Global heating is accelerating, warns scientist who sounded climate alarm in the 80s

Oliver Milman

THE GUARDIAN
Wed, November 1, 2023 

Global heating is accelerating faster than is currently understood and will result in a key temperature threshold being breached as soon as this decade, according to research led by James Hansen, the US scientist who first alerted the world to the greenhouse effect.

The Earth’s climate is more sensitive to human-caused changes than scientists have realized until now, meaning that a “dangerous” burst of heating will be unleashed that will push the world to be 1.5C hotter than it was, on average, in pre-industrial times within the 2020s and 2C hotter by 2050, the paper published on Thursday predicts.

Related: ‘We are damned fools’: scientist who sounded climate alarm in 80s warns of worse to come

This alarming speed-up of global heating, which would mean the world breaches the internationally agreed 1.5C threshold set out in the Paris climate agreement far sooner than expected, risks a world “less tolerable to humanity, with greater climate extremes”, according to the study led by Hansen, the former Nasa scientist who issued a foundational warning about climate change to the US Congress back in the 1980s.

Hansen said there was a huge amount of global heating “in the pipeline” because of the continued burning of fossil fuels and Earth being “very sensitive” to the impacts of this – far more sensitive than the best estimates laid out by the UN’s Intergovernmental Panel on Climate Change (IPCC).

“We would be damned fools and bad scientists if we didn’t expect an acceleration of global warming,” Hansen said. “We are beginning to suffer the effect of our Faustian bargain. That is why the rate of global warming is accelerating.”

The question of whether the rate of global heating is accelerating has been keenly debated among scientists this year amid months of record-breaking temperatures.

Hansen points to an imbalance between the energy coming in from the sun versus outgoing energy from the Earth that has “notably increased”, almost doubling over the past decade. This ramp-up, he cautioned, could result in disastrous sea level rise for the world’s coastal cities.

The new research, comprising peer-reviewed work of Hansen and more than a dozen other scientists, argues that this imbalance, the Earth’s greater climate sensitivity and a reduction in pollution from shipping, which has cut the amount of airborne sulphur particles that reflect incoming sunlight, are causing an escalation in global heating.

“We are in the early phase of a climate emergency,” the paper warns. “Such acceleration is dangerous in a climate system that is already far out of equilibrium. Reversing the trend is essential – we must cool the planet – for the sake of preserving shorelines and saving the world’s coastal cities.”

To deal with this crisis, Hansen and his colleagues advocate for a global carbon tax as well as, more controversially, efforts to intentionally spray sulphur into the atmosphere in order to deflect heat away from the planet and artificially lower the world’s temperature.

So-called “solar geoengineering” has been widely criticized for threatening potential knock-on harm to the environment, as well as over the risks of a whiplash heating effect should the injections of sulphur cease, but is backed by a minority of scientists who warn that the world is running out of time and options to avoid catastrophic temperature growth.

Hansen said that while cutting emissions should be the highest priority, “thanks to the slowness in developing adequate carbon-free energies and failure to put a price on carbon emissions, it is now unlikely that we can get there – a bright future for young people – from here without temporary help from solar radiation management”.

This year is almost certain to be the hottest ever reliably recorded, with temperatures in September described as “gobsmackingly bananas” by one climate researcher. A report this week found that the carbon budget to limit the world to 1.5C of heating is now nearly exhausted due to the continued burning of fossil fuels and deforestation.

But while scientists are clear about this being part of an upward trend of global heating, there is as yet no agreement that this trend is accelerating.

Michael Mann, a climate scientist at the University of Pennsylvania, said that Hansen and his co-authors are “very much out of the mainstream” in identifying an acceleration in surface heating that has “continued at a remarkably constant rate for the past few decades”. Mann said that cuts to shipping emissions have only a tiny effect on the climate system and that calls for solar geoengineering are misguided and a “very slippery slope”.

Bärbel Hönisch, a paleoclimatologist at Columbia University, said she had “some reservations” about the certainties expressed in Hansen’s research about the state of the Earth’s climate millions of years ago, which helps predict the consequences of warming today. “I’d be a little more reserved, but they may well be correct – it’s a nicely written paper,” she said. “It raises a lot of questions that will trigger a lot of research that will bring our understanding forward.”

Some other researchers are less skeptical of Hansen’s dire warning of supercharged global heating, highlighting his previous prescient warnings about the climate crisis that have largely played out due to decades of inaction to stem the use of fossil fuels.

