James Hansen, former top NASA climate scientist – his new paper warns the climate is already committed to extreme changes that will devastate life on this planet, including humanity. Alex investigates “Global Warming in the Pipeline”. Dr. Barry Lomax reports a near-miss extinction in recent decades – from UV-B that caused “The Great Dying” 250 million years ago.
Listen to or download this Radio Ecoshock show in CD Quality (57 MB) or Lo-Fi (14 MB)
Before we start on this week’s critical information – I want to thank all my regular monthly donors. With confidence coming from your continuing support, a few months ago I bought a relatively expensive power backup system, with electrical protection. Without that, our 106 radio stations would not have received this show! With less than an hour before my deadline to post – the power went out for this whole area. With your help, no problem! My studio kept running long enough to post. You literally keep the show going! Thank you.
“The madman jumped into their midst and pierced them with his eyes. “Whither is God?” he cried; “I will tell you. We have killed him—you and I. All of us are his murderers. But how did we do this? How could we drink up the sea? Who gave us the sponge to wipe away the entire horizon? What were we doing when we unchained this earth from its sun?”
That is from Friedrich Nietzsche in his 1880’s book “The Gay Science”. Find that book and read it. Yes indeed, “Who gave us the sponge to wipe away the entire horizon?”
James Hansen, former top NASA climate scientist, has a new paper arguing the climate is already committed to extreme changes that will devastate life on this planet, including humanity. His team finds greenhouse gases have already doubled pre-industrial levels – and the impacts are much greater than we have been told. For example, quote:
“Global warming in the pipeline is greater than prior estimates. Eventual global warming due to today’s GHG forcing alone — after slow feedbacks operate — is about 10°C.” More about that later.
Hansen’s team say a major “hinge point’ in climate is already behind us, in 2010. Warming in coming decades could be 50 to 100% greater than what we’ve already seen since 1980. If true, that is catastrophic for civilization. Mass extinctions of plants, animals, insects and sea creatures would follow.
The paper is titled simply “Global Warming in the Pipeline.” It has been submitted for peer-review before publication. I just heard back from Jim Hansen. He cannot talk to media about it until the final publication version is ready. Hansen retired from NASA Goddard Space Institute in April 2013.
This paper is not just James Hansen. There are 14 co-authors, many well-known scientists. A non-scientist, independent researcher Leon Simons is also a co-author. I interviewed him about his findings that sulfur emission controls on ships has changed cloud cover and revealed more warming. You can listen to that intriguing 32 minute interview here:
Given the gravity of the paper, I did a quick informal survey of three leading climate scientists among my regular email correspondents. One simply said Hansen and crew are right. Two others agreed with part of the paper, but strongly disagreed with the critical estimation of how hot Earth might get. They say the model used by the new paper to estimate climate sensitivity has already been thrown into doubt by other recent scientific works. We will get to that.
Hansen has also been warning of far higher sea level rise than most institutional science, especially reports from the Intergovernmental Panel on Climate Change, the IPCC. Hansen says sea level rise just this century could be several meters, like twelve feet or more. It is hard to imagine what a new world that would make. Goodbye New York, Shanghai, and London. A billion humans might have to move away from the flooding coasts to higher ground, if they have ground high enough.
As Hansen and colleagues write in the new paper:
“Eventual impacts would include loss of coastal cities and flooding of regions such as Bangladesh, the Netherlands, a substantial portion of China, and the state of Florida in the United States. For practical purposes, the losses would be permanent. Such outcome could be locked in soon, which creates an urgency to understand the physical system better and to take major steps to reduce the human- made drive of global warming.”
Again, other scientists of note still object to Hansen’s high sea level projections for this century.
The paper “Global Warming in the Pipeline” is, as it says, about the warming. The team has already announced a second big paper is coming: “Sea Level Rise in the Pipeline“. That paper, he says, quote: “presents evidence that continued warming and increasing ice melt can cause shutdown of the overturning ocean circulations within decades and large sea level rise within a century.”
Five years ago, the Warming in the Pipeline paper might be shrugged off. It could be the outlier, a brilliant scientist who has gone too far. But deep within science, there have been objections to the low-end conservative statements by institutions and the IPCC. It seems they were always behind the changes we are already experiencing.
