Global Warming, History of Earth's Temperature

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A recent study published in Science indicates that Earth has not experienced temperatures this cold in 350-450 million years, with the Global Mean Surface Temperature dropping from 27°C to approximately 11°C over the last 40 million years. This period is described as a 'Golden Age' for warm-blooded animals. Discussions highlight concerns regarding the implications of climate change, particularly the potential for significant disruptions to human life and ecosystems due to rising sea levels, agricultural challenges, and extreme temperatures. Critics argue that despite efforts to reduce CO2 emissions since the 1980s, there has been little to no meaningful impact on global emissions, primarily due to increasing emissions from developing nations like China and India. The pandemic temporarily reduced emissions, but the long-term effects of current measures remain uncertain. The conversation also touches on the complexities of climate science, the challenges in predicting outcomes, and the need for substantial changes in energy production to address climate change effectively.
  • #51
Should people elected and appointed to the highest Offices act as if the science based advice is valid - advice governments commissioned in order to make informed policy choices? I think they do. Like the bad dam example, few if any will be personally capable of assessing the validity of that advice yet communities rely on them to respond appropriately to that advice. It shouldn't be a personal choice on their part whether to take the expert advice seriously, it should be their duty to do so.

Just because constituent irrigation farming communities downstream are dependent on the dangerous dam for their livelihoods oppose draining it - and accuse the engineers making the assessments of "green" political bias or can even find other engineers who will make assessments more to their liking - doesn't make the duty to act on the advice go away.

I think making the climate problem entirely about public opinion - where a lie that presses people's buttons is on an equal footing to the IPCC or NOAA or NASA or etc (that have been extraordinarily good at predicting the course of climate change) has been profoundly inhibiting. Making it NOT about those in highest Offices having a duty to seek out such advice and act on it (until and unless overwhelming public opinion supports it) has been incredibly dangerous in my view.

It doesn't make the need to help out those communities in the face of what needs to be done go away either. But people holding high Offices have a great array of expertise and resources to draw on that ordinary people do not - expert advice including for how to reduce the risks AND support affected communities.

If addressing the climate problem effectively is up to successful political activism instead of those holding the Offices with the duty that says more about the negligent (and corrupt) failures of those holding the actual Offices where the duty lies to step up and do their jobs than about climate activists.
 
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  • #52
Ken Fabian said:
Should people elected and appointed to the highest Offices act as if the science based advice is valid - advice governments commissioned in order to make informed policy choices? I think they do.
Ken Fabian said:
Making it NOT about those in highest Offices having a duty to seek out such advice and act on it (until and unless overwhelming public opinion supports it) has been incredibly dangerous in my view.
But what does that say about democracy? Why elect leaders to make decisions in the first place if there are known people who know best, who we shouldn't disagree with? Why not just let the scientific community make all the decisions?

In Canada, we have the Green Party of Canada to let the people express their opinions about green politics. Founded in 1983, it finally got 1 candidate elected in 2011, went up to 3 in 2019, and now they have 2. They used to be invited to the debates during an election campaign, but they are not anymore because their impact is not considered large enough.

There is such a party in every province. As of today, out of the 10 provinces, only 6 candidates are in Office, in 3 provinces. Around 2019, there were 15 within 4 provinces, with 8 of them being elected in Prince Edward Island (where the population is about 180 000 people).

The political option is there. People have spoken. They don't care. We - who is "we" exactly? - can tell ourselves that people are idiots and don't know what is good for them, but then why give them the right to vote?

And this brings me back to my initial point: The role of the scientific community is to influence the voters, not the politicians. They are failing big time because of their arrogance and they shouldn't blame anyone but themselves for failing to communicate their message.
 
  • #53
This thread is moderately interesting but IMO really should have been tied off a long time ago.
 
  • #54
Ken Fabian said:
Should people elected and appointed to the highest Offices act as if the science based advice is valid - advice governments commissioned in order to make informed policy choices? I think they do.
You CLEARLY are not paying attention to the current American administration.
 
