Carbon rise could cause cloud tipping point

The planet’s temperature could zoom in an ever more greenhouse world, as researchers identify a dangerous possible cloud tipping point.

Climate scientists have confirmed a high-level hazard, a cloud tipping point, that could send global warming into a dramatic upwards spiral.

If carbon dioxide concentrations in the atmosphere become high enough, the clouds that shade and cool some of the tropical and subtropical oceans could become unstable and disperse. More radiation would slam into the ocean and the coasts, and surface temperatures could soar as high as 8°C above the levels for most of human history.

And this dramatic spike would be independent of any warming directly linked to the steady rise in carbon dioxide concentrations themselves, the scientists warn.

In Paris in 2015, a total of 195 nations vowed to take steps to contain global warming to “well below” a maximum of 2°C above the average before the start of the Industrial Revolution, powered by the exploitation of fossil fuels.

In the last 200 years, levels of the greenhouse gas carbon dioxide in the atmosphere have increased from 288 parts per million to around 410 ppm and the average global temperature has already increased by about 1°C.

“Our results show that there are dangerous climate change thresholds that we have been unaware of”

Researchers have repeatedly warned that the Paris promises have yet to be turned into coherent and consistent action, and that if the world goes on burning coal, oil and natural gas on a “business as usual” scenario, catastrophic consequences could follow.

Now US researchers warn in the journal Nature Geoscience that they know a bit more about the climate mechanisms by which global warming could accelerate.

If carbon dioxide ratios climb to 1,200 ppm – and without drastic action this could happen in the next century – then the Earth could reach a tipping point, and the marine stratus clouds that shade one-fifth of the low-latitude oceans and reflect between 30% and 60% of shortwave radiation back into space could break up and scatter.

The sunlight they normally block would slam into the deep blue sea, to warm the planet even faster.

Avoidance possible

“I think and hope that technological changes will slow carbon emissions so that we do not actually reach such high CO2 concentrations,” said Tapio Schneider, an environmental scientist at the Jet Propulsion Laboratory, the research centre managed for the US space agency NASA by the California Institute of Technology.

“But our results show that there are dangerous climate change thresholds that we have been unaware of.”

The role of clouds in the intricate interplay of sunlight, forests, oceans, rocks and atmosphere that controls the planet’s climate has been the subject of argument. Do clouds really slow warming? And if so, by how much, and under what conditions?

There may not be a simple answer, although researchers are fairly confident that the thinning of clouds over the California coasts may have made calamitous wildfires in the state more probable.

So to resolve what Professor Schneider calls “a blind spot” in climate modelling, he and his colleagues worked on a small-scale computer simulation of one representative section of the atmosphere above the subtropical ocean, and then used supercomputers to model the clouds and their turbulent movement over a mathematical representation of the sea. And then they started to tune up the atmospheric concentrations of carbon dioxide.

Carbon threshold

They found that, once CO2 levels reached 1,200 ppm, the decks of stratocumulus cloud vanished, and did not reappear until CO2 levels dropped to well below this dangerous threshold.

If – and this has yet to happen – other researchers use different approaches to confirm the result, then the US scientists will have established a better understanding of one component of natural climate control.

The research may also illuminate a puzzle of climate history: 50 million or more years ago, during a geological epoch called the Eocene, the Arctic ice cap melted. Climate models have shown that, for this to happen, atmospheric carbon ratios would need to rise to 4,000 ppm.

These, the Caltech team, suggests, would be “implausibly high” CO2 levels. The latest study suggests this might be an overestimate: a mere 1,200 ppm would be enough to set the planetary thermometer soaring. − Climate News Network

About the Author

Tim Radford, freelance journalistTim Radford is a freelance journalist. He worked for The Guardian for 32 years, becoming (among other things) letters editor, arts editor, literary editor and science editor. He won the Association of British Science Writers award for science writer of the year four times. He served on the UK committee for the International Decade for Natural Disaster Reduction. He has lectured about science and the media in dozens of British and foreign cities. 

Science that Changed the World: The untold story of the other 1960s revolutionBook by this Author:

Science that Changed the World: The untold story of the other 1960s revolution
by Tim Radford.

Click here for more info and/or to order this book on Amazon. (Kindle book)