A HISTORY OF RECOGNIZING THE WORST IN CLIMATE
Should we believe the future predicted in the new Hansen-led paper? Ten years ago, most scientists might have said “no”. But you need a little history of the chorus of worry and discontent growing within the scientific community over the last two decades. This is how we got here.
The pioneers, once again, were science fiction writers. One of the early scientific breakaways was the erratic genius, James Lovelock in the UK. After looking over futurecast models at the Hadley Centre, Lovelock predicted by 2100, quote: “billions of us will die and the few breeding pairs of people that survive will be in the Arctic, where the climate remains tolerable.” That kind of matches the inevitable result of 8 or 10 degrees C of warming. More about Lovelock below.
Then the first conference: the “4 Degrees and Beyond International Climate Conference” at Oxford in 2009. 140 scientists and experts attended. Major speakers included Prof John Schellnhuber, Potsdam Institute for Climate Impact Research, Richard Betts, Met Office Hadley Centre, and Prof Stefan Rahmstorf, Potsdam Institute for Climate Impact Research who presented on “Sea-level rise in a 4 degrees world”. Radio Ecoshock guest Professor David Karoly, University of Melbourne spoke on “Wildfire in a 4+ C degree World”. About a dozen papers from that conference were published by Philosophical Transactions of the Royal Society in 2011.
In the radio show, I run a 2 minute piece from BBC at 2009 the conference, where one scientist says warming of 4 degrees is possible much sooner than expected, even by 2060!
You can find my October 2009 show with a digest of John Schellnhuber’s speech in this show (CD Quality 57 MB) or Lo-Fi (14 MB)
A follow-up conference, Four Degrees Or More? Australia in a Hot World, was held at the University of Melbourne, Australia in In July 2011. It was a doozy. Again, on Radio Ecoshock I broadcast the Keynote speech from Joachim Schellnhuber. In the show I play a quick clip; from Dr. John Schellnhuber at the Conference in Melbourne.
I covered that Australia 4 degrees or more conference in this August 2011 show.
CLIMATE: FOUR DEGREES OR MORE. How hot can we get? Are we headed for climate disaster? Disturbing speech by world’s most influential climate scientist, Dr. Hans Joachim “John” Schellnhuber of the Potsdam Institute. Keynote at “Four Degrees or More” Conference Melbourne Australia July 12, 2011. New Science you must hear. Radio Ecoshock 110831 1 hour CD Quality 56 MB or Lo-Fi 14 MB.
Then we had the “World Scientists’ Warning to Humanity: A Second Notice”. About 15,000 scientists signed on, warning our future was bleak – humans needed emergency action to save the environment we all inhabit. That was in 2017, and I quickly had the instigator Dr. Bill Ripple on this show. Listen to or download this 15 minute interview with Bill Ripple
THE VOICES OF “ALARMISM” ARE GETTING LOUDER
A continuing stream of scientists began to adopt more extreme language for our common future, calling for emergency action. Another key breakaway point: Dr. Jem Bendell left his Sustainability presentations at major international conferences, saying none of this is sustainable. Just last fall, a group of eminent scientists released their paper “Climate Endgame: Exploring catastrophic climate change scenarios”. The IPCC was criticized for studying 1.5 degrees of warming, when much higher levels are in the cards. We gravely underestimated climate risks. Now have to consider global warming beyond 3 degrees C. Our Radio Ecoshock guest was lead author, Dr. Luke Kemp. In this program, I play a quick 3 minute from that show.
You can listen to/download the whole interview with Luke Kemp here in CD Quality or Lo-Fi
All of this lends credibility to the extremes found by James Hansen and his colleagues. We need to take this prediction as deadly serious. But let’s keep open minds and proper scientific doubt as well. This terrible hot world may not happen, or not for hundreds of years. Natural systems are notoriously complex and ever-changing. Humans amplify that. No one knows the future for sure. Don’t run away to your survival cave just yet. But our guesses are getting more educated as the evidence pours in and yes, it looks “worse than we thought”.
WHAT IS JIM HANSEN SAYING?