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  • #55
phinds said:
You CLEARLY are not paying attention to the current American administration.
The poster is clearly expressing an opinion about the current administration. This thread should be closed, it's nothing but political anymore.
 
  • #56
jack action said:
Why does a flat-earther think it is so important for me to believe the Earth is flat?
I think your knowledge of Science must be much greater than your knowledge of human nature. Flat Earth is a club of people who get pleasure from baiting people like you. Why should they admit to modern day Science if they are having fun.
See also the panel game Mornington Crescent. It's been running for decades on the wireless "BBCR4 I'm sorry I haven't a clue". My poor father in law never got the joke and spent all his time looking for rules whilst it was being played.
 
  • #57
gmax137 said:
The poster is clearly expressing an opinion about the current administration. This thread should be closed, it's nothing but political anymore.
It would be nice to discuss some of the studies regarding climate change, it is possible to do this without getting into too much politics.
I think this is the longest thread on the subject since I have been on the site in ten years.
I am curious to know why @jack action has reached the conclusion he has reached.
 
  • #58
jack action said:
But what does that say about democracy?
For Democracy to work well it requires an informed public. When people holding or aspiring to Office encourage their constituents to mistrust the science based advice - and get their votes on the false basis that that the expert advice is false or driven by (extremist) politics - that looks more like Populism than Democracy.

jack action said:
The role of the scientific community is to influence the voters, not the politicians.
I disagree. Orgs like the NAS were formed to inform governments. The IPCC was formed to inform governments. And I believe those who hold or aspire to the relevant Offices - as well as the specific Agencies that have the climate issue as part of their role - have a duty to pass on the gist of the expert advice correctly - and have an ethical duty to repudiate false and misleading claims about it; to encourage and feed them is extremely dangerous... to Democracy.
 
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  • #59
Im new here but figured i'd offer what seems common sense to the discussion. There have been many ice ages over millions of years, the last of which ended about 12k years ago. There were no carbon emitting cars and coal plants 12k years ago, which means the earth has it's own heat cycle and we are just here for the ride. But fear is an easy way to manipulate populations, we must use common sense. I'll just leave it at that.
 
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  • #60
GR86 said:
Im new here but figured i'd offer what seems common sense to the discussion. There have been many ice ages over millions of years, the last of which ended about 12k years ago. There were no carbon emitting cars and coal plants 12k years ago, which means the earth has it's own heat cycle and we are just here for the ride. But fear is an easy way to manipulate populations, we must use common sense. I'll just leave it at that.
That is completely at odds with the best available science. It is good sense to pay attention to the science based advice rather than presume you know better than the science agencies and institutions that study climate and dismiss it.

That Earth's climate has high susceptibility to change seems to be why it is highly susceptible to change from GHG emissions.

Despite the evidence of wide variation in long ago paleo climate the Holocene - what immediately preceded this warming - had exceptional stability compared to most of the period since homo sapiens emerged as a species. There are good grounds to think the stability of climate over the Holocene was crucial to successful agriculture persisting for long enough for civilisations to arise.
 
  • #61
GR86 said:
I'll just leave it at that.

Yes, and hundreds of thousands of scientists, people trained in this particular field, NEVER ever thought about it. I assume you would say the exact same thing about relativists, right? If not, then ask yourself, WHY not. Have you ever thought about why do relativists want to manipulate people with fear? Have you ever even read any peer-revieved paper about issues of global warming? Or do you only rely on your local newspapers? I see no common sense in that, and this thread is really going nowhere.

Mind you all, this is SCIENCE forum, not facebook.
 
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  • #62
Climate change is a very tricky issue.

All we can predict is probabilities:


We don't discuss politics here, so I will only note managing something where all you can know about are probabilities is very hard.

Being a free society with all sorts of competing views, combined with only knowing probabilities, makes it very hard to do anything about it (or even if required).

