Arguments
How do we know more CO2 is causing warming?
The skeptic argument...
Increasing CO2 has little to no effect
"While major green house gas H2O substantially warms the Earth, minor green house gases such as CO2 have little effect.... The 6-fold increase in hydrocarbon use since 1940 has had no noticeable effect on atmospheric temperature ... " (Environmental Effects of Increased Atmospheric Carbon Dioxide)
What the science says...
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An enhanced greenhouse effect from CO2 has been confirmed by multiple lines of empirical evidence. Satellite measurements of infrared spectra over the past 40 years observe less energy escaping to space at the wavelengths associated with CO2. Surface measurements find more downward infrared radiation warming the planet's surface. This provides a direct, empirical causal link between CO2 and global warming. |
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The greenhouse gas qualities of carbon dioxide have been known for over a century. In 1861, John Tyndal published laboratory results identifying carbon dioxide as a greenhouse gas that absorbed heat rays (longwave radiation). Since then, the absorptive qualities of carbon dioxide have been more precisely quantified by decades of laboratory measurements (Herzberg 1953, Burch 1962, Burch 1970, etc).
The greenhouse effect occurs because greenhouse gases let sunlight (shortwave radiation) pass through the atmosphere. The earth absorbs sunlight, warms then reradiates heat (infrared or longwave radiation). The outgoing longwave radiation is absorbed by greenhouse gases in the atmosphere. This heats the atmosphere which in turn re-radiates longwave radiation in all directions. Some of it makes its way back to the surface of the earth. So with more carbon dioxide in the atmosphere, we expect to see less longwave radiation escaping to space at the wavelengths that carbon dioxide absorb. We also expect to see more infrared radiation returning back to Earth at these same wavelengths.
Satellite measurements of outgoing longwave radiation
In 1970, NASA launched the IRIS satellite that measured infrared spectra between 400 cm-1 to 1600 cm-1. In 1996, the Japanese Space Agency launched the IMG satellite which recorded similar observations. Both sets of data were compared to discern any changes in outgoing radiation over the 26 year period (Harries 2001). The resultant change in outgoing radiation was as follows:
Figure 1: Change in spectrum from 1970 to 1996 due to trace gases. 'Brightness temperature' indicates equivalent blackbody temperature (Harries 2001).
What they found was a drop in outgoing radiation at the wavelength bands that greenhouse gases such as carbon dioxide (CO2) and methane (CH4) absorb energy. The change in outgoing radiation is consistent with theoretical expectations. Thus the paper found "direct experimental evidence for a significant increase in the Earth's greenhouse effect".
This result has been confirmed by subsequent papers using more recent satellite data. The 1970 and 1997 spectra were compared with additional satellite data from the NASA AIRS satellite launched in 2003 (Griggs 2004). This analysis was extended to 2006 using data from the AURA satellite launched in 2004 (Chen 2007). Both papers found the observed differences in CO2 bands matching the expected changes from rising carbon dioxide levels. Thus we have empirical evidence that increased CO2 is causing an enhanced greenhouse effect.
Surface measurements of downward longwave radiation
A compilation of surface measurements of downward longwave radiation from 1973 to 2008 find an increasing trend of more longwave radiation returning to earth, attributed to increases in air temperature, humidity and atmospheric carbon dioxide (Wang 2009). More regional studies such as an examination of downward longwave radiation over the central Alps find that downward longwave radiation is increasing due to an enhanced greenhouse effect (Philipona 2004).
Taking this a step further, an analysis of high resolution spectral data allows scientists to quantitatively attribute the increase in downward radiation to each of several greenhouse gases (Evans 2006). The results lead the authors to conclude that "this experimental data should effectively end the argument by skeptics that no experimental evidence exists for the connection between greenhouse gas increases in the atmosphere and global warming."
Figure 2: Spectrum of the greenhouse radiation measured at the surface. Greenhouse effect from water vapor is filtered out, showing the contributions of other greenhouse gases (Evans 2006).
Conservation of Energy
Huber and Knutti (2011) published a paper in Nature Geoscience, Anthropogenic and natural warming inferred from changes in Earth’s energy balance. They take an approach in this study which utilizes the principle of conservation of energy for the global energy budget using the measurements discussed above, and summarize their methodology:
"We use a massive ensemble of the Bern2.5D climate model of intermediate complexity, driven by bottom-up estimates of historic radiative forcing F, and constrained by a set of observations of the surface warming T since 1850 and heat uptake Q since the 1950s....Between 1850 and 2010, the climate system accumulated a total net forcing energy of 140 x 1022 J with a 5-95% uncertainty range of 95-197 x 1022 J, corresponding to an average net radiative forcing of roughly 0.54 (0.36-0.76)Wm-2."