The new paper, December 2022, “Global Warming in the Pipeline” was posted on a publicly-available archive server for comment. The team expects expert comment at this stage, rather than a review in the media, like this one. But I also think Hansen, now 80, has taken every step to alert the public, directly, as soon as he can. His 2009 book was explicit “Storms of My Grandchildren: The Truth About the Coming Climate Catastrophe and Our Last Chance to Save Humanity”. It carried many of the same themes in the new paper, especially about extreme storms (California anybody? Puerto Rico?) and more rapidly rising seas. The emphasis on heat seem news.
But in August 2021, Hansen and constant co-author Makiko Sato published a temperature analysis at Columbia University’s Earth Institute. Top climate reporter Bob Berwyn’s headline was “The Rate of Global Warming During Next 25 Years Could Be Double What it Was in the Previous 50, a Renowned Climate Scientist Warns”. Hansen was already pointing to regulations that cut sulfur pollution for a new round of warming. We heard from co-author Leon Simons about that last week.
The Rate of Global Warming During Next 25 Years Could Be Double What it Was in the Previous 50, a Renowned Climate Scientist Warns
Part of my point: we should discuss this latest paper, even before publication, because we can draw from a series of works published by Hansen over the years. I first heart James Hansen speak about “warming in the pipeline” when I was recording presentations at the 2012 meeting of the The American Association for the Advancement of Science in Vancouver. He has been at this for a while. I admit not understanding his concerns fully until this new paper. What is “the pipeline”? This paper, with helpful case study by Simons, makes the clearest case yet.
The concept of the pipeline is simple enough. More energy is coming into Earth than is escaping it. If scientists add up the “extra” energy, Hansen says warming should be greater than we are experiencing. Something is holding back full expression of the heat-potential already in the planetary system. His team finds the hidden cooling agent in pollution. Sulfates are the main culprit. Earth is loaded with sulfur. The heavy oil fuel burned by ships contained up to 3.5 percent sulfur by weight.
World goods are transported by a constant stream of large ships. Sulfur goes up the stack into the atmosphere, condensing into small particles that do two things: they reflect sunlight, and they probably seed formation of more clouds. Both functions cool the surface, acting against the forces of warming, hiding our true impacts. International regulations just cut those sulfur emissions to .5% by weight. Sulfur in land-based diesel trucks has also been slashed. That cooling effect is already gone, but more sulfates continue to come from older coal power plants.
But sulfur pollution is not the whole problem. All sorts of dust, chemicals, and especially soot are dumped into the air by humans. We have car smog, and giant clouds forming over India due to both industrial emissions and a billion smoky cook-stoves and heaters. We know from earlier studies by Ramanathan (Asian Brown Cloud) that about nine percent less sunlight hit the ground in China in the early 2000’s compared to before1950. India will be driven toward cleaner air soon. I am told that Europe now receives about 75 more hours of sunshine a year than in the 1980’s when air pollution was thickest.
All this pollution blocks some sunlight and cools the surface. It also leads to premature deaths for millions of people a year globally. Bit by bit, by popular demand, governments and industry are reducing that smog. Then we will find out what warming is waiting from the changes we made in the atmosphere. We will find out what is in the pipeline.
HANSEN AND SATO THINK 2024 WILL BE OFF THE HEAT CHARTS WITH EL NINO
In his August Temperature Update posted September 2022 at Columbia, Hansen and team said:
“We suggest that 2024 is likely to be off the chart as the warmest year on record. It is unlikely that the current La Niña will continue a fourth year. Even a little futz of an El Niño should be sufficient for record global temperature.”
A few scientists and news articles say this year, 2023 could be very hot – in the second half of the year as El Nino replaces La Nina. But from memory (can’t cite a source) I recall Kevin Trenberth (master of ENSO science) saying the second year of El Nino tends to be the hottest. It takes a while to build? That would support the Hansen team looking to 2024 to punish us with more record-busting heat waves.
CLIMATE SENSITIVITY AND THE DOUBLING
But here we get into rocky ground. The very high predictions of committed warming now advanced by these scientists is based on two premises. It all has to do with ‘Equilibrium climate sensitivity’ or (ECS). That is a kind of resting point, or end-point, for warming caused by additional greenhouse gases. The scientific standard has been: what happens when humans double the carbon dioxide from pre-industrial levels around 270 parts per million? That result depends on the reaction of the whole Earth system, from oceans through land mass and ice to the very top of the atmosphere. We will call that result the ECS, climate sensitivity.
