Tuesday, May 29, 2012

Question: If no human actually understands how the climate works, can humans write a Fortran program that accurately models how the climate works?

Climate models ignored by media (except for their critics) | Ars Technica

You won’t find them next to the operating systems on the shelves of your favorite store, but climate models are pretty important software packages. They allow climate scientists to test hypotheses about the causes of climate events in the past, and they can also compute the probable effects of, say, continued fossil fuel use over the next century.

Climate is complex—there are a myriad of interconnections between components governed by different physical, chemical, and biological processes. You simply can’t stuff it all into your head and mentally work through the consequences of that interplay. That’s where computers come in. They solve this network of equations at each location on the planet, and for each time step, simulating an entire climate system at your command.

All scientists get George Box’s dictum beaten into them: “All models are wrong, but some are useful.” And some are very useful, indeed. Gravitational models of the solar system, for example, allow space agencies to slingshot their spacecraft around planets and land on a moving bulls-eye more than 50 million miles away. If you’re not impressed by that, you might need medical attention.

Because of their key role in the future projections that drive public policy decisions, however, climate models have become a flash point in the popular debate over climate change. The Heartland Institute’s NIPCC report (the industry think tank’s not-so-subtle response to the Intergovernmental Panel on Climate Change reports) described climate models as “nothing more than a statement of how the modeler believes a part of the world works”.

Flashback: 'High School Physics' - WSJ.com

That's how Al Gore described the science of climate change this week, by which we suppose he meant it's elementary and unchallengeable.

Flashback: Remember when we almost spent $45 trillion based on some secret Fortran code written by left-wing idiots with no common sense?

ModelE breaks down climate into the basic laws of physics. The equations are written in Fortran, a computer language that is, as Dr. Schmidt puts it, "very old and not very trendy." The computer code is 126,327 lines, to be exact, and when Dr. Schmidt scrolls through it on his computer screen, it looks like nothing so much as an extensive (and incomprehensible) grocery list.

In his office, not long ago, Dr. Schmidt tried to translate a few lines:

QNX=QMO2*BYAM(LMIN+1)

QSATC=QSAT(TNX,LHX,PL(LMIN+1))

DQ=MCLOUD*(QSAT-CQNX)/(1.+SLH*QSATC*DQSATDT(TNX,LHX))

"These lines," he said, "calculate how much water vapor condenses out of air to form a cloud as the temperature decreases."

1 comment:

papertiger said...

What are the chances we could have Schmidt deported back to England?