Essentially, Huber and Knutti take the estimated global heat content increase since 1850, calculate how much of the increase is due to various estimated radiative forcings, and partition the increase between increasing ocean heat content and outgoing longwave radiation. The authors note that more than 85% of the global heat uptake (Q) has gone into the oceans, including increasing the heat content of the deeper oceans, although their model only accounts for the upper 700 meters.
Figure 3 is a similar graphic to that presented in Meehl et al. (2004), comparing the average global surface warming simulated by the model using natural forcings only (blue), anthropogenic forcings only (red), and the combination of the two (gray).
Figure 3: Time series of anthropogenic and natural forcings contributions to total simulated and observed global temperature change. The coloured shadings denote the 5-95% uncertainty range.
In Figure 4, Huber and Knutti break down the anthropogenic and natural forcings into their individual components to quantify the amount of warming caused by each since the 1850s (Figure 4b), 1950s (4c), and projected from 2000 to 2050 using the IPCC SRES A2 emissions scenario as business-as-usual (4d).
Figure 4: Contributions of individual forcing agents to the total decadal temperature change for three time periods. Error bars denote the 5–95% uncertainty range. The grey shading shows the estimated 5–95% range for internal variability based on the CMIP3 climate models. Observations are shown as dashed lines.
As expected, Huber and Knutti find that greenhouse gases contributed to substantial warming since 1850, and aerosols had a significant cooling effect:
"Greenhouse gases contributed 1.31°C (0.85-1.76°C) to the increase, that is 159% (106-212%) of the total warming. The cooling effect of the direct and indirect aerosol forcing is about -0.85°C (-1.48 to -0.30°C). The warming induced by tropospheric ozone and solar variability are of similar size (roughly 0.2°C). The contributions of stratospheric water vapour and ozone, volcanic eruptions, and organic and black carbon are small."
Since 1950, the authors find that greenhouse gases contributed 166% (120-215%) of the observed surface warming (0.85°C of 0.51°C estimated surface warming). The percentage is greater than 100% because aerosols offset approximately 44% (0.45°C) of that warming.
"It is thus extremely likely (>95% probability) that the greenhouse gas induced warming since the mid-twentieth century was larger than the observed rise in global average temperatures, and extremely likely that anthropogenic forcings were by far the dominant cause of warming. The natural forcing contribution since 1950 is near zero."
Conclusion
There are multiple lines of empirical evidence that increasing carbon dioxide causes an enhanced greenhouse effect. Laboratory tests show carbon dioxide absorbs longwave radiation. Satellite measurements confirm less longwave radiation is escaping to space at carbon dioxide absorptive wavelengths. Surface measurements find more longwave radiation returning back to Earth at these same wavelengths. The result of this energy imbalance is the accumulation of heat over the last 40 years.
Last updated on 10 December 2011 by dana1981. View Archives
You obviously have some ulterior motive for asking that because a few seconds of searching found this, up to the end of 2010 :
Real Climate 2010 updates to model-data comparisons
Were you looking for something else ?
My guess is that the model temperature predictions based on CO2 rise alone will not match the observed temperature record since 2000. If that is the case then the radiative forcing components that Meehl used in 2004 were not accurate and that forcing from natural climate variability has not been properly accounted for. Or to put it another way, the temperature record for the last decade can not be reproduced in the model with anthropogenic forcing alone.
Of course not. Even a brief look at papers on model parameterisation, or a look at the FAQ at realclimate would show that model parameters are not "fitted" to temperature. This is a common denialist assertion repeated without a shred of supporting evidence. If you are going to repeat it, then I do not think it unreasonable to ask for a paper showing a model parameter that was tuned to global temperature.
I would also suggest looking at RC post on what IPCC models really say.
You might also consider how successful Wally Broecker was at forecasting 2010 temperature in 1975, using results from a model so primitive that it didnt have parameterizations.