In the first point, Hansen and his colleagues say we have already reached that doubling point. At first that seems strange. A doubling of CO2 from 280 parts per million before industrial times, would be 560 parts per million. Yet the 2022 measured global average for carbon dioxide in the atmosphere is only 417 parts per million. Why are they saying it has doubled?
A lot of recent science, and conference documents, are now talking about “carbon dioxide equivalent” instead of just CO2. The reality is: humans produce a lot of other warming gases, some of them thousands of times more powerful that carbon dioxide. The worst are certain chlorinated or brominated chemicals called halogens. Most of those chemicals never existed before the year 1800.
But we cause a lot of nitrous oxide and enough methane to cause up to one third of the warming now hitting the world. When all of those powerful greenhouse gases are added to the 417 ppm of carbon dioxide, the atmosphere has already hit a doubling point, Hansen’s group says.
A few scientists object because some of those gases do not last long in the atmosphere. The main warming thrust of methane only lasts about 12 years for example. So even if we have reached the doubling, it might be only a relatively temporary state, possibly healing within a few decades if those emissions stop. The amount of carbon dioxide on the other hand, can last thousands of years in the atmosphere. So that should be the real measure of doubling. I am not qualified to judge, but I tend to lean toward the doubling claimed by Hansen et al.
The second part of the new Hansen paper is harder for some top-level scientists to accept. I will relay my uneducated understanding of the problem. It is ‘Equilibrium climate sensitivity’. If we accept doubling is now, what should we expect to happen? The science on that is not settled.
In the new paper, the Hansen group calls on results from the latest big climate model CMIP6. That showed global temperatures during the last great ice age were far colder than we realized. That was only around 20,000 years ago. In a note published December 13th, 2022, Hansen and Sato say, quote:
“We were spurred to write this paper in part by papers of Tierney et al. and Seltzer et al., which made a persuasive case that global temperature during the Last Glacial Maximum (LGM, ~20,000 years ago) was about 6°C colder than the Holocene.”
As they say, it was really cold during the peak of the last ice age, just 10,000 years before humans developed agriculture and cities. Humanity had to survive near the tropics.
This matters a lot. Hansen and associates also draw on recent work that finds humans have been warming the planet with atmospheric changes over thousands of years. When they look at the great temperature distance between the glacial times and the 1800’s, a relatively small change to the atmosphere, measured in parts per million, made very large changes in the climate. The ice sheets retreated and the Northern Hemisphere became habitat for humans and all sort of plants and animals. If the climate changes that much with so little new gases, the system is very sensitive, they argue. That should mean Earth will get much hotter, faster, than we thought. It may already be committed to eight or ten degrees warming (over pre-industrial).
The authors do not say exactly WHEN this will happen. Will that extreme warming arrive within the lifetimes of babies born today – or hundreds, even a thousand years from now? We don’t know, and part may depend on whether we continue to add greenhouse gases, or a whole range of other possibilities. Those may include successful carbon capture, geoengineering to block the sun, an unpredictable run of volcanoes exploding, or even an asteroid strike. But they do say, with air pollution cleanup regulations, we should expect warming to develop up to twice as fast in the next twenty five years. Considering the climate chaos already striking around the world, that is ominous and a little frightening.
Some well-known scientists are urging caution about this new paper, because of that high sensitivity. Michael Mann says wait for the peer-review, which may modify the new paper. Others find published science showing the estimates of 6 degrees colder for glacial times is wrong due to a fault in models, particularly the role of clouds in previous models. For example, there is a paper published in Nature on April 20, 2020 titled: “High climate sensitivity in CMIP6 model not supported by paleoclimate”. They, and other papers, find the equilibrium climate sensitivity is about 3.4 degrees Celsius, with an uncertainty ranging from 2.4 degrees C to 4.5 degrees C). The worst result of the doubling would be a world 4.5 degrees C. hotter on average, which is absolute disaster. But it is a very long way from the ten degrees that Hansen and their colleagues warn about.
I’m not qualified to say who is right. Unfortunately, we may just find out by living it. Either way, we have severely damaged the atmosphere and there is literally hot Hell to pay for it. Under discussion here: is it survivable?
