A new study warns that exceeding 1.5°C, even briefly, causes irreversible climate impacts. Immediate action to achieve net-negative emissions is essential.
A new study published today in Nature warns that, while it may be possible to reverse global temperature increases after a temporary overshoot of 1.5°C, some climate impacts, such as rising sea levels and other damages experienced at peak warming, will be irreversible.
The study is the culmination of a three-and-a-half-year project, backed by the European innovation fund HORIZON2020, looking at so-called ‘overshoot’ scenarios where temperatures temporarily exceed the Paris Agreement’s 1.5°C limit, before descending again by achieving net-negative CO2 emissions.
“This paper does away with any notion that overshoot would deliver a similar climate outcome to a future in which we had done more, earlier, to ensure to limit peak warming to 1.5°C,” explains Carl-Friedrich Schleussner, Integrated Climate Impacts Research Group Leader in the IIASA Energy, Climate, and Environment Program and scientific advisor at Climate Analytics, who led the study. “Only by doing much more in this critical decade to bring emissions down and peak temperatures as low as possible, can we effectively limit damages,” he adds.
It matters how high and for how long we let temperatures rise
The paper highlights that if we were to exceed 1.5°C there are clear benefits to reversing warming by acting to achieve net negative emissions globally. Achieving long-term temperature decline could lower sea level rise in 2300 by about 40 cm compared to a situation in which temperatures merely stopped rising.
“Until we get to net zero, warming will continue. The earlier we can get to net zero, the lower peak warming will be, and the smaller the risks of irreversible impacts,” notes study co-author Joeri Rogelj, professor of climate science and policy and Director of Research of the Grantham Institute at Imperial College London and senior research scholar in the IIASA Energy, Climate, and Environment Program. “This underscores the importance of countries submitting ambitious new reduction pledges, or so-called Nationally Determined Contributions (NDCs), well ahead of next year’s climate summit in Brazil.”
Full carbon dioxide removal capacity is needed to hedge against higher warming
The study emphasizes that while there are still pathways open to limiting warming to 1.5°C or lower in the long run, there is a need to ‘hedge’ against higher warming outcomes if the climate system warms more than median estimates. To do this, ambitious emissions reductions need to go hand in hand with scaled and environmentally sustainable carbon dioxide removal technologies. A ‘preventive capacity’ of several hundred gigatons of net removals might be required.
“There’s no way to rule out the need for large amounts of net negative emissions capabilities, so we really need to minimize our residual emissions. We cannot squander carbon dioxide removal on offsetting emissions we have the ability to avoid,” commented study coauthor Gaurav Ganti, research assistant at IIASA and a research analyst at Climate Analytics.
“Our work reinforces the urgency of governments acting to reduce our emissions now, and not later down the line. The race to net zero needs to be seen for what it is – a sprint,” Schleussner concludes.
Reference: “Overconfidence in climate overshoot” by Carl-Friedrich Schleussner, Gaurav Ganti, Quentin Lejeune, Biqing Zhu, Peter Pfleiderer, Ruben Prütz, Philippe Ciais, Thomas L. Frölicher, Sabine Fuss, Thomas Gasser, Matthew J. Gidden, Chahan M. Kropf, Fabrice Lacroix, Robin Lamboll, Rosanne Martyr, Fabien Maussion, Jamie W. McCaughey, Malte Meinshausen, Matthias Mengel, Zebedee Nicholls, Yann Quilcaille, Benjamin Sanderson, Sonia I. Seneviratne, Jana Sillmann, Christopher J. Smith, Norman J. Steinert, Emily Theokritoff, Rachel Warren, Jeff Price and Joeri Rogelj, 9 October 2024, Nature.
DOI: 10.1038/s41586-024-08020-9
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30 Comments
Few things on planet Earth are “permanent.” The last time Earth was this warm, the oceans stood a lot higher (6-9 m). Sea level obviously came down from that, and hasn’t even caught up.
If model estimates don’t agree with reality (they don’t) then it is time to go back to the ‘drawing board.’
