Comment by PaulDavisThe1st | Hacker News Reader

Comment by PaulDavisThe1st | Hacker News Reader

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PaulDavisThe1st

> Adding energy to the system

Best estimates I've found to date: [ EDIT: 0.6-0.8 ] * Petawatts * of extra energy circulating in the atmosphere as a result of anthropogenic changes to radiative forcing.

EDIT: For the people downvoting this because "watts are units of power not energy", please read the Wikipedia page on radiative forcing https://en.wikipedia.org/wiki/Radiative_forcing

For the people downvoting because they can't believe the number, here's where i took the value from: https://www.easterbrook.ca/steve/2012/01/how-much-extra-ener... ... I did quote it incorrectly, by 1 order of magnitude (out of 16!)

For the people who still argue with the use of watts, despite that being a standard for this, here's the author of the above link on this point:

> Note: Before anyone complains, I’ve deliberately conflated energy and power above, because the difference doesn’t really matter for my main point. Power is work per unit of time, and is measured in watts; Energy is better expressed in joules, calories, or kilowatt hours (kWh). To be technically correct, I should say that the earth is getting about 300 terawatt hours of energy per hour due to anthropogenic climate change, and humans use about 16 terawatt hours of energy per hour. The ratio is still approximately 18.

Out of interest, you can also convert it to calories. 1kWh is about 0.8 million calories. So, we’re force-feeding the earth about 2 x 1017 (200,000,000,000,000,000) calories every hour. Yikes.

With regard to your edit: take a look at the note at the end of the article you are quoting, where the author acknowledges being sloppy with respect to units. Here, he says anthropogenic climate change is heating up the Earth by 300 terawatt-hours per hour (which is, of course - and more simply stated as - a rate of 300 TW or 0.3 PW). Therefore, while it would be correct to say that this results in an extra 0.3 petawatt-hours every hour, this is not the same as nor justifies the statement "...0.3 petawatts of extra energy circulating in the atmosphere as a result of anthropogenic changes...", which is incoherent.

As for "1 order of magnitude (out of 16!)", the "out of 16" is meaningless - the number 16 is merely a consequence of the arbitrary choice of unit size. Your original figure was simply off by a factor of ten, in any units.

Watts aren’t energy, so no idea what this means.

Sufferable people know how to google instead of commenting. https://en.wikipedia.org/wiki/Radiative_forcing

Radiative forcing is measured in watts per square meter. If you compute the total surface area of the earth [0] in square meters and that by multiply the radiative forcing number, you get watts.

[0] technically some layer of the earth between the ground and whatever you define as the edge of the atmosphere.

Next time you might just apologize for incorrectly using the word "energy" when you meant flux, and for being off by an order of magnitude... The defensive stance is not a good look.

I think you mean Joules?

A Watt is a joule of energy transferred over one second, i.e. they're a rate.

Feel free to take it up with the scientists who study and discuss radiative forcing in units of watts/m^2

I'm not familiar with the term, and I must have missed it the first time I read the comment.

Thank you for a new term to research :)

Do not be bamboozled by the attempt to insinuate that it is you who has misunderstood something here (for more details, see some of the other replies.)

> 0.6-0.8 * Petawatts * of extra energy circulating

What is that as a percentage of total energy circulating? The number by itself is meaningless - the Earth is large, it has a lot of energy, that's not news.

I can't find reliable, straightforward numbers for the total amount of energy in the atmosphere. Reddit provides one pretty believable number of the amount of energy required to raise the atmospheric temperature by 1C: 3.7x10^21 J [0]

Taking my main source's figure for the number of calories per hour that we're adding (2x10^17 calories aka 4x10^17 joules), that suggests that we are causing enough extra heat to be retained to raise the atmospheric temperature 1C every 9000 hours or roughly every year.

[0] https://www.reddit.com/r/theydidthemath/comments/16c167g/req...

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