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Earth at risk of becoming 'hothouse' if tipping point reached, report warns

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Re: Earth at risk of becoming 'hothouse' if tipping point reached, report warns

#21

Post by fallingfrog »

i6mi6 wrote: post #13
mapleoin wrote: post #9

Earlier quoted context omitted.

https://www.eea.europa.eu/data-and-maps/indicators/global-an... > According to different observational records of global average annual near-surface (land and ocean) temperature, the last decade (2008–2017) was 0.89 °C to 0.93 °C warmer than the pre-industrial average, which makes it the warmest decade on record. Of the 17 warmest years on record, 16 have occurred since 2000. The year 2017 was one of the world’s thre…

But 100-200 years is very little time for comparison isn't it? Is there any presumed data on what it was before that?

Now, it's kind of silly to keep asking HN people to google things for you. But:

https://en.wikipedia.org/wiki/Geologic_temperature_record#/m...

Re: Earth at risk of becoming 'hothouse' if tipping point reached, report warns

#22

Post by zerealshadowban »

mapleoin wrote: post #9
i6mi6 wrote: post #5

I don't know, I've seen what temperatures have been in the past decade in Europe and I can tell that it doesn't get any hotter, in fact, it could be getting colder. Can anyone show some statistics supporting the global warming? Edit: I know how to google myself but I am asking people to get a little more involved and not lay out facts out of memory. I thought I could make a good discussion on the topic but kept getti…

https://www.eea.europa.eu/data-and-maps/indicators/global-an... > According to different observational records of global average annual near-surface (land and ocean) temperature, the last decade (2008–2017) was 0.89 °C to 0.93 °C warmer than the pre-industrial average, which makes it the warmest decade on record. Of the 17 warmest years on record, 16 have occurred since 2000. The year 2017 was one of the world’s thre…

What exactly is "the pre-industrial average"? does that correspond to the Little Ice Age? why is that a good reference point, or baseline for comparison?

https://en.wikipedia.org/wiki/Little_Ice_Age

Re: Earth at risk of becoming 'hothouse' if tipping point reached, report warns

#23

Post by _Codemonkeyism »

0xfaded wrote: post #12
rntz wrote: post #6

> "hothouse" temperatures could stabilize 4°C to 5°C (39 to 41 Fahrenheit) higher than pre-industrial levels. A change of 4-5°C is a change of 7-9 degrees Fahrenheit, not 39-41.

Lol, looks like the Google result of "convert 4C to Fahrenheit". In the authors defence, it isn't their fault the Americans still use Fahrenheit.

Wasn't 100 Fahrenheit the temperature of a chicken on tuesday in the sunshine? Can't quite remember how that scale was created.

Re: Earth at risk of becoming 'hothouse' if tipping point reached, report warns

#24

Post by AndrewDucker »

i6mi6 wrote: post #13
mapleoin wrote: post #9

Earlier quoted context omitted.

https://www.eea.europa.eu/data-and-maps/indicators/global-an... > According to different observational records of global average annual near-surface (land and ocean) temperature, the last decade (2008–2017) was 0.89 °C to 0.93 °C warmer than the pre-industrial average, which makes it the warmest decade on record. Of the 17 warmest years on record, 16 have occurred since 2000. The year 2017 was one of the world’s thre…

But 100-200 years is very little time for comparison isn't it? Is there any presumed data on what it was before that?

Loads: https://en.wikipedia.org/wiki/Global_temperature_record

Do bear in mind that most of the costs of global warming are based around:

1) It is happening much faster than we can cope with. If it was happening over 10,000 years then we'd slowly adapt. Or die out. One or the other.

2) Our cities are mostly built on coastlines, and will therefore be hit dramatically by severe weather and by sea rises.

Re: Earth at risk of becoming 'hothouse' if tipping point reached, report warns

#25

Post by _Codemonkeyism »

_juu5 wrote: post #20
martythemaniak wrote: post #14

Earlier quoted context omitted.

People blaming governments and corporations are merely using faceless scapegoats because the truth is too terrible to behold. Normal every day people don't really believe in climate change, don't really want to do anything and in fact don't have the dimmest clue as to what needs to be done, nor how to do that. I think dealing with the above fact is too much for people, so instead we simplify using familiar models and…

Education would be a good start. Guess who can decide about what we are taught? Governments.

People know their personal largest impact is cars and meat. But personal convenience has always beaten doing the right thing.