In 2020, the world tried an ‘experiment’ of temporarily reducing anthropogenic CO2 emissions. The 2020 seasonal ramp-up phase of CO2 is indistinguishable from the preceding and following years, despite the anthro’ emissions declining as much as 14-18% in April, the month before the annual peak. It raises questions about how effective “net zero” would be.
The thermostat is busted, and it’s getting hot and dry in an inflammatory way. The pigs busted it, and they refused to fix it. They won’t even participate in the troubleshooting process, and we have weird randos heckling the clever critters, interfering with those warning them of the consequences of inaction. What is the nature of those obscure hecklers, and what precisely do they want?
“What is the nature of those obscure hecklers, and what precisely do they want?”
How about, for a start, “The truth, the whole truth, and nothing but the truth.”?
“…….how effective “net zero” would be……”. Qualification; how effective Net Zero would be during how long a period of time. Clearly, the seasonal “‘ramp up phase” was not long enough to be effective.
I don’t think that you understand. Every year, during the Fall-Winter-Spring, biological decomposition, tree-root respiration, and anthropogenic emissions result in increased CO2. During the Summer, photosynthetic plants and plankton remove CO2. There appears to be very little lag (perhaps a couple of weeks) in the CO2 response to the changing light and temperatures.
https://wattsupwiththat.com/2022/03/22/anthropogenic-co2-and-the-expected-results-from-eliminating-it/
If there is no measurable change in the rate of increase, or peak, during the several months of the ramp-up phase, why would you believe that it would suddenly show up over a longer period of time? Please explain.
Oceans, among other things, absorb carbon in a dangerous spring-loading way. When those processes reach their maximum loading capacity, we are a hair trigger away from all hell breaking loose. Your denial, enabled by your ignorance and exacerbated by laziness and obstinance, multiplied by how many other can’t-get-rights are out there, is terrifying to me.
When I make a claim that is not commonly accepted, I provide support for it, such as the link in my comment above, which goes to an article I wrote, complete with citations. That puts to the lie your claim that I’m ignorant, lazy, and obstinate. On the other hand, all you provide is your personal opinion. It would seem that those insulting words are a better description of you because you haven’t gone to the trouble to research and publish the support for your opinion and, instead, just regurgitate claims made by professional wordsmiths who like to call themselves “science journalists.” All too often they also make unsupported claims that demonstrates that their understanding is simplistic and incomplete, at best. I can’t be responsible for you experiencing unwarranted terror. That is a personal problem.
However, it also demonstrates inappropriate priorities. The scientists who monitor the Doomsday Clock have recently moved it closer to midnight than it has ever been because of their judgement that we are moving closer to nuclear annihilation with Russia engaged in saber rattling, North Korea sending troops to Ukraine, and Israel meting out punishments of biblical proportions — all countries with nuclear capabilities. I’m reminded of an old cartoon: Frank and Ernest are sitting on a park bench and one of them says, “I need to get my priorities in order. But, there are a lot of other things I need to do first.”
This paper is pure nonsense. Sea level can be restored by freezing the poles. That mainly requires higher albedo. The problem is that emissions are marginal to heat. As James Hansen has argued, albedo loss is causing four times as much heating as emissions, due to accelerating feedbacks involving ice, snow, clouds and aerosols. These are all ultimately driven by emissions, but cutting emissions cannot slow them. It is the height of absurdity for this paper to falsely state “Only by doing much more in this critical decade to bring emissions down and peak temperatures as low as possible, can we effectively limit damages”. Emissions in this decade will be swamped by albedo loss as a heat factor, regardless of emission level, unless we make the immediate paradigm shift to an albedo climate policy focus. The science community has failed to properly see or respond to this critical observation.
” As James Hansen has argued, albedo loss is causing four times as much heating as emissions, due to accelerating feedbacks involving ice, snow, clouds and aerosols.”