“Global Warming in the Pipeline” is a big work with more than a dozen authors. There are six parts to the new paper, each of them crammed with science, insight mixed with a little fear and controversy:
1. Climate sensitivity
2. Global warming in the pipeline (i.e. how much warming?)
3. Climate response times (how fast)
4. Aerosol climate forcing
5. Summary of present climate status
6. Policy implications
I will end my review with one short quote from the new paper “Global Warming in the Pipeline”, which I think all my scientific guests would agree with:
“Given the time required for the ocean to warm and ice sheets to shrink to new equilibria, this is not a warming that will be experienced by today’s public, but it is an indication of the path upon which we have set our planet. Moreover, we are in the process of setting the planet upon an even more extreme course as the net human-made climate forcing and global temperature are continuing to rise, even at accelerating growth rates. As long as there is such a large gap between the present climate and the equilibrium climate, the climate system will drive hard toward hotter climate.
Doubled CO2 is already a huge climate forcing that will have large impacts, if left in play for long. The large global warming in the pipeline today is not widely appreciated. Civilization and its infrastructure are not set up for a 2×CO2 world. We need to reduce human-made climate forcing before it exerts its full influence on the climate system.”
Science historian Naomi Noreskes says James Hansen is a “tragic hero”. Others count Hansen among those brilliant people who can be greatly right and sometimes mistaken. Even the greats can be wrong. I think of British scientist James Lovelock, who just passed away in July 2022 on his 103rd birthday. Of course, I am not comparing Hansen the accomplished scientist to Lovelock the erratic scientist and inventor. This is just to say even greatness can be wrong, so as with all science, caution.
Lovelock told Congress CFCs were harmless, when, as we hear in this week’s interview with Dr. Barry Lomax, CFCs would irradiate the world into a Great Dying level extinction. But Lovelock’s invention of the electron microscope changed science and society. He showed us how to measure global warming gases, among myriad other things. His theory of Gaia is the seed for a new green religion. Collapse and the Gaian Way coming up next week, on Radio Ecoshock.
The final word of this segment goes again to the nineteenth century German philosopher Friedrich Nietzsche and his “Parable of the Madman”, written only a few years before Nietzsche himself went mad.
“…’I have come too early,’ he said then; ‘my time is not yet. This tremendous event is still on its way, still wandering; it has not yet reached the ears of men. Lightning and thunder require time; the light of the stars requires time; deeds, though done, still require time to be seen and heard. This deed is still more distant from them than most distant stars – and yet they have done it themselves.'”
LATE ADDITION: DUST IS COOLING US UP TO 8% TOO
James Hansen and his team talked about human pollution causing a cooling that hides our real climate impact. But we also know humans are the dusty species. Agriculture can lead to wind-blown dust. Trucks and off-road vehicles are driving all over the surface of the Earth kicking it up. Add mining, and desertification which is both natural and man-made from land use change. From space, the “Blue Planet” has become “the dusty planet”. Here is a new paper finding, as the Guardian article says “increasing dust may have hidden up to 8% of warming from carbon emissions.” The Guardian also says: “Material from dry landscapes has surged since the 1800s, possibly helping to cool the planet for decades”.
Excess dust is unlikely to stop due to pollution controls of changes in sulfur fuel. I imagine only a crash of civilization would let the dust settle – leading to another bump in revealed warming. Should we call this “warming in the pipeline” too? Perhaps not.
BARRY LOMAX- THE MASS EXTINCTION WE JUST MISSED A FEW DECADES AGO…
Speaking of extinction, there is a little good news from breaking science. In the late 1980’s, right around the time George Michael shared the hit music charts along with Guns N’ Roses – we narrowly avoided our own extinction. The organized world managed to act just before we triggered another mass dying by polluting the atmosphere. True story.
Two hundred and fifty million years ago, massive volcanic eruptions caused warming, low oxygen and acidification in the sea. That wiped out around 90 percent of ocean life. It has been called “The Great Dying”. But what killed the land animals? Widespread extinctions are happening now, so we better know how this works. A new answer comes with the paper “Dying in the Sun: direct evidence for elevated UV-B radiation at the end-Permian mass extinction“.
Dr. Barry Lomax is one of the authors. He is Professor and Chair of Plant Palaeobiology, at the University of Nottingham UK. Lomax has been investigating ancient plants and climate for a long time. Barry also works with well-known scientist D.J. Beerling on several papers. What little I know about paleobotany comes from Beerling’s fabulous book “The Emerald Planet”.