The modeled trend is about +0.2C per decade, which fits scenario C the best. But scenario C assumed no further emissions after 2000. Why the discrepancy? Scenario B predicted +0.27C per decade. What are the forecasts for 2020, 2050, 2100? From what I read, separating climate sensitivity to CO2 from natural climate variability is still a work in progress, especially considering the observed temperature record over the last decade. How can you say with confidence that most of the warming over the last 30 years is from CO2 rise when it seems that ENSO/PDO/AMO/AO (and solar) are playing a much more significant role in changes in global surface temperatures?
Observed forcing are just that - observed. They are the measured inputs to the model. In a really crude form a model is Output(eg temperature) = F(input) where F is the model. Input is climate state plus forcing. A forcing isnt modelled, but the measurement obviously has error bars too like any other. So forcing are: GHG, Albedo, TSI, and aerosols. GHG forcing is determined from atmospheric measurement. Confirmation of radiative change comes from both satellite and ground stations. Albedo, TSI are measured by satellite; aerosols are more complex involving sampling, satellite and ground observations. Uncertainties increase as you go back in time. For the model run, changes in albedo attributed to landuse change, change in GHG, and change in non-volcanic aerosols are anthro. Its important to realise that these are no free variables that the modellers can change at well to fit a result. The numbers are published by the relevant observing network. Meehl does not adjust model parameters to match observations.
As to scenario C versus scenario B, its done to death in Hansen's 1988 prediction thread. In short, the 1988 model used by Hansen (also very primitive) had sensitivity of 4, while more recent research (IPCC models) estimate it at 3.
http://catallaxyfiles.com/2011/08/03/stop-press-climate-talk-on-cable-today/
[DB] Salby is essentially speaking gibberish. In the past, temps tended to lead CO2 increases, with the notable exceptions of methane peturbations. How things are different today is that we have injected immense quantities of previously sequestered CO2 back into the carbon cycle, turning CO2 from it's normal feedback into a forcing.
Salby has been discussed to some degree already on RC, Open Mind and internally here at SkS.
There are no credible physics to support his assertions. As a further note, his reputation within the community is less than you make it out to be.
He seems to have it in his head that annual CO2 emissions (that is the natural flux of CO2 in and out of biological reservoirs like forests and the oceans, plus human emissions, should follow human CO2 emission trends on a year-to-year basis. He doesn't explain why he thinks that, but he's wrong anyway - El Nino/La Nina and droughts in the Amazon for instance, can drive large swings in the flux of CO2 in and out of natural systems. Human CO2 simply adds to the pool size which natural systems can draw from.
The rest of his argument stems from that basic misunderstanding of the carbon cycle. Maybe he should have stuck with atmospheric physics?
If you're curious about Salby's work and want to know more--arguments for and against--then you shouldn't present the work as if it's the Holy Sword of Scientific Truth. If you do, you'll be expected to use that Sword. Perhaps instead you should say something like, "What about this _____ chap who claims ____? He seems legit--he's got lots of titles and such."
So often those Skeptic Silver Bullets turn out to be chrome plated brass. Yet they keep firing them and the AGW monster keeps coming.
Now if he can come up with an theory that explains why the conservation of mass should not hold, he might have something that really would make him famous. Otherwise, he should be asking, "what could I be doing wrong here?" That's what a true skeptic does when he evaluates all the evidence.
Instead, Salby simply ignores one of the most fundamental and easily understood tenets of physics as we experience it here on earth. What is depressing is that Judith Curry apparently didn't see through this immediately and shepherd her flock away fromthe road. It's also depressing (and telling) that this topic still has any legs at all among the larger community of so called "skeptics."
And Salby has not published a single paper on the carbon cycle that I am aware of.
Really this is just smoke and mirrors and people like Dale lap it up to reinforce their denial. For example, one of the commentators to that advertisement for his talk (50% of which was about him, not the subject he is trying to speaking to) states:
"But I thought the science was settled??"
Now there is a true "skeptic, not. His mission has been accomplished before the paper has even made it though peer review. This is very, very likely just another Trojan paper to make people think "the science isn't settled so we don;t have to do anything".
PS:
"Skeptics" claim that temperatures have not warmed since November 1996, if Salby's hypothesis is correct then why have CO2 levels continue to rise, perhaps even accelerate since then?