“I think [Hansen’s] contention that the IPCC has underestimated climate sensitivity somewhat will prove to be correct,” said Rob Jackson, a Stanford University scientist and chair of the Global Carbon Project. “It’s hard to know what’s unlikely any more in terms of warming. No fossil fuel has declined in use yet globally, not even coal.

“I think Hansen’s pessimism is warranted. He stood up 35 years ago and sounded the alarm – and the world mostly ignored him, and all of us.”

Experts underestimate how fast Earth is warming, top climate scientist says in new study

Doyle Rice, USA TODAY
Updated Thu, November 2, 2023 

A woman is silhouetted against the setting sun as triple-digit heat indexes continued in the Midwest Sunday, Aug. 20, 2023, in Kansas City, Mo.

Legendary climate scientist James Hansen, in a new study published Thursday, predicts that the Earth's temperature rise will accelerate in the upcoming decades and will reach 2 degrees Celsius above preindustrial temperatures by 2050. This is significantly more than the most common estimates from groups such as the Intergovernmental Panel on Climate Change, or IPCC, typically considered the planet's gold standard for climate forecasts.

According to Hansen's new study, the revised prediction is due to previous underestimations of the effects of greenhouse gases on the atmosphere, along with the effects of aerosols, which have acted to mask some of global warming.

Although the IPCC and other experts acknowledge the impact that aerosols have on the climate system – for example, NASA says that "if not for aerosol pollution, Earth would be even warmer than it already is" – Hansen and his co-authors say that that impact is "underestimated."

Specifically, Hansen told USA TODAY that the study's main point is that the Earth's climate is "more sensitive" to both greenhouse gases and air pollution than the IPCC realized.

Why does 2 degrees matter?

According to NASA, a "2-degree rise in global temperatures is considered a critical threshold above which dangerous and cascading effects of human-generated climate change will occur."

Hansen and his co-authors write in the paper that "impacts on people and nature will accelerate" as global warming increases toward the 2-degree threshold.

Beyond the temperature increase, the risks of weather and climate catastrophes also rise, as heat waves and death from extreme weather dramatically increase, according to an earlier United Nations scientific report.

In the American West, extreme fire weather will likely be more intense and last longer, NASA reports.

Exceptionally warm weather moved into the upper Midwest on Aug. 22 as a pedestrian walks at sunset in Oconomowoc, Wis. Climate scientist James Hansen predicts that the Earth's temperature rise will accelerate in the upcoming decades.

Coastal cities threatened by sea level rise

NASA said that if warming reaches 2 degrees Celsius, more than 70% of Earth's coastlines will see sea level rise greater than 0.66 feet, "resulting in increased coastal flooding, beach erosion, salinization of water supplies and other impacts on humans and ecological systems."

We "must avoid 2 degrees global warming, which would otherwise result in the loss of our coastal cities near the end of this century," Hansen told USA TODAY.
Earth's climate 'more sensitive than usually assumed'

Using improved paleoclimate data, Hansen's new study finds that the Earth's climate "is more sensitive than usually assumed" to both carbon dioxide and aerosols.

The authors conclude that much of the expected greenhouse gas warming in the past century has been offset by the cooling effect of human-made aerosols – fine airborne particles found in air pollution. According to the study, aerosols have declined in amount since 2010 because of reduced air pollution in China and global restrictions on aerosol emissions from ships.

"This aerosol reduction is good for human health, as particulate air pollution kills several million people per year and adversely affects the health of many more people," Hansen said. "However, aerosol reduction is now beginning to unmask greenhouse gas warming that aerosol cooling hid."

The study authors term aerosol cooling a “Faustian bargain” because, as humanity eventually reduces air pollution, payment in the form of increased warming comes due.
What should we do?

The study recommends three actions humanity can undertake to avoid the 2-degree rise in global temperature:

(1) A global increasing price on greenhouse gas emissions accompanied by the development of abundant, affordable, dispatchable clean energy.

(2) East-West cooperation in a way that accommodates developing world needs.

(3) Conduct research and development for temporary actions to address Earth’s now enormous energy imbalance.

“We live on a planet with a climate characterized by delayed response, which is a recipe for intergenerational injustice,” Hansen concludes. “Young people need to understand this situation and the actions needed to assure a bright future for themselves and their children.”

The new study, "Global warming in the pipeline," appeared in the journal Oxford Open Climate Change, which is published by Oxford University Press.

