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We Just Breached the 410 PPM Threshold for CO2

scientificamerican.com

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Re: We Just Breached the 410 PPM Threshold for CO2

#221

Post by akvadrako »

EGreg wrote: post #209
Turing_Machine wrote: post #178

Earlier quoted context omitted.

"Millions of years" is an eyeblink in the history of the earth. In fact, the CO2 level has been much higher than this level in the past (like, orders of magnitude higher). The earth was fine. And no, this isn't the era of the "highest disappearance of species". Not even close. https://en.wikipedia.org/wiki/Extinction_event

Regardless of all this, it's pretty clear what's causing this currently buildup of CO2. So why deny that man's activity is a major factor? As for "the earth will be fine": yes the planet will still be here, but will humans survive this? In the past, these changes were far more gradual, letting life adapt. As for "not even close", please show me a period when the rate of extinction was higher: https://en.wikipedia.org…

1. Historical temperature changes were often quite abrupt and of greater magnitude than our current one.

2. Life is anti-fragile, so I think you're really underestimating humans and animals in general if you think a few degrees is something we can't handle.

Re: We Just Breached the 410 PPM Threshold for CO2

#222

Post by DiThi »

akvadrako wrote: post #218
DiThi wrote: post #6

Earlier quoted context omitted.

Life on Earth will be fine. The problem is the survival of our own species. It heavily relied in ~15,000 years of stable climate to flourish, and we're cutting that stability short.

It's not a foregone conclusion that a stable climate is more conductive to a flourishing society than a challenging one. Northern Europe, Japan and North America are roughly the most developed areas on Earth. They also have some of the most natural disasters and harshest weather.

Two of these three have low dense population. And harsh weather in those areas are not indicative of how tough will climate change be. After all, it has been about as harsh since humans inhabited those. But climate may get worse all over the world. A lot of people will have to migrate from coastal cities, both rich and poor.

Re: We Just Breached the 410 PPM Threshold for CO2

#223

Post by gjm11 »

Turing_Machine wrote: post #197
mark-r wrote: post #190

Earlier quoted context omitted.

Yes, we'll be safe from the direct effects of CO2 increases. But the indirect effects could be much more severe. That's the interesting part of the problem, we don't have accurate models of all the side effects. Ecosystems are complicated and fragile.

"But the indirect effects could be much more severe." Or they could make things better. "That's the interesting part of the problem, we don't have accurate models of all the side effects." In fact, we do know that the CO2 level of the earth's atmosphere has been much higher in the past, and that this didn't produce anything like the "all life on earth dies" scenario that the doomsayers keep touting. "Ecosystems are c…

I think the "all life on earth dies" scenario is mostly a straw man. I mean, I'm sure there are some people speculating about such things and making comparisons with Venus, but so far as I can tell the overwhelming majority of people who are concerned about climate change are worried about much more modestly-bad scenarios.

So. Yes, the CO2 level has been much higher in the past. For instance, in the Cambrian period it was much higher than it is now. ... And, in the Cambrian, the surface temperature of the earth was about 7 degrees C higher than it is now.

As someone else remarked: no, "the ecosystem" did not survive the Chicxulub event. Life survived it, sure, but it wiped out the dinosaurs (other than the birds). That's kinda a big deal.

Re: We Just Breached the 410 PPM Threshold for CO2

#224

Post by hyperbovine »

shouldbworking wrote: post #207
35bge57dtjku wrote: post #131

Earlier quoted context omitted.

So because someone simply mentioned using a single chemical to cool the atmosphere, you assume that it would work and that it would work at a large enough scale to fix everything? That sounds like a textbook case of believing everything you hear.

It's well known that large volcanic eruptions have caused global cooling for a few years that's severe enough to lower the temperature of earths surface several degrees. I don't think anyone can deny that it's possible to cool the Earth by putting stuff in the upper atmosphere because we've already seen it happen during recorded history.

The Tambora phenomenon is well documented. But that does nothing to solve other problems like e.g. ocean acidification, and potentially causes many problems of its own. It's a really complex system and we need to spend way more time and money understanding it than we currently are.

