Hot answers tagged

38

Your question about water vapour is quite a common one among people learning about the greenhouse effect. Once you discover the relevant proportions of water vapour and CO2 in the atmosphere, it's perhaps natural to assume that the CO2 can't be playing a major role. In reality it doesn't work like this, for at least a couple of reasons. First, let's look at ...


14

Photosynthesis increase in the northern hemisphere spring, especially in the Siberian Taiga, and carbon dioxide decrease in atmosphere. During autumn and winter, decomposition of plant material and increased combustion, bring more carbon dioxide to the atmosphere. Measurements from e.g. the South Pole shows the same pattern, but much less and in opposite ...


12

Yes, according to this paper in the Proceedings of the National Academy of Sciences. But they also say that this "lake" of liquid CO2 is covered by CO2 clathrate, so it's not quite your average brine pool. Note about clathrates: The following image is from the Wikipedia article on CO2 clathrate. It is a CO2 hydrate P-T phase diagram with experimental data (...


12

Here is the mass-calculation. We will consider a column of the atmosphere with a footprint of 1m × 1m. This column weighs about 10,000 kg (per square metre). In these days of climate change we will assume the current average CO2 concentration is 400 ppm, yielding a total mass of CO2 in this column of 4 kg. The rain doesn't wash out the entire thickness of ...


11

Experiments don't necessarily prove things, per se; and in particular, a single experiment tends not to prove anything - at the very least, replication of the experiment is required. Experiments provide contributory evidence. Confidence in a hypothesis can come about from a combination of theory, lab experiments and natural experiments. Our knowledge about ...


9

Diamonds are expensive. Really expensive. Even "cheap" synthetic diamonds are orders of magnitude more expensive than conventional fossil fuel. By using them as fuel, you will increase demand, thus increasing their price even more. And synthetic diamonds have to be made somehow, and you need energy for that. Diamonds burn, but they don't burn well. For ...


7

The short answer to your question really is just this: Yes, CO2 causes global warming. There are many resources out there on the internet that explain this in about as much detail as you can tolerate, and whatever we could answer here does not come close to what others have already collected. I would suggest you start at the wikipedia page on global warming ...


7

The short answer is that most of the Earth's original allotment of CO2 got locked up in various carbonate minerals, largely calcite (limestone, marble, and chalk). According to this article there is currently ~800 gigatons of carbon in the atmosphere today; there is ~39,000,000 gigatons of carbon locked up in calcite minerals. All that carbon was once in ...


7

Earth travels along its orbit at about 30km/s. If you plug that number into a time dilation calculator, you'll find that one second on Earth passes every 1.0000000050069 seconds in a Sun-centric reference frame. Carbon-14 dating is good only to about 40,000 years into the past; Earth's time dilation would reduce that 40,000 years by a little under two hours,...


7

One of the consequences that I find more fascinating with the increased CO2 problem is the changes that affect specific components of the environment. One example that I like is the effect on poison ivy. Researchers at Duke University (Mohan et al., 2006), as part of their Free-Air CO2 Enrichment (FACE) experiment, reported a large change in poison ivy ...


6

You have the right idea, but you have your units and orders of magnitude confused. You have started with knowing that Canada has 34 million people, and emits 0.55Gt - i.e. $0.55 \times 10^9$ tonnes - per year. Now rather than just using those figures, think about the units that you have, and the units that you've been asked to give the answer in. How many ...


6

Schneider von Deimling et al. in Estimating the near-surface permafrost-carbon feedback on global warming Biogeosciences, 9, 649–665, 2012 evaluated carbon dioxide and methane release under four senarios, the worst being RPC8.5. Under RPC8.5, they calculated release of carbon from permafrost through 2100 of 63 gigatons (Gt) as CO2 and 0.5Gt as methane. ...


6

If you increase CO2 concentration and keep all other parameters at there current level, then biomass production should go up. The reason is simply that CO2 is one of the building blocks biomass is made of in photosynthesis. In the real world it's trickier than that of course. Here you have to take into account how natural cycles will be affected by ...


6

To see why we can't perform an experiment in lab conditions to verify the greenhouse effect, we need to start by considering how the [rather badly named] greenhouse effect operates: The Earth is in (to all intents and purposes) a vacuum, so it can only gain or lose heat via radiation. The sun emits most of its radiation at visible and UV wavelengths. The ...


6

The Faint Young Sun Paradox - how greenhouse gases can keep a planet warm: When the Earth formed 4.5 billion years ago the Sun was around 30% less luminous than it is today and it has increased steadily since, based on well established models of solar evolution. Simple energy balance models of the Earth show that, with a similar atmosphere to today, the ...


