dangers ahead remains “dangerously underexplored”, experts have warned.

An international team of researchers led by the University of Cambridge has said that “catastrophic” scenarios could be triggered by global warming worse than many have predicted, or by cascading events – or both at once.

As a result, they have said the world needs to start preparing for the possibility of a “climate endgame” for our species.

In order to fully assess the range of risks, the team has proposed a research agenda to address worst-case scenarios.

These include outcomes ranging from a loss of 10 percent of the world’s population to complete human extinction.

The researchers are asking the UN’s climate panel (IPCC) to dedicate a future report to “catastrophic climate change”, which they hope will stimulate research and inform the public.

“There are many reasons to believe that climate change could be catastrophic, even at modest levels of warming,” said lead author Dr Luke Kemp of Cambridge’s Center for the Study of Existential Risk.

“Climate change has played a role in every mass extinction. It has helped fallen empires and shaped history. Even the modern world seems to be adapted to a particular climate niche,” he said.

“Pathways to disaster are not limited to direct impacts of high temperatures, such as extreme weather events. Consequences such as economic crises, conflicts and new disease outbreaks can trigger other disasters and hinder recovery from potential disasters such as nuclear war.”

Dr. Kemp and his colleagues have said that the consequences of 3C warming and beyond, and related extreme risks, have been investigated.

Modeling by the team shows areas of extreme heat – an annual average temperature of more than 29C – could affect two billion people by 2070.

These areas are not only some of the most densely populated, but also some of the most politically fragile.

“Average annual temperatures of 29 degrees are currently affecting about 30 million people in the Sahara and Gulf Coast,” said co-author Chi Xu of Nanjing University.

Abandoned houses in Hong Kong.  Scientists say we need to examine the worst-case climate scenarios more closely (getty)

Abandoned houses in Hong Kong. Scientists say we need to examine the worst-case climate scenarios more closely (getty)

“By 2070, these temperatures and the social and political consequences will directly affect two nuclear powers and seven maximum containment laboratories housing the most dangerous pathogens. There is a serious potential for catastrophic consequences, he said.

Last year’s IPCC report suggested that if atmospheric carbon dioxide doubles from pre-industrial levels – which the planet is halfway towards – then there is about an 18 per cent chance that temperatures will rise more than 4.5C.

The research team said the scientific community’s current methodology increasingly tends to examine less risky future scenarios that require a smaller-scale response.

Dr Kemp co-authored a “text mining” study of existing IPCC reports, published earlier this year, which found that IPCC assessments have shifted away from high-end warming to increasingly focus on lower temperature increases.

This builds on previous work he has done showing that extreme temperature scenarios are “under-explored relative to their likelihood”.

“We know the least about the scenarios that matter the most,” Dr Kemp said.

The team has now proposed a research agenda including what they call “the four horsemen” of the climate endgame. These are: famine and malnutrition, extreme weather, conflicts and vector-borne diseases.

Global food supplies face huge risks from a warmer climate, according to the team, with the likelihood of “breadbasket failures” increasing as the world’s most agriculturally productive areas suffer “collective meltdowns”.

Warmer and more extreme weather can also create conditions for new disease outbreaks as habitats for both humans and wildlife shift and shrink.

The experts also warned that environmental breakdown is likely to exacerbate other “interacting threats”. They highlighted rising levels of inequality, misinformation, the potential for democratic breakdowns and even new forms of destructive artificial intelligence (AI) weapons.

A dystopian scenario envisioned in the paper is described as “hot wars” – where technologically enhanced superpowers battle for dwindling carbon space while conducting giant experiments to divert sunlight and reduce global temperatures.

The team said there needs to be a greater focus on identifying any potential tipping points that could push us towards a “Hothouse Earth”.

These include methane released by melting permafrost to the loss of forests that act as “carbon sinks”, and even the potential for disappearing cloud cover.

“The more we learn about how our planet works, the greater the cause for concern,” said co-author Professor Johan Rockström, director of the Potsdam Institute for Climate Impact Research.

“We increasingly understand that our planet is a more sophisticated and fragile organism. We need to calculate catastrophe to avoid it,” he said.

Dr Kemp added: “We know that temperature rise has a ‘fat tail’, meaning a wide range of lower-probability but potentially extreme outcomes. Facing a future of accelerating climate change while remaining blind to worst-case scenarios is at best naive risk management and at worst fatally foolish.”

The research is published in the journal Proceedings of the National Academy of Sciences.

Leave a Reply

Your email address will not be published. Required fields are marked *