Re: We Just Breached the 410 PPM Threshold for CO2

#225

Post by eveningcoffee »

mtempm wrote: post #165
eveningcoffee wrote: post #24

There is an aspect that is perhaps not very well communicated. Higher the environmental CO2 level, more of it you need to dilute the air in the confined environment (i.e. buildings) to the desired level. This means that you have to move more air that will require more energy directly but also indirectly through higher heating/cooling need. It will also decrease the comfort due to more tangible airflow.

I'm interested by your comment, but I can't figure out what you are intending to say. Why do you need to dilute CO2?

Mostly because you do not want to die into CO2 poisoning when inside. :)

Every building has some designed air change rate with the outside that will keep its habitants alive and comfortable. This can happen through so called natural ventilation or through controlled ventilation.

As far I know, the common standard for the commercial buildings is 800 ppm (parts per million (1)) CO2 in the air. It is assumed that this level of CO2 would on average provide environment where people do not loose their productivity due to the air quality.

This is what I mean by diluting - part of the CO2 rich air inside is replaced with the less CO2 rich air from the outside.

Because habitants are producing CO2 with some rate, you have to replace the air with the rate that can keep up with this CO2 production rate.

If the air outside has higher levels of CO2 then more of the replacement air is needed and the replacement rate must be higher to keep the projected inside CO2 levels.

Replacing air faster will require more energy.

Disclaimer: I am not a ventilation engineer, I just got interested of this topic during the home renovation.

(1) Air contains about 21% of oxygen that is 210000 ppm of it. It follows that when the air feels "stuffy", it is not due to lack of oxygen but due to too much CO2 in it.

Re: We Just Breached the 410 PPM Threshold for CO2

#226

Post by Turing_Machine »

burke wrote: post #206
Turing_Machine wrote: post #187

Earlier quoted context omitted.

Modding stuff down doesn't actually change the facts, you know. CO2 levels: http://www.geocraft.com/WVFossils/Carboniferous_climate.html The sources are all linked from this site. Note that the CO2 level in the Cambrian was around 7,000 ppm, or about 17 times the level that this article is having hysterics about. Note that even during the Jurassic (when there were plenty of large land animals and a flourishing ecosys…

* A CO2 level of 7kppm is not compatible with human flourishing. * Consensus is that the elevated CO2 levels of the Ordovician-Silurian and Jurassic-Cretaceous periods came on over tens or hundreds of thousands of years, not mere tens or hundreds. This gave life a chance to adapt. * Previous mass extinctions have been caused by things like complete ocean ecosystem collapse and massive asteroid impacts. Despite the fa…

"A CO2 level of 7kppm is not compatible with human flourishing."

Yes, that's higher than we would like. It's also 17 times higher than the level the original article is freaking out about.

"Consensus is that the elevated CO2 levels of the Ordovician-Silurian and Jurassic-Cretaceous periods came on over tens or hundreds of thousands of years,"

Link to this "consensus"? Thanks.

"it is certainly noteworthy and a little horrifying that it's reached a scale that comparison is meaningful."

Anything can be "compared". Did you look at the chart in the Wikipedia article? The current extinction rate isn't even a blip.

"The Earth will obviously be fine; I don't think any reasonable person will argue this point."

Really? So I've just been imagining all the people who are worried about turning the Earth into Venus? I mean, I agree that these people are unreasonable, but there certainly are a lot of them.

Re: We Just Breached the 410 PPM Threshold for CO2

#227

Post by Turing_Machine »

IanCal wrote: post #213
Turing_Machine wrote: post #195

Earlier quoted context omitted.

"The death of millions would be a statistical blip in geological timescale." Well, I actually do care about people. So, there's that. "In 1998, over 75% of the total area of the country was flooded, including half of the capital city Dhaka. ... 30 million people were made homeless and the death toll reached over a thousand." That's sad, all right. How many routinely died in famines before the advent of modern, high-e…

"Reducing energy consumption" does not mean nobody can use tools from post 1800, and it also doesn't mean that nobody can help after a drought. There's even a quote in your link describing it as a man made famine.

