Talk:Earth's energy budget

From Wikipedia, the free encyclopedia

It would be interesting to have some comparison here with human energy production. Terry 05:02, 2 Oct 2004 (UTC)

(William M. Connolley 21:32, 18 Oct 2004 (UTC)) Thats a fair point. Another that would be of interest is the contribution from stars; other planets (in particular reflected light from the moon (I think there was a paper on this a couple of years back)); and the cosmic microwave background.

Hmm, well, having just written about this I added the (direct) human contribution. In the course of which I notice a problem: the article says:

The total flux of power entering the Earth's atmosphere is estimated at 174 petawatts. This consists of:

• solar radiation (99.985%, or nearly 174 petawatts; or about 341.5 W/m²)
  • This is equal to the product of the solar constant, about 1366 watts per square metre, and the area of the Earth's disc as seen from the Sun, about 1.28 × 10¹⁴ square metres. The figure of 341.5 W/m² is then the global average value.
• geothermal energy (0.013%, or about 23 terawatts; or about 0.18 W/m²)
  • This is produced by stored heat and heat produced by radioactive decay leaking out of the Earth's interior.
• tidal energy (0.002%, or about 3 terawatts; or about 0.02 W/m²)
  • This is produced by the interaction of the Earth's mass with the gravitational fields of other bodies such as the Moon and Sun.
• Waste heat from fossil fuel consumption is about 13 terawattts of 0.025 Wm² [1].

Note that the ratio of TW and W/m2 for tidal energy and geothermal is not the same as for my newly added human numbers, or for the solar radiation. I suspect a factor of 4 error somewhere, but where...?

The problem was that the solar constant is specified over the area of the Earth's disc (πr² = 1.3e14 m²), but the other figures are specified over the Earth's surface (4πr² = 5.1e14 m²). It's fixed now. --Heron 20:31, 21 November 2005 (UTC)

[edit] Greenhouse effect

Just to say that I've added categories so that this article appears alongside climate forcing/change articles. Seemed a bit of an omission for this article. It probably needs an explicit subsection on anthropogenic alterations to the energy budget. --Plumbago 09:13, 21 November 2005 (UTC)

Seems fair enough. I've added a little section. William M. Connolley 18:35, 21 November 2005 (UTC).

[edit] The term "power budget"

I would like to delete the paragraph about "power budget" (second paragraph of the article). Does this term come from a reliable source, or was it coined by a Wikipedian editor? We're not supposed to coin new terms on Wikipedia pages. WP:NOR. Also, I don't agree with that paragraph. It's fine to talk about power (energy per unit time) and also talk about "energy budget". With a money budget, one is often also talking about money per unit time, e.g. rent in dollars per month. There s nothing wrong with that. We don't call it a "money per unit time budget".--Coppertwig 22:51, 14 January 2007 (UTC)

Don't delete the para, its useful. I agree that "energy budget" would be a more common term, so why not just relabel the section as that? The numbers don't change William M. Connolley 23:00, 14 January 2007 (UTC)

Maybe you misunderstood. The paragraph I would like to delete is:

Note: although the term "energy budget" is widely used, the flow of energy in and out of the Earth is actually measured in units of power (watts), not units of energy (joules). Therefore, "power budget" would be a more accurate term.

This paragraph seems to be saying essentially that a bunch of other people, outside Wikipedia, should stop using the term that they've been using and start using a different term. I don't think that's appropriate or encyclopedic: it's prescriptive. This remark seems to belong on the talk page, not as part of the article. What do you find useful about it? I don't mind either the term "energy budget" or "power budget" being used -- I just want the article to contain encyclopedic-style stuff, not arguments about who should really be saying what. Is there a citation to support the claim being made in this paragraph? --Coppertwig 04:06, 30 January 2007 (UTC)

Actually, given that the article repeatedly refers to the "power budget", this seems to be the least of its problems. I can't say I've ever seen "power budget" used in this fashion; "energy budget" (or sometimes "heat budget" depending on terms of reference) is the default term in my experience (though I've only tangentially used energy budgets in my own work). Checking article abstracts on the Web of Knowledge, I find that "power budget" appears in 272 articles (the first few of which don't appear to be Earth science), but "energy budget" is in 2312 articles. Anyway, rather than focus on this intro paragraph (the first sentence of which is fine by me anyway), I'd suggest hacking to replace "power budget" with "energy budget" more widely. Cheers, --Plumbago 09:30, 30 January 2007 (UTC)

Since no one was able to explain what's useful about that paragraph, and since it was non-encyclopedic (criticising the sources for using the wrong word?), I deleted it. I took what I think may be useful from it, though, and transformed it into a sentence in parantheses near the beginning of the next section, explaining the relationship between power and energy. I also substituted "energy" for "power" in a number of places, as you suggest. For example, in one place it said "flux of power". Power means flux of energy; "flux of power" isn't really a meaningful quantity. --Coppertwig 21:00, 3 February 2007 (UTC)

[edit] February 2007 comment

Anon 66.156.178.220 just added the following comment to the main article. I've removed it to here.

(Please Note: My reading indicate that the leaves of Foliage, trees and grasses, reflect 70-90% of the Infra-Red striking their surface, explaining why they remain COLD in the sun. Carbon atoms abosorbs nearly 100%. Has greenery -vs- Asphalt been included in this definition of Normal ?)

Cheers, --Plumbago 17:35, 26 February 2007 (UTC)