lee wrote on Nov 15^th, 2013 at 10:27am:


Models are used to design ships, aircraft, bridges, roads, the space shuttle etc.,

And many of these models are less complex than those employed and devised by Climatologists to predict climate trends. Do you fly much?

Most systems and mechanisms in science and engineering are very complicated and sometimes even obey chaotic laws of motion etc. (they are often non linear, unstable and have no precise analytical solutions - hence the role of numerical methods and high computer power)

Just to give you an example, if you drop a sphere into a container of water, you can theoretical model and characterise the behaviour of the falling sphere. If you change the fluid from water to a thicker fluid with a yield stress, or a visco-elastic fluid, then you cant solve the equations of motion analytically.

You have a choice of numerically solving the equations, or conducting experiments to determine empirical parameters that are important to the behaviour of the falling sphere.

Some of the most sophisticated modelling is carried out in the fields of climate science and weather prediction.

In my opinion, when I look at a model that is either theoretical or numerical in nature, I look at two critical areas. The first is the assumptions made, and the second is the predictive error.

These help you compare models, and if predictions are wayward, you can often see why.

A ship is not a road either.  An aircraft is not a bridge, but you can have a bridge on a ship.


Deep.

Chimp_Logic wrote on Nov 15^th, 2013 at 7:43pm:



Lucky they didn't get the guys who did the climate models to do those models too, the ships would have sunk, the planes would have crashed, the bridges would have fallen down, the roads would have broken up and the space shuttle would have crashed on take off 

Innocent bystander wrote on Nov 15^th, 2013 at 8:01pm:


I see,

so you are content with scientists using models to predict behaviour and characteristics in complex systems, as long as they don't use models in the field of Climatology.

Interesting religion you worship

Do you ever read the 5 day weather forecast for the area you live in?

Innocent bystander wrote on Nov 15^th, 2013 at 8:19pm:



Exactly.  They can't get tomorrow's weather right, yet AGW alarmists think these "scientists" can predict climate change.

Perhaps this will be of interest to the cult members:

Now if you can just point me to the calculation on Climate Sensitivity to CO2.

Climate is a chaotic system.

I note that in AR4 SRES A2 projection was between 2.0 and 5.4
In AR5 SRES A2 is between 1.5 and 5.4.

Given that the is now more data I would have expected a tightening of projection rather than a loosening. About 15%.

Seeing as confidence is at an all time high- up from 90% to 95%; I wonder what the confidence level would have been had SRES A2 remained at 2.0 to 5.4?

lee wrote on Nov 15^th, 2013 at 10:04pm:


Actually weather events can be chaotic in nature.

Climate is a general collection of environmental parameters that have regional importance - like rainfall, temperature range, frequency and intensity of extreme events such as firestorms, cyclones, floods etc...

In any case, chaotic systems are very sensitive to the initial conditions or boundary limits. This does not mean you cannot characterise the behaviour and make predictions.

What it means is that a tiny change in the boundary conditions can result in very complicated and major effects as time evolves.

You really do need to distinguish between WEATHER and CLIMATE - a very common mistake made by many people in here I notice.

Climate is far easier to characterise and predict than individual weather events (even a few days from now)

As far as pointing you in a direction with regards to CO2/climate sensitivity, you may be better advised to nail down the difference between climate and weather first, before you tackle some of the more intricate details of the AGW scientific fact.