"Reducing energy consumption" does not mean nobody can use tools from post 1800

Until you actually demonstrate functional and economic alternatives, that is exactly what it means.

Re: We Just Breached the 410 PPM Threshold for CO2

#228

Post by Turing_Machine »

snowwrestler wrote: post #202
Turing_Machine wrote: post #197

Earlier quoted context omitted.

"But the indirect effects could be much more severe." Or they could make things better. "That's the interesting part of the problem, we don't have accurate models of all the side effects." In fact, we do know that the CO2 level of the earth's atmosphere has been much higher in the past, and that this didn't produce anything like the "all life on earth dies" scenario that the doomsayers keep touting. "Ecosystems are c…

The ecosystem did not survive the Chicxulub event. "Ecosystem" is not shorthand for "life exists on Earth somewhere." An ecosystem is a particular state of the dependencies between life forms. The ecosystem that existed before the big asteroid strike was thoroughly and rapidly destroyed; a new ecosystem developed afterward. That's fine from a general "life finds a way" perspective, but it sucked for the sauropods, wh…

By your definition "the ecosystem" never "survives", because it has been in a state of constant change since life first developed on earth.

"What do you think it's going to be like when about a billion people have to migrate inland due to sea level rise?"

Considering that even the worst-case doom-crying scenarios issued by the IPCC predict a sea level increase of the order of 1 meter over the period of a century (i.e., ~1 cm per year), your (and Hollywood's) suggestion of rioting mobs fleeing the tsunami-like rising ocean is just not based in reality.

Re: We Just Breached the 410 PPM Threshold for CO2

#229

Post by EGreg »

akvadrako wrote: post #221
EGreg wrote: post #209

Earlier quoted context omitted.

Regardless of all this, it's pretty clear what's causing this currently buildup of CO2. So why deny that man's activity is a major factor? As for "the earth will be fine": yes the planet will still be here, but will humans survive this? In the past, these changes were far more gradual, letting life adapt. As for "not even close", please show me a period when the rate of extinction was higher: https://en.wikipedia.org…

1. Historical temperature changes were often quite abrupt and of greater magnitude than our current one. 2. Life is anti-fragile, so I think you're really underestimating humans and animals in general if you think a few degrees is something we can't handle.

I think you need to prove both these assertions. They are quite startling responses to "we have produced a quick rise to the most CO2 in millions of years" or "we have seriously damaged the biodiversity of large animals on this planet". It's as if someone said "we set the entire rainforest ablaze" and someone said "Relax! Nothing to worry about, this happened a few times naturally in the history of the Earth."

Can you at least admit that humans are behind this rise in CO2? I mean, it's not like wind and solar energy generation is going to kill the economy. So why is this even debated so much?

Re: We Just Breached the 410 PPM Threshold for CO2

#230

Post by saalweachter »

mark-r wrote: post #182
saalweachter wrote: post #89

Earlier quoted context omitted.

Why is there still a pop culture cliche of weathermen being terrible at their job? Precipitation forecasts are usually accurate several days out and temperature forecasts are good a week or two out, in my experience. If I want to know if it's going to rain on Saturday I check the weather on Thursday and it's usually right. When there's a big storm comin', a local meteorologist does rolling updates with the latest dat…

Yes they're usually right about whether it's going to rain or not, but often they're completely wrong about how much it's going to rain. They can tell you whether tomorrow will be warmer or colder than today, but the exact temperature still eludes them. Since the whole climate debate is about a matter of degrees, it's natural to be skeptical.

I'm also pretty satisfied with the forecasts on those numbers as well, within the bounds of what is reasonable to forecast. During big events, snowstorms and hurricanes, the local meteorologist will break the area I'm in into ~7 regions and give guidance like 'zones 5-7 will get 3-6" of snow, zones 1&2 12-18"' or '3-4 inches of rain north of 84'.
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