Mark Lynas: The hellish vision of life on a hotter planet

Share

Buried within the newly released IPCC report is an apocalyptic warning: if greenhouse gas emissions continue to rise at current rates, global warming by the end of the century could total 6.4C. The scientists don't say so explicitly, but a rise in temperatures of this magnitude would catapult the planet into an extreme greenhouse state not seen for nearly 100 million years, when dinosaurs grazed on polar rainforests and deserts reached into the heart of Europe. It would cause a mass extinction of almost all life and probably reduce humanity to a few struggling groups of embattled survivors clinging to life near the poles.

An eco-alarmist fantasy? Unfortunately not - having spent the past three years combing the scientific literature for clues to how life will change as the planet heats up, I know that life on a 6C-warmer globe would be almost unimaginably hellish. A clue to just how unpleasant things can get is contained within a narrow layer of strata recently exposed at a rock quarry in China, dating from the end of the Permian period, 251 million years ago. For reasons that are still not properly understood, temperatures rose by 6C over just a few thousand years, dramatically changing the climate and wiping out up to 95 per cent of species alive at the time. The end-Permian mass extinction was the worst ever: the closest that this planet has ever come to becoming just another lifeless rock orbiting the sun. Only one large land animal survived the bottleneck: the pig-like Lystrosaurus, which for millions of years after the disaster had the globe pretty much to itself.

Clues as to how the world looks in a long-term extreme greenhouse state also come from the Cretaceous period, 144 to 65 million years ago, when there was no ice on either pole and much of Europe and North America was flooded by the higher seas. Tropical crocodiles swam in the Canadian high Arctic, whilst breadfruit trees grew in Greenland. The oceans were incredibly hot: in the tropical Atlantic they may have reached 42C, whilst at the North Pole itself, the oceans were as warm as the Mediterranean is today. The tropics and sub-tropics were so hot that no forests grew, and desert belts probably extended into the heart of modern-day Europe.

During the Cretaceous, of course, species evolved over millions of years to be able to survive on a much hotter planet. Nowadays very few species could survive such a sudden transition. Cold-adapted species like polar bears would obviously be an early casualty, and coral reefs will also disappear from the tropics. The Met Office's Hadley Centre has predicted that the Amazonian rainforest could start to burn as early as 2050, gradually transforming towards desert as temperatures soar in the interior of South America. Ash and smoke would blanket much of the southern hemisphere, and nearly half of the world's terrestrial biodiversity would be wiped out at a stroke.

How people might fare is anyone's guess. With the tropics too hot to grow crops, and the sub-tropics too dry, billions of people would find themselves in areas of the planet which are essentially uninhabitable. This would probably even include southern Europe, as the Sahara desert crosses the Mediterranean. As the ice-caps melt, hundreds of millions will also be forced to move inland due to rapidly-rising seas. As world food supplies crash, the higher mid-latitude and sub-polar regions would become fiercely-contested refuges. The British Isles, indeed, might become one of the most desirable pieces of real estate on the planet. But with a couple of billion people knocking on our door, things might quickly turn rather ugly.

Six Degrees: Our Future on a Hotter Planet by Mark Lynas will be published by Fourth Estate on 19 March.

React Now

Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Wind Farm Civil Design Engineer

£55000 - £65000 Per Annum: The Green Recruitment Company: The Green Recruitmen...

Principal Marine Mechanical Engineer

£60000 - £70000 Per Annum: The Green Recruitment Company: The Green Recruitmen...

Principle Geotechnical Engineer

£55000 - £65000 Per Annum: The Green Recruitment Company: The Green Recruitmen...

Renewable Energy Construction Manager

£40000 - £50000 Per Annum: The Green Recruitment Company: The Green Recruitmen...

Day In a Page

Read Next
A cyclist rides by a Google self-driving car at the Google headquarters  

The driverless car puts us on the road to a ‘hands‑free’ world. But do we really want to go?

Alice Jones
Mathew Baynton (Gus) & Elizabeth Berrington (Marie)  

Plane-crash comedy makes it hard to laugh

David Lister
Dress the Gaza situation up all you like, but the truth hurts

Robert Fisk on Gaza conflict

Dress the situation up all you like, but the truth hurts
Save the tiger: Tiger, tiger burning less brightly as numbers plummet

Tiger, tiger burning less brightly

When William Blake wrote his famous poem there were probably more than 100,000 tigers in the wild. These days they probably number around 3,200
5 News's Andy Bell retraces his grandfather's steps on the First World War battlefields

In grandfather's footsteps

5 News's political editor Andy Bell only knows his grandfather from the compelling diary he kept during WWI. But when he returned to the killing fields where Edwin Vaughan suffered so much, his ancestor came to life
Lifestyle guru Martha Stewart reveals she has flying robot ... to take photos of her farm

Martha Stewart has flying robot

The lifestyle guru used the drone to get a bird's eye view her 153-acre farm in Bedford, New York
Former Labour minister Meg Hillier has demanded 'pootling lanes' for women cyclists

Do women cyclists need 'pootling lanes'?

Simon Usborne (who's more of a hurtler) explains why winning the space race is key to happy riding
A tale of two presidents: George W Bush downs his paintbrush to pen father’s life story

A tale of two presidents

George W Bush downs his paintbrush to pen father’s life story
Restaurateur Mitch Tonks has given the Great Western Pullman dining car a makeover

The dining car makes a comeback

Restaurateur Mitch Tonks has given the Great Western Pullman dining car a makeover
Gallery rage: How are institutions tackling the discomfort of overcrowding this summer?

Gallery rage

How are institutions tackling the discomfort of overcrowding this summer?
Louis van Gaal has £500,000 video surveillance system installed to monitor Manchester United players

Eye on the prize

Louis van Gaal has £500,000 video surveillance system installed to monitor Manchester United players
Women's rugby: Tamara Taylor adds fuel to the ire in quest to land World Cup

Women's rugby

Tamara Taylor adds fuel to the ire in quest to land World Cup
Save the tiger: The day America’s love of backyard tigers led to a horrific bloodbath

The day America’s love of backyard tigers led to a horrific bloodbath

With only six per cent of the US population of these amazing big cats held in zoos, the Zanesville incident in 2011 was inevitable
Samuel Beckett's biographer reveals secrets of the writer's time as a French Resistance spy

How Samuel Beckett became a French Resistance spy

As this year's Samuel Beckett festival opens in Enniskillen, James Knowlson, recalls how the Irish writer risked his life for liberty and narrowly escaped capture by the Gestapo
We will remember them: relatives still honour those who fought in the Great War

We will remember them

Relatives still honour those who fought in the Great War
Star Wars Episode VII is being shot on film - and now Kodak is launching a last-ditch bid to keep celluloid alive

Kodak's last-ditch bid to keep celluloid alive

Director J J Abrams and a few digital refuseniks shoot movies on film. Simon Usborne wonders what the fuss is about
Once stilted and melodramatic, Hollywood is giving acting in video games a makeover

Acting in video games gets a makeover

David Crookes meets two of the genre's most popular voices