Listen to or download this interview with Dr. Barry Lomax in CD Quality or Lo-Fi
Are we sure volcanoes can damage the ozone layer when they erupt? A 2019 study led by Hans Brenna looked at volcanic activity during the last 200,000 years. They found, quote: “global, long-lasting impact on the ozone layer affecting atmospheric composition and circulation for a decade.“ Barry, what made your team investigate the UV-B impact 250 million years ago?
Lomax’s work includes several studies using fossil leaves to determine climate. I first learned about that in a 2008 interview with Dr. Bob Spicer. It’s still good stuff, with a couple of thousand downloads at Radio For All.
Barry Lomax led a paper in 2019 finding a carbon isotope in plant tissue is not a reliable measure of ancient atmospheres. But that does not hamper the current study. The new study depends on analysis of pollen grains taken in Tibet. Scientists now hope to duplicate those results in other parts of the world, in part to show this was a global event rather than just a local one.
Before the world woke up and took action, environmentalists and scientists warned about damage from the sun if the protective ozone layer was damaged. We heard about rabbits going blind in Peru, a lot of impacts. The Montreal Protocol banned CFCs, the prime chemical damaging the ozone in our atmosphere. But the ozone hole is still there.
Did we just dodge a big bullet with ozone depletion – one that killed most living things ages ago?
Here is the Abstract from the new paper, led by Wesley Fraser with Barry Lomax as second author:
“Land plants can adjust the concentration of protective UV-B-absorbing compounds (UACs) in the outer wall of their reproductive propagules in response to ambient UV-B flux. To infer changes in UV-B-radiation flux at the Earth’s surface during the end-Permian mass extinction, we analyze UAC abundances in ca. 800 pollen grains from an independently-dated Permian-Triassic boundary section in Tibet.
Our data reveal an excursion in UACs that coincide with a spike in mercury concentration and a negative carbon-isotope excursion in the latest Permian deposits, suggesting a close temporal link between large-scale volcanic eruptions, global carbon- and mercury-cycle perturbations, and ozone-layer disruption. Because enhanced UV-B radiation can exacerbate the environmental deterioration induced by massive magmatism, ozone depletion is considered a compelling ecological driver for the terrestrial mass extinction.”
NEVER TRUST A VOLCANO
We really don’t know a lot about volcanoes. But so far, experts are not predicting thousands years of massive eruptions like the End Permian. Do we know how many large eruptions it would take to damage our ozone layer? Could it happen again?
Another deadly element is involved. We only learned in the last century how absolutely toxic mercury is for most plants and animals. It turns out mercury from volcanic eruptions also played a role in the process of that ancient mass extinction event about 250 million years ago.
It sounds like this mass extinction event was not just one thing, but an unfortunate concatenation of environmental deterioration. Can we pin UV-B as THE driver of that mass extinction on land, or is it one deadly player among others?
There have been other theories on the cause of the Great Dying. For example, Dr. Peter Ward suggested a dying ocean switched to sulfur-based bacteria that emitted clouds of toxic hydrogen sulfide gas. But this paper from Lomax et al. suggests a much different reason so many land-animals died: radiation poisoning due to a damaged ozone layer.
This interview is a parable about the need for real emergency action to save this planet from rapid climate change.
[Comment by Alex Smith]
Did you know plants could make their own sunscreen, but animals find that hard to digest? Did you know rising UV-B radiation eventually leaves much more carbon in the atmosphere? Plants are miracle chemical factories. Some plants managed to create their own sunscreen chemical to protect leaves from radiation damage. Perhaps they evolved that capability many millions of years ago.
But most plants died off due to radiation damage. That changed the carbon cycle. Remember, the bit of carbon you and I add to the atmosphere daily does not just sit there for 100,000 years. Our carbon, dragged out of long-term storage deep in the Earth, re-enters the carbon cycle. It may be captured by land plants, or sea plants, or soil organisms, or be tossed in the sea. But eventually that same bit of carbon comes back into the atmosphere. Our additional carbon just adds to the amount of carbon cycling around. More carbon dioxide is found in the atmospheric stage, which is what matters directly for warming.
