climate change

[welshbairn]

As a non scientist or mathematician there's a great programme about how they calculate climate change on BBC 4 at the moment: Climate Change by Numbers. Good on general statistics too. Bit Open University but worth a watch. Available at all BBC I players near you.

Edited March 2, 2015 by welshbairn

[dorlomin]

Climate change: 2015 'shattered' global temperature record by wide margin

why did no one say this could happen.

[Miguel Sanchez]

Boy this thread is depressing

[Nkomo-A-Gogo]

Needs more pictures of skinny polar bears.

Its easy to get dramatic pictures of big cliffs of ice falling into the sea but not so interesting to watch them slowly forming. Couldnt really care less about climate change tbh. If it means a quicker end to the human race then bring it on.

[Central]

 

[dorlomin]

Weather buoy near North Pole hits melting point

https://www.washingtonpost.com/news/capital-weather-gang/wp/2016/12/22/weather-buoy-near-north-pole-hits-melting-point/?utm_term=.1b1640a67771

 

 

Weather not climate and all that but still. 

[banana]

Snow falls in the Sahara for the first time since 1979.

http://www.businessinsider.com/snowfall-in-sahara-desert-photos-2016-12

Weather not climate and all that but still.

[RadgerTheBadger]

There's no such thing as climate change, there's only nature

[Miguel Sanchez]

What a meeting of the minds we have here. I guess we can all just give up on the concept of scientific research.

[dorlomin]

On 24/12/2016 at 09:56, banana said:

Snow falls in the Sahara for the first time since 1979.

 

Weather not climate and all that but still.

Morocco has a ski resort

http://www.completemorocco.com/activities/skiing 

Thought that is not in the actual Sahara. It did happen in the Sahara in 2005 and 2012

https://weather.com/news/weather/news/snow-blankets-sahara-desert-sands-in-algeria

In winter it gets cold enough to snow at altitude in the Sahara, its just usually too dry for precipitation. 

 

[banana]

31 minutes ago, dorlomin said:

In winter it gets cold enough to snow at altitude in the Sahara, its just usually too dry for precipitation.

Four days for someone to pick up on that, utterly disgusting.

[Zetterlund]

I've never quite understood what the skeptics' argument is. Given that the spike in CO2 levels since the industrial revolution is a measurable fact, is the argument that it isn't man-made, or that it doesn't affect temperatures? 

If the former, I'd be interested to hear other theories about what has caused the rise, given the scale of its break from the normal cycles going back hundreds of millennia.

[banana]

2 minutes ago, Zetterlund said:

I've never quite understood what the skeptics' argument is. Given that the spike in CO2 levels since the industrial revolution is a measurable fact, is the argument that it isn't man-made, or that it doesn't affect temperatures? 

If the former, I'd be interested to hear other theories about what has caused the rise, given the scale of its break from the normal cycles going back hundreds of millennia.

There are various arguments on all sides, mostly hard to follow as laymen as they quickly turn into chains of very precise scientific points and counterpoints with various hard-to-decipher/tunnel vision graphs and an seemingly endless stream of variables and terminology.

The CO2 thing is about how much of an affect humans have on the amount of global CO2, and the amount of effect CO2 has on 'global' temperatures (even this is a somewhat controversial topic - how do you measure a 'global' temperature?), or whether rises in CO2 are in itself an effect of temperature rises rather than a cause (i.e. correlation rather than causation), etc etc etc. CO2 levels have at periods in history been higher than now, with colder temperatures (or something along those lines), and I think also the opposite (lower -> warmer).

Controversy also centers around the variety of models used, with skeptics claiming like all models they can be adjusted to get the results you want/expect.

It's also very political, so there's a fair amount of bullshit flying around on all sides.

My suggestion is to go onto YouTube and find some debates from climate scientists. They will be hard to follow, inconclusive, and both sides will have seemingly strong and weak parts of their case, which should be a reasonable indication that propaganda memes like '97% of scientists agree!' aren't all they're cracked up to be.