Each side retreats to its entrenched position, and you can see the progress being made for yourself. It goes without saying in a democracy, the ballot box is generally how it is resolved.

If you are interested in nuclear energy as a possible solution, we have a section devoted to only that.

Thanks
Bill
 
  • #63
weirdoguy said:
Yes, and hundreds of thousands of scientists, people trained in this particular field, NEVER ever thought about it. I assume you would say the exact same thing about relativists, right? If not, then ask yourself, WHY not. Have you ever thought about why do relativists want to manipulate people with fear? Have you ever even read any peer-revieved paper about issues of global warming? Or do you only rely on your local newspapers? I see no common sense in that, and this thread is really going nowhere.

Mind you all, this is SCIENCE forum, not facebook.
Wow you are nearly insulting instead of simply answering me. I don't use FB or read the newspaper. If it's very common, why not just answer? It's simple, we had many ice ages and many thaws, all without humans adding our carbon footprint. If they happened thousands and millions of years in the past, than humans cannot be the cause. Im not saying there isn't climate change, im just saying the evidence suggests we are not the cause.
 
  • #64
Changes in the past driven by non-human forces does not mean that current changes are not driven by humans in some way.
Nor does it mean that changes in things now will not have any effect.
In addition, these current climate changes will probably have a lot of deleterious effects on human populations.

Since this is a pretty strict science forum, you should come up with a real science sources for your statements. That's what the facebook and newspaper comment was probably about. You sound like you are passing on rumors. And now you are getting evasive about sourcing things.
 
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  • #65
BillTre said:
Changes in the past driven by non-human forces does not mean that current changes are not driven by humans in some way.
Nor does it mean that changes in things now will not have any effect.
In addition, these current climate changes will probably have a lot of deleterious effects on human populations.

Since this is a pretty strict science forum, you should come up with a real science sources for your statements. That's what the facebook and newspaper comment was probably about. You sound like you are passing on rumors. And now you are getting evasive about sourcing things.
Well the common claims we hear are that humans are producing a carbon footprint in such a way that we are heating up the earth. But how can anybody know that without acknowledging and measuring how much the earth would heat up with no humans here? We know it's happening, either heating up or cooling off at any given time, but unless we have that data how can we claim our own contribution if any?

It could be 1/1000 of one percent per century and we are all wasting our time giving gasX to cows. But all we hear are claims that things are so bad, we need to make changes NOW. Until we see data on the earth's own patterns (without human influence), many people aren't going to listen.

You are not wrong, im not just passing along sources, im just saying what makes sense. I mean do i really need to link data to prove the earth had prior ice ages that also ended? I mean who refutes that? Sounds like people are being pedantic so they don't have to address my point.
 
  • #66
GR86 said:
figured i'd offer what seems common sense

GR86 said:
we had many ice ages and many thaws, all without humans adding our carbon footprint
Apply a bit of your 'common sense' to imagining what life could be like in another ice age or hot age for either your lifestyle or that of the whole of Earth's population. How much would your personal circumstances need to change before you would handle them with no problems? It wouldn't just be the underprivileged masses who would suffer; it would be you and I who would have to change our lifestyles and 'suffer' even if we didn't die.

The causes of climate changes are many. Often, the changes are due to biological causes. Photosyntheses turned things totally upside down - in our favour, as it happens. Species extinctions due to human activity are in progress as we speak and we have no actual idea of the effect of just one single organism taken out of the chain.. The social media have no moderation system so you cannot trust anything that you read there. (From either camp). Whilst it's true that Science Research can be biased, in general what 'good Science' yields is less suspect than the statements from big business and governments.

I'd recommend that, along with your denial, you actually consider (and equate) the personal inconvenience of going for Net Zero with the inconvenience of a major change of climate on you, personally.

A parallel conversation between two cockroaches would probably have a totally different conclusion.
 
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  • #67
GR86 said:
Wow you are nearly insulting instead of simply answering me.

I asked you questions. Do you think relativists want to manipulate people with fear? If not, then why climate physicists would do that?

