Watts Up With That?

Update 2: Reader Jesse Michael forwarded me this animated image above, which does a better job than the flawed NASA image or it’s replacement I found below. It takes about a minute to complete the whole sequence, patience.

While looking for something else, I came across this image from the NASA visualization website. I located the hires TIFF image and annotated it as seen below. I also made a desktop wallpaper out of the TIFF file for those interested. It reminded me to remind you all about perspectives, so here is some perspective on size, solar luminosity, and on our planetary energy budget.

Click here for a larger (TIFF format without annotation) image from NASA
Click here for a desktop wallpaper image (1280×1024 JPEG)

UPDATE: It appears that the NASA provided image above , the source of which is from this NASA page, unbelievably, is wrong.  As reader Erik points out, the sun is too large. I initially had some misgivings about the solar size also, but figured NASA wouldn’t possibly botch such a basic comparison. Shades of the Hubble mirror fiasco. 

Here is another image from NASA JPL that appears to be correct:

Click for larger image from JPL
Note: image above is L-R mirrored for comparison to first image.

Note that distance is not to scale, but planetary and solar size is. To get an idea of distance scale, read this excellent example from Kitt Peak Observatory.

A few factoids:

• It would take about 109 earths to equal the width of the suns diameter (Sun=1.39 million km Earth=12,700 km)
• Over 1 million Earths would fit inside the Sun’s volume
• The sun has a total luminosity output of 386 YottaWatts
  (386,000,000,000,000,000,000,000,000 watts, some background here and here)
• The total luminous energy output received by earth from the sun is 174 PETAWATTS (174,000,000,000,000,000) watts.
• A 0.1% increase in luminosity dumps an extra 174 trillion watts (174,000,000,000,000) watts into our planetary energy balance.

Data source for graph: http://www1.ncdc.noaa.gov/pub/data/paleo/climate_forcing/solar_variability/lean2000_irradiance.txt

Note: In the graph above, the low flatline from 1645-1715 is the Maunder Minimum, a period of virtually no sunspots, where the historical reports from the northern hemisphere tell a story of dramatic climate change: harsh winters, cools summers, crop failures, famine and disease.

From the abstract referenced above: “Estimated increases since 1675 are 0.7%, 0.2% and 0.07% in broad ultraviolet, visible/near infrared and infrared spectral bands, with a total irradiance increase of 0.2%. “

So its not just 0.1 %, it is 0.2% which translates to a 348 TeraWatts global irradiance increase.

Now lets put 348 trillion watts into perspective:

Hurricanes: the heat energy released by a hurricanes category 1-5 equals about 50 to 200 trillion watts or about the same amount of energy released by exploding a 10-megaton nuclear bomb every 20 minutes.

Katrina, released about 200 trillion watts over its life cycle.

Now imagine double that amount of extra energy being added to earth’s atmosphere every second by small increases in the suns output that have been documented to exist. That’s what the increase in solar irradiance is doing. Since 1675, after the depths of the Maunder Minimum, we’ve seen an increase in solar irradiance of about 2.5 watts per square meter.

Climate modelers say that the extra CO2 equates to a forcing of about 2 watts per square meter, which totals about 1.12 Petawatt (1,120,000,000,000,000 watts). The problem is, they can’t always recreate that reliably between all of the different models out there, with the positive and negative feedback mechanisms, and other variables involved. There’s disagreement on the total contribution. A lot of it. Nonetheless they seem all to agree that CO2 makes some contribution, and that’s likely true. But compared to the sun, I believe it’s minimal.

Now lets look at us: 13.5 TeraWatts is the average total power consumption of the human world in 2001.

Compared to solar variance, do you think we could change the planets atmospheric energy balance with that if we squeezed all the power we made that year together and radiated it into our atmosphere ?

What is very clear though, when you look at history, and the graph above, is that our earths atmosphere and resulting climate is extremely sensitive to variations in solar output. The sweet center point seems to be about 1365 watts per square meter of irradiance…what we consider as “normal” climate. Take 1.5 watts/sq. meter away, and we get significant cooling, harsh winters, cool summers, and increases in ice and glaciers. Add 1.5 watts,/sq. meter and we get hotter summers, mild winters, and melting of ice and glaciers.

Now irradiance aside, as it’s only one component, there’s also the chnage in the suns dynamic magnetic field and solar wind, which according to Svensmark, which modulates the number of cosmic rays that enter our atmosphere (I think there may be some possible effect also due to modulation of the earth’s magnetic field), which modulates the number of clouds that form, hence changing the net surface irradiance. Plots of changes in the suns magnetic field line up very well with climate change.

Here is a little more on perspective and our place in the universe: Read the rest of this entry »