Comment from Gavin Schmidt at RealClimate:
This has nothing whatsoever to do with attribution of the temperature rise. The response of the CC to temperature is a specific thing - and it doesn't matter if it is originally driven by Milankovitch and ice sheets (over the ice age cycle), solar and volcanic activity over the pre-industrial, or by human activity/martian fairies/the PDO or whatever today. ENSO is an internal source of temperature changes on short time scales, and Pinatubo is an external source of temperature change over a short time period - both are included in any modern period regression such as Salby must have used. And the sensitivity of the carbon cycle to such changes is noticeable, but small and nothing like enough to explain the 20th C change. But even without thinking about this that deeply at all, it is obvious that Salby is wrong - we have put more than twice as much CO2 into the air as has actually accumulated over the last 100 years. To posit that the rise is not anthropogenic implies finding sinks that have totally taken up the anthropogenic CO2 *and* new sources that have put half of it back again. Meanwhile, all the actual reservoirs have more carbon than they had previously. Furthermore, the 13C and 14C data (up until the bomb peak) support a predominantly fossil fuel source. And the O2/N2 levels are dropping at the rate expected (given that we are burning C, and taking O2 from the air). The idea that a poorly performed regression undermines all this is ludicrous. - gavin"
I wonder how these 'spells of warming' manage to both increase and decrease CO2 in sync with human economic activity, even down to as fine a scale as the day/night differences associated with weekday traffic (also here). And I can only marvel at how these 'warming spells' know to take the weekends off.
Spells? Sounds a bit like witchcraft to me.
It is not an issue of conservation of mass. Atmospheric CO2 is part of a complex equilibrium system. The CO2 that we are emitting does not remain in the atmosphere, but reacts according to the many natural chemical equations on this planet. If the amount we were adding was insignificant, then the environmental equations involving CO2 would use up the excess CO2 and form more products, keeping the atmospheric concentration relatively constant. Salby's own numbers indicate that nature is only using 45% of the excess CO2, with 55% remaining in the atmosphere.
His assertion that CO2 is simply reacting to increasing temperatures would be more believable if it followed the recent temperature profile. However, temperatures have oscillated significantly during the past 130 years, while CO2 emissions have consistently increased.
You know, Judith should really just step away form her keyboard-- she is continuing to make an utter fool of herself.
These "huge increases in CO2 concentrations" that Curry is so excited about are a) transient and b> < 2 ppmv.
Or a touch of the vapors.
Good enough for me, too.
There are threads to discuss denialism vs skepticism, but this thread is not one. If that is your wish, then please use the Search function to find one & place those comments there.
Defend your ideas; on this thread, the topic is CO2 causing warming. Other topics = other threads.
1) water vapor has a much broader absorption in more regions than any of the GHGs addressed here; it cannot be ignored!!!! H2O covers 70% of the Earth's surface (plus a lot of it in the vapor phase as well), it therefore is hit by most of the incoming solar radiation (uv or high-energy) - the H2O absorbs uv and emits it as IR, this is undeniable. therefore, the radiative energies coming from the H2O are well outside of the 298K band. so the water on the surface and in the ATM has a massive effect on the temperature. this cannot be ignored in a "model" - the biggest part of the system must be included in the model.
2) what about the interaction of the Earth's and Sun's magnetic fields (solar wind)? this effects the temperature as well. maybe we should be more worried about the things we cannot change than the ones we can. we cannot accurately study a system so dynamic and not completely understood, and ignore the major contributors to an effect while having a limited amount of sample data. we need temperature date from 1000 times more points to make a valid conclusion toward surface warming. the Earth is larger and more dynamic than the model(s) account for.
Both of these topics are covered on this site, along with a legion of others. There is a search function, and a helpful list link "Arguments" on the top left of the page.
1) Explaining how the water vapor greenhouse effect works
2) Could cosmic rays be causing global warming?
I agree with the first part of the statement. Will you support this endeavor with your tax dollars?
You should really move the modeling comments and questions to the appropriate threads, though. Water vapor, by the way, is not ignored in the models. It has a short atmospheric residence time, though, and the quick cycling stabilizes it as an element of the long-range atmospheric dynamic (climate). Take a good read here and here, and reply on those threads.
"this cannot be ignored in a "model"
indeed it's not.
As for the cosmic rays, take a look and comment here.
If you have data to substantiate this claim, please provide links to it on the cosmic rays thread. I've looked and haven't found much of any quantitative information.
"maybe we should be more worried about the things we cannot change than the ones we can."
That is an interesting suggestion. After we've worried about the things we cannot change for a while, what do you propose we do about them?