GR86 said:
It's simple,

No it's not. People learn for many years to be able to do reasearch on that topic. How many years have YOU learned about it?

GR86 said:
im just saying the evidence suggests we are not the cause.

People more knowledgable in the field says otherwise. You are not a scientis working in the field. This is not an insult. It's stating a fact. We are on a scientific forum.
 
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  • #68
GR86 said:
im just saying what makes sense.

Both relativity and quantum physics does not make sense to the majority of the people in the world. How can that be an argument on anything?
 
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  • #69
GR86 said:
but unless we have that data how can we claim our own contribution if any?

[...] Until we see data on the earth's own patterns (without human influence), many people aren't going to listen.
I don't have any sources to cite but I think the data shows that:
  • CO2 emissions contribute to rising temperatures;
  • Humans have increased CO2 emissions a lot;
  • This rise in temperature is happening much faster than any previous one.
This is why scientists who use common sense conclude that human emissions play a big role in climate change.
 
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  • #70
GR86 said:
Well the common claims we hear are that humans are producing a carbon footprint in such a way that we are heating up the earth.

The claims made by scientists, if you read the literature, are varied. I linked to a lecture by Tim Palmer explaining why this is. So, you know who Tim Palmer is; he is the founding member of the Centre for Medium-term Climate Prediction. This is one of the central bodies used when, for example, a cyclone is forming and is called on to say where it will hit. Like long-term climate prediction, it, too, is probabilistic. The centre has an enviable record of predicting probabilities. This is very important so plans can be made to mitigate effects optimally. That is all that can be done. We can't say where it will hit; just probabilities so sensible plans can be made.

We know the risks and probabilities. If I remember correctly, the branch of engineering that deals with this is systems engineering. We have several technological 'weapons' at our disposal, e.g. hydroelectricity and nuclear. Even simple planting of trees. We must design a solution that considers probabilities, solutions, and economics. It is an engineering problem and is how it should be addressed.

However, it is an issue that generates a lot of passionate debate and has become part of the political landscape. It is necessary to somehow return this to an engineering issue where it belongs. But the political landscape has made this difficult; for example, we have the spectacle here in Australia of the energy minister making claims well beyond his competency. I will not comment on the political situation except to say Google is your friend. If you find any technical claims and want to check their validity, this forum is about that. But, by our charter, we can't be drawn into the politics.

What can be said is there is an issue (as I said, the models used by Tim Palmer have a proven record in medium-term prediction); we have the tools to mitigate it; what we do is up to us, just as it is up to us when when a cyclone is forming (for example).

Thanks
Bill
 
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  • #72
GR86 said:
Well the common claims we hear are that humans are producing a carbon footprint in such a way that we are heating up the earth. But how can anybody know that without acknowledging and measuring how much the earth would heat up with no humans here?
Another disappointingly low grade argument, as poor as (paraphrasing) natural processes cause climate change, therefore human influences do not cause climate change.

Welcome to the test tube. I much prefer computer modeling based on understanding of physical climate processes myself, before seeing what happens to this world with 450 or 500 ppm or (by abandoning all efforts to restrain emissions) much more CO2 than that.

And I will continue to see it as the duty of those holding positions of responsibility, trust, power and influence to take the science based expert advice seriously.
 
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  • #73
jack action said:
This is why scientists who use common sense conclude that human emissions play a big role in climate change.
Common sense and a good appreciation of what statistics can tell us. But it's such an inconvenient truth and people would rather not alter their lifestyle to help the situation. We need something dramatic enough for the human race to be convinced and to move it into their 'intuition' mailbox.

It's funny that, once that switch has been made, humans are quite prepared to take significant action. When the brakes fail we still press as hard as we can on the brake pedal; we don't think twice about it. All we can hope is that the remaining stopping power will make a difference. No one would take out a pen and paper and write down the SUVAT equations at the time (which is what the denyers seem to do).
 