Despite having degrees in astronomy and physics, I’m left with the impression that Hansen is unfamiliar with Fresnel’s equation for specular reflection. Water can have a reflectivity greater than snow and ice for glancing angles of incidence such as is found on the limbs between the dark and sunlit sides of the globe. In particular, the areas in the Arctic between about 60 and 90 degrees latitude experience rapid changes in reflectivity off water.
https://wattsupwiththat.com/2016/09/12/why-albedo-is-the-wrong-measure-of-reflectivity-for-modeling-climate/
I picked up on that detail as well. The problem is that your mind is limited by how you perceive time versus the reality of deep time processes. Even the part about how fast tipping points can trip. Many people don’t understand that even if the thermostat is turned down, the heat will continue to build for a time. The amount of time it takes for a whole planet is beyond your comprehension. Indeed, modelers are uncertain about those estimates.
I’m impressed by your deep understanding of the unfathomable. Just how did you go about freeing your mind to be able to see things that mere mortals cannot? Does it have anything to do with making unsupported claims and assuming that they are factual, when in fact, they are not? How does a house continue to warm if the furnace is not running and it is radiating and conducting heat to the surroundings? You are more impressed with your intellectual superiority than I am.
I don’t believe their scaremongering model one bit. But I don’t live on the coast so I don’t really care.
In fact, if the polar caps melt in their entirety, and the sea reaches its maximum level, the place where I live will become a nice coastal town. So, win-win for me.
Ok, Lex Luthor, you should stop hiding behind that Boba persona.
Thank you for that profound contribution. I don’t know how the readership would have survived without it.
In respect of low glancing angles for sunlight, how much heat is conveyed from the sun when compared with when it is higher in the sky? Especially in high latitudes? Simple question.
Simple answer, not a lot. However, it is the wrong question. What is being compared is the amount of open ocean to ice-covered ocean, and how that impacts sunlight absorbed. The sun angle is the same for both. So, the reduction of reflectivity is not really a big concern.
The point being, researchers (who should know better) are claiming that the open ‘dark’ water will absorb a lot more heat than ice/snow covered water. The water appears dark because all the light falling on it is reflected in a narrow sheaf where one has to be in a special viewing position to observe it, while snow is a diffuse reflector that scatters light approximately equally in all directions.
Hello Rob, you should know that the sun converts 600 million tons of hydrogen into helium every second, the biggest star they discovered is 8 billion times the size of the sun, and it will take a few trillion years for this star to run out of fuel
Your energy, which I have monitored for some time now, seems to be an adamant resistance to a concerted effort by humanity to apply Delta to attempt to counter the roughly 200 years of Delta applied due to Industrial development. Vladimir Putin wants the Arctic Ocean ice-free due to his imperialist role-playing fantasies. What’s your angle? Please respond, as I enjoy studying bizarre extremophile organisms. Alternatively, are you a bot operating without Dr Asimov’s safeguards?
You have been monitoring my “energy?” Can I assume that you have been doing so by ‘remote viewing,’ or are you just reading my mind? I initially thought that your behavior could be explained by the typical liberal behavior of believing that you are smarter than everyone else who doesn’t see the world the same way that you do. I’m now leaning towards a simpler hypothesis that you are just out of touch with reality.
Vladimir Putin is not a good person, he thought he would take Ukraine in a war in two weeks, but America did not let Vladimir Putin succeed. Putin is a dictator, where did he get 70 billion wealth? Putin supports the dictatorial and criminal regime of the Islamic Republic. Khamenei is a dirty dictator, a fool, devil and evil, and his hand is stained with the blood of the youth. I ask God that these two Punish the dirty dictator
Face it WERE TOAST
W ere warned 30 years ago and did nothing
Now i`m trying to figure how to keep my family alive in a world facing mass starvation and a return of the indentured servant as more and more resources are sqandered trying to maintain our CURRENT_> ME FIRST lifestyle, or ruined by climate change
With the resulting mass relocating of eco and economic refugees fighting over what’s left.
WHATEVER happened to Kennedys” ask. Not what your country can do for you but what you can do for your country?”
