The cooling world

The Washington Times ^ | 4/3/06 | Mikey_1962

[palmer]

In fact, it's because climate models available at that time were insufficient to evaluate the Earth's climate state.

And they are now?

[Seadog Bytes]

Ping to #1

[cogitator]

And they are now?

Yes. Not for accurate predictions, mind you*, but for actual evaluation of current climate influences and trends, they can (and are) used to evaluate Earth's climate

* partly due to unresolvable uncertainty regarding societal, technological, and economic changes in the future

[palmer]

Here's one problem with your models: the MCS that came through No. VA this morning affected our climate temporarily affected our climate by bringing down colder air from aloft and leaving behind lingering clouds. None of that is in current models (resolution of about 200 miles). It certainly matters to accurately model the effects of water vapor in both condensed and uncondensed forms. Without that, you fail to model the consequences of forcing (man-made increases in CO2 causing slight warming causing increases in water vapor). There is no way to accurately depict the extra water vapor without clouds and precipitation that are often localized phenomena (a small local vortex in our case).

Fortunately, computation power is increasing and adequate models should arrive in the next decade or so.

[cogitator]

The short answer is, the current state of the models is sufficient to determine Earth's climate state and discern the primary effects of changing climate "drivers" There is still uncertainty in the size of some climate influences and feedbacks, clouds notably being one of the larger uncertainties. For this reason, every model output is always associated with some uncertainty, so that model output will not provide exact replication of events and trends. For example, while coupled-ocean atmosphere models generally reproduce ENSO frequency, they have yet to capture a good reproduction of individual event intensity or actual event timing. But they still characterize the ENSO contribution to global climate over decades well.

[TheLion]

"Writer JG Ballard has a number "doom and gloom" stories out there, I think written before wacko environmentalism spang up: The Drowned World, The Wind From Nowhere, etc. They'd make good fodder for the doomsday crowd."

I think they were good science fiction.

[palmer]

I am aware that models don't need to recreate real events, just a reasonable facsimile of them. The problem is that the smaller scale events matter because they effect the larger scale weather. The medium scale vortex that happened here can't exist in any 200 mile climate model. OTOH, ENSO requires no small or medium scale modelling to reproduce accurately. Modelling ENSO relies on large scale inputs like overall reflectivity of clouds, reradiation of enery, etc. Those can be derived from fine weather models, but they are not in the GCM models used to model ENSO.

The lenticular clouds I see outside my window right now are from the MCS and are blocking the sun. Is it ok if we just subsitute the insolation from Richmond instead? I don't think so.

[o_zarkman44]

So the question is; should I have my Crown Royal at room temperature or on the rocks? If the heat or the cold don't kill me, the Crown will make the choice of what to believe easier at least. Another Crown will kill the pain from the quivering fear that something may kill me. But I bet it isn't the weather.

[cogitator]

Brief reply: the question regarding the current state of climate models is one of spatial and temporal resolution. The current state of the GCMs is that they have sufficient spatial and temporal resolution to ascertain the primary factors driving global climate with reasonable accuracy. They don't have sufficient spatial and temporal resolution to accurately reproduce annual meteorological variability. Does that make sense?

[palmer]

The GCM's have enough accuracy to model large scale phenomena that result from large scale continuous inputs. For example the ENSO phenomenon can be modeled from coarse simulations of the atmosphere, land and oceans. That coarseness is acceptable in both the space and time domains since ENSO takes years and happens over a huge area. The question is whether global climate can be modeled the same way. The key issue is whether forcing can be modeled in a coarse time and space model, or does forcing depend on accurate modeling of local meteorological phenomena. The answer is pretty simple when you look at what forcing is: it is the postulated increase in water vapor due to the increase in CO2. How that increase affects warming is the key question that that the models need to answer.

The leftover lenticular clouds from my MCS yesterday either had no effect on climate or they had an effect that a model can average over space and time by adding a parameter. Will there be fewer or more MCS's with increased water vapor? How will their cooling affect larger scale weather and climate? We don't get the answer from the model since they aren't modeled. We don't know how THE primary factor driving global climate leads to a mixture of cooling and warming over what areas. That does not lead to a global climate prediction of "reasonable" accuracy at all.