Introduction to forcing functions

The source is from an advocacy forum citing another 'blog'. So let's not run around with hair on fire. What I found useful was a listing of forcing functions:

• global energy conservation - a net sum zero
• 240 W/m2 outbound radiation
• 150-390 W/m2 variation over globe
• Clausius-Clapeyron relationship - We called them "steam table"
• Radiation distribution, greenhouse effects
  • 50% water vapor
  • 25% clouds
  • 25% non-condensing greenhouse gases
    • 20% CO{2}
    • 5% CH4, N20, O3, and CFCs

There are more points that I have to study and understand. But these are basic engineering mechanisms. Once I've worked them out, I live in Huntsville AL and I look forward to sharing the relationships. But more interesting points:

• "10 gigatons of carbon/yr (roughly equivaent to 10 cubic km of coal/yr, which when burned adds about 5 ppm CO2 to the atmosphere, half of which remains there for many centures)." - Now this is an interesting half-life problem but also suggests the issue is carbon sinks are running at about half the rate we generate CO2.
• "They should also pay attention to the geological record that points to an atmospheric CO2 level of 450 ppm as being incompatible with polar ice caps, a level that is expected to be reached by the end of this century. While it may take a thousand years for the polar ice to melt, the future course is being prepared for a 70 meter rise in sea level." - This is a consistent view from climate modeling, the loss of polar ice volume.

The advocacy article is aimed at teaching physicist about fundamental relationships. Some of the claims I did not quote are ones I need to understand. Ignorance is neither an agreement or disagreement, it is a puzzle to work out. But I love seeing data points that we can start to correlate with current satellite and terrestrial observations.

An advocacy source can often provide basics and pointers to hard science. Like high school courses, they provide an introduction that is refined in undergraduate and post-graduate studies. In this case, useful to me and hopefully those who can understand the physics and engineering.

Bob Wilson

 

There was a recent paper on CO2 observations: First direct observation of carbon dioxide's increasing greenhouse effect

They found that CO2 was responsible for a significant uptick in radiative forcing at both locations, about two-tenths of a Watt per square meter per decade. They linked this trend to the 22 parts-per-million increase in atmospheric CO2 between 2000 and 2010.
​

Now we can do some maths:

0.2W/m2 / 22 ppm ~= .0091 W/m2 / ppm- the CO2 radiation rate as a function of concentration
0.0091 W/m2 * 400 ppm ~= 3.64 W/m2

3.64 W/m2 / (240 W/m2 (solar) - 100 W/m2 (reflected) ) ~= 2.6%

• 2.6% < 3.62% :: Mojo referenced number
• 2.6% << 20% :: Andy Lacis referenced number

​

Well that was an unexpected result. I understand IPCC only claims 1.66 W/m2, an even smaller number.

Like 'tar baby,' another source: CO2 no-feedback sensitivity | Climate Etc.

Bob Wilson

 

Thanks!

Right now, my interest is in the energy flows ... our planet as a solar and internal heat powered engine. Eventually I'll work back to surfaces and greenhouse gases.

Bob Wilson

 

Source: Antarctic ice shelves rapidly thinning

A new study led by Scripps Institution of Oceanography at the Univ. of California, San Diego (UC San Diego) researchers has revealed that the thickness of Antarctica’s floating ice shelves has recently decreased by as much as 18% in certain areas over nearly two decades, providing new insights on how the Antarctic ice sheet is responding to climate change.​

The important thing is an 18 year interval. Study of Antarctica is difficult so I understand the sparse data even in the days of satellite observation.

Bob Wilson