This article originally appeared on USA TODAY: Global warming to accelerate faster than expected, James Hansen says

The planet is heating up faster than predicted, says scientist who sounded climate alarm in the 1980s

Laura Paddison, CNN
Thu, November 2, 2023

The planet is on track to heat up at a much faster rate than scientists have previously predicted, meaning a key global warming threshold could be breached this decade, according to a new study co-authored by James Hansen — the US scientist widely credited with being the first to publicly sound the alarm on the climate crisis in the 1980s.

In the paper, published Thursday in the journal Oxford Open Climate Change, Hansen and more than a dozen other scientists used a combination of paleoclimate data, including data from polar ice cores and tree rings, climate models and observational data, to conclude that the Earth is much more sensitive to climate change than previously understood.

“We are in the early phase of a climate emergency,” according to the report, which warns a surge of heat “already in the pipeline” will rapidly push global temperatures beyond what has been predicted, resulting in warming that exceeds 1.5 degrees Celsius above pre-industrial levels in the 2020s, and above 2 degrees Celsius before 2050.

The findings add to a slew of recent research that concludes the world is hurtling toward 1.5 degrees, a threshold beyond which the impacts of climate change — including extreme heat, drought and floods — will become significantly harder for humans to adapt to.

“The 1.5-degree limit is deader than a doornail,” said Hansen on a call with reporters. “And the 2-degree limit can be rescued, only with the help of purposeful actions.”

Some other scientists, however, have cast doubt on the paper’s conclusions that climate change is accelerating faster than models predict.

Hansen, a director at the Earth Institute at Columbia University, is a renowned climate scientist whose 1988 testimony to the US Senate first brought global attention to climate change.

He has previously warned that the Earth has an energy imbalance, as more energy comes in through sunlight than leaves through heat radiating into space.

The resulting excess heat is equivalent to 400,000 Hiroshima atomic bombs a day, with most of the energy absorbed by the ocean, Hansen’s research found a decade ago.

US scientist James Hansen, pictured in 2013, is credited as the first to publicly raise the alarm about climate change in the 1980s. 

- CARL DE SOUZA/AFP/Getty Images

In this recent paper, Hansen and his co-authors say the energy imbalance has now increased, in part because of successful efforts to tackle particle air pollution, especially in China and through global restrictions on shipping pollution. While this kind of pollution is a serious health hazard, it also has a cooling effect, as particles reflect sunlight away from the Earth.

The imbalance is set to cause accelerated global warming, bringing disastrous consequences, according to the paper, including rapid sea level rise and the potential shutdown of vital ocean currents within this century.

Hansen said he is particularly concerned about the melting of the Antarctic ice sheet and especially the Thwaites Glacier, which acts as a cork, holding back the ice on land and providing an important defense against catastrophic sea level rise.

But the warming is not necessarily locked in, according to the paper, which calls for “extraordinary actions.”

Measures it recommends include taxing carbon pollution, increasing nuclear power to “complement renewable energies” and strong action from developed countries to help developing countries move to low carbon energy. While the highest priority is to drastically reduce planet-heating pollution, this alone will not be enough, the report found.

“If we’re going to keep sea level close to where it is, we actually have to cool the planet,” said Hansen.

One way to do this, the report suggests, is solar geoengineering. This controversial technology aims to cool temperatures by reflecting sunlight away from the Earth, or allowing more heat to escape into space. That can be done through injecting aerosols into the atmosphere or spraying clouds with salt particles to make them more reflective, for example.

Critics warn of unforeseen consequences, including impacts on rainfall and monsoons, as well as “termination shock” if geoengineering were suddenly halted and pent-up warming released.

But Hansen said it should be considered. “Rather than describe those efforts as ‘threatening geoengineering,’ we have to recognize that we are geoengineering the planet right now,” he said, by burning large amounts of planet-heating fossil fuels.

The paper’s findings are alarming and come as the world is experiencing unprecedented heat. This year is on course to be the hottest on record, with every month from June onwards breaking records for the hottest such month.

But while science is clear that the rate of global warming is increasing, the idea that it is accelerating beyond what models predict is controversial.

The findings “are very much out of the mainstream,” said Michael Mann, a leading climate scientist at the University of Pennsylvania.

While the Earth’s surface and its oceans are warming, the data does not support claims that the rate is accelerating, he told CNN in an email. “As I like to say, the truth is bad enough!” Mann said. “There is no evidence that the models are under-predicting human-caused warming.”

He also cast doubt on the role of pollution reduction in warming trends, saying the total impact is very small, and warned that solar geoengineering is “unprecedented” and “potentially very dangerous.”