6

Instead of using sodium bicarbonate why not use limestone instead? Limestone is already used on an industrial scale to neutralise acids and acidic solutions. Also, sodium bicarbonate needs to be manufactured, whereas limestone just needs to be dug up. The manufacturing of sodium bicarbonate would unnecessarily use energy and potentially create more carbon ...


6

So where did it go? Carbon was never there (or here) to begin with. You need to look at this from the opposite way. By asking "where did it go" you assuming the Earth was here first, with carbon, and then the carbon was removed somehow. But, Earth formed from a gaseous solar nebula that had all the elements. As the Earth-forming materials started ...


5

If you accept GE's estimate of the number of global fossil fuel power plants ( 17,500 ) and compare it to the number of CCS projects out there ( 22 ), you get roughly 0.1 %. The Global CCS Institute released its 2014 annual report; The world’s first large-scale carbon capture and storage (CCS) project in the power sector commenced operation in ...


5

The difference is that a carbon sink accumulates carbon, whereas a carbon reservoir has accumulated carbon. That is to say: A carbon sink is an ongoing process which is increasing the amount of carbon stored in it. Whereas although a carbon reservoir might exchange individual carbon-based molecules with other parts of the carbon cycle, as much will go out ...


5

According "The youngest natural oil on earth" Doklady Chemistry vol. 438, pages 144-147: Prior to this paper, it was known that oil of the Guaymas basin is from young sediments and is 5000 years old. However, their work shows that oil in the Kamchatka volcanic area is "less than 50 years old". Oil is shown through carbon dating to have formed between 1962 ...


5

If plants were growing poorly when atmospheric CO2 was 200ppm, it was probably because Earth was in the middle of an ice age and covered with glaciers, not because plants were starved of carbon dioxide. All things being equal, increasing the amount of carbon dioxide available in the atmosphere can benefit some plants, but the problem is that all things do ...


4

It seems that tropical forests absorb more carbon dioxide than many scientists have believed before. NASA and NCAR scientists have shown that tropical forests absorb 1.4 billion metric tons out of a total global absorption of 2.5 billion metric tons. This estimate is much larger than previous estimates and the tropical contribution seems to be much larger ...


4

CO2 can only enhance plant growth when other resources such as nutrients or water are not limiting growth. If N for instance is scarce, no matter how much you increase CO2, plants will not take advantage of the increased CO2 concentration.


4

There are several reasons why the ocean floor is not a pool of liquid $\ce{CO_2}$: Solubility of gaseous $\ce{CO_2}$ in brine is low. Mass transfer of gaseous $\ce{CO_2}$ from the atmosphere is slower than the time to react with water to make carbonate/bicarbonate Carbonate/bicarbonate act as a buffer for atmospheric $\ce{CO_2}$ precipitating and ...


4

No, it is not due to lush vegetation (that was not around until just hundreds of millions of years ago). The period around 2.5 billion years ago is known as the Great Oxygenation period. No one knows for sure, but it was probably caused by anaerobic bacteria producing oxygen for the previous billion years. They basically destroyed their environment by ...


4

I'd have to say, yes. Once life evolved in the world's oceans, the vast majority of limestone formation has been through the organic process. However, before life did evolve, limestone formed through an inorganic process where rain water falling through a CO2-rich atmosphere reacted to form a weak carbonic acid solution that then reacted with calcium-...


3

I Can't quantify the answer, but intuitively, nearly all of a burning tree's carbon is converted to CO2 - assuming the fire is hot enough. You are correct in assuming that termites and bacteria convert some of the carbon to other organic species, as do fungi, yeasts, moulds, and slow weathering. In addition, some of the rotting tree's carbon is converted to ...


3

I'm going to answer assuming you are referring to the time between the moment when the organism absorbs the carbon and the moment when it is trapped in sediments. I'm also going to answer by talking about what I know best, i. e. diatoms, which happens to be the major component of the biological pump. The variation you are referring to is consistent with the ...


3

Rate.. no. Brute Force We can treat this as an industrial chemistry question. The brute-force method for carbon sequesteration is simply: Extract CO2 from the air (using the acid/base chemistry, Sodium Hydroxide will scrub it as fast as you can supply air) Reduce CO2 to elemental carbon and oxygen. The exact details are not actually important - that's one ...


3

I'm no expert on such subjects, but did Google and immediately this Guardian article offering a dataset apparently attributed to Camden Council/travelfootprint.org/Clear Zone Partnership. There are a lot of different values, but (if I understand the columns labels correctly), a rough breakdown of the footprints would be ranges of: Bus: 20-90 g CO$_2$/km ...


Only top voted, non community-wiki answers of a minimum length are eligible