16
votes
Accepted
How did CO₂ originate on Earth before there was life?
The answer is Volcanos. There might be other inorganic processes capable to produce $\text{CO}_2$, but on Earth, the main inorganic source of $\text{CO}_2$ are volcanoes.
In some period of Earth's ...
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14
votes
Accepted
CO2 emissions per calorie (food)
I answered this question on SustainableLiving.SE. Since no one voted to close this as off-topic, I'll link and summarize my answer here.
I'm glad you asked for it by calorie, since answers on that ...
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13
votes
Is the Mauna Loa CO$_\mathsf{2}$ record affected by the nearby mantle plume?
How is ist possible that Mauna Loa Observatory is the International Reference Observatory for CO2 Global Meassurments
I don’t know that it is ‘the International Reference Observatory’. The Mauna Loa ...
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13
votes
Accepted
Is volume of air increasing as CO2 levels increase?
[Major edits below]
In short the answer is NO.
Before we get into volume changes, I have to say that volume is a tricky measure to apply to the atmosphere as a whole, because there is no clear limit ...
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12
votes
Accepted
Does climate change cause increase in CO2?
One reason is that we know exactly where the current increased CO2 comes from. That is, we know from economic data how much petroleum, natural gas, & coal is extracted and burned. From that ...
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11
votes
Accepted
Which percentage of $\text{CO}_2$ emissions are human made emissions?
First of all, the amount of carbon cycling trough the Earth's system is irrelevant to the discussion of the changes in atmospheric $\text{CO}_2$ concentration or ocean acidification. In the same way ...
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10
votes
Carbon dioxide on Mars, Venus and Earth
Firstly, Mars is farther away from the sun than Venus or Earth, so it gets less heat from the sun. Secondly, Venus & Earth are volcanically active, whereas Mars is volcanically inert. Thirdly, the ...
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9
votes
Are Ice Ages Affected by the Freezing Out of CO2 in Antarctica?
The freezing point of carbon dioxide is -78.5C.
The temperature at which carbon dioxide sublimates is not a fixed value. It instead is a function of the partial pressure of carbon dioxide. That value ...
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9
votes
How much heat was released from the 2019-2020 Australian bush fires?
Right. We can make some estimates of the scale of the problem, but they will come with a healthy margin of error.
If we assume that wood has a calorific value of 18.5 GJ/t (from the phyllis2 database)...
- 504
9
votes
Review of calculation of CO$_2$ contribution to warming
This reminds me of using Bjørn Lomborg's book in statistics, as examples how not to do statistics, his calculations never make any sense or just make unfounded leaps to conclusions.
Erik seems to have ...
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9
votes
Accepted
Are small reductions in CO2 emissions better than no reductions, in terms of mitigating climate change?
Yes, because carbon emissions are like a budget. The Mercator Institute has one of the most commonly cited analyses of our carbon budget:
the atmosphere can absorb, calculated from end-2017, no more ...
- 1,410
9
votes
Accepted
Can we run out of air because of global warming?
No, you can't blame the $CO_2$ concentration per se for your shortness of breath. From the Minnesota (U.S.) Department of Health:
The outdoor concentration of carbon dioxide is about 400 parts per ...
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8
votes
Why are CO2 sensors so expensive when CO sensors aren't?
Carbon monoxide (CO), natural gas & hydrocarbons, VOCs, ammonia, etc.
In this Chemistry SE answer and this Electronics SE question I discuss how the family of MOS gas sensors work. They can ...
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8
votes
Accepted
Could earth run out of O2?
No, that will not happen. There is just too much oxygen in the atmosphere.
Over 20% of our atmosphere is oxygen.
Only about 0.04 % of our atmosphere is CO2, so too much CO2 would kill us much sooner ...
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7
votes
Does natural plant decomposition release more greenhouse gases than burning
Another way of looking at the question:
I take 2 standard wheelbarrows of bits of plants from my garden. One wheelbarrow is used to fill the compost bin. The other goes to the bonfire.
How much ash ...
- 564
7
votes
Accepted
What are the ranges of natural (or pre-industrial era) levels of CO2 in the atmosphere in ppm and tons?
There is no such thing as a single "natural" level of $CO_2$: In Earth's history, there have been levels much higher and much lower than currently, and they are all natural.
What we should consider ...
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7
votes
Has the present rise of CO2 ppm been proved to be caused by human activity?
Possibly the strongest human "fingerprint" on rising CO2 levels comes from the changing ratio of carbon isotopes.
Basically, there are three isotopes of carbon -- carbon atoms with varying weights of ...
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6
votes
Accepted
What is the residue after plant matter is completely decomposed?
From Mary, et al., 1996, Figure 1 on the second page shows a nice breakdown of there the Carbon and Nitrogen go when a plant decomposes. Hadas, et al., 2002 has experimental data from plants with C:N ...
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6
votes
Does climate change cause increase in CO2?
Your comparison to water vapor is a bad one.
The amount of water vapor in the atmosphere does increase with atmospheric temperature. This is because more evaporation occurs and can be held as ...
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6
votes
Why is there a seasonal cycle to the amount of CO2 in the atmosphere?
The magnitude of these seasonal variations differ from location to location. The graph below portrays variations in CO2 levels at Point Barrow Alaska (PTB), La Jolla California (LJO), Mauna Loa ...
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6
votes
Is the impact of carbon emision dependent on the location on the earth?
The climate impacts of CO2 are not constrained to the location they are emitted, but rather the whole globe will feel the effects. CO2 is a long-lived molecule that takes 100+ years to convert or ...
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6
votes
Accepted
Technical term for percentage of CO2 remaining in the atmosphere
We call this the airborne fraction, although as the name suggests, it's normally expressed as a fraction rather than a percentage.
Raupach et al (2014) is an (open access) example of it being used in ...
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6
votes
Has the present rise of CO2 ppm been proved to be caused by human activity?
US EPA
Some of the carbon goes into the oceans and soil:
Wikipedia
The cumulative contribution to the atmosphere is the area of the light blue region of this chart.
CarbonBrief, Le Quéré, C. ...
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6
votes
Do carbon dioxide hydrates exist in nature?
By far most naturally occurring hydrates are methane hydrates. However, Dillon[1] documents hydration of other gases including carbon dioxide in some places such as the Gulf of Mexico:
Many gas ...
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5
votes
Accepted
Does organic decay release the same CO2 as burning?
I can't quantify the answer, but intuitively, nearly all of a burning tree's carbon is converted to $\small\mathsf{CO_2}$ - assuming the fire is hot enough. You are correct in assuming that termites ...
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5
votes
Accepted
How was it possible that CO2 levels were higher nearly 650,000 years ago?
The explanation is that human activities are not the only processes that affect atmospheric composition.
Last time CO2 levels were higher than today was 10-15 million years, during the Miocene ...
- 5,959
5
votes
Building massive seawall around endangered Islands like Mauritius to save from climate change
This is more of an engineering question. For some situations it may be possible to build such a wall around some islands. Such a sea wall would be a cofferdam, which have been used for small scale ...
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5
votes
Is volume of air increasing as CO2 levels increase?
Let me answer this question indirectly. When a pressure cooker partially filled with liquid water is heated up, there will be more water vapour molecules in the air inside pressure cooker but volume ...
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5
votes
Total CO$_2$ is not constant?
First of all, earth doesn't have the same atmosphere it had, back when dinosaurs walked the earth, when most of current carbon-deposits formed. Some atmospheres earth had would even be toxic to humans....
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5
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Total CO$_2$ is not constant?
The total amount of carbon is constant, the total amount of CO2 rises, mainly due to the burning of fossil fuels.
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