But if a significant number of those carbon-grabbing plants die – the carbon pump weakens, and more CO2 stays in the atmosphere. In that way, when the protective ozone layer weakens, global warming is an eventual end result. I always wondered at the connection between the ozone layer and climate change. Now we know. Plants are the mechanism.
When the Montreal Protocol was signed in 1987, and enacted in 1990, the whole reason was to protect human health. Scientists and doctors knew more radiation would lead to excess cancer, especially deadly skin cancer. They did not know, and nobody knew, that a weaker ozone layer would boost global warming. Action to save the ozone layer was taken, just in time, without knowing the most powerful threat. That is where we are now with climate change. We know too many reasons why global warming could wreck our lives and our civilization. But we probably only know the half of it. The story of UV-B explains we must act on imperfect knowledge.
Humans managed once, thirty years ago, to act as one species to save ourselves. We banned ozone-depleting chemicals. But now, again facing a threat as great as our own extinction, we failed to act. We could still save ourselves from outright catastrophe. We still have an atmosphere friendly to humans and all our kindred animals and plants. That nurturing atmosphere is being destroyed in front of our eyes,
We must change fundamentally our way of life, our beliefs, and assumptions. Humanity has no golden ticket out of Earth’s long history of creation and destruction of species. In fact, we are among the most fragile animals, with strict and limited environmental needs. There are no guarantees, no guardian angels to swoop in, and no easy way out. There is a difficult way out, which is partly the way back, to when we were a sustainable species. But there is still a way out. That is a limited-time offer.
I’m Alex Smith. Thank you for listening to Radio Ecoshock this week, and caring about our world.
Please support this program with your monthly donation. More help is needed. It is easy to set up here.
Wow, such a terrific detailed summary Alex. Your tremendous work continues to demonstrate just how much our ineffective global leaders are neglecting climate science (& global ecology) & how they are ignoring the hard work of tens of thousands of dedicated scientists.
My own (layperson) understanding of all this is that during the past million years, (& prior to the Holocene) Earth atmospheric CO2 levels (not including CO2-equivalent) didn’t exceed 300 ppm. In the last glacial maximum (20K ya) global CO2 levels were 180ppm. The mean temp then was 6°C lower than the early Holocene period (10K ya) when global CO2 had stabilized at 280ppm by 1800CE.
Hansen indicates this 100ppm upward swing (in the short geologic period of 10K ya) demonstrates that the subsequent raising of global mean temp by 6°C reinforces how sensitive global mean temperature is to CO2 fluctuation.
From this he assesses the rise in CO2 from 1800-2022CE (totalling 137ppm) will have a corresponding effect in raising global mean temperature (over time) – especially as adding CO2-equivalent now raises the total to over 500-550 CO2-Eq. This is apparently where his “+10°C in the pipeline” is coming from.
He shows that CO2 & equivalents are the main drivers of disruption to climate equilibrium & the Earth’s energy imbalance, with all other albedo effects, earth system changes, self reinforcing feedbacks etc being driven by this overall greenhouse gas effect – but with mitigating effects from the aerosol pollutants effect.
I understand that greenhouse gases are not distributed evenly around the globe (latitudes/jetstreams etc), with the ~800 years of paleo isotopic data on CO2/CH4 coming from (regional) polar ice core drilled samples.
So in the future there may still be many localized temp variations suggesting habitable niches in, say, polar regions. However, the corresponding warming of oceans in a +4-10°C future world will doubtless test Peter Ward’s hydrogen sulfide hypothesis!
Finally, I understand that changes to global temps during Malenkovitch Cycles (regardless of CO2 levels persisting within the various phases) are not believed to vary much within a range of ± 1°C so are hardly ever discussed in considering the big climate picture.
Back in 2017 the science was already clear that we are headed for a 10deg C or so GAT rise which I summarized in this presentation
It was rather rushed due to limited time and my inclusion of peak oil analyses. I think a thawing Antarctica (not the Arctic, which will be ice free and malaria ridden) is the most likely refuge for human survivors, assuming of course that the US war mongers do not drive us to nuclear extinction tomorrow, a much more immediate threat. Provocation for war began in 2014 with the Nuland/Mcain Maidan coup The two Minsk agreements were delaying tactics by NATO as Merkel, Hollande and Poroshenko admitted.
We need to achieve a more comprehensive understanding of all our existential threats if we are to have any hope of avoiding them.