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  • #74
sophiecentaur said:
We need something dramatic enough for the human race to be convinced and to move it into their 'intuition' mailbox.

What I find utterly shocking is that people in my country (Poland) can't seem to aknowledge that winters has almost disappeared. I'm 34 and when I was young all seasons were, you know, proper. Polish summers were hot, winters were cold, there was a lot of snow, etc. And this has disappeared, blended into mixture of spring and fall, with a little bit of snow once or twice during whole season (and once it was snowing in may). And some people are like, "yeah, nothing happens, that's the way it should be, no global warming, no changes". On the other hand, during spring and summer we have droughts. Grass is yellow. And everything is fine.
 
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  • #75
sophiecentaur said:
Common sense and a good appreciation of what statistics can tell us. But it's such an inconvenient truth and people would rather not alter their lifestyle to help the situation. We need something dramatic enough for the human race to be convinced and to move it into their 'intuition' mailbox.

It's funny that, once that switch has been made, humans are quite prepared to take significant action. When the brakes fail we still press as hard as we can on the brake pedal; we don't think twice about it. All we can hope is that the remaining stopping power will make a difference. No one would take out a pen and paper and write down the SUVAT equations at the time (which is what the denyers seem to do).
I saw a video by someone who says they have been monitoring climate denial in social media for a decade or more. He said that the message has changed from denial that climate change is happening to undermining the solutions. For example: "the electricity from a wind power isn't enough to boil a kettle - you need energy from fossil fuels to do that". Or that "solar power doesn't work at night".

I find it impossible to imagine where this is heading. If the world drifts towards global dictatorship, then currently that would be a climate-change denying dictatorship. That could flip and one day all the dictators could decide to switch the power off, as it were. Who knows?
 
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  • #76
PeroK said:
I find it impossible to imagine where this is heading.

You're not the only one.

In my case, I point out this is an engineering problem, and the solution will involve engineers. We need televised debates discussing engineering issues. The misinformation about solutions (e.g., nuclear power) promulgated by the misinformed (on both sides) is so tainted by ideology that it's no wonder the public is confused.

Tim Palmer (who is getting older and no longer contributing to the IPCC) thinks we need a CERN for climate change with powerful computing facilities to get the best predictions (even though the climate is chaotic). I also support him in that.

On a positive note, this site can provide facts. However, it isn't easy due to the stories in the press. Australia, for example, has a long history of floods and droughts. People correctly point out that we have always had such. I have to admit it doesn't seem more or less frequent than when I was young. But one of the main drivers of climate here in Australia - El Niño and La Niña - is affected by climate change:

https://www.csiro.au/en/news/all/articles/2023/may/climate-change-affecting-el-nino

That is virtually never pointed out - anecdotal evidence rather than facts is usually discussed.

Thanks
Bill
 
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  • #77
PeroK said:
I find it impossible to imagine where this is heading.
Really? It seems obvious: Most people will continue to act in their own short-term interests (same as it ever was). Temperatures will continue to rise, low-lying land will be submerged, food crops will follow different patterns, hurricanes will be more severe, ...
 
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  • #78
gmax137 said:
Really? It seems obvious: Most people will continue to act in their own short-term interests (same as it ever was). Temperatures will continue to rise, low-lying land will be submerged, food crops will follow different patterns, hurricanes will be more severe, ...
Yeah, the big question to me is if/when we reach a point where enough people switch from saying they care to acting like it, to actually make a significant difference, and what the situation looks like at that point.
 
  • #79
sophiecentaur said:
Common sense and a good appreciation of what statistics can tell us.
Most of all raised atmospheric CO2 causes warming is a conclusion based on an understanding of the physical processes, where energy coming in and the processes whereby energy flows back out to space and the imbalance between those all add up right. Statistics is a valuable tool for identifying patterns in complex data but ultimately the physics of physical processes are what confirm the connection between raised GHG's (and albedo changes and aerosols and etc) and global heat balance.
 