Additionally, on a cloudy day, temperatures go down, not up. Heat rising with water vapor in it tends to create more clouds and thunderstorms, which cool things even more. I can see how (at night) cloud cover would keep some heat from escaping the atmosphere, but once you're more than a few feet off the ground (even in the heat of summer) the air temperature drops dramatically. I have personally observed this as a glider pilot. Even 3000' off the ground you can see ice crystals form on your canopy with the sun shining and ground temp at 90 degrees.
So someone explain it to me (taking real world observations into account).
Has anyone considered that the sheer numbers of humans exhaling has increased several fold over the past 100 years? Where are we now 6 billion? It was barely 2 billion when I was a kid. Could that account for increased CO2?
CO2 is a trace gas
Water vapour
It's the Sun
Human exhalation of CO2
We know with a high degree of accuracy how much the added CO2 has changed over the past century and we know the radiative forcing change for it (and the other man-made greenhouse gases) is about 2.4W/m2. That is a big change that turns up the thermostat and causes more water vapor to be held in the atmosphere.
Human's exhaling doesn't actually add to the carbon in the atmosphere because, well, where did that carbon come from? It was already part of the natural carbon cycle. The problem comes from burning ancient carbons in the form of fossil fuels.
I really hate the term "climate denier", it says to me that someone has made up their mind and their is no room for debate. In fact none of this is carved in stone and we're still figuring it out. I have to quote the article
"So skeptics are right in saying that water vapor is the dominant greenhouse gas. What they don't mention is that the water vapor feedback loop actually makes temperature changes caused by CO2 even bigger."
The fact is that water vapor IS the dominant greenhouse gas, and if all this happened many times before man entered the picture, that says to me that we are not the problem and that this is a natural process. Just because it might not end well for man doesn't mean it's our fault.
You really do not seem to understand the science behind climate change and the theory of AGW, and that is confusing you.
Also, no reputable climate scientist are claiming that ALL the observed warming is due to increased GHGs from burning fossil fuels and land use change. Nor do the IPCC assessment reports make that claim.
As for fingerprints indicating that the warming is because of an enhanced greenhouse effect, well they are everywhere (follow the link below for more information).
[Source]
No one disputes that. However, this time around we have intervened and the climate is changing, in large part because of that sudden and unprecedented intervention.
Using the 'its changed before' argument begs two questions: Do we know what caused climate change in the past? Answer: mostly yes. Do we know if those same mechanisms are making climate change now? Answer: We know very well they are not.
Let's use an analogy: The last time your house burned down, it was due to a lightning strike, an entirely natural cause. Does that mean that an arsonist can't burn it down the next time? Does that mean you shouldn't be concerned when you see smoke coming out of the attic?
muocounter, one volcano can throw out more CO2 and ash into the upper atmosphere than all the coal power plants on the planet combined. What are your plans to stop that? Outlaw volcanoes and undersea gas jets? The planet is a dynamic system that tends to correct itself. WE ARE A PART OF THAT SYSTEM, not some separate alien invader corrupting it. So even if it is 'man made' it's still 100% natural. The earth created us and it can destroy us just as easily. I'm fine with that, but you all seem to think you're some splendid shepherds of the planet, when in fact we're just another life form on it.
Name calling and demonizing someone because they don't agree with your 'deeply held beliefs' is the first sign that you've lost the argument. [snip]
Your understanding of climate science is deeply flawed. The shift to the term "climate change" because the effect of global warming goes far beyond a simple increase in temperature. It affects rainfall pattern, ocean acidity etc. Global warming is the cause, climate change are the symptoms. No working climatologist believes that we are heading into an ice age.
Global warming theory came long before the first computer arrive, and the theory have been verified through multiple observations and experiments. None of the 10 fingerprints albatross cited requires the use of a computer model. Computer models themselves are tested continuously against observations to ensure that the physics are captured correctly. You should also check out How reliable are climate models?
Your belief that Volcano emits more CO2 is flat out wrong, as Dikran pointed out.
Actually, claiming somebody has lost the argument based on some trivia entirely unrelated to the science is a fairly sure sign that you have no substantive argument to offer.
As an aside, the whole "global warming"/"climate change" issue is a complete non-issue that just makes you look silly (watch the video - you'll know what I mean).
What a useless tautology. Cars are man-made and are therefore 100% natural (by your 'logic'). Yet there are laws to control the use of cars. Should nature just self-correct wayward drivers?
