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What’s the hottest the Earth’s ever been?

climate.gov

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Re: What’s the hottest the Earth’s ever been?

#21

Post by throwaway3b03 »

samwillis wrote: post #12
Helmut10001 wrote: post #10

It is strange why many politicians and countries (Germany included) appear to close their eyes and still promote or work on the 1.5 °C goal, which seems pretty unrealistic at this stage. Maybe it is to calm the public, besides knowing better. Instead, there is a need for more realistic plans to model and prepare for 3°C or 5°C increase of average temperature by 2060 (or 2100). Looking at these bigger swings in temper…

Trouble is most politicians are incentivised to think in the short term and are increasing just in a perpetual campaigning mode. They are thinking about their careers and re-election. They cannot except and talk about bad news, and a 3-5degC increase is bad news. On top of that you have had climate activists pushing for very large change to happen incredibly quickly (arguably needed). But it’s an incredibly hard sell…

> 1. People are unwilling to make changes that they perceive as being a net negative to their quality of life.

I don't think that's the case. It's a coordination problem. People don't want to reduce their quality of life if they don't know for sure that others won't do that as well. Most things in life and in human psychology are relative, in constant comparison to our peers.

Re: What’s the hottest the Earth’s ever been?

#22

Post by samwillis »

throwaway3b03 wrote: post #21
samwillis wrote: post #12

Earlier quoted context omitted.

Trouble is most politicians are incentivised to think in the short term and are increasing just in a perpetual campaigning mode. They are thinking about their careers and re-election. They cannot except and talk about bad news, and a 3-5degC increase is bad news. On top of that you have had climate activists pushing for very large change to happen incredibly quickly (arguably needed). But it’s an incredibly hard sell…

> 1. People are unwilling to make changes that they perceive as being a net negative to their quality of life. I don't think that's the case. It's a coordination problem. People don't want to reduce their quality of life if they don't know for sure that others won't do that as well. Most things in life and in human psychology are relative, in constant comparison to our peers.

Possibly, but it's true even on a group rather than an individual scale.

I think it also helps to give people multiple reasons for making a change. So for example as a household we changed our diet by only have meat once a week now, combination of health and environmental benefits pushed us to make the change (Could never go fully vegetarian though).

Pushing people to walk/cycle works because you have both environmental/health arguments.

The difficult one is encouraging people to not excessively heat their houses (we should all be turning our thermostats down a couple of degrees), but maybe cost is a factor there.

Re: What’s the hottest the Earth’s ever been?

#23

Post by gorpovitch »

It is interesting to keep these numbers in mind, but these facts are not sufficient to think correctly about climate.

The earth is a dynamic system, and the rate of temperature growth is as much, if not more, important than temperature average here. A car going from 100 to 0 kmph in 15 seconds is definitely not the same as a car going from 100 to 0 kmph in 0.1 seconds in terms of damage.

the temperature rises described in the article (e.g. during the eocene) are about a few degrees every few hundreds of thousands of years. Flore and fauna had time to evolve.

Today we are talking about 4 degrees in less than a hundred years. That's more than thousand times faster.

Re: What’s the hottest the Earth’s ever been?

#24

Post by vixen99 »

Helmut10001 wrote: post #10

It is strange why many politicians and countries (Germany included) appear to close their eyes and still promote or work on the 1.5 °C goal, which seems pretty unrealistic at this stage. Maybe it is to calm the public, besides knowing better. Instead, there is a need for more realistic plans to model and prepare for 3°C or 5°C increase of average temperature by 2060 (or 2100). Looking at these bigger swings in temper…

Which data sources have persuaded you that the realistic and likely increases of 3 or 5 degrees are more probable?

"In 1979, the Charney Report from the US National Academy of Sciences suggested that ECS was likely somewhere between 1.5C and 4.5C per doubling of CO2. Nearly 40 years later, the best estimate of sensitivity is largely the same. This has led some to question why there has been so little progress on estimating climate sensitivity."

Is this quote above now no longer true? If not, please provide a link.

Re: What’s the hottest the Earth’s ever been?

#26

Post by dalmo3 »

gorpovitch wrote: post #23

It is interesting to keep these numbers in mind, but these facts are not sufficient to think correctly about climate. The earth is a dynamic system, and the rate of temperature growth is as much, if not more, important than temperature average here. A car going from 100 to 0 kmph in 15 seconds is definitely not the same as a car going from 100 to 0 kmph in 0.1 seconds in terms of damage. the temperature rises describ…

Without any knowledge in the field I wonder if the timescale difference could be attributed to the measurement methods used for the last centuries vs literal ages ago.

