Climate Change Thread

[a completely inoffensive name]

Wait arent cows also part of the cycle that nullifies human co2 production?

What cycle nullifies human CO2 production?

Cows generate methane, which is more potent as a greenhouse gas than CO2. The CO2 removed to grow the food for the cows becomes a net negative since it is converted to large amounts of methane.

[Fragony]

Take longer periods, you will see nothing weird

[Greyblades]

What cycle nullifies human CO2 production?

I was referring to CO2 produced through breathing, as you had just said:

The carbon that is exhaled is cycled, not added to the atmosphere as that carbon is taken from the atmosphere to begin with to become the food we eat...

I wondered why there isnt a cycle for methane, considering that there has almost certainly been methane production on the same scale as our current cow population throughout the planet's history (somehow I dont believe that dinosaurs didnt have similar bodily functions as modern bovine.) That earth hasnt turned into mars from it indicates there must be some countering force.

[Viking]

That earth hasnt turned into mars from it indicates there must be some countering force.

I presume you mean Venus, although Venus has an atmosphere of 96% carbon dioxide.

[Greyblades]

I thought we were talking methane.

[Viking]

Yes, and you seemed to be asking why the earth doesn't have more methane than it does. If methane could just accumulate, the planet would get hotter and hotter and thus more similar to Venus; which is a planet with a very strong greenhouse effect. Mars, on the other hand, is a very cold place.

[HopAlongBunny]

Climate change is not really at issue; with 90+% of scientists agreeing, that's about as settled as you get.
The issue is "pay now or pay later".
There will be a cost to moving from fossil fuels to renewables; offset over time by reductions in health care and expanding tech, engineering and infrastructure opportunities.
Or we pay later in damage control; war, famine and (perhaps) massive human migration. These things all exist...it's just a matter of scale...

[Husar]

Methane is not stable in the atmosphere, and is converted into carbon dioxide in 8-9 years on average (it's also vulnerable to UV radiation, which is why its discovery on Mars is interesting):
http://www.giss.nasa.gov/research/fe...00409_methane/

Thus, the direct effect of this methane should not last long as it comes from a storage that will deplete.

So we try to cshock-release all the methane at once by heating the earth as fast as possible and then wait 8-9 years until we're all crisp and the methane is gone again? Surely the people and plants in Africa, India, China, South, Central and North America, Southern Europe etc. could survive a mere 8-9 years of hellish desertification without whining too much about not having any food or water.

I wondered why there isnt a cycle for methane, considering that there has almost certainly been methane production on the same scale as our current cow population throughout the planet's history (somehow I dont believe that dinosaurs didnt have similar bodily functions as modern bovine.) That earth hasnt turned into mars from it indicates there must be some countering force.

Quite a few things were different back then, there was also more oxygen in the atmosphere and insects could grow much larger due to that.
Are you saying that you'd want to revert to a time where spiders groiw so large that they could eat you?

Also here: http://www.livescience.com/44330-jur...n-dioxide.html

There is one thing to keep in mind though: A lot of natural changes are very slow, giving living things centuries to adapt in most cases. Sudden changes on the other hand often lead to extinction, such as that of the dinosaurs. The graph in the OP nicely demonstrates that this could be a comparatively fast change that we are looking that. Now imagine that a lot of the plants and animals we rely on for food just die out because they can't handle the changes so fast. That we have air conditioning is useless if all the crops and trees die because the bees succumbed to the heat for example... (fictional example, I'm not sure which temperature changes would be required to kill off which species, but coral reefs die now already)

[Greyblades]

I dont need to be persuaded over global warming, it's the cows methane being a great contributor I have problems getting my head around; there must be a way that methane has been extracted from the atmosphere otherwise we'd already be at venus levels after ~3.5 billion years of buildup.

[Legs]

I dont need to be persuaded over global warming, it's the cows methane being a great contributor I have problems getting my head around; there must be a way that methane has been extracted from the atmosphere otherwise we'd already be at venus levels after ~3.5 billion years of buildup.

Perhaps the thing with cows is the intensification/industrialisation over the past century.

[Viking]

there must be a way that methane has been extracted from the atmosphere otherwise we'd already be at venus levels after ~3.5 billion years of buildup.

The stability of methane in the atmosphere is explained in post #13. That means that if you want more methane in the atmosphere, you need more sources of methane, which more cows may represent.

[Fragony]

Can I say something that sounds really nasty, stop helping people who are overbreeding. Most sibblings used to die but science caught up and most survive. And need recourses.

[Seamus Fermanagh]

meant to reply to this yesterday but got caught up.

Yes, the exhale thing is already part of the cycle so to speak. The real greenhouse burden is the sheer number of humans and their concomitant desire for power and services.

My key points really boiled down to:

1) the predicted heat levels are not going to scour life from the planet or eliminate biodiversity. Earth has be much hotter in the past and still had a rich variety and breadth of life forms (source of those fossil fuels as you will recall). I will stipulate that a large "die-off" among current species would engender problems for human beings, it is just that the real doom-and-gloomers (we are killing the planet types) are a bit off base.

2) efforts to ameliorate the anthropomorphic warming that is part of the current up cycle (see this source are warranted, but that our primary response will have to be adaptation to a new normal.

Consider:

In 1900, which a number of sources point to as the last point in history when human greenhouse impact was clearly within the carrying capacity of the planet, humans consumed approximately 50 exajoules of energy from various sources, the bulk of which were non-fossil. Our current consumption is about 550 exajoules (source). In that time span, world population totals have gone from roughly 2 billion to 7.4 billion. Thus our energy consumption per capita has more than tripled.

Trying to take the Earth back to that "carrying capacity" point (and yes it is arguable, but I needed some baseline) would require that we collectively stop the use of 90% of the world's current power use or replace that power use with non-fossil sources (or some combination of both).

Replacement has a LONG way to go also, since non-fossil sources are being used for only 130 exajoules or so of that 550. Worldwide, solar power constitutes less than 60 gigajoules (and remember that giga is 10 to the 9th, whereas exa is 10 to the 18th). Hydropower and nuclear sources constitute no more than 75 exajoules (non-fossil biofuels making up the rest of the 130 exajoule figure noted above).

ALL of the non-fossil alternatives are substantially more costly than the fossil fuels in terms of power generation. A coal-fired power generation plant is cheap in relative terms.


NOT saying we cannot make an impact in the warming trend -- we have already, so we can clearly do so in the other direction -- but the current crop of solution ideas our there (more government control, economic cutbacks, punish the fossil energy companies) can't do more than slow the trend moderately. So yes, we must start and continue to reduce our production of greenhouse gasses, particularly the more persistent forms.

We will have to grow ourselves out of this -- the growth of our species signals the need for MORE, not less power consumption. Solar delivered through our atmosphere is a nothing, so how do we get the unadulterated stuff down here for our use? Fission is useful, but though it's waste is a small amount, the radiation concerns are lengthy ones, can we make fusion practical before my son is old and gray? Can we rework our aging agriculture irrigation systems to be power generating systems at the same time? Maybe Tesla was correct and we have merely to tap into the existing energy that is the earth itself?


In short:

We are too far along in this trend to shift it's direction fast enough to avoid significant consequences. SO, make the necessary adaptations.

Curtailment of energy uses is at best a limited response, though we should convert more and more to non-greenhouse sources as resources allow.

Something "new" will have to be created to truly solve the problem.