Have fun down the rabbit hole.

[Zetterlund]

1 hour ago, banana said:

There are various arguments on all sides, mostly hard to follow as laymen as they quickly turn into chains of very precise scientific points and counterpoints with various hard-to-decipher/tunnel vision graphs and an seemingly endless stream of variables and terminology.

The CO2 thing is about how much of an affect humans have on the amount of global CO2, and the amount of effect CO2 has on 'global' temperatures (even this is a somewhat controversial topic - how do you measure a 'global' temperature?), or whether rises in CO2 are in itself an effect of temperature rises rather than a cause (i.e. correlation rather than causation), etc etc etc. CO2 levels have at periods in history been higher than now, with colder temperatures (or something along those lines), and I think also the opposite (lower -> warmer).

Controversy also centers around the variety of models used, with skeptics claiming like all models they can be adjusted to get the results you want/expect.

It's also very political, so there's a fair amount of bullshit flying around on all sides.

My suggestion is to go onto YouTube and find some debates from climate scientists. They will be hard to follow, inconclusive, and both sides will have seemingly strong and weak parts of their case, which should be a reasonable indication that propaganda memes like '97% of scientists agree!' aren't all they're cracked up to be.

Have fun down the rabbit hole.

I'm familiar with much of the science for man-made climate change and find it convincing. I've just always found the skeptic side very unscientific and not based on any countering evidence of its own - rather it seems to consist of attacking the credibility of the other side and their models etc.

I don't approach it from any kind of political or ideological angle myself and can be swayed by any new evidence. I don't think there can be much debate that the leap in CO2 in the last 150 years is man-made, considering how far above the normal range it has spiked in such a short time and how much we know we pump out. So the remaining argument is that CO2 levels don't affect the temperature/climate, and I'm not sure if there's much out there supporting this.

[banana]

Suggest again to watch some debates on Youtube, and read back and forth articles/comments sections on sites such as:

Skeptic:

• http://realclimatescience.com
• https://wattsupwiththat.com

Counter-skeptic:

• https://skepticalscience.com/

The best back and forth seems to happen on Watts site including various climate scientists doing actual research, though the comments section is still quite echo-chambery in favour of skepticism.

[dorlomin]

2 hours ago, banana said:

CO2 levels have at periods in history been higher than now, with colder temperatures (or something along those lines), and I think also the opposite (lower -> warmer).

Main sequence, hydrogen burning stars get warmer as they age. This is because as hydrogen is burnt into helium, the helium is twice and dense, this increases the density of the core burning hydrogen faster. Running this back in time, astronomers noticed that very quickly we would expect to see the Earth get a lot colder yet there were periods it was clearly warmer. This was called the "faint young Sun paradox". 

Dana Royer has done a lot of working mapping the linkage between CO2, solar luminosity and global temperature

 

Quote

Atmospheric CO2 is positively correlated with globally averaged surface temperatures for most of the Phanerozoic. This pattern has been previously shown at coarse 10-million-year timescales and is demonstrated here at finer resolutions (one million to five million-year timescales). The two longest-lived Phanerozoic glaciations during the Permo-Carboniferous and late Cenozoic are the only  Phanerozoic intervals associated with consistently low levels
of CO2 (<500 ppm). This pattern supports predictions
from global climate models for a CO2-ice threshold of
560–1120 ppm (DeConto and Pollard, 2003; Pollard and
DeConto, 2005).

http://droyer.web.wesleyan.edu/PhanCO2(GCA).pdf

 

Higher CO2 levels in the deep past (older than 65 million years ago) helps explain a major puzzle linking astrophysics with our understanding of paleoclimate. 

In 2009 professor Richard Alley produced an hour long seminar to the AGU on the state of paleoclimate research, anyone interested can listen here. 

 

 

Edited December 28, 2016 by dorlomin

[dorlomin]

11 minutes ago, banana said:

The best back and forth seems to happen on Watts site including various climate scientists doing actual research, 

Watts is a moron with no clue about high school level physics. 