I.e. if we (or someone a million years from now) tried to estimate the 21th century's temperatures using the same techniques used to estimate temperatures a million years ago, would we be able to detect that 4 degree change?

Conversely, can scientists today detect or rule out that there was an outlier century a million years ago in which temps varied as much as today?

Re: What’s the hottest the Earth’s ever been?

#27

Post by Helmut10001 »

vixen99 wrote: post #24
Helmut10001 wrote: post #10

It is strange why many politicians and countries (Germany included) appear to close their eyes and still promote or work on the 1.5 °C goal, which seems pretty unrealistic at this stage. Maybe it is to calm the public, besides knowing better. Instead, there is a need for more realistic plans to model and prepare for 3°C or 5°C increase of average temperature by 2060 (or 2100). Looking at these bigger swings in temper…

Which data sources have persuaded you that the realistic and likely increases of 3 or 5 degrees are more probable? "In 1979, the Charney Report from the US National Academy of Sciences suggested that ECS was likely somewhere between 1.5C and 4.5C per doubling of CO2. Nearly 40 years later, the best estimate of sensitivity is largely the same. This has led some to question why there has been so little progress on esti…

I could cite individual observations and reports, but the field is difficult to summarize in a single HN comment. There are many factors that we cannot completely oversee, primarily tipping points (disappearing reflective polar caps) and feedback loops (melt of permafrost with methane release).

More concretely, have a look at the latest IPCC report [1], page SPM-16. Three of the five scenarios include temperature rises from 3 to 5 °C. Based on the last decade, the world has not reduced total CO2 emissions at all (not even slowed), despite its knowledge about climate change. Therefore, I have reason to believe that the three bad scenarios (intermediate to high CO2 emission), are more likely to happen than scenarios covering halted or little CO2 emission.

[1]: https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6...

Re: What’s the hottest the Earth’s ever been?

#28

Post by have_faith »

dalmo3 wrote: post #26
gorpovitch wrote: post #23

It is interesting to keep these numbers in mind, but these facts are not sufficient to think correctly about climate. The earth is a dynamic system, and the rate of temperature growth is as much, if not more, important than temperature average here. A car going from 100 to 0 kmph in 15 seconds is definitely not the same as a car going from 100 to 0 kmph in 0.1 seconds in terms of damage. the temperature rises describ…

Without any knowledge in the field I wonder if the timescale difference could be attributed to the measurement methods used for the last centuries vs literal ages ago. I.e. if we (or someone a million years from now) tried to estimate the 21th century's temperatures using the same techniques used to estimate temperatures a million years ago, would we be able to detect that 4 degree change? Conversely, can scientists…

> would we be able to detect that 4 degree change?

I'm far from an expert on this. Assumedly the damage we are seeing currently and expecting in the near future due to our current warming would be detecteble over a a very large time scale. We seem to be able to detect much more subtle changes going very far back with our current techniques.

Re: What’s the hottest the Earth’s ever been?

#29

Post by thatguy0900 »

dav_Oz wrote: post #18
samwillis wrote: post #12

Earlier quoted context omitted.

Trouble is most politicians are incentivised to think in the short term and are increasing just in a perpetual campaigning mode. They are thinking about their careers and re-election. They cannot except and talk about bad news, and a 3-5degC increase is bad news. On top of that you have had climate activists pushing for very large change to happen incredibly quickly (arguably needed). But it’s an incredibly hard sell…

Update after 2 years of 'crisis management': The social fabric of the western societies had been severely damaged. Trust in science is at an all time low. The absurdly rich are absurdly richer. Not few people are now flirting openly with the idea to simply abandon those bulky civil liberties of the 20th century (2nd half) in order to save the world in the long run. So, in order to satisfy 2. ("green washing") and 3.…

I don't know how fair it is to bring the last two years up. Our society was no closer in 2018 to solving climate change.

Re: What’s the hottest the Earth’s ever been?

#30

Post by CJefferson »

Helmut10001 wrote: post #10

It is strange why many politicians and countries (Germany included) appear to close their eyes and still promote or work on the 1.5 °C goal, which seems pretty unrealistic at this stage. Maybe it is to calm the public, besides knowing better. Instead, there is a need for more realistic plans to model and prepare for 3°C or 5°C increase of average temperature by 2060 (or 2100). Looking at these bigger swings in temper…

I can't imagine anything most countries could reasonably do to prepare for 5c, what type of things would you suggest?
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