“Whether or not the 1.5 degrees Celsius target is reachable is a matter of policy, not climate physics, at this point,” Mann said.

But Hansen rejected criticisms of the research, saying it’s based on hard numbers and straightforward physics.

“This is not fringe, this is the correct physics and it is the real world,” he said, “and it sometimes takes the community a while to catch on.”

James Hansen study warns Earth warming faster than previously thought

Patrick Hilsman
Thu, November 2, 2023 

The Earth's temperature could be increasing faster than was previously understood, according to a new research paper from James Hansen, the scientist who played a major role in raising public awareness about climate change in the 1980s. File Photo by John Angelillo/UPI


Nov. 2 (UPI) -- A new study led by James Hansen, a scientist responsible for raising public consciousness about climate change in the 1980s, suggests global temperatures are increasing faster than expected.

The study suggests global temperatures will reach a crucial 2 degrees Celsius above pre-industrial levels by the year 2050, faster than was previously expected by scientific consensus.

Hansen's study implies that the highly regarded Intergovernmental Panel on Climate Change, which is often used as a reference point for climate study, underestimated the urgency of the impact of global climate change.

NASA estimates that a global increase of 2 degrees Celsius could cause major flooding along Earth's coastlines.

"Our principal motivation in this paper is concern that IPCC has underestimated climate sensitivity and understated the threat of large sea level rise and shutdown of ocean overturning circulations," Hansen's researchers said in the paper.

The paper suggests that reductions in certain kinds of pollution, notably sulfur-based pollutants that reflect sunlight, may have accelerated the heating of the Earth.

The researchers used data from ice core samples to evaluate past greenhouse gas quantities.

"Air bubbles in Antarctic ice cores -- trapped as snow piled up and compressed into ice -- preserve a record of long-lived GHGs for at least 800,000 years. Isotopic composition of the ice provides a measure of temperature in and near Antarctica," researchers said.

The paper advises that climate change is still mitigable.

"Warming in the pipeline need not appear. We can take actions that slow and reverse global warming; indeed, we suggest that such actions are needed to avoid disastrous consequences for humanity and nature," the researchers said.

The study suggests that while the reduction of greenhouse gas emissions is crucial to combating climate change, it is insufficient without being paired with other actions.

"Reduction of greenhouse gas emissions as rapidly as practical has highest priority, but that policy alone is now inadequate and must be complemented by additional actions to affect Earth's energy balance," researchers said.


NASA scientist issues grim warning 35 years after his original prediction: ‘[W]e knew it was coming’
Stephen Proctor
Wed, November 1, 2023



James Hansen, who was a NASA climate scientist when he first warned the world that the planet was heating in 1988, is back with another stark warning — this time hoping for different results.

When Hansen appeared before the United States Senate in June of 1988, the world had just experienced the warmest first five months of any year in recorded history, The New York Times reported at the time.

Up until that time, scientists had been cautious about blaming the warming of the planet on pollutants put into the air by human activity. But Hansen told the committee that NASA was 99% certain that the warming trend was caused by the buildup of carbon dioxide and other gases in the atmosphere.

Sadly, the problem has continuously gotten worse worldwide in the decades since. And Hansen has continued his fight to bring attention to the issue. In 2011, he was one of 140 people to be arrested while protesting the construction of the controversial Keystone XL pipeline.

In a recent statement released by Hansen alongside two other scientists, Hansen predicted the warming of the planet to accelerate in the coming years, musing about a “new climate frontier.”

“There’s a lot more in the pipeline, unless we reduce the greenhouse gas amounts,” Hansen told the Guardian. “These superstorms are a taste of the storms of my grandchildren. We are headed wittingly into the new reality — we knew it was coming.”

Speaking of the heat waves that have ravaged much of the Northern Hemisphere recently, Hansen told the Guardian he cannot help but feel “a sense of disappointment that we scientists did not communicate more clearly and that we did not elect leaders capable of a more intelligent response.”

Of the lack of response by humanity as a whole, Hansen added, “It means we are damned fools. We have to taste it to believe it.”

Though it’s been 35 years since Hansen first warned the world in Senate testimony about what we’re now seeing with our own eyes, there is reason for optimism.

The move away from dirty energy is kicking into high gear. Sales of electric cars continue to rise, with an expected growth of 35% from 2022 to 2023, electric boats with solar-powered charging stations are now available, and grassroots efforts to make renewable energy more widely available are underway.