His website is chock full of conspiracy theories and discredited predictions of imminent ice ages, proclomations of Earth shattering new theories that get swept under the carpet and an outlet for every garden-shed Galileo that thinks you do science by writing blog posts. 

[RadgerTheBadger]

The only people who are causing problems to the climate are the ones that aren't letting nature take its course

[LongTimeLurker]

3 hours ago, Zetterlund said:

I've never quite understood what the skeptics' argument is. Given that the spike in CO2 levels since the industrial revolution is a measurable fact, is the argument that it isn't man-made, or that it doesn't affect temperatures? 

It tends to revolve around whether CO2 levels are the main driver of global mean temperature or not. What complicates matters is that the intensity of sunlight isn't a fixed constant and water vapour rather than CO2 is the main greenhouse gas in the atmosphere and cloud formation can reflect away incident sunlight as well as promoting a greenhouse effect. Be wary of anybody that claims to know all the answers on this stuff, because the models that have been developed don't work that well.

[dorlomin]

49 minutes ago, LongTimeLurker said:

It tends to revolve around whether CO2 levels are the main driver of global mean temperature or not.

There is no debate. CO2 is the primary driver of recent temperature rises. In the Earths climate history CO2 acts as a feedback to Milankovitch\orbital forcing, that is the changes to the Earths orbit that pace the glacial\interglacials. Some vested interests try to use this to manufacture the illusion of a debate. 

Quote

What complicates matters is that the intensity of sunlight isn't a fixed constant

Variation in solar intensity over hundreds and thousands of years is of very little consequence when compared with the currently observed changes in CO2. 

One can map TSI (total solar intensity against recent temperature changes

 

TSI here for pre 1979 is inferred from sunspot activity from Kirova et al 2009, after 2009 it is taken from satellite data. 

Compare with CO2 vs temperature. 

 

 

 

Quote

and water vapour rather than CO2 is the main greenhouse gas in the atmosphere

H2O is a condensing gas in the atmosphere, that is the amount of H20 the atmosphere can hold is determined by its temperature. This is a very well known phenomina, its a damn site more humid when its warm that cold. This is called the Clausius Clapeyron Relation. This means that as it cools in the evening or as it cools towards water vapour will condense out of the atmosphere. It cannot drive a change in temperature, only act as a feedback. CO2 does not condense out, the natural CO2 cycles act on the scale of thousands to hundreds of thousands of years, these can affect global temperature, for example when there is one of the rare large igneous provinces are created. These are gigantic volcanic events that create enough lava to cover all of Britain or larger i.e. the Siberian Traps. 

 

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

 

Quote

 cloud formation can reflect away incident sunlight as well as promoting a greenhouse effect. 

Couple of argument jump straight to mind. Firstly the fastest warming places on Earth are the high northern latitudes, these have not shown any weird sudden drops in clouds. But these are expected to be the fastest warming places when the Earth is warmed by an enhanced greenhouse effect.

The other is the "greenhouse effect fingerprint" that was predicted by Manabe and Weatherald 1967, this paper predicts that as the troposphere warms from more CO2, the stratosphere will cool. This has been observed.

 

(image from https://www.star.nesdis.noaa.gov/star/smcdTeam_StratosTemp.php  )

 

There is a mountain of evidence to support CO2 as the primary driver of currently observed climate change. Some of it very technical and other parts make easy to understand graphics. People can hand wave and make vague claims about "but clouds" or "but how can we be sure". Virtually all of the worlds leading science academies endorse the over all picture. 

Quote

Be wary of anybody that claims to know all the answers on this stuff, 

Since no one claims to know all the answers, this is a strawman. But we have the basics. its based on physics that goes back to the early 19th century in many places. Vacuous handwaving and insinuation is not an argument. It is just a thinly veiled conspiracy theory. 

Edited December 28, 2016 by dorlomin