This election just speeds the whole thing along
Pump more oil, close the wind farms. Everybody wants that new car.
I’m frankly terrified for us all.
In a world where obesity is a common co-morbidity, you are worried about your family starving. That is an interesting conflict to be dealing with. It would seem to me that the major problem is one of distribution of food, not crop failures from climate change.
I have to say one thing about age and life. My age is 60, but it is possible that my life is more than sixty. When translating the above comment, there is no difference between age and life. This translation ruins everything
Sometimes the text that I am sending is translated incorrectly. In the above text, I meant that scientists have wrongly estimated the age of the earth. The age of the earth is not 4.5 billion years. It is much more than 4.5 billion years. The earth and other rocky planets are 4.5 billion years old. The arms of the galaxy were placed next to the sun
The earth and rocky planets, along with all the moons of gas planets, were transformed into solar bodies from the Milky Way galaxy in the last four and a half billion years
Excuse me, the objects of the Milky Way have collided with the solar system dozens of times during 4.5 billion years, and the Kuiper Belt and the outer and inner belts were formed due to these collisions, and the moons of the gaseous planets were the small planets of the Milky Way that became moons, and the gas of the gaseous planets is from Collisions of very, very small stars are the Milky Way galaxy. These very small stars collided on the surface of Jupiter hundreds of millions of years ago and caused the temperature of Jupiter’s surface to reach thousands of degrees Celsius. You know that rivers of molten iron in The level of Jupiter is still in progress and the atmosphere of Jupiter is gloomy
In the comment above, I meant 25 trillion miles, this is the distance from the Earth to the planets of the Alpha Centauri star, but there are planets and dwarf stars in the Kuiper belt, but it is very difficult to send a probe to the planets in the Kuiper belt to examine the surface of these planets, perhaps this is not necessary. Those who are familiar with my articles know that what I reported is very close to reality regarding the past of the solar system. May you be successful and victorious in all phases of your life
The earth’s climate will change a lot in the next few thousand years, the sky will be dark and the water will freeze at the equator
The earth passed through difficult years, the sky became dark several times, at that time we were not born on the earth, but the materials of our bodies were on this earth, the objects of the Milky Way reached the earth, after hitting the sun, the rocky planets landed on the entire surface, and the life of creatures was destroyed. and again from the era of ocean water, life started from single-celled organisms until it reached the stage of evolution of mammals, but no one except God witnessed these changes
Are there 124 elements on the surface of the exoplanets? There are never 124 elements on the surface of the planets outside the solar system. These various elements are only present in the core to the front of the planets and stars. When the Milky Way bodies collide with the sun, after the collapse of all the elements that exist from the core to the front of these planets and stars. Collapse on the surface of the planets, stones are thrown, you must know that the story of the collision of the objects of the Milky Way with the Sun is true. I have always pointed out that the reason for the destruction of life on the planet Earth is the same thing that has destroyed life on the planet Earth in many eras. I have mentioned this important issue in previous articles, but unfortunately most of our audience on this website do not think about this important issue
The features that exist in the solar system that caused the earth to have oil and different metals. Different metals and different stones are not found on the surface of the planets other than the solar system. The sun does not go around the core of the galaxy with the stars of the Milky Way. The Milky Way revolves around the core of the galaxy much faster than the Sun. As a result, the objects of the Milky Way constantly interfere with the solar system, and the stars and very small planets of the Milky Way collided with the Sun in the past, and because of these collisions, the life of the planet Earth was disrupted. and the aquatics were piled up on the beaches by the waves, and just as meteorites were dumped on the carcasses of dinosaurs and aquatics, after millions of years, the aquatic corpses turned into oil and gas under the soil of the beaches. The arms of the galaxy revolve around the core, the tragic event of the collision of the Milky Way objects with the sun is repeated. If you look closely at the Earth map, you will notice that the shape of the continents, some islands, and some seas are shaped like humans and Four-legged creatures and the continent of North America are shaped like birds in flight