Re: Earth at risk of becoming 'hothouse' if tipping point reached, report warns

#26

Post by megaman22 »

rntz wrote: post #6

> "hothouse" temperatures could stabilize 4°C to 5°C (39 to 41 Fahrenheit) higher than pre-industrial levels. A change of 4-5°C is a change of 7-9 degrees Fahrenheit, not 39-41.

Pre-industrial levels when we were still coming out of significant cooling period. In every other period of human history, increased average temperatures have coincided with golden ages. Depending on where you peg your baseline for what "normal" temperatures are, the projections can look more or less scary.

https://en.wikipedia.org/wiki/Roman_Warm_Period

https://en.wikipedia.org/wiki/Medieval_Warm_Period

I'm suspicious of anyone attempting to boil down the operations of such a dynamic, chaotic system as climate into simple cause and effect. There's so damn many things that feed back on each other, and that's just the tip of the iceberg that we think we understand. Much more research needs to be done.

Re: Earth at risk of becoming 'hothouse' if tipping point reached, report warns

#27

Post by m_mueller »

I'm worried that this could be just 'the tip of the iceberg' [1]. I have a suspicion that even J. Hansen is still underestimating the issue. Just looking at [2] the variability of current estimates of stored methane is enormous - going from 10E2 to 5x10E4 Gigatonnes! Methane does greenhouse forcing 20-25x as strong as CO2 over 100 years, or as much as ~160x if you only count 10 years. Depending on how fast methane gets released this really matters - if the released methane triggers more methane to come out through warming we may be in big trouble, even without burning all coal, oil and gas reserves currently known.

Further reading concerning methane: [3], [4].

Reason why dismissing this using PETM boundary is probably invalid: There was with high certainty less methane around since PETM didn't immediately follow a cold high-storage period, solar energy was also weaker, and most importantly, PETM was caused by methane alone, not a combination of fossil fuel burning in addition to methane [5].

Just to clarify: If we get the effects of PETM alone, this means around +8C global average on top of what we're doing. But from what I'm reading, PETM effects are not the whole story as pointed out above. Not that it really matters, +10-12C global average is almost certainly a global killer alone (except bacteria), it's just that I don't think it would stabilise there, it would go on to pressure cook earth's surface until absolutely nothing is left.

This stuff has me worried by far the most, especially for my now 2yo son.

[1] https://www.kairoscanada.org/wp-content/uploads/2011/12/PBP2...

[2] http://oceanrep.geomar.de/30683/1/GasHydrates_Vol1_screen.pd...

[3] https://www.sciencedirect.com/science/article/pii/S187661021...

[4] http://science.sciencemag.org/content/327/5970/1246

[5] http://www.columbia.edu/~jeh1/mailings/2013/20130415_Exagger...

Re: Earth at risk of becoming 'hothouse' if tipping point reached, report warns

#28

Post by jsjohnst »

megaman22 wrote: post #26
rntz wrote: post #6

> "hothouse" temperatures could stabilize 4°C to 5°C (39 to 41 Fahrenheit) higher than pre-industrial levels. A change of 4-5°C is a change of 7-9 degrees Fahrenheit, not 39-41.

Pre-industrial levels when we were still coming out of significant cooling period. In every other period of human history, increased average temperatures have coincided with golden ages. Depending on where you peg your baseline for what "normal" temperatures are, the projections can look more or less scary. https://en.wikipedia.org/wiki/Roman_Warm_Period https://en.wikipedia.org/wiki/Medieval_Warm_Period I'm suspicio…

> Much more research needs to be done.

Yet the current US stance is to defund such research. :(

Re: Earth at risk of becoming 'hothouse' if tipping point reached, report warns

#30

Post by skywhopper »

i6mi6 wrote: post #13
mapleoin wrote: post #9

Earlier quoted context omitted.

https://www.eea.europa.eu/data-and-maps/indicators/global-an... > According to different observational records of global average annual near-surface (land and ocean) temperature, the last decade (2008–2017) was 0.89 °C to 0.93 °C warmer than the pre-industrial average, which makes it the warmest decade on record. Of the 17 warmest years on record, 16 have occurred since 2000. The year 2017 was one of the world’s thre…

But 100-200 years is very little time for comparison isn't it? Is there any presumed data on what it was before that?

Plenty if you care to look. See https://en.wikipedia.org/wiki/Global_temperature_record for more recent temperature evidence on the scale of a few thousand years, and https://en.wikipedia.org/wiki/Geologic_temperature_record for geologic evidence of temperature patterns over the past half-billion years.

This graph shows just how far off the norm we are for the past two millenia:

https://en.wikipedia.org/wiki/Global_temperature_record#/med...

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