This Article Originally Appeared On Climate News Network

Related Books

InnerSelf Market

Amazon

enafarzh-CNzh-TWdanltlfifrdeiwhihuiditjakomsnofaplptruesswsvthtrukurvi

follow InnerSelf on

facebook-icontwitter-iconrss-icon

 Get The Latest By Email

{emailcloak=off}

EVIDENCE

What Is Climate Sensitivity?
What Is Climate Sensitivity?
by Robert Colman and Karl Braganza
Humans are emitting CO2 and other greenhouse gases into the atmosphere. As these gases build up they trap extra heat…
There Are No Time-travelling Climatologists: Why We Use Climate Models
There Are No Time-travelling Climatologists: Why We Use Climate Models
by Sophie Lewis and Sarah Perkins-Kirkpatrick
The first climate models were built on fundamental laws of physics and chemistry and designed to study the climate…
What Caused Major Climate Change In The Past?
This Is What Caused Major Climate Change In The Past
by James Renwick
Earth had several periods of high carbon dioxide levels in the atmosphere and high temperatures over the last several…
Will Three Billion People Really Live In Temperatures As Hot As The Sahara By 2070?
Will Three Billion People Really Live In Temperatures As Hot As The Sahara By 2070?
by Mark Maslin
Humans are amazing creatures, in that they have show they can live in almost any climate.
Tree Rings And Weather Data Warn Of Megadrought
Tree Rings And Weather Data Warn Of Megadrought
by Tim Radford
Farmers in the US West know they have a drought, but may not yet realise these arid years could become a megadrought.
We Just Spent Two Weeks Surveying The Great Barrier Reef. What We Saw Was An Utter Tragedy
We Just Spent Two Weeks Surveying The Great Barrier Reef. What We Saw Was An Utter Tragedy
by Terry Hughes and Morgan Pratchett
Author supplied The Australian summer just gone will be remembered as the moment when human-caused climate change…
5 Ways To Teach Children About Climate Change
5 Ways To Teach Children About Climate Change
by William Finnegan
Climate change is an interdisciplinary subject that both school children and adults think is important. And as we deal…
Polar Ice Melt Raises Sea Level Dangers
Polar Ice Melt Raises Sea Level Dangers
by Tim Radford
Greenland’s polar ice is now melting far faster than 30 years ago, Antarctic ice is retreating at an accelerating rate,…

LATEST VIDEOS

Talking About Energy Change Could Break The Climate impasse
Talking About Energy Change Could Break The Climate Impasse
by InnerSelf Staff
Everyone has energy stories, whether they’re about a relative working on an oil rig, a parent teaching a child to turn…
Crops Could Face Double Trouble From Insects And A Warming Climate
Crops Could Face Double Trouble From Insects And A Warming Climate
by Gregg Howe and Nathan Havko
For millennia, insects and the plants they feed on have been engaged in a co-evolutionary battle: to eat or not be…
To Reach Zero Emissions Government Must Address Hurdles Putting People Off Electric Cars
To Reach Zero Emissions Government Must Address Hurdles Putting People Off Electric Cars
by Swapnesh Masrani
Ambitious targets have been set by the UK and Scottish governments to become net-zero carbon economies by 2050 and 2045…
Spring Is Arriving Earlier Across The US, And That's Not Always Good News
Spring Is Arriving Earlier Across The US, And That's Not Always Good News
by Theresa Crimmins
Across much of the United States, a warming climate has advanced the arrival of spring. This year is no exception.
The Last Ice Age Tells Us Why We Need To Care About A 2℃ Change In Temperature
The Last Ice Age Tells Us Why We Need To Care About A 2℃ Change In Temperature
by Alan N Williams, et al
The latest report from the Intergovernmental Panel on Climate Change (IPCC) states that without a substantial decrease…
A Georgia Town Gets Half Of Its Electricity From President Jimmy Carter's Solar Farm
A Georgia Town Gets Half Of Its Electricity From President Jimmy Carter's Solar Farm
by Johnna Crider
Plains, Georgia, is a small town that is just south of Columbus, Macon, and Atlanta and north of Albany. It is the…
Majority of US Adults Believe Climate Change Is Most Important Issue Today
by American Psychological Association
As the effects of climate change become more evident, more than half of U.S. adults (56%) say climate change is the…
How These Three Financial Firms Could Change The Direction Of The Climate Crisis
How These Three Financial Firms Could Change The Direction Of The Climate Crisis
by Mangulina Jan Fichtner, et al
A silent revolution is happening in investing. It is a paradigm shift that will have a profound impact on corporations,…

LATEST ARTICLES

Heatwaves Too Hot And Wet For Human Life Are Here
Heatwaves Too Hot And Wet For Human Life Are Here Now
by Tim Radford
Lethal heatwaves carrying air turned too hot and wet to survive are a threat which has arrived, thanks to climate…
How Dangerous Is Low-level Radiation To Children?
How Dangerous Is Low-level Radiation To Children?
by Paul Brown
A rethink on the risks of low-level radiation would imperil the nuclear industry’s future − perhaps why there’s never…
What We Do Now Could Change Earth's Trajectory
What We Do Now Could Change Earth's Trajectory
by Pep Canadell, et al
The numbers of people cycling and walking in public spaces during COVID-19 has skyrocketed.
Marine Heatwaves Spell Trouble For Tropical Reef Fish — Even Before Corals Die
Marine Heatwaves Spell Trouble For Tropical Reef Fish — Even Before Corals Die
by Jennifer M.T. Magel and Julia K. Baum
Despite the many challenges facing the world’s oceans today, coral reefs remain strongholds of marine biodiversity.
Warnings of Worse-Than-Usual Hurricane Season Point to Trouble Ahead
Warnings of Worse-Than-Usual Hurricane Season Point to Trouble Ahead
by Eoin Higgins
Hurricane season is about to start and its risks will only grow and potentially compound any impacts from the pandemic.
Australia, It's Time To Talk About Our Water Emergency
Australia, It's Time To Talk About Our Water Emergency
by Quentin Grafton et al
There’s another climate change influence we must also face up to: increasingly scarce water on our continent.
Fossil Fuels Are Heading Down, But Not Yet Out
Fossil Fuels Are Heading Down, But Not Yet Out
by Kieran Cooke
Renewable energy is making rapid inroads into the market, but fossil fuels still wield enormous global influence.
Human Action Will Decide How Much Sea Levels Rise
Human Action Will Decide How Much Sea Levels Rise
by Tim Radford
Sea levels will go on rising, because of human action. By how much, though, depends on what humans do next.