Comments on: Ice and solar power

By: .

Mon, 16 Aug 2010 16:27:01 +0000

"Happily, to see the problem of global warming in terms of this flow of energy is to see its solution. By putting a little of the cosmic energy to use — by developing wind power, appropriate energy crops, hydropower and, most promising of all, solar power — we could do away with the need for that sky-thickening carbon dioxide. Other flows of energy could help too — flows of heat from the depths of the Earth and of radiation bequeathed to us in the uranium of dead stars. But it is solar energy, indirectly or directly, that will dominate the picture, simply because of its abundance. The Sun delivers more energy to the Earth in an hour than humanity uses in a year. To substitute these flows for the fossil fuels poised to despoil our planet and also run out on us — worst of both worlds — is an epic task. But the message that frames all the other messages of “Earthrise” is that we can rise to epic tasks. Look where the photo was taken. “If we can put a man on the Moon ...” quickly became shorthand for society’s failure to achieve goals that seemed far simpler. But still: we put a man on the Moon, and that does say something. Efforts on a similar scale aimed at harvesting the energy flowing about us are entirely appropriate, and could make things a great deal better. We cannot solve all problems; some climate change is inevitable. But catastrophe is not."

By: .

Wed, 14 Apr 2010 19:27:09 +0000

"Wherever it comes from, waste heat is not usually taken into account in global climate calculations for the simple reason that it is utterly trivial in comparison to the heat trapped by the carbon dioxide that is released when you burn fossil fuels to supply energy. For example, that 6 trillion Watts of waste heat from coal burning would amount to only 0.012 Watts per square meter of the Earth’s surface. Without even thinking very hard, you can realize that this is a tiny number compared to the heat-trapping effect of CO2. As a general point of reference, the extra heat trapped by CO2 at the point where you’ve burned enough coal to double the atmospheric CO2 concentration is about 4 Watts per square meter of the Earth’s surface — over 300 times the effect of the waste heat. The “4 Watts per square meter” statistic gives us an easy point of reference because it is available from any number of easily accessible sources, such as the IPCC Technical Summary or David Archer’s basic textbook that came out of our “Global Warming for Poets” core course. Another simple way to grasp the insignificance of the waste heat effect is to turn it into a temperature change using the standard climate sensitivity of 1 degree C of warming for each 2 Watts per square meter of heat added to the energy budget of the planet (this sensitivity factor also being readily available from sources like the ones I just pointed out). That gives us a warming of 0.006 degrees C for the waste heat from coal burning, and much less for the incremental heat from switching to solar cells. It doesn’t take a lot of thinking to realize that this is a trivial number compared to the magnitude of warming expected from a doubling of CO2."

By: Climate change and winter

Climate change and winter — Wed, 09 Dec 2009 15:34:04 +0000

[...] thus always be colder than the equator during those spans. Indeed, this is a nice demonstration of what a massive amount of energy the sun adds to the Earth system. None of this disproves the fact that greenhouse gasses being added to the atmosphere warm the [...]

By: .

Thu, 19 Nov 2009 19:56:21 +0000

Oil: enough energy to melt glaciers! From a sharp-eyed reader comes this ad for Humble Oil (which later merged with Standard to become, yes, Exxon). It may win the All Time Millenial Award for Maximal Irony.

By: Milan

Milan — Wed, 04 Mar 2009 21:03:50 +0000

Another way to look at this is to note that for every watt of energy humanity uses for its own purposes, it is adding over 65 watts of warming power to the climate system.

By: Milan

Milan — Wed, 04 Mar 2009 21:00:23 +0000

Every square metre of the Earth’s surface receives about 340 watts from the sun. Anthropogenic climate change has increased that by about 1.66 watts per metre: a total increase of 850 trillion watts (terawatts, TW).

For the sake of contrast, all of industrial civilization uses 13TW. The flow of heat from the Earth’s core to the surface – driver of volcanism and continental plate movement – is 40 TW. The net primary productivity of all of Earth’s ecosystems is around 130TW, 15-30TW of which are human croplands, pastures, and forestry plantations.

That gives some sense of just how enormous the influence of our greenhouses gasses is, because it affects the massive energy flow from the sun.

Note: All of these figures are from Morton, Oliver. Eating the Sun: How Plants Power the Planet.