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  • #80
gmax137 said:
Most people will continue to act in their own short-term interests (same as it ever was).

Indeed.

But let's get concrete. The government is transitioning to renewables in Australia and moving away from coal. Gas is seen as an intermediate technology. The problem is that they promised to reduce electricity bills by $275 per household, and Australia would become a renewable energy superpower. It failed on both counts, even though many engineers predicted it. Of course, they produced papers from the CSIRO supporting their policies, but many think they are flawed. The article I wanted to link to is behind a paywall, so a precis follows.

Start of Precis
Renewable energy advocates have seized on a new report by the CSIRO that nuclear energy is financially unviable in Australia. The analysis asserts that wind and solar are the lowest-cost new-build electricity generation in Australia, significantly below the price of nuclear power. This is a significant finding given that Australia is gambling its traditional energy security on 82 per cent of its power generation coming from renewables by 2030, which seems unlikely to be achieved. The upfront cost of a nuclear power plant is expensive. The CSIRO estimates the capital cost of a large-scale nuclear plant in Australia is $8655 per kilowatt, equating to about $8.6 billion for a one-gigawatt reactor. This is expensive but fails to provide a fair apples-with-apples comparison between nuclear and renewables.

Nuclear lasts at least 80 years, not 30. Nuclear power plants provide always-on power for more than 80 years. Solar panels last about 30 years. Wind turbines last 25 years. Batteries last 15 years. After these expire, billions of dollars must be spent – again – on replacements. Hence, the cost of energy sources should be benchmarked over a “like for like” whole-of-life period of 80 years for nuclear. The CSIRO says it uses 30 years because it is the time commercial finance is usually available before repayment is required. Modern nuclear plants overseas run at over 90% of their capacity - not the 53%-89% assumed in the report. The costs of nuclear are low after the upfront build, so they run near full throttle. Finally, the CSIRO uses the levelised cost of electricity (LCOE) to compare the competitiveness of power generation technologies. But it underplays the advantage of always-on, dispatchable power, such as nuclear, over mainly off, intermittent wind and solar generation. This is misleading.

The LCOE should be calculated on a reliability-equal, whole-of-life-basis. Solar power is fully on about 20-25 per cent of the 24-hour day and off about 75-80 per cent of the day. Wind power is fully on 30 per cent of the day and off 70 per cent. The CSIRO attempts to adjust for the unreliability of renewables in its LCOE estimates by including costs of storage, transmission and firming. But the assumptions underpinning the renewable integration costs are murky because the CSIRO says it doesn’t want to release modelling that could contradict the Australian Energy Market Operator’s integrated system plan. The CSIRO admits that LCOE is a simple screening tool and is not a substitute for detailed project cash-flow analysis or electricity system modelling which provides more realistic estimation of costs. It says nothing about the revenue side of the commercial equation: what prices can the generator earn on the wholesale market and, given their costs, what profits can be earned? For the 60 to 80 per cent of the time when intermittent power cannot be supplied at any price, its economic cost can be considered infinite.

A renewable energy audit is required that includes: the direct cost of subsidies; the system-wide costs – including transmission, storage and back-up dispatchable power including the cost of subsidies to keep coal-fired power stations operating; the economic, social and environmental losses wind, solar and new transmission lines are inflicting on farmers and others living in regional communities; and the welfare costs of a more volatile and less reliable grid.
End of Precis

I give the above analysis not in support of it (although in the interests of full disclosure I agree with it), but to show we must design a low carbon system using engineers and engineering economists and seriously debate their proposals. IMHO consumers are just acting rationally, and those making decisions must, and it has become extremely urgent, understand all the consequences of their proposals when subjected to scrutiny. I see that as the main issue, rather than people being short-sighted, which is only natural. We have the technology to address carbon emissions and people's natural tendency to be more concerned about immediate issues, such as rising energy prices, IMHO. I believe televised debates with experts can change the current situation and have Australia on a better path (whatever that is).

Thanks
Bill
 
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