Volcanoes? Biggest in recent memory was Pinatubo and it did have an effect on climate - for about 2 years. So?
You can learn something about the science here. Thus far your claims (such as 'volcanoes emit more CO2') have all been factually incorrect and everyone commenting has politely told you so -- with references. No one is name-calling and demonizing; the first to accuse another of doing that is usually the one who has lost the argument.
If you find it necessary to go that path, you'll find the moderators will quickly show you the door.
Alleycat, The idea that the planet tends to correct itself has a definite problem: what is "correct"? What is the ideal state? You don't know, because if you did, and you had evidence, you'd either be considered a major prophet or everyone would already also know. Humans have enjoyed a relatively stable climate for roughly 10,000 years. It's understandable that climate instability is not an element of any original narrative--except perhaps as a distant echo in certain practices and pieces of wisdom. It's also understandable, then, why climate stability might be represented with a Gaia-type character: Earth-and-biosphere-as-being, and as a being in some sort of balance that has recently been upset. No. The earth is what its historical and material conditions (including us) make it. It has been wildly variable in the distant past, and for long periods (very inhospitably so). There is no base climate that the Earth returns to after excursions. There is no base climate that the Earth is heading for (well, there is a set of unpleasant end scenarios involving the "death" of the sun and the "heat death" of the universe). To think that we can't alter climate is to set us outside of nature. We can alter nature, and we make choices every day that increase or decrease the long-range chances for our own happiness, health, security, and freedom (and the same for other parts of the biosphere). I assume from your use of "outlaw" that you are concerned with individual freedom and government regulation. The more that AGW is allowed to become a problem, the more likely a government solution will be necessary--perhaps even a global government solution.
At some point, you're going to have to set aside the universals and start up from basic physics. Do you accept that CO2 absorbs and emits (in all directions) at a specific set of pressure-broadened frequencies within the range at which the Earth emits (having been initially warmed by the sun)? If no, then read the advanced version of this page (again) and provide evidence for your position here. If yes, then do you accept that humans are the primary reason why atmospheric carbon has been rapidly increasing over the last 150 years? If no, then provide evidence for your position here and/or here. If yes, then you are pretty much forced to believe that humans are responsible for the activation conditions of a warming mechanism. The question then becomes one of energy balance. Is there enough warming (through positive forcings and feedbacks) to overcome the effects of negative forcings and feedbacks? Answer that question here after reading the article(s).
The climate system is complex, no doubt, but scientists have increased their understanding on it immensely over the last 150 years or so. Not knowing everything, does not equate to knowing nothing. We do not know everything about how the human heart operates, but surgeons operate and save lives each and every day. We have known for some time (and past climate change has aided scientists in understanding this) now that doubling or trebling or even quadrupling CO2 levels in a very short time is going to have a dramatic impact on the climate system and biosphere. Indeed, those changes are already evident in data collected/observed across many scientific disciplines. No models required.
You say "The planet is a dynamic system that tends to correct itself."
You seem to be trying to apply Le Chatelier's principle, but in the wrong context. I encourage you to read this great article by Dr. Bill Chameides.
"If this was all so obvious, then the majority of scientists would concur, but they don't."
It has been quite obvious for quite some time now actually (e.g., seminal research by Tyndall,Arrhenius, Callendar etc.). Not that science is done by consensus, but the vast majority of scientists who are working in climate related fields do agree on the theory (not hypothesis) of anthropogenic global warming or anthropogenic climate change. That there is allegedly "no consensus" is currently ranked as Skeptic Myth #4. Regardless, the agreement goes beyond "consensus", it is in fact consilience.
Hope that this helps.
But all that aside, even if people here were being rude or whatever, that would not be an excuse to dismiss the physics, the data and the observations.
I think skeptics sometimes find comfort in the idea that the planet will pull all that carbon back out of the atmosphere naturally. And that's realistic... over the next 10+ million years. I, for one, don't care much about what the planet will be like in that amount of time. What I care about is that we at least try not to create undue (and avoidable) hardships on near term future generations.
As it is already, with another, what, 0.6C of warming baked into the system and not a lot of progress towards significantly changing our ways, the latter half of the 21st century is going to be pretty hellish for billions of less well off people. It's awful but I don't think that is avoidable. What